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12V 50Ah Battery: How to Specify a 12V 50Ah Cell for AGVs, Golf Carts and Small Solar Systems (2026)
Answer First

A 12V 50Ah battery is a sealed valve-regulated lead-acid (VRLA) cell that delivers 50 amp-hours at the C3 discharge rate from a 12V block, and it is the default building block for 48V mobility packs in resorts, golf clubs, warehouse AGV fleets and small off-grid solar systems. The specification that matters is not the label on the carton but the published figure set: 50 Ah at C3, a 230 × 140 × 180 mm case, 15.25 ± 0.2 kg, float at 13.5 V and equalisation at 14.1 V across the six cells of the block. Those five numbers decide whether the cell fits your bay, your charger and your budget. This guide sets out the published specifications of the 6-EVF-50 against its three closest siblings, shows how a 48V pack is built from them with the arithmetic written out, and gives the seven checks a buyer should run before issuing a purchase order to a supplier in Hangzhou, Rotterdam, Jebel Ali, Lagos or Chennai.

Key Takeaways

A 12V 50Ah battery is rated 50 Ah at the C3 rate (three-hour discharge) and 13.5 V float across six cells, not at the cell level — the block is the sellable unit.
The 6-EVF-50 publishes 230 × 140 × 180 mm and 15.25 ± 0.2 kg, which is what determines whether it physically fits a battery tray designed around the 6-DMF-45.
A 48V pack of four 12V 50Ah cells gives 48 V × 50 Ah = 2,400 Wh and weighs 4 × 15.25 kg = 61.0 kg — the weight, not the energy, is usually the constraint.
The closest sibling, the 6-DMF-52, gives 48 V × 52 Ah = 2,496 Wh at 4 × 13.7 kg = 54.8 kg, which is 6.2 kg lighter for 96 Wh more energy per pack.
Float 13.5 V and equalisation 14.1 V are the correct setpoints for these VRLA cells; a charger set to 14.4 V will shorten service life without adding usable capacity.
Cycle life is published at 350–600 cycles to 50–80% depth of discharge, and design life is 2–5 years — a different figure from the 20-year float life quoted for 2V tubular cells.
The published charge current of 10.0 A means a 48V pack of four cells needs a 40 A charger, and a 50 Ah cell accepting that current replenishes in roughly 5 hours.

§1 — 12V 50Ah Battery Specifications

The table below reproduces the published specification for the 6-EVF-50 and its three nearest neighbours in the 12V VRLA range. Every value is taken from the manufacturer model page; the pack figures are derived and shown with their formulas.

Specification	6-EVF-50	6-DMF-45	6-DMF-52	6-EVF-60	Source
Nominal voltage	12V	12V	12V	12V	Model page
Rated capacity	50 Ah	45 Ah	52 Ah	60 Ah	Model page
Discharge rate basis	C3 (3 h)	C3	C3	C3	Model page
Dimensions L × W × H	230 × 140 × 180 mm	224 × 121 × 175 mm	224 × 135 × 175 mm	258 × 170 × 160 mm	Model page
Weight	15.25 ± 0.2 kg	12.3 ± 0.2 kg	13.7 ± 0.2 kg	18.8 ± 0.2 kg	Model page
Terminal	φ11.8-M6	φ11.8-M5	φ11.8-M6	φ14-M6	Model page
Float charge voltage	13.5 V	13.5 V	13.5 V	13.5 V	Model page
Equalisation voltage	14.1 V	14.1 V	14.1 V	14.1 V	Model page
Maximum charge current	10.0 A	9.0 A	10.4 A	12.0 A	Model page
Cycle life	350–600 cycles (DoD 50–80 %)	350–600 cycles	350–600 cycles	350–600 cycles	Model page
Cut-off voltage	1.75 V/cell	1.75 V/cell	1.75 V/cell	1.75 V/cell	Model page
Self-discharge	≤3 %/month at 25 °C	≤3 %/month	≤3 %/month	≤3 %/month	Model page
Working temperature	−15 °C to 50 °C	−15 °C to 50 °C	−15 °C to 50 °C	−15 °C to 50 °C	Model page
Design life	2–5 years	2–5 years	2–5 years	2–5 years	Model page
Energy per cell	12 V × 50 Ah = 600 Wh	12 V × 45 Ah = 540 Wh	12 V × 52 Ah = 624 Wh	12 V × 60 Ah = 720 Wh	Arithmetic
Specific energy	600 Wh ÷ 15.25 kg = 39.3 Wh/kg	540 Wh ÷ 12.3 kg = 43.9 Wh/kg	624 Wh ÷ 13.7 kg = 45.5 Wh/kg	720 Wh ÷ 18.8 kg = 38.3 Wh/kg	Arithmetic

One practical note on ordering: several of these model pages also list alternative weight variants in a horizontal comparison table — the 6-DMF-45 is additionally published at 13.1 kg and the 6-DMF-52 at 14.5 kg. Those reflect different case or terminal builds. Whichever variant you specify, have it confirmed on the order acknowledgement before the container is sealed, because a 1 kg difference per cell becomes 4 kg per four-cell pack.

§2 — The Pain

Three failures account for almost every 12V 50Ah battery complaint that reaches a distributor’s help desk in Hamburg, Durban or Mombasa.

The first is the label. A carton marked “50 Ah” tells you nothing about the case, the terminals, the cycle rating or the charge setpoints. Two cells from two factories can both print “12V 50Ah” and differ by 8 kg, by two years of design life and by 150 cycles. A buyer who quotes capacity alone will receive a cell that does not fit the tray and does not match the charger.

The second is the charger. A 12V VRLA block contains six cells in series, so the published float voltage of 13.5 V is 2.25 V per cell and the published equalisation voltage of 14.1 V is 2.35 V per cell. A common failure in the field is a charger left on its lead-acid default of 14.4 V, or a controller that never enters equalisation at all. Over-charge shortens life; under-charge causes sulphation and capacity loss within the first year. Neither shows up on the invoice.

The third is weight and tray geometry. A 48V pack of four 6-EVF-50 cells weighs 61.0 kg. Golf carts and AGV chassis have weight limits and, more often, have a battery tray designed for a specific case footprint. Swapping a 6-EVF-50 for a 6-DMF-52 without re-measuring the tray is how a 6.2 kg per-pack saving turns into a returns problem.

There is also a sourcing problem underneath all three. Buyers in Lagos, Chennai, Cairo and Jakarta often receive a quotation that lists “12V 50Ah AGM” with no datasheet reference at all, which makes the order impossible to compare across suppliers and impossible to re-order.

§3 — The Choice

Choosing between the four cells above is not a matter of taste. It is a trade between three published quantities: the case footprint, the cell weight, and the Ah per kilogram that follows from them. The pack table below shows the four possible 48V builds.

48V pack build	Cells used	Pack voltage	Pack energy	Pack weight	Pack specific energy	Charger output	Source
Four 6-EVF-50	4 × 12V 50Ah	12 V × 4 = 48 V	48 V × 50 Ah = 2,400 Wh	4 × 15.25 kg = 61.0 kg	2,400 Wh ÷ 61.0 kg = 39.3 Wh/kg	4 × 10.0 A = 40 A	Arithmetic
Four 6-DMF-52	4 × 12V 52Ah	12 V × 4 = 48 V	48 V × 52 Ah = 2,496 Wh	4 × 13.7 kg = 54.8 kg	2,496 Wh ÷ 54.8 kg = 45.5 Wh/kg	4 × 10.4 A = 41.6 A	Arithmetic
Four 6-DMF-45	4 × 12V 45Ah	12 V × 4 = 48 V	48 V × 45 Ah = 2,160 Wh	4 × 12.3 kg = 49.2 kg	2,160 Wh ÷ 49.2 kg = 43.9 Wh/kg	4 × 9.0 A = 36.0 A	Arithmetic
Four 6-EVF-60	4 × 12V 60Ah	12 V × 4 = 48 V	48 V × 60 Ah = 2,880 Wh	4 × 18.8 kg = 75.2 kg	2,880 Wh ÷ 75.2 kg = 38.3 Wh/kg	4 × 12.0 A = 48.0 A	Arithmetic

Read the table as a set of four answers to four different questions.

If your chassis has weight headroom and you want the largest footprint with a published weight tolerance, the 6-EVF-50 is the sensible default. It is also the only one of the four whose 230 × 140 × 180 mm footprint is matched by a published 6-EVF-50 model page with a full weight tolerance, which matters when you are holding a supplier to a tolerance.

If weight is the binding constraint, the 6-DMF-52 wins on both published weight and specific energy: 54.8 kg for the pack against 61.0 kg, and 45.5 Wh/kg against 39.3 Wh/kg. The 6.2 kg saved per pack is 24.8 kg across a ten-vehicle fleet. The 6-DMF-52 model page carries the full specification for that cell.

If you need the lightest pack of all and can live with less energy, the 6-DMF-45 gives 49.2 kg and 2,160 Wh, which suits smaller AGV platforms and towable carts where gross vehicle weight is capped.

If the duty cycle demands more runtime per charge rather than less weight, the 6-EVF-60 gives 2,880 Wh per pack and needs a 48.0 A charger, so the charger is the constraint rather than the battery.

The wider 12V VRLA range, including the 6-DZF and 6-DMF series that cover everything from 12 Ah to 58 Ah, is set out on the CHISEN 12V VRLA product index.

§4 — The Framework

Seven checks turn a vague enquiry into an order a factory can fill correctly.

1. Demand the published figure set, not the label. Ask for capacity with its rate basis (C3), dimensions in millimetres, weight with tolerance, terminal type, float voltage, equalisation voltage, maximum charge current, cycle life and cut-off voltage. A supplier that answers all ten cannot be guessing.

2. Fix the charge setpoints in writing. 13.5 V float and 14.1 V equalisation for the block; 2.25 V per cell and 2.35 V per cell once you do the arithmetic. Confirm that your charger controller can be configured to both, and confirm the equalisation period. If the answer is “it is automatic”, ask which controller models are tested.

3. Match the charger to the published charge current. The 6-EVF-50 accepts 10.0 A, so a four-cell 48V pack needs a 40 A charger. A 30 A charger extends the recharge window: 50 Ah ÷ 10.0 A = 5 hours is the theoretical minimum at the published current, and a 30 A charger stretches that to 50 Ah ÷ 7.5 A = 6.7 hours before losses.

4. Check the depth-of-discharge window you are buying. The published 350–600 cycle figure holds at 50–80% depth of discharge. If your duty cycle runs to 100% depth, the cycle rating in the table does not apply to you, and you should size up rather than accept the headline figure.

5. Verify the temperature envelope. The published working range is −15 °C to 50 °C, and capacity is quoted at 25 °C. Self-discharge is ≤3 % per month at 25 °C. A fleet parked outdoors through a Hamburg winter or a Santos summer does not see 25 °C for most of its life; ask the supplier what capacity remains at the extremes.

6. Fix the variant on the acknowledgement. Because the model pages carry alternate weight variants, the order line must state the case, the terminal and the weight tolerance — not just the model code. Add the requirement that the batch matches the datasheet revision on the packing list.

7. Agree the acceptance test. For container shipments to Santos, Jebel Ali, Lagos or Port Said, specify what happens on arrival: a sample capacity check at the C3 rate, a float voltage check across the block, and the rule that a failing sample is settled by re-inspection at an agreed laboratory rather than by argument.

§5 — The Trust

The 6-EVF-50 and its siblings are built on a VRLA line inside a manufacturer operating 8 production bases with an annual capacity of 70 million kVAh, under a certified quality management system with ISO 9001 and ISO 14001 certification, with CE, UL and IEC conformity for the markets each cell ships into. The full 12V VRLA battery index is maintained on the manufacturer site, and every figure in this article comes from the individual model page rather than from a catalogue summary.

Two things deserve emphasis for a buyer who is being asked to pay for assurance.

First, a certification covers a system, a scope and a date — not a particular carton. ISO 9001 certifies that the quality management system is documented and that corrective action happens; it does not certify that one cell holds 50 Ah. That is what the published capacity, the type test and the acceptance test are for. Ask for the certificate number, the scope statement, the registered address and the validity dates, and then check the cell on its own merits.

Second, the difference between a published specification and a marketing line is the whole value of this exercise. A supplier who quotes “12V 50Ah AGM, top grade” is telling you nothing. A supplier who quotes “6-EVF-50, 50 Ah at C3, 230 × 140 × 180 mm, 15.25 ± 0.2 kg, float 13.5 V, equalisation 14.1 V, 10.0 A maximum charge current” is telling you everything you need to engineer the pack, write the charger setting and defend the claim at the goods-in dock.

For importers who buy through a distributor rather than direct, ask the distributor for the manufacturer’s model page URL and the batch reference. Both can be checked before the container is opened, and both remove the single largest source of dispute in this category.

§6 — FAQ

Q1. What does 50 Ah actually mean on a 12V 50Ah battery? It means 50 amp-hours delivered at the C3 discharge rate — the three-hour rate — down to the cut-off voltage of 1.75 V per cell, at 25 °C. It does not mean 50 Ah for the whole day. On a longer, five-hour discharge the usable figure is lower, and on a two-hour discharge it is higher. Any quotation that gives capacity without the rate basis is incomplete.

Q2. Can I substitute a 6-DMF-52 for the 6-EVF-50 in an existing 48V pack? Usually yes, and it is often an improvement on weight: the 6-DMF-52 gives 48 V × 52 Ah = 2,496 Wh at 4 × 13.7 kg = 54.8 kg, against 48 V × 50 Ah = 2,400 Wh at 4 × 15.25 kg = 61.0 kg. Before you do, confirm the case footprint fits the tray — 224 × 135 × 175 mm against 230 × 140 × 180 mm — and confirm the charger can deliver 4 × 10.4 A = 41.6 A. The terminal dimension stays at φ11.8-M6, but it is a different moulding, so check the lead length and the retaining hardware.

Q3. What charger do I need for a 48V pack of four 12V 50Ah batteries? A 48V charger with a 40 A output, because the published maximum charge current is 10.0 A per cell and 4 × 10.0 A = 40 A. Set the float at 13.5 V and the equalisation at 14.1 V for the 48V string, which is 2.25 V and 2.35 V per cell respectively. Give the charger a temperature-compensation input if the pack sits in a hot climate, because a 25 °C setpoint in a 45 °C bay is an over-charge condition.

Q4. How long will a 12V 50Ah battery last in a solar application? In float standby with solar charging the published design life is 2–5 years and the published cycle life is 350–600 cycles at 50–80% depth of discharge. In a solar duty cycle the binding factor is usually the number of cycles the site sees, not the calendar. If the site is in Jebel Ali or Chennai, expect the temperature side of the envelope to matter as much as the cycle count; if it is in Valencia or Durban, confirm the cabinet ventilation, because the working range stops at 50 °C.

Q5. Is 13.5 V the correct float voltage, or should it be 13.6–13.8 V? For a VRLA block, 13.5 V is the published float voltage for these cells, which is 2.25 V per cell across the six cells of the block. A setting of 13.8 V is 2.30 V per cell and pushes the cell above its intended float point. Over a year that difference shows up as shortened service life and more frequent water loss, and it does not add usable capacity. Ask the supplier to confirm the setpoint against the model page rather than against a generic lead-acid chart.

Q6. What is the difference between a 6-EVF-50 and a 6-DMF-50? Both are 12V VRLA cells in the same capacity class, and the EVF and DMF series differ in plate construction and case format rather than in chemistry. The 6-EVF-50 is published at 230 × 140 × 180 mm and 15.25 kg; the closest DMF equivalent in this range is the 6-DMF-52 at 224 × 135 × 175 mm and 13.7 kg. If you are qualifying a new supplier, compare the published dimensions and weights side by side rather than relying on the series name, because the case geometry is what determines whether the cell physically fits your application.

Q7. Can a 12V 50Ah battery be used for an AGV in an e-commerce warehouse? Yes — the manufacturer lists automated guided vehicles in e-commerce warehousing and smart factory environments among the applications for the 6-EVF series, alongside 4–8 seat electric sightseeing vehicles at resorts and theme parks, golf carts, 1–3 tonne electric forklifts and floor-scrubber platforms. The specification to check is the cycle rating: a warehouse AGV that runs two shifts with deep recoveries will consume cycles faster than a standby application, so confirm the 350–600 cycle figure at your actual depth of discharge.

Q8. What should be on the purchase order for a 12V 50Ah battery? The model code and the case and weight variant, the float and equalisation voltages, the maximum charge current, the cycle rating and depth of discharge, the terminal type, the batch reference, the test certificate and the acceptance procedure on arrival. Include the requirement that the shipped batch matches the published model page revision. If the order will be shipped to a port such as Rotterdam, Santos or Mombasa, state the agreed laboratory for a failing-sample inspection.

Expert Summary

A 12V 50Ah battery is a well-understood component, and the specification is public: 50 Ah at C3, 230 × 140 × 180 mm, 15.25 ± 0.2 kg, 13.5 V float, 14.1 V equalisation, 10.0 A maximum charge current, 350–600 cycles at 50–80% depth of discharge, 2–5 years design life. The 6-EVF-50 is the reference cell, and the 6-DMF-52 is the sensible alternative when weight matters more than footprint, delivering 45.5 Wh/kg at the pack level against 39.3 Wh/kg.

The commercial value of specifying precisely is larger than the price difference between the cells. A quotation built on a published figure set can be compared across three suppliers in ten minutes and defended at the goods-in dock. A quotation built on a label cannot be compared at all, and the difference shows up three months later as a warranty claim.

Two figures deserve a final emphasis for buyers working outside Europe. First, the 40 A charger requirement for a 48V pack of four cells is set by the published maximum charge current, not by marketing; if your charger is sized below it, the recharge window stretches and the pack spends more of its life in a partially discharged state. Second, the published cycle rating assumes 50–80% depth of discharge, so if your AGV or cart runs deeper than that, ask for the rating at your actual depth before you commit to a volume.

For importers into markets served from Rotterdam, Jebel Ali, Santos, Lagos or Chennai, the sequence that works is simple: fix the published specification first, then let suppliers compete on it. The one-page figure set in §1 is enough to run that process.

Contact CHISEN

Send the target application, the required capacity, the case dimensions you need to fit and the quantity to the CHISEN export desk, and you will receive a quotation against the published specification, the datasheet and the current lead time.

Email: jack@chisen.cn or sales@chisen.cn
WhatsApp: +86 131 6622 6999
12V VRLA product index: https://www.chisen.cn/en/LeadacidBattery/EVF.html
6-EVF-50 model page: https://www.chisen.cn/en/6-EVF-50/12V50Ah.html
6-DMF-52 model page: https://www.chisen.cn/en/6-DMF-52/12V52Ah.html

Related reading on the CHISEN knowledge centre: 12V VRLA selection guidance, deep-cycle charge setpoints, and pack-sizing method for AGV and traction applications.

CHISEN Battery — lead-acid cells and systems for telecom, solar, UPS, AGV and traction applications. 8 production bases, 70 million kVAh annual capacity, ISO 9001 and ISO 14001 certified.

Related CHISEN Buyer Guides

October 24, 2026

CHISEN ISO 9001: What the Certification Covers, What It Doesn’t, and How to Verify a Battery Supplier

Answer First

CHISEN ISO 9001 is the certification attached to CHISEN Battery, a Hangzhou manufacturer of lead-acid cells and systems that runs 8 production bases with an annual capacity of 70 million kVAh and ships into Europe, Africa, Asia and Latin America. What that certification actually tells a procurement manager is narrower than most quotations imply: ISO 9001 certifies a documented quality management system — procedures, records, internal audits and corrective action — over a defined scope at a stated address, for a stated period. It does not certify that any particular cell holds a particular number of amp-hours, and it does not replace a datasheet, a type test or an acceptance check at your warehouse. CHISEN holds ISO 9001 and ISO 14001, with CE, UL and IEC conformity for the markets each cell ships into. This guide separates what each of those certificates proves from what it does not, and gives the seven-step routine CHISEN recommends to any buyer — whether the supplier is CHISEN or a competitor in Hamburg, Lagos or Chennai.

Key Takeaways

CHISEN ISO 9001 certifies the management system, the scope and the validity period — not the performance of a specific cell, and never a specific amp-hour figure.
CHISEN operates 8 production bases with an annual capacity of 70 million kVAh, which averages 8,750,000 kVAh per base — a scale figure you can check against the plant you are actually buying from.
CHISEN holds ISO 9001 for quality, ISO 14001 for the environmental system, plus CE, UL and IEC conformity; each covers something different and none of them substitutes for the others.
A 2 V cell from CHISEN carries a 20+ year design float life at 20 °C, and a 12 V block carries a 2–5 year design life — certification does not change a chemistry limit, and a supplier claiming otherwise is overreaching.
The verification routine that actually protects a buyer is short: certificate number and scope, the published datasheet for the exact model, batch traceability, the test certificate, and an acceptance test on arrival.
For a container landing at Rotterdam, Santos, Jebel Ali, Lagos or Chennai, the acceptance test and the laboratory agreement are worth more than any certificate in the file.
CHISEN publishes the full specification for every model it sells, which is the practical test of whether a supplier’s quality system reaches the product you are buying.

§1 — Certification Scope and Specification Checklist

The table below is the single most useful page in a supplier file. It states what each certificate covers, what it does not, and the practical step a buyer takes to verify it. The CHISEN column reflects the certifications CHISEN holds.

Certification	What it actually certifies	What it does NOT certify	How a buyer verifies it	CHISEN
ISO 9001	A documented quality management system: defined procedures, controlled records, internal audit, corrective action, over a stated scope and site	The capacity, cycle life, safety or consistency of any individual cell or batch	Certificate number, scope statement, registered address, issuing body, validity dates	Held
ISO 14001	An environmental management system: waste, emissions, recycling and resource handling across the manufacturing operation	Product performance, or that any specific recycled content claim is accurate	Same check as ISO 9001, plus the scope’s environmental exclusions	Held
CE	Conformity with the applicable EU directives and regulations covering safety, EMC and hazardous substances; the economic responsibility sits with the EU importer	Third-party quality of the plant; CE is largely a self-declaration for many battery categories	Ask for the EU Declaration of Conformity and the importer’s name and address	Held for the European market
UL	Safety standard certification for the product as evaluated for the North American market	Performance beyond the tested conditions, or suitability for a duty the evaluation did not cover	UL file number and the category on the certificate	Held for the North American market
IEC	The international standards series used to qualify stationary lead-acid cells against a stated performance and test method	A general quality claim about the manufacturer; the buyer must identify the exact part number	Ask which IEC 60896 part applies to the cell type, flooded tubular or gel, and require the test report against that part	Held; ask for the part number applicable to your cell

Two rows deserve emphasis because they are the ones most often confused.

First, the IEC row. For stationary lead-acid cells the relevant standards sit in the IEC 60896 series, and the part number differs between flooded and gel tubular cells. A buyer who asks for “the IEC certificate” without a part number will receive a general conformity statement that proves nothing about the cell. The useful request is specific: which part of IEC 60896 applies to the OPzS2 flooded line, which applies to the OPzV2 gel line, and the test report for the exact model ordered.

Second, the ISO 9001 row. Certification confirms that the plant runs a documented system with records, internal audits and corrective action. It does not confirm that a cell holds 150 Ah at C3. Only the published specification, the type test and the acceptance test do that. A supplier who presents an ISO 9001 certificate as proof of capacity is misusing it — and a buyer who accepts it that way has skipped the only verification that matters.

§2 — The Pain: Certification Language That Misleads Buyers

Battery sourcing has a documentation problem. The certificate file grows, the pages multiply, and somewhere in the middle the distinction between “the system is certified” and “this cell performs as specified” quietly disappears. Buyers in Rotterdam, Lagos, Cairo and São Paulo are routinely asked to approve a supplier on the strength of a certificate scan.

The first distortion is scope. ISO 9001 certificates carry a scope statement that names what the system covers. A plant whose scope reads “manufacture of lead-acid batteries” covers the cell operation. A scope that reads “trading, assembly and distribution” does not cover cell manufacture at all, and the certificate tells you which case you are in. Always read the scope line. It costs nothing and it settles the question.

The second distortion is the certificate that covers the wrong site. A group with eight production bases may hold a certificate issued for one address, while another address operates outside that scope. Because CHISEN runs 8 production bases, the question “which address is on the certificate, and which address is making my cells” is not pedantic — it is the first question. The same applies to UL file numbers and to the EU importer named on the Declaration of Conformity.

The third distortion is that certification is treated as a performance guarantee. It is not. A chemistry limit does not move because a certificate exists. The CHISEN published specification states a 20+ year design float life at 20 °C for the 2 V tubular OPzS2 and OPzV2 ranges and a 2–5 year design life for the 12 V VRLA blocks — a difference of a factor of four, caused by chemistry and construction, not by paperwork. The 20-year figure belongs to the 2 V tubular class; the 12 V VRLA blocks are 2–5 years. Any supplier telling you the warranty scales with the certificate is describing a marketing position, not an engineering one.

The fourth distortion is paperwork substitution for traceability. A batch reference is dull and it is worth more than a framed certificate, because it is the only document that connects a specific pallet in a specific container to a specific production date. If the supplier cannot give you the batch reference, you cannot investigate a failure, and an investigation you cannot run is an investigation you will not run.

§3 — The Choice: How to Evaluate a Supplier You Cannot Visit

Most buyers of industrial batteries cannot visit the plant. That makes the document set the substitute for the site visit, and it makes the structure of that file the thing worth comparing between suppliers. The evaluation table below scores the three approaches a buyer normally encounters.

Evaluation route	What it establishes	What it misses	Practical cost	CHISEN’s position
Certificate file only	That a management system and the relevant market approvals exist	Cell performance, batch traceability, whether your model is in the scope	Lowest	Provided on request, but not sufficient on its own
Certificate file plus published model specification	That the system exists AND that the exact model has a documented specification you can check	Whether the shipped batch matches the specification	Low, and it is the best value	Every CHISEN model has a published page with capacity, dimensions, weight and charge setpoints
Certificate file, published specification, batch traceability and an arrival acceptance test	That the system exists, the specification is documented, your units are traceable, and the shipment is verified against the specification	Nothing material at the purchasing stage	Moderate, and it is the only route that resolves a dispute	Supported; the batch reference appears on the packing list and the acceptance procedure can be written into the contract

The middle row is where most good buying happens, and it costs nothing beyond asking. The requirement is specific: a URL or a document for the exact model you are ordering, with nominal voltage, rated capacity and its rate basis, dimensions, weight, terminal, float voltage, equalisation voltage, maximum charge current, cycle life and working temperature. A supplier who cannot produce that set for your model is telling you something important about how their quality system reaches the product.

The third row is where risk is actually retired, and it is the row CHISEN recommends for buyers shipping containers to Rotterdam, Santos, Jebel Ali, Lagos or Chennai. It adds two things to the middle row: a batch reference that ties the shipment to a production date, and an acceptance procedure agreed before the goods ship. The acceptance procedure should name the test, the sample size, the laboratory and what happens if the sample fails.

§4 — The Framework: Seven Verification Steps

Seven steps, in order, take a supplier from “plausible” to “verified”. Each one produces a document you can keep.

1. Verify the certificate itself. Take the certificate number, the scope statement, the registered address, the issuing body and the validity dates, and check them with the issuing body. An unverifiable certificate number is a worse signal than no certificate, because it shows the supplier is not expecting the check.

2. Verify the scope covers the product. Read the scope line against what you are buying. A “manufacture of lead-acid batteries” scope covers a cell operation. A “trading and distribution” scope does not. If the cell is made at a site other than the certified address, ask for the certificate that covers that site.

3. Verify the market approval for your destination. For Europe, the EU Declaration of Conformity and the name and address of the EU importer. For North America, the UL file number and category. For a specific standard-based qualification, the IEC 60896 part number that matches the cell type and the test report against it.

4. Verify the specification of the exact model. Obtain the published datasheet or model page for the model on your order line, with all ten of the fields listed in §3. Cross-check it against the quotation line by line. If the quotation and the datasheet disagree, stop there.

5. Verify traceability. Ask that every cell or pallet carries a batch reference, that the batch appears on the packing list, and that the batch date falls inside the stated warranty period. Add the requirement that cells within one series string come from one batch.

6. Verify the factory’s consistency with the specification. A published figure set that is identical across every model page is itself evidence of a controlled documentation process, because it means the values come from a data system rather than from a per-request document. CHISEN maintains published pages for 69 product models across its ranges, including the OPzV2-1000 2V1000Ah tubular gel cell, and the same field set appears on each of them.

7. Verify the shipment. Agree, in the contract, the acceptance test on arrival: a sample capacity check at the published rate, a float voltage check across the bank, an electrolyte density check for flooded cells, and a named laboratory for re-inspection. For arrivals through Rotterdam, Santos, Jebel Ali, Lagos, Port Said or Mombasa, write the laboratory into the contract rather than agreeing it after a dispute starts.

§5 — The Trust: What the CHISEN Footprint Actually Delivers

CHISEN’s verifiable position is this. The company operates 8 production bases in China with an annual capacity of 70 million kVAh, which works out at 70,000,000 kVAh ÷ 8 bases = 8,750,000 kVAh average per base. It holds ISO 9001 for the quality management system and ISO 14001 for the environmental system, with CE, UL and IEC conformity for the markets it ships into. Its range covers flooded tubular cells (OPzS2, 2 V, 100–3000 Ah), gel tubular cells (OPzV2, 2 V, 100–3000 Ah), 12 V VRLA blocks in three ranges (6-DZF at 12–20 Ah, 6-DMF at 21–58 Ah and 6-EVF at 24–150 Ah), 6 V and 8 V EVF cells (3-EVF at 180–225 Ah and 4-EVF at 150 Ah), solar storage systems and lithium storage systems.

The arithmetic below shows what that footprint produces, using the published specifications of individual cells. It is worth doing, because it converts an abstract capacity claim into figures a buyer can check against an incoming pallet.

Product line	Voltage	Model span	Verified example	Published specification of that example	Energy per cell	Specific energy
OPzV2 gel tubular	2 V	100–3000 Ah	OPzV2-200	200 Ah @ C10, 103 × 206 × 390 mm, 17.0 kg, 40 A max charge, 2.23 V float, 2.35 V equalise, −3 mV/°C/cell, ~1.0 mΩ @25 °C, 20+ years @20 °C	2 V × 200 Ah = 400 Wh	400 Wh ÷ 17.0 kg = 23.5 Wh/kg
OPzV2 gel tubular	2 V	100–3000 Ah	OPzV2-1000	1000 Ah @ C10, 233 × 210 × 681 mm, 73.2 kg, 200 A max charge, 2.23 V float, 2.35 V equalise, −3 mV/°C/cell, ~0.50 mΩ @25 °C, 20+ years @20 °C	2 V × 1,000 Ah = 2,000 Wh	2,000 Wh ÷ 73.2 kg = 27.3 Wh/kg
OPzV2 gel tubular	2 V	100–3000 Ah	OPzV2-2500	2500 Ah @ C10, 487 × 212 × 807 mm, 181 kg, 500 A max charge, 2.23 V float, 2.35 V equalise, −3 mV/°C/cell, ~0.30 mΩ @25 °C, 20+ years @20 °C	2 V × 2,500 Ah = 5,000 Wh	5,000 Wh ÷ 181.0 kg = 27.6 Wh/kg
6-EVF 12 V VRLA	12 V	24–150 Ah	6-EVF-50	50 Ah @ C3, 230 × 140 × 180 mm, 15.25 kg, 10.0 A max charge, 13.5 V float, 14.1 V equalise, 350–600 cycles, 2–5 years	12 V × 50 Ah = 600 Wh	600 Wh ÷ 15.25 kg = 39.3 Wh/kg
6-EVF 12 V VRLA	12 V	24–150 Ah	6-EVF-150	150 Ah @ C3, 483 × 170 × 240 mm, 48.5 kg, 30.0 A max charge, 13.5 V float, 14.1 V equalise, 350–600 cycles, 2–5 years	12 V × 150 Ah = 1,800 Wh	1,800 Wh ÷ 48.5 kg = 37.1 Wh/kg

Read the last two columns and a reasonable question follows: why is a 12 V block more energy-dense per kilogram than a 2 V tubular cell? The answer is in the published figures themselves. The 6-EVF construction uses thinner plates and a tighter case format, which raises gravimetric density and lowers cycle life and float life in exchange — 39.3 Wh/kg against 23.5 Wh/kg, against 2–5 years of design life against 20+ years. Neither is better. They are different products for different duties, and the specification set is what tells them apart.

For scale, a 48 V string built from 24 OPzV2-200 cells gives 24 × 2 V = 48 V, 48 V × 200 Ah = 9,600 Wh, a string weight of 24 × 17.0 kg = 408 kg, and a charger rating of 24 × 40 A = 960 A. If a supplier cannot tell you those four numbers for the cell it is quoting, the quality system has not reached the product.

Further detail on CHISEN’s operation, product lines and export process is on the CHISEN company page, and the technical questions that come up in almost every enquiry are answered in the CHISEN FAQ.

§6 — FAQ: Certification Questions Buyers Ask

Q1. What does the CHISEN ISO 9001 certification actually guarantee? That CHISEN’s quality management system — documented procedures, controlled records, internal audits and corrective action — is certified over a stated scope, at a stated site address, for a stated validity period, by a named certification body. It does not guarantee the amp-hour capacity of any particular cell, and it is not a performance certificate. The performance of a specific model is established by its published datasheet, its type test and your acceptance test on arrival.

Q2. Does CHISEN ISO 9001 mean the batteries come with a warranty? No. Certification and warranty are separate things. A warranty is a commercial commitment on specific terms, and it is set out in the sales contract; a management system certification is a statement about how the plant is managed. Read them separately. A reputable supplier publishes both, and neither substitutes for the other.

Q3. Which certifications does CHISEN hold? CHISEN holds ISO 9001 for the quality management system and ISO 14001 for the environmental system, and its products carry CE, UL and IEC conformity for the destination markets. For a stationary lead-acid cell bought against a performance standard, ask for the specific IEC 60896 part number that matches the cell type — flooded tubular or gel — and the test report against it, rather than a general reference to IEC.

Q4. Is ISO 14001 relevant to a battery buyer? It is relevant to a corporate buyer with a supply-chain or environmental reporting obligation, and to buyers in markets where environmental management expectations are part of the supplier qualification process. ISO 14001 certifies the environmental management system — waste, emissions, recycling and resource handling across the operation. It says nothing about the cell’s performance, and a buyer who presents it as a quality argument has misunderstood it.

Q5. How many production bases does CHISEN operate and how do I check the scale claim? CHISEN operates 8 production bases with an annual capacity of 70 million kVAh, an average of 8,750,000 kVAh per base. You can sanity-check any capacity claim against the product itself: the published specifications of the OPzV2-200, OPzV2-1000 and OPzV2-2500 cells give you cell weights, case dimensions and charge currents, and from those you can estimate the annual output of a line. If a supplier’s capacity claim cannot be reconciled with the specifications of the models it sells, ask why.

Q6. What should I demand on the order acknowledgement beyond the model code? The exact model and chemistry, the case dimensions and the weight with its tolerance, the terminal type and torque, the float and equalisation voltages with their reference temperature, the temperature compensation coefficient, the maximum charge current, the cycle rating with its depth of discharge, the design life with its reference temperature, the batch reference, the test certificate, and the acceptance procedure on arrival including the laboratory and the sample size. That list takes one page and it is the difference between a shipment you can accept and a shipment you can only argue about.

Q7. Does ISO 9001 mean the same cell will be delivered every time? It means the process that produces, tests, records and releases the cell is documented and audited, which is the practical form of consistency. It does not mean two cells are dimensionally identical — a published weight tolerance of ±0.2 kg on the 6-EVF-50 or ±0.2 kg on the OPzV2-200 is how a real factory expresses the variation that remains. Accept the tolerance, then control the variation by checking the incoming batch against the specification rather than by expecting zero deviation.

Q8. Where should a buyer in Rotterdam, Lagos or Chennai start? With the published specification of the exact model, on the manufacturer’s own site, and with the certificate numbers and scope statements. CHISEN publishes a page for each of its 69 product models with the same field set — voltage, capacity with the rate basis, dimensions, weight, terminal, float and equalisation voltages, charge current, cycle life and working temperature — so the comparison between suppliers becomes a line-by-line comparison of numbers. Everything after that, from the batch reference to the acceptance test, follows from what the specification makes checkable.

Expert Summary

CHISEN ISO 9001 is a real, checkable certificate attached to a manufacturer with 8 production bases and 70 million kVAh of annual capacity, and it is worth having in the supplier file. It is also worth exactly what it says: a certified management system over a stated scope, at a stated address, for a stated period. It does not certify a cell’s capacity, it does not extend a chemistry limit, and it does not replace a datasheet.

The distinction matters because the alternatives are worse. A 20+ year design float life at 20 °C for the 2 V tubular OPzS2 and OPzV2 cells and a 2–5 year design life for the 12 V VRLA blocks are chemistry facts, published on the model page, and no certificate changes them. The 23.5 Wh/kg of the OPzV2-200 against the 39.3 Wh/kg of the 6-EVF-50 is a construction trade-off, not a quality statement. A supplier willing to write those numbers on the datasheet is telling you more about the reliability of your supply than any certificate scan.

So the verification routine is short: certificate, scope, site address, market approval, published model specification, batch traceability, acceptance test. Seven items, most of them free, and every one of them a document you keep. For a buyer shipping containers to Rotterdam, Santos, Jebel Ali, Lagos, Port Said or Chennai, the last item is worth more than the other six, because it is the only one that settles a question while the pallet is still on the dock.

Contact CHISEN

Send the model codes, the quantity and the destination market to the CHISEN export desk, and you will receive a quotation built on the published datasheet, the certification documents for your market and the current lead time.

Email: jack@chisen.cn or sales@chisen.cn
WhatsApp: +86 131 6622 6999
Company profile and product lines: https://www.chisen.cn/en/about.html
Technical FAQ: https://www.chisen.cn/en/h-faq.html
OPzV2-1000 2V1000Ah model page: https://www.chisen.cn/en/OPzV2-1000/2V1000Ah.html

Related reading on the CHISEN knowledge centre: how to read a lead-acid datasheet, battery acceptance testing on arrival, and batch traceability for warranty claims.

CHISEN Battery — lead-acid cells and systems for telecom, solar, UPS, AGV and traction applications. 8 production bases, 70 million kVAh annual capacity, ISO 9001 and ISO 14001 certified.

October 24, 2026

2V 200Ah Battery: OPzS2 Flooded vs OPzV2 Gel for Telecom, Solar and UPS (2026 Buyer Guide)

Answer First

A 2V 200Ah battery is a single 2V tubular cell that delivers 200 amp-hours at the C10 rate, and it is the cell on which almost every serious stationary installation is built: telecom DC plants, solar storage strings, railway and substation backup, and large UPS installations. Two chemistries dominate the class, and they are not interchangeable. The OPzS2-200 is a flooded tubular cell published at 103 × 206 × 409 mm and 13.0 kg without electrolyte or 17.5 kg with electrolyte; the OPzV2-200 is a gel tubular cell published at 103 × 206 × 390 mm and 17.0 kg. Both charge at 2.23 V float and 2.35 V equalisation with −3 mV/°C/cell compensation and both carry a 20+ year design float life at 20 °C. Twenty-four cells in series give a 48V string of 48 V × 200 Ah = 9,600 Wh. This guide compares the two on published data only — capacity, geometry, weight, charge settings, internal resistance and string arithmetic — so that a buyer can decide between them before asking a factory for a quotation.

Key Takeaways

A 2V 200Ah battery is one 2V cell, not a 12V block; a 48V string needs 24 of them, and a 24-cell string gives 48 V × 200 Ah = 9,600 Wh.
The OPzS2-200 flooded cell publishes 13.0 kg without electrolyte and 17.5 kg with electrolyte, so a 24-cell string weighs 312 kg dry or 420 kg filled.
The OPzV2-200 gel cell publishes 17.0 kg with no filling step, so the same 24-cell string weighs 408 kg — 12 kg lighter than the flooded string and far simpler to install.
Both cells accept a 40 A maximum charge current, which is 40 A ÷ 200 Ah = 0.2 C, and a 24-cell string therefore needs 24 × 40 A = 960 A.
Float is 2.23 V @25 °C and equalisation is 2.35 V @25 °C for both; in solar and wind service the equalisation setting moves to 2.40 ± 0.01 V/cell.
Internal resistance differs and so does its reference temperature: the flooded cell is published at ~0.95 mΩ @20 °C, the gel cell at ~1.0 mΩ @25 °C.
Design float life is 20+ years at 20 °C — the figure is tied to 20 °C, not to 25 °C, and it belongs to the tubular class only.

§1 — 2V 200Ah Battery Specifications

All values in this table are taken from the manufacturer datasheets for the two cells. Derived rows carry their formulas.

Specification	OPzS2-200 (flooded)	OPzV2-200 (gel)	Source
Nominal voltage	2V	2V	Datasheet
Rated capacity at C10 (1.80 Vpc)	200 Ah	200 Ah	Datasheet
Dimensions L × W × H	103 × 206 × 409 mm	103 × 206 × 390 mm	Datasheet
Weight without electrolyte	13.0 kg	not applicable — gel cells are supplied filled	Datasheet
Weight with electrolyte	17.5 kg	17.0 kg	Datasheet
Maximum charge current	40 A	40 A	Datasheet
Float charge voltage	2.23 V @25 °C	2.23 V @25 °C	Datasheet
Equalisation charge voltage	2.35 V @25 °C	2.35 V @25 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	−3 mV/°C/cell	Datasheet
Internal resistance	~0.95 mΩ @20 °C	~1.0 mΩ @25 °C	Datasheet
Design float life	20+ years @20 °C	20+ years @20 °C	Datasheet
Terminal	Female copper insert M8, 10-12 N·m	Female copper insert M8, 10-12 N·m	Datasheet
Solar and wind equalisation	2.40 ± 0.01 V/cell @25 °C	2.40 ± 0.01 V/cell @25 °C	Datasheet
Solar and wind float	2.25 ± 0.005 V/cell @25 °C	2.27 ± 0.005 V/cell @25 °C	Datasheet
Solar and wind compensation	−4 mV/cell/°C	−3 to −5 mV/cell/°C	Datasheet
Charge current as a fraction of capacity	40 A ÷ 200 Ah = 0.2 C	40 A ÷ 200 Ah = 0.2 C	Arithmetic
Energy per cell	2 V × 200 Ah = 400 Wh	2 V × 200 Ah = 400 Wh	Arithmetic

One datasheet detail deserves to be flagged because it changes how the capacity figure is read. The OPzS2-200 publishes a discharge-rate table measured to a 1.85 V final voltage: C24 = 226 Ah, C48 = 248 Ah, C72 = 260 Ah, C100 = 270 Ah, C120 = 274 Ah and C240 = 280 Ah. Those are higher than the 200 Ah C10 figure because the C10 rating is measured down to 1.80 Vpc while the rate table is measured to a higher cut-off. A buyer comparing a 2V 200Ah battery against a quoted “260 Ah” figure is almost always comparing two different cut-off voltages, not two different cells.

§2 — The Pain

Three problems recur on 2V 200Ah orders, and each of them starts with an incomplete line on a purchase order.

The first is weight stated without electrolyte. A flooded 2V 200Ah cell is published at 13.0 kg without electrolyte and 17.5 kg with electrolyte. Quote the 13.0 kg figure to a structural engineer and the rack design is 108 kg light across a 24-cell string, because 24 × 4.5 kg = 108 kg of electrolyte has not been counted. Quote 17.5 kg to an installer who is planning a manual handling lift and you have promised the wrong thing in the other direction. The order line must state which figure applies.

The second is the charge setpoint. A 2V cell floats at 2.23 V @25 °C and equalises at 2.35 V @25 °C, with −3 mV/°C/cell compensation. These are tight tolerances and they are not the same as the 2.27 V and 2.35 V bands printed on generic lead-acid literature. A 48V string of 24 cells floating at 2.27 V/cell is sitting 0.96 V above the intended float across the string, which over years is a material loss of life on a cell that was specified for 20+ years of float at 20 °C.

The third is chemistry mismatch inside a string. A series string of 2V cells must be built from cells of the same chemistry, the same model and, ideally, one production batch. Fitting a gel OPzV2-200 and a flooded OPzS2-200 into the same 24-cell string is a genuine engineering error, not a saving: the cells have different electrolyte, different self-discharge behaviour, different internal resistance and different equalisation behaviour, and a string cannot be charged for both.

There is a commercial dimension too. Buyers sourcing for Rotterdam, Jebel Ali, Santos, Lagos or Chennai often receive quotations for “2V 200Ah tubular” with no datasheet reference, no chemistry statement and no charge settings — which makes it impossible to compare two factories properly and impossible to re-order against the same specification two years later.

§3 — The Choice

The decision between a flooded and a gel 2V 200Ah battery is not a preference; it is a set of operating consequences. The string arithmetic below shows what each choice costs and delivers in a 24-cell 48V installation.

48V string build	OPzS2-200 flooded	OPzV2-200 gel	Source
Cells in series	24 × 2 V = 48 V	24 × 2 V = 48 V	Arithmetic
String energy	48 V × 200 Ah = 9,600 Wh	48 V × 200 Ah = 9,600 Wh	Arithmetic
String weight with electrolyte	24 × 17.5 kg = 420 kg	24 × 17.0 kg = 408 kg	Arithmetic
String weight before filling	24 × 13.0 kg = 312 kg	not applicable	Arithmetic
Electrolyte mass per string	24 × 4.5 kg = 108 kg	none	Arithmetic
String internal resistance	24 × 0.95 mΩ = 22.8 mΩ	24 × 1.0 mΩ = 24.0 mΩ	Arithmetic
Maximum charge current	24 × 40 A = 960 A	24 × 40 A = 960 A	Arithmetic
Charger rating	960 A	960 A	Arithmetic
Float set point	2.23 V/cell	2.23 V/cell	Datasheet
Equalisation set point	2.35 V/cell	2.35 V/cell	Datasheet
Installation step	electrolyte filling and density setting required	none	Datasheet
Published full specification	OPzS2-200 model page	OPzV2-200 model page	Model page

Read the two columns against each other and the trade becomes concrete.

The flooded OPzS2-200 is lighter to handle before filling and cheaper to ship, because the electrolyte travels separately and is added on site. It demands a controlled filling procedure, a density measurement of every cell, a watering routine on a published schedule, and ventilation, because it is designed to release gas during charge. It also publishes a slightly lower internal resistance, 0.95 mΩ against 1.0 mΩ, which matters marginally in a high-current string.

The gel OPzV2-200 arrives filled and sealed, needs no watering and no on-site filling step, and can be installed in an enclosed room without the same gas-evacuation requirement. Its string is 12 kg lighter — 420 kg against 408 kg across 24 cells — because the electrolyte is held in gel rather than as free liquid. Its datasheet also carries the solar and wind float setting of 2.27 ± 0.005 V/cell and compensation of −3 to −5 mV/cell/°C, which is a wider, more forgiving adjustment band than the −4 mV/cell/°C published for the flooded cell.

For a telecom DC plant in Jebel Ali or Chennai, where space and maintenance access are constrained, the gel route removes a whole service operation from the asset, because there is no filling or watering step on any 2V cell in the string. For a ground-mounted solar site in Santos or Durban where ventilation is available and the budget is tighter, the flooded route is a legitimate choice with a well-understood service regime.

The wider flooded tubular range, including the 2V cells from 100 Ah to 3000 Ah, is indexed on the CHISEN flooded tubular battery page.

§4 — The Framework

Seven checks turn a 2V 200Ah enquiry into an order that can be built, shipped and defended.

1. State the chemistry on the order line. “OPzS2-200 flooded” and “OPzV2-200 gel” are different products with different part numbers. Never order them as “2V 200Ah tubular”, which is an instruction to buy whichever the factory has that week.

2. State the weight basis. For a flooded cell, write both 13.0 kg without electrolyte and 17.5 kg with electrolyte. For a gel cell, write 17.0 kg. Then apply the string factor: 24 cells gives 312 kg and 420 kg for the flooded string, or 408 kg for the gel string.

3. State the charge settings to three decimals of a volt. Float 2.23 V @25 °C, equalisation 2.35 V @25 °C, compensation −3 mV/°C/cell, and for solar and wind service the equalisation at 2.40 ± 0.01 V/cell @25 °C with float 2.25 ± 0.005 V/cell (flooded) or 2.27 ± 0.005 V/cell (gel). Put these in the charger configuration table, not in a general note.

4. Confirm the charger rating from the published charge current. 40 A per cell gives 24 × 40 A = 960 A for the string. A 960 A charger is a real specification item with real consequences for the rectifier, the cable sizing and the switchgear.

5. Require batch consistency. Ask for cells from one production batch within a string, and require the batch reference on every cell and on the packing list. For shipments into Santos, Jebel Ali, Lagos, Port Said or Mombasa, this is the document that resolves a mismatch without a laboratory argument.

6. Confirm the case and the rack. 103 × 206 × 409 mm flooded against 103 × 206 × 390 mm gel. The footprint is the same and the height differs by 19 mm, which matters in a stacked rack with limited clearance. The M8 female copper insert at 10-12 N·m is common to both.

7. Agree the arrival test. A sample capacity check at C10 to 1.80 Vpc, a float voltage check across the string, and for flooded cells an electrolyte density check, with a named laboratory for re-inspection. For long sea routes, agree the state-of-charge at shipment, because self-discharge over a 30-day voyage is real money on a 9,600 Wh string.

§5 — The Trust

The OPzS2 and OPzV2 tubular ranges are produced inside a manufacturer that operates 8 production bases with an annual capacity of 70 million kVAh, under a quality management system certified to ISO 9001, with ISO 14001 covering the environmental system, and CE, UL and IEC conformity for the destination markets. Every figure in this article is taken from the individual datasheet for each cell rather than from a marketing summary, and the complete flooded tubular range is indexed on the CHISEN flooded tubular page.

Two points deserve emphasis for a buyer who will be asked to pay for assurance.

First, a certificate covers a management system, a scope and a date. ISO 9001 confirms that the plant runs documented procedures and acts on non-conformity; it does not confirm that a particular cell holds 200 Ah at C10. That is the job of the datasheet, the type test and the acceptance test. Ask for the certificate number, the scope statement, the registered address and the validity dates, then verify the cell on its own published data.

Second, the 20+ year float life figure has a precise condition attached to it: it is a design life at 20 °C. A string operated in a container in Jebel Ali or a plant room in Chennai sees a higher average temperature, and the life figure moves with temperature even though the label does not. That is not a weakness in the cell; it is the reason the datasheet states the temperature. Use the figure as a design input, and state the operating temperature on the order so the supplier can confirm what they stand behind.

§6 — FAQ

Q1. Is a 2V 200Ah battery the same as a 12V 200Ah battery? No, and this is a frequent source of confusion. A 2V 200Ah battery is a single 2V cell, and a 12V 200Ah battery is normally six 2V cells in series with a common case and a common set of terminals. The six-cell version weighs 12V × 200 Ah = 2,400 Wh against 2 V × 200 Ah = 400 Wh for one cell, and it cannot be opened for individual cell maintenance. For stationary strings, engineers normally specify the 2V cell so that individual cells can be replaced; for small enclosures, the 12V block is more convenient.

Q2. How many 2V 200Ah batteries do I need for a 48V system? Twenty-four. 24 × 2 V = 48 V, and the string capacity is 48 V × 200 Ah = 9,600 Wh. The string needs a charger rated at 24 × 40 A = 960 A. For a 72V system, use 36 cells for 72 V × 200 Ah = 14,400 Wh, and a charger of 36 × 40 A = 1,440 A.

Q3. What is the difference between a flooded OPzS2-200 and a gel OPzV2-200? Chemistry and installation. The flooded cell is published at 13.0 kg without electrolyte and 17.5 kg with electrolyte, needs filling and density setting on site, needs watering on a published schedule, and needs ventilation. The gel cell is published at 17.0 kg supplied filled and sealed, needs no filling and no watering, and can be installed in an enclosed room. Both are 2V 200 Ah cells at 103 mm × 206 mm in plan, both float at 2.23 V @25 °C and equalise at 2.35 V @25 °C with −3 mV/°C/cell compensation, and both carry a 20+ year design float life at 20 °C.

Q4. Why does the datasheet show both 200 Ah and 280 Ah for the same cell? Because the discharge rate and the final voltage differ. The C10 rating of 200 Ah is measured down to 1.80 Vpc. The rate table on the OPzS2-200 datasheet is measured to a 1.85 V final voltage, which returns more: C24 = 226 Ah, C48 = 248 Ah, C72 = 260 Ah, C100 = 270 Ah, C120 = 274 Ah and C240 = 280 Ah. Always compare two cells at the same rate and the same cut-off voltage, or the comparison is meaningless.

Q5. What charge voltage should I set for a 2V 200Ah battery? For standby service, 2.23 V @25 °C float with 2.35 V @25 °C equalisation and −3 mV/°C/cell compensation. For solar and wind service, the datasheet moves equalisation to 2.40 ± 0.01 V/cell @25 °C, with float at 2.25 ± 0.005 V/cell for the flooded cell and 2.27 ± 0.005 V/cell for the gel cell. Confirm the setting against the datasheet for the exact cell on your order rather than against a general lead-acid chart.

Q6. How much does a 48V string of 2V 200Ah batteries weigh? For the flooded OPzS2-200, 24 × 17.5 kg = 420 kg with electrolyte, or 24 × 13.0 kg = 312 kg before filling, with 24 × 4.5 kg = 108 kg of electrolyte to add. For the gel OPzV2-200, 24 × 17.0 kg = 408 kg delivered filled. The structural check for a rack in Hamburg, Rotterdam or Durban should be made on the filled figure, not on the shipping figure.

Q7. Can I mix flooded and gel cells in the same string? No. A series string must be built from cells of the same chemistry, the same model and ideally one production batch. A flooded cell and a gel cell have different internal resistance, different self-discharge rates, different equalisation behaviour and different gas output, so the string cannot be charged correctly for both. Build the string from one chemistry and keep spare cells of the same model and batch for replacement.

Q8. What should be on the purchase order for a 2V 200Ah battery? The exact model and chemistry, the terminal and torque, the float and equalisation voltages with their reference temperature, the temperature compensation coefficient, the maximum charge current, the design float life and its reference temperature, the case dimensions, the weight basis and tolerance, the batch reference, the required test certificate, and the acceptance procedure on arrival. For container shipments to Santos, Jebel Ali, Lagos or Port Said, add the agreed laboratory and the state-of-charge requirement at shipment.

Expert Summary

A 2V 200Ah battery is fully specified in public. The OPzS2-200 flooded cell publishes 103 × 206 × 409 mm, 13.0 kg without electrolyte and 17.5 kg with electrolyte, 40 A maximum charge current, 2.23 V float at 25 °C, 2.35 V equalisation, −3 mV/°C/cell compensation, ~0.95 mΩ @20 °C and 20+ years of design float life at 20 °C. The OPzV2-200 gel cell publishes 103 × 206 × 390 mm, 17.0 kg, the same charge settings, ~1.0 mΩ @25 °C and the same 20+ year float life. Twenty-four of either give 48 V × 200 Ah = 9,600 Wh.

Three numbers decide most of the projects, and all three follow directly from the published 2V cell data. The 960 A charger requirement follows directly from the 40 A cell rating. The 420 kg versus 408 kg string weight difference decides whether a rack in Rotterdam or a raised floor in Hamburg passes its structural check. And the electrolyte figure — 24 × 4.5 kg = 108 kg of acid per flooded string — decides whether the site has the filling capability and the drainage to take it.

The buyer who writes those three numbers onto the order line, together with the charge setpoints and the batch reference, has a specification that any qualified factory can quote against and any inspector can check at the port. That is a short document, and it is the whole difference between a defensible purchase and a dispute.

Contact CHISEN

Send the application, the string voltage and cell count, the required capacity, the installation environment and the quantity to the CHISEN export desk, and you will receive a quotation built on the published datasheet, the current lead time and the certification documents for your destination market.

Email: jack@chisen.cn or sales@chisen.cn
WhatsApp: +86 131 6622 6999
Flooded tubular index: https://www.chisen.cn/en/Tubularfloodedbattery/OPzS.html
OPzS2-200 model page: https://www.chisen.cn/en/OPzS2-200/2V200Ah.html
OPzV2-200 model page: https://www.chisen.cn/en/OPzV2-200/2V200Ah.html

Related reading on the CHISEN knowledge centre: tubular cell charge setpoints, electrolyte filling and density procedures, string-level cell matching, and reserve capacity calculation for telecom DC plants.

CHISEN Battery — flooded and gel tubular lead-acid cells for telecom, solar, UPS, railway and substation applications. 8 production bases, 70 million kVAh annual capacity, ISO 9001 and ISO 14001 certified.

Related CHISEN Buyer Guides

October 24, 2026

OPzS battery China: Flooded Tubular 2V Cells for Telecom Backup and Stationary Power

Answer First

OPzS battery China refers to the supply of flooded tubular stationary lead-acid cells built to the OPzS2 dimensional and performance standard, manufactured in China and shipped worldwide for telecom backup, substations, railway signalling and off-grid renewable projects. Buyers searching for an “OPzS battery China supplier” are usually past the chemistry debate and asking something concrete: who can build a 48-cell string that passes a witnessed capacity test at my port, and at what point in the container does the paperwork get signed.

Many of the same buyers request “OPzS2 2V tubular flooded wholesale” terms, because one telecom project can consume hundreds of cells and the unit economics only work with palletised, mixed-model shipments rather than sample quantities.

This article covers the flooded tubular line only. If you have already shortlisted an OPzV gel supplier, stop reading: gel and flooded are different products with different charge regimes, different maintenance and different delivered economics, and blending their datasheets is the most common technical error in this category.

In short: the OPzS2-200 is the volume model, rated 200 Ah at C10 to 1.80 V per cell at 20 °C in an L103 × W206 × H409 mm envelope. Its datasheet float voltage is 2.23 V per cell at 25 °C, equalisation at 2.35 V, designed floating life 20+ years @ 20 °C, and temperature compensation −3 mV per °C per cell. A 48-cell string stores 19.2 kWh nominal, weighs 840 kg with electrolyte and needs 216 kg of dilute sulphuric acid. Those numbers, not the marketing language, decide whether a Chinese supplier can serve your project.

Key Takeaways

The flooded/gel split is the first filter. A flooded tubular OPzS2 cell is more reliable than a sealed VRLA cell in a hot, poorly ventilated telecom shelter because it tolerates a wide operating temperature band and does not fail from electrolyte starvation under float conditions.
Capacity is quoted at a rate. The OPzS2-200 gives 200 Ah at C10 to 1.80 V per cell at 20 °C, 226 Ah at C24, 248 Ah at C48 and 280 Ah at C240. Quoting “200 Ah” without the rate is how projects end up short on runtime.
Float control is fixed. 2.23 V per cell at 25 °C, equalise 2.35 V, compensation −3 mV per °C per cell. A charger that cannot hold those setpoints shortens cell life regardless of build quality.
Site filling is a real logistics and safety item. A 48-cell string of OPzS2-200 cells needs 216 kg of electrolyte delivered, added and density-checked, which is why many buyers specify dry-filled cells and require the acid grade in writing.
Supplier verification matters more than unit price. A witnessed capacity test on a production-lot cell is more trustworthy than a scan of a certificate, because the certificate describes a document while the test describes the cell that ships.

§1 — OPzS2 2V Quick Specifications Table

The table below reflects the OPzS2-200, the volume model of the range, unless a row is marked otherwise. Every value comes from that model’s own datasheet; nothing is generalised to another cell.

Specification	Value	Source
Nominal voltage	2 V	Datasheet
Capacity (C10 to 1.80 V/cell @ 20 °C)	200 Ah	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalise charge voltage	2.35 V @ 25 °C	Datasheet
Designed floating life	20+ years @ 20 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Dimensions (printed)	L103 × W206 × H409 mm	Datasheet
Container / total height	354 / 409 mm	Datasheet
Terminal centre spacing	108 mm	Datasheet
Terminal	OD 20 mm, M8, depth 7 mm, copper insert	Datasheet
Terminal torque	10–12 N·m	Datasheet
Weight without electrolyte	13.0 kg (28.7 lbs)	Datasheet
Weight with electrolyte	17.5 kg (38.6 lbs)	Datasheet
Electrolyte	Diluted sulphuric acid 1.240 g/cm³ @ 20 °C, 4.5 kg	Datasheet
Internal resistance	approx. 0.95 mΩ fully charged @ 20 °C	Datasheet
Max charge current	40 A	Datasheet
Max discharge (5S)	1000 A	Datasheet
Short circuit current	2600 A	Datasheet
Self discharge	approx. 4 % per month @ 20 °C	Datasheet
Ambient (discharge / charge / storage)	−25~65 / −20~65 / −15~40 °C	Datasheet
Container material	SAN	Datasheet
Standards	IEC 60896-11, DIN 40736, IEC 61427, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet
Certifications	ISO 9001 (EIC), ISO 14001 (UKAS/UCC), OHSAS 18001:2007 / GB/T 28001 (UCC), CE, UL Recognized Component (cURus / RU)	Datasheet
Constant charge current	0.15 CA to 2.40 V (20 °C)	Datasheet
Cycle life at 10 %–100 % DoD	up to 7000 cycles	Datasheet
Long-time discharge C24 to C240 @ 1.85 V	226 / 248 / 260 / 270 / 274 / 280 Ah	Datasheet
Solar/wind disconnect thresholds	OV disconnect 2.47 ± 0.01 V/cell; LV alarm 1.95 ± 0.005 V/cell; LV disconnect 1.90 ± 0.005 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind charge setpoints	Regulation/equalise 2.40 ± 0.01 V/cell; float setting 2.25 ± 0.005 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind reconnection	Array reconnection 2.23 ± 0.005 V/cell; load reconnect 2.09 ± 0.01 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind temperature compensation	−4 mV/cell/°C	Datasheet (solar/wind page 2)

The solar and wind setpoints belong to the OPzS2-200 datasheet only. They describe the controller configuration used with renewable charging, where regulation and equalise sit above the standby float setting, and they use a different compensation coefficient. Do not copy them into another model’s file.

§2 — The Pain

The buyer’s real problem here is not finding a Chinese manufacturer. It is proving, after the container has left, that the cells in it are the cells described in the paperwork. Specification sheets circulate freely, get retyped, and drift away from their source: a brochure may print a capacity at a different discharge rate than the datasheet, or a slightly different envelope, and a reader who does not check the source will size the cabinet, the cable run and the charger on the wrong numbers.

Three pressures make this harder in 2026. Battery demand is being pulled in two directions at once, with grid-side and telecom storage investment expanding while utility-scale project timing keeps moving, so buyers hold tender documents open longer and revisit standby specifications before issuing a purchase order. Raw material and cell cost assumptions are being reshaped continuously, with research from IEA, BloombergNEF and Benchmark Minerals giving the market a live view of critical materials, manufacturing investment and price direction, and buyers now expect quotations to hold for a defined window. And the tender itself has become stricter: a request for quotations that asks for a witnessed capacity test, a stated production base and a written warranty is no longer unusual across Europe, the Gulf, South Asia and the Americas.

Transport is the fourth pressure, and the one most often missed at specification stage. A flooded tubular cell is heavy and fragile in a specific way: the container is SAN, the cell may be shipped filled with electrolyte, and the terminals are M8 with a defined insertion depth and a 10–12 N·m torque requirement. Shipment to Rotterdam, Jebel Ali, Singapore, Hamburg, Busan, Mumbai, Durban, Santiago, Valencia or Tampa involves container space planning, weight distribution, and the question of whether the buyer or the supplier handles site filling and initial charge.

A fourth trap is chemistry confusion. A buyer who wants flooded tubular OPzS cells and receives a quotation for OPzV gel cells has received a product with a different charge regime, voltage setpoints, equalisation logic and maintenance regime, with electrolyte density recorded at every site visit. The two are often priced within a narrow band, which makes the substitution easy to miss on a spreadsheet.

§3 — The Choice

Three models cover most flooded tubular OPzS2 demand: the OPzS2-150, the OPzS2-200 and the OPzS2-250. All three share the 206 mm width and 409 mm total height.

	OPzS2-150	OPzS2-200	OPzS2-250
Capacity @ C10 to 1.80 V @ 20 °C	150 Ah	200 Ah	250 Ah
Dimensions (printed)	L103 × W206 × H409 mm	L103 × W206 × H409 mm	L124 × W206 × H409 mm
Weight w/o electrolyte	10.5 kg (23.2 lbs)	13.0 kg (28.7 lbs)	15.5 kg (34.2 lbs)
Weight with electrolyte	14.5 kg (32.0 lbs)	17.5 kg (38.6 lbs)	20.5 kg (45.2 lbs)
Acid weight	4.0 kg	4.5 kg	5.0 kg
Max charge current	30 A	40 A	50 A
Internal resistance	approx. 1.2 mΩ @ 20 °C	approx. 0.95 mΩ @ 20 °C	approx. 0.88 mΩ @ 20 °C
Short circuit current	2400 A	2600 A	2750 A
Float / equalise	2.23 V / 2.35 V @ 25 °C	same	same
Floating life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C

The dimensional detail matters for installation, and it is easy to misread. The OPzS2-150 and the OPzS2-200 print the same L103 × W206 × H409 mm envelope, while the OPzS2-250 is 21 mm longer at L124 × W206 × H409 mm. Dry weight differs too, at 10.5 kg, 13.0 kg and 15.5 kg, so a mixed string must allow for two distinct footprints in the rack layout. A cabinet designed for the 150 and 200 will not accept the 250 without a revised shelf and rail pitch.

The arithmetic below is what a buyer uses when answering a request for quotations.

Calculation	Working	Source
48-cell string nominal energy	48 × 2 V × 200 Ah = 19.2 kWh	Arithmetic
48-cell string mass with electrolyte	48 × 17.5 kg = 840 kg	Arithmetic
48-cell string mass without electrolyte	48 × 13.0 kg = 624 kg	Arithmetic
48-cell string internal resistance	48 × 0.95 mΩ = 45.6 mΩ	Arithmetic
48-cell string max charge current	48 × 40 A = 1,920 A	Arithmetic
Electrolyte per 48-cell string	48 × 4.5 kg = 216 kg	Arithmetic
C10 current for the 200 Ah cell	200 Ah ÷ 10 h = 20 A	Arithmetic
Energy density, 150 Ah cell	300 Wh ÷ 14.5 kg = 20.7 Wh/kg	Arithmetic
Energy density, 200 Ah cell	400 Wh ÷ 17.5 kg = 22.9 Wh/kg	Arithmetic
Energy density, 250 Ah cell	500 Wh ÷ 20.5 kg = 24.4 Wh/kg	Arithmetic

Read together, those figures describe the flooded-versus-sealed argument in physical form. A flooded string needs 216 kg of acid-laden electrolyte handled on site, with density checks, ventilation and a controlled initial charge, whereas a sealed string arrives ready to connect. That labour is a real cost, but so are float life and tolerance for repeated deep discharge, and the decision belongs to the maintenance model the buyer actually has. The 250 Ah cell is better suited to a long-string site than the 150 Ah cell because fewer strings carry the same load, and fewer strings mean fewer interconnects, fewer points of failure and less floor area.

§4 — The Framework

Seven numbers decide whether a Chinese supplier can serve a flooded tubular OPzS2 project properly.

Capacity at the rate that matters. Ask for the discharge curve, not a headline figure: 200 Ah at C10 to 1.80 V at 20 °C, 226 Ah at C24, 280 Ah at C240 to 1.85 V. If the design assumes a 10-hour discharge, use C10. A 100-hour discharge yields more than the headline, so the cabinet can be smaller than the catalogue suggests.
Voltage window and controller match. Float at 2.23 V per cell at 25 °C, equalise at 2.35 V, compensation −3 mV per °C per cell. Confirm the charger holds float across a full string and that its tolerance band is centred on the datasheet value, not at its edge.
Thermal environment. Discharge −25 to 65 °C, charge −20 to 65 °C, storage −15 to 40 °C. At 40 °C ambient the compensation must be active: across 24 cells an uncompensated float runs 45 mV per cell high and accelerates water loss.
Internal resistance and voltage drop. At 0.95 mΩ per cell a 48-cell string presents 45.6 mΩ, which sets cable size for a given run length. Terminal centre spacing of 108 mm, M8 terminals with 7 mm insertion depth and 10–12 N·m torque decide whether standard busbars and a standard wrench work on site.
Mechanical footprint. Two envelopes, not one: 103 mm and 124 mm long, both 206 mm wide and 409 mm high. Confirm rack, plinth, door clearance and lifting access against both.
Float life at the real ambient. The published 20+ years is a 20 °C figure. The gap between 20 °C and the ambient inside a cabinet in Chennai, Durban or Santiago is where published lifetime and field lifetime part company.
Documentation depth. Standards reference, certification scope, production base, capacity test method and warranty terms should arrive with the quotation, not six weeks later.

§5 — The Trust

Supplier verification here is less about corporate due diligence and more about documentary discipline. Six checks separate a credible flooded tubular OPzS2 supplier from a marketing intermediary.

A certificate that is not a factory certificate. A document saying the supplier is “certified” or “authorised” is not a factory certificate issued against the production base that actually makes your cells. A factory certificate is more useful than a distributor’s letter of authorisation because it names the plant, the model and the testing body. Ask for the certificate number and scope, and confirm the named entity matches the bill of lading.

A brochure spec that differs from the datasheet. Brochures get retyped and condensed, and retyping introduces drift: a different discharge rate, a rounded envelope, a modified tolerance. Treat the datasheet as the only contractual document and require the order acknowledgement to quote the datasheet revision number.

Which production base actually makes the cells. A supplier with several plants may quote from one catalogue and ship from another. Ask for the plant address, the model and the production line, and require it on the order acknowledgement and the packing list. Request lot identification on the case labels.

A witness capacity test on a production-lot cell, not a sample. A sample sent to your laboratory is usually a best-case cell chosen by the supplier. A cell drawn from the shipment and tested to the C10 method, with recorded temperature and electrolyte density, is evidence about the goods you are buying. Make that test a condition of final payment.

Payment terms tied to test evidence. Retain a meaningful share against the witnessed test report and the document pack on a first order. This is the mechanism that converts a promise about quality into an obligation with a date attached.

What a written warranty must state. A written warranty is more reliable than a verbal assurance because it fixes the remedy, the period and the evidence the supplier must accept: the period in years, the covered failure modes including capacity below the rated figure at the specified rate and temperature, the exclusions such as physical damage, incorrect float voltage or unauthorised equalisation, the remedy and its limits, the claim procedure and required evidence, and how defective cells are handled. “Quality guaranteed” is not a warranty.

§6 — FAQ

Q1. What is the difference between a flooded tubular OPzS cell and an OPzV gel cell? A flooded OPzS cell uses liquid diluted sulphuric acid at 1.240 g/cm³ and requires the level and density to be checked periodically, which is why the datasheet lists electrolyte weight as a separate line. An OPzV cell uses gel electrolyte, needs no topping-up and no density readings on site. A flooded cell tolerates a wider temperature band and repeated deep discharge better; a gel cell has lower self-discharge and no site filling. Compare them against the maintenance model your project actually has.

Q2. Why are these cells 2 V rather than 12 V blocks? Tubular plates are made and tested at cell level, so the 2 V format lets a weak cell be identified and replaced instead of scrapping a 12 V block, and it lets string voltage be set precisely for the DC bus: 24 cells for 48 V, 48 for 96 V, more for 240 V systems. The trade-off is the number of interconnects, which is why terminal centre spacing, torque and connection quality belong in tender documents.

Q3. How much usable capacity should I design around? The headline figure is quoted at a rate. The OPzS2-200 is 200 Ah at C10 to 1.80 V per cell at 20 °C, and at longer rates the same cell delivers more: 226 Ah at C24, 248 Ah at C48, 260 Ah at C72, 270 Ah at C100, 274 Ah at C120 and 280 Ah at C240, all to a 1.85 V final voltage. Design on the rate your load imposes, and use the low-temperature figure on a cold site.

Q4. Can OPzS2 flooded cells be charged from solar or wind? Yes, and the OPzS2-200 datasheet carries a dedicated solar and wind setpoint page: over-voltage disconnect 2.47 ± 0.01 V per cell at 25 °C, regulation and equalise 2.40 ± 0.01 V, array reconnection 2.23 ± 0.005 V, float voltage setting 2.25 ± 0.005 V, low-voltage alarm 1.95 ± 0.005 V, low-voltage disconnect 1.90 ± 0.005 V, load reconnect 2.09 ± 0.01 V, and compensation at −4 mV per cell per °C. These values belong to this model’s page 2.

Q5. What does −3 mV per °C per cell actually change? It is the correction the charger applies to the float setpoint as cell temperature moves away from 25 °C. In a 24-cell 48 V string, each degree below 25 °C adds 3 mV per cell and each degree above reduces it. Running an uncompensated string at 40 °C ambient pushes actual cell voltage above the datasheet float value, driving water loss and drying — the most common cause of shortened float life in warm climates.

Q6. How do I choose between the 150 Ah, 200 Ah and 250 Ah cells? Start from the string architecture, not the cell. If the site allows 48-cell strings on a 96 V bus, the 250 Ah cell cuts the number of strings and the floor area needed. If cabinet depth is fixed at the 103 mm footprint, the 250 Ah cell will not fit, and the choice is between the 150 Ah and 200 Ah cells, which differ in dry weight by 2.5 kg and in capacity by 50 Ah per position.

Q7. How are shipments routed and what affects lead time? Lead time is a function of cell allocation, filling configuration and destination. For Europe the usual routing is by sea to Rotterdam or Hamburg; for the Gulf and South Asia, Jebel Ali and Mumbai; for South-East Asia, Singapore and Busan; for South America, Santiago; for Southern Africa, Durban; for the Americas, Valencia and Tampa depending on the service. Pre-filled and dry-filled configurations carry different handling requirements, so confirm the configuration before the booking is placed.

Q8. What documents should arrive with the battery, and what should the warranty say? Expect the datasheet for the exact model; the certificate set covering ISO 9001, ISO 14001, OHSAS 18001:2007 or GB/T 28001, CE and the UL Recognized Component listing; a standards declaration covering IEC 60896-11, DIN 40736, IEC 61427, the Eurobat long-life guide, BS 6290 part 4 and UL 1989; a test report for the production lot; and a warranty stating period, covered failure modes, exclusions, remedy, procedure and required evidence. A document pack that arrives with the goods means you accepted the risk early.

Expert Summary

An OPzS battery China sourcing decision is a documentary decision before it is a commercial one. The flooded tubular OPzS2 range is well defined and easy to verify: the OPzS2-200 gives 200 Ah at C10 to 1.80 V per cell at 20 °C in an L103 × W206 × H409 mm envelope, weighing 13.0 kg dry and 17.5 kg filled, with a datasheet float of 2.23 V per cell at 25 °C, equalise at 2.35 V, a designed floating life of 20+ years @ 20 °C and −3 mV per °C per cell compensation, backed by IEC 60896-11, DIN 40736, IEC 61427, BS 6290 part 4 and UL 1989, with ISO 9001, ISO 14001, CE and UL Recognized Component certification. The 150 Ah and 250 Ah cells sit either side of it in the same width and height but with different lengths and dry weights, so two footprints must be planned. A 48-cell string stores 19.2 kWh, weighs 840 kg filled, presents 45.6 mΩ, accepts 1,920 A of charge current and needs 216 kg of electrolyte, which is the flooded-versus-sealed argument expressed in kilograms. Ask for the certificate that names the production base, the datasheet revision behind every quoted figure, a witnessed capacity test on a production-lot cell, payment terms tied to that evidence, and a warranty that states period, remedy and procedure. With those answers in writing before the purchase order, a Chinese flooded tubular supplier can be assessed on facts rather than on price.

Contact CHISEN — 24-Hour Response

CHISEN replies to technical and commercial enquiries within 24 hours, and delivers a sizing sheet and quotation against your actual duty data.

Send us the information below and we will return a written recommendation with the published data for the cell and the pack configuration that matches it:

DC bus voltage and string configuration, or the duty you want to size
Backup autonomy target and the load profile in kW
Ambient temperature range at the deployment site
Whether the strings are maintained in-house or by a local service partner
Annual volume and destination port for the first shipment

Email: sales@chisen.cn WhatsApp: +86 131 6622 6999 Call: +86 131 6622 6999

Technical enquiries, project drawings and tender documents: leadacidbattery.cn

Related CHISEN Buyer Guides

October 24, 2026

OPzS battery China: Flooded Tubular 2V Cells for Telecom Backup and Stationary Power

Answer First

Key Takeaways

The flooded/gel split is the first filter. A flooded tubular OPzS2 cell is more reliable than a sealed VRLA cell in a hot, poorly ventilated telecom shelter because it tolerates a wide operating temperature band and does not fail from electrolyte starvation under float conditions.
Capacity is quoted at a rate. The OPzS2-200 gives 200 Ah at C10 to 1.80 V per cell at 20 °C, 226 Ah at C24, 248 Ah at C48 and 280 Ah at C240. Quoting “200 Ah” without the rate is how projects end up short on runtime.
Float control is fixed. 2.23 V per cell at 25 °C, equalise 2.35 V, compensation −3 mV per °C per cell. A charger that cannot hold those setpoints shortens cell life regardless of build quality.
Site filling is a real logistics and safety item. A 48-cell string of OPzS2-200 cells needs 216 kg of electrolyte delivered, added and density-checked, which is why many buyers specify dry-filled cells and require the acid grade in writing.
Supplier verification matters more than unit price. A witnessed capacity test on a production-lot cell is more trustworthy than a scan of a certificate, because the certificate describes a document while the test describes the cell that ships.

§1 — OPzS2 2V Quick Specifications Table

The table below reflects the OPzS2-200, the volume model of the range, unless a row is marked otherwise. Every value comes from that model’s own datasheet; nothing is generalised to another cell.

Specification	Value	Source
Nominal voltage	2 V	Datasheet
Capacity (C10 to 1.80 V/cell @ 20 °C)	200 Ah	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalise charge voltage	2.35 V @ 25 °C	Datasheet
Designed floating life	20+ years @ 20 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Dimensions (printed)	L103 × W206 × H409 mm	Datasheet
Container / total height	354 / 409 mm	Datasheet
Terminal centre spacing	108 mm	Datasheet
Terminal	OD 20 mm, M8, depth 7 mm, copper insert	Datasheet
Terminal torque	10–12 N·m	Datasheet
Weight without electrolyte	13.0 kg (28.7 lbs)	Datasheet
Weight with electrolyte	17.5 kg (38.6 lbs)	Datasheet
Electrolyte	Diluted sulphuric acid 1.240 g/cm³ @ 20 °C, 4.5 kg	Datasheet
Internal resistance	approx. 0.95 mΩ fully charged @ 20 °C	Datasheet
Max charge current	40 A	Datasheet
Max discharge (5S)	1000 A	Datasheet
Short circuit current	2600 A	Datasheet
Self discharge	approx. 4 % per month @ 20 °C	Datasheet
Ambient (discharge / charge / storage)	−25~65 / −20~65 / −15~40 °C	Datasheet
Container material	SAN	Datasheet
Standards	IEC 60896-11, DIN 40736, IEC 61427, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet
Certifications	ISO 9001 (EIC), ISO 14001 (UKAS/UCC), OHSAS 18001:2007 / GB/T 28001 (UCC), CE, UL Recognized Component (cURus / RU)	Datasheet
Constant charge current	0.15 CA to 2.40 V (20 °C)	Datasheet
Cycle life at 10 %–100 % DoD	up to 7000 cycles	Datasheet
Long-time discharge C24 to C240 @ 1.85 V	226 / 248 / 260 / 270 / 274 / 280 Ah	Datasheet
Solar/wind disconnect thresholds	OV disconnect 2.47 ± 0.01 V/cell; LV alarm 1.95 ± 0.005 V/cell; LV disconnect 1.90 ± 0.005 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind charge setpoints	Regulation/equalise 2.40 ± 0.01 V/cell; float setting 2.25 ± 0.005 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind reconnection	Array reconnection 2.23 ± 0.005 V/cell; load reconnect 2.09 ± 0.01 V/cell @ 25 °C	Datasheet (solar/wind page 2)
Solar/wind temperature compensation	−4 mV/cell/°C	Datasheet (solar/wind page 2)

§2 — The Pain

§3 — The Choice

Three models cover most flooded tubular OPzS2 demand: the OPzS2-150, the OPzS2-200 and the OPzS2-250. All three share the 206 mm width and 409 mm total height.

	OPzS2-150	OPzS2-200	OPzS2-250
Capacity @ C10 to 1.80 V @ 20 °C	150 Ah	200 Ah	250 Ah
Dimensions (printed)	L103 × W206 × H409 mm	L103 × W206 × H409 mm	L124 × W206 × H409 mm
Weight w/o electrolyte	10.5 kg (23.2 lbs)	13.0 kg (28.7 lbs)	15.5 kg (34.2 lbs)
Weight with electrolyte	14.5 kg (32.0 lbs)	17.5 kg (38.6 lbs)	20.5 kg (45.2 lbs)
Acid weight	4.0 kg	4.5 kg	5.0 kg
Max charge current	30 A	40 A	50 A
Internal resistance	approx. 1.2 mΩ @ 20 °C	approx. 0.95 mΩ @ 20 °C	approx. 0.88 mΩ @ 20 °C
Short circuit current	2400 A	2600 A	2750 A
Float / equalise	2.23 V / 2.35 V @ 25 °C	same	same
Floating life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C

The arithmetic below is what a buyer uses when answering a request for quotations.

Calculation	Working	Source
48-cell string nominal energy	48 × 2 V × 200 Ah = 19.2 kWh	Arithmetic
48-cell string mass with electrolyte	48 × 17.5 kg = 840 kg	Arithmetic
48-cell string mass without electrolyte	48 × 13.0 kg = 624 kg	Arithmetic
48-cell string internal resistance	48 × 0.95 mΩ = 45.6 mΩ	Arithmetic
48-cell string max charge current	48 × 40 A = 1,920 A	Arithmetic
Electrolyte per 48-cell string	48 × 4.5 kg = 216 kg	Arithmetic
C10 current for the 200 Ah cell	200 Ah ÷ 10 h = 20 A	Arithmetic
Energy density, 150 Ah cell	300 Wh ÷ 14.5 kg = 20.7 Wh/kg	Arithmetic
Energy density, 200 Ah cell	400 Wh ÷ 17.5 kg = 22.9 Wh/kg	Arithmetic
Energy density, 250 Ah cell	500 Wh ÷ 20.5 kg = 24.4 Wh/kg	Arithmetic

§4 — The Framework

Seven numbers decide whether a Chinese supplier can serve a flooded tubular OPzS2 project properly.

Capacity at the rate that matters. Ask for the discharge curve, not a headline figure: 200 Ah at C10 to 1.80 V at 20 °C, 226 Ah at C24, 280 Ah at C240 to 1.85 V. If the design assumes a 10-hour discharge, use C10. A 100-hour discharge yields more than the headline, so the cabinet can be smaller than the catalogue suggests.
Voltage window and controller match. Float at 2.23 V per cell at 25 °C, equalise at 2.35 V, compensation −3 mV per °C per cell. Confirm the charger holds float across a full string and that its tolerance band is centred on the datasheet value, not at its edge.
Thermal environment. Discharge −25 to 65 °C, charge −20 to 65 °C, storage −15 to 40 °C. At 40 °C ambient the compensation must be active: across 24 cells an uncompensated float runs 45 mV per cell high and accelerates water loss.
Internal resistance and voltage drop. At 0.95 mΩ per cell a 48-cell string presents 45.6 mΩ, which sets cable size for a given run length. Terminal centre spacing of 108 mm, M8 terminals with 7 mm insertion depth and 10–12 N·m torque decide whether standard busbars and a standard wrench work on site.
Mechanical footprint. Two envelopes, not one: 103 mm and 124 mm long, both 206 mm wide and 409 mm high. Confirm rack, plinth, door clearance and lifting access against both.
Float life at the real ambient. The published 20+ years is a 20 °C figure. The gap between 20 °C and the ambient inside a cabinet in Chennai, Durban or Santiago is where published lifetime and field lifetime part company.
Documentation depth. Standards reference, certification scope, production base, capacity test method and warranty terms should arrive with the quotation, not six weeks later.

§5 — The Trust

Supplier verification here is less about corporate due diligence and more about documentary discipline. Six checks separate a credible flooded tubular OPzS2 supplier from a marketing intermediary.

§6 — FAQ

Expert Summary

Contact CHISEN — 24-Hour Response

CHISEN replies to technical and commercial enquiries within 24 hours, and delivers a sizing sheet and quotation against your actual duty data.

Send us the information below and we will return a written recommendation with the published data for the cell and the pack configuration that matches it:

DC bus voltage and string configuration, or the duty you want to size
Backup autonomy target and the load profile in kW
Ambient temperature range at the deployment site
Whether the strings are maintained in-house or by a local service partner
Annual volume and destination port for the first shipment

Email: sales@chisen.cn WhatsApp: +86 131 6622 6999 Call: +86 131 6622 6999

Technical enquiries, project drawings and tender documents: leadacidbattery.cn

Related CHISEN Buyer Guides

October 24, 2026

OPzV2-1200 2V1200Ah Tubular Gel Battery for Data Center and UPS Backup

Answer First

The OPzV2-1200 2V1200Ah is a sealed tubular-plate gel stationary cell rated 1200 Ah at C10 to 1.80 V/cell at 20 °C, published with a designed floating life of 20+ years at 20 °C, an internal resistance of approx. 0.46 mΩ fully charged at 25 °C and a maximum charge current of 240 A — the cell that a 48 V data center or telecom UPS string is usually built from when the rack depth is fixed and the battery room has to be filled from 48 V cabinets rather than from 12 V racks.

OPzV2-1200 refers to a gel-electrolyte stationary cell in the OPzV series: the trailing 2 denotes the 2 V nominal cell voltage, 1200 is the nominal capacity in ampere-hours, and the OPzV prefix identifies the tubular-plate construction with a gel electrolyte rather than a flooded one. Every rating a technical evaluator needs is published against a stated condition — capacity against C10 to 1.80 V/cell at 20 °C, internal resistance fully charged at 25 °C, float life referenced to 20 °C — which is what allows a string to be engineered before any commercial discussion begins.

Demand-side commentary from the IEA, BloombergNEF and Benchmark Minerals is useful for framing the direction of data centre and network standby power spending, and it also deserves a caution: none of those institutions publishes a cell-level specification, so none of them can confirm a capacity, a float life or a terminal torque. Procurement is settled at the datasheet level, and this datasheet is unusually complete. On the published data the OPzV2-1200 resolves the three questions that dominate a large backup installation: whether the cell can carry a 24-cell string without voltage derate, whether the recharge programme can restore a full string inside the maintenance window, and whether the cell can be installed in the existing cabinet geometry without redesigning the rack.

Key Takeaways

The rating is condition-bound. 1200 Ah is quoted at C10 to 1.80 V/cell at 20 °C, which is a 120 A discharge for ten hours. A capacity figure quoted without its rate, its end voltage and its temperature cannot be compared against anything else in the market, because every supplier chooses a different set of conditions.

Float life is a 20 °C number. The datasheet states 20+ years of floating life at 20 °C, and the same 20 °C reference is used for the self-discharge rate of approx. 2 % per month. A supplier quoting a lifetime for a warmer ambient is making a different claim, and that difference belongs in the commercial comparison rather than in a footnote.

A 24-cell string is fully calculable. 24 × 2 V × 1200 Ah = 57.6 kWh nominal, with 11.04 mΩ of string internal resistance, a 5,760 A string charge ceiling, and 2,016 kg of cells on the floor. Every one of those figures follows directly from the cell data and can be checked before an order is placed.

Three sizes, three footprints. The OPzV2-1000 and OPzV2-1200 print the same 681 mm total height but differ in length at 233 mm against 275 mm, and the OPzV2-1500 rises to 831 mm. A mixed installation must be planned for three envelopes, not one.

Verification is inexpensive when the data is published. Setpoints, the temperature compensation coefficient, drawing dimensions, terminal torque, internal resistance, the short circuit current and the full standards list are all stated, so a technical approval can be completed against the datasheet and the supply question settled afterwards.

§1 — OPzV2-1200 2V1200Ah Quick Specifications Table

Parameter	Published value	Source
Model	OPzV2-1200, tubular-plate gel stationary cell, 2 V 1200 Ah	Model page
Nominal voltage	2 V	Datasheet
Nominal capacity	1200 Ah at C10 to 1.80 V/cell at 20 °C	Datasheet
C10 discharge current	120 A (1200 Ah ÷ 10 h)	Arithmetic
Designed floating life	20+ years @ 20 °C	Datasheet
Printed dimensions (L × W × H)	275 × 210 × 681 mm	Datasheet
Drawing container height	646 mm	Datasheet
Drawing total height	681 mm	Datasheet
Terminal centre spacing	108 mm across width, 140 mm along length	Datasheet
Terminal	20 mm OD, M8 thread, 7 mm depth, female copper insert M8	Datasheet
Terminal tightening torque	10–12 N·m	Datasheet
Approximate weight	84 kg (185 lbs)	Datasheet
Internal resistance	Approx. 0.46 mΩ, fully charged at 25 °C	Datasheet
Maximum charge current	240 A	Datasheet
Charge characteristic	Constant charge at 0.15 CA to 2.40 V at 20 °C	Datasheet
Maximum discharge current (5S)	2500 A	Datasheet
Short circuit current	6400 A	Datasheet
Self discharge	Approx. 2 % per month at 20 °C	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalise charge voltage	2.35 V @ 25 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Ambient, discharge	−40 °C to +65 °C	Datasheet
Ambient, charge	−30 °C to +65 °C	Datasheet
Ambient, storage	−25 °C to +45 °C	Datasheet
Container material	ABS, UL94-V0 optional	Datasheet
Applicable standards	IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet

The final voltage recommended for a given discharge rate is published as well: at currents below 0.05 C the cell supports at least 1.90 V per cell, between 0.05 C and 0.08 C at least 1.85 V, between 0.08 C and 0.2 C at least 1.80 V, between 0.2 C and 0.6 C at least 1.75 V, between 0.6 C and 1.0 C at least 1.70 V, and from 1 C to 2 C at least 1.60 V. Those figures, not a nominal 2 V, are what a battery management system should be configured against.

§2 — The Pain

A large backup installation fails on paperwork long before it fails on chemistry. The three recurring problems are specification ambiguity, string-level arithmetic that nobody owns, and cabinet geometry that was settled before the cell was chosen.

Specification ambiguity is the first. A 1200 Ah cell arriving from a supplier with no stated rate, no stated end voltage and no stated temperature is not a 1200 Ah cell, it is a marketing label. The same applies to float life quoted at a different ambient than the one the site will see, and to internal resistance quoted without a temperature. Without the conditions, a comparison against a competing quotation is a comparison of adjectives. The buyer who asks for the conditions discovers immediately whether the competing offer was engineered or estimated.

String-level arithmetic is the second. A 24-cell string is not 24 times a cell in every respect that matters. The nominal energy is easy, but the string internal resistance of 11.04 mΩ, the 5,760 A charge ceiling and the 2,016 kg of cells are the numbers that determine cable cross-section, busbar rating, floor loading, cabinet count and the lifting plan on the day the container is unloaded. When those are calculated after the order is placed, they are usually calculated by a subcontractor who does not carry the responsibility for the result.

Cabinet geometry is the third. The OPzV2-1200 prints 275 × 210 × 681 mm with a 646 mm container height, and the terminal centres sit 108 mm apart across the width and 140 mm along the length. Those are not interchangeable with a cell of the same nominal voltage and capacity from another supplier. Installing a 1200 Ah cell into a cabinet drawn for a different footprint means either a mechanical rework on site or a string that cannot be assembled at all, and both are discovered with the container already on the dock.

§3 — The Choice

The OPzV2-1200 sits between two other published sizes, and the comparison is a matter of footprint against charge acceptance rather than of any single headline number.

	OPzV2-1000	OPzV2-1200	OPzV2-1500
Capacity @ C10 to 1.80 V @ 20 °C	1000 Ah	1200 Ah	1500 Ah
Printed dimensions	L233 × W210 × H681 mm	L275 × W210 × H681 mm	L275 × W210 × H831 mm
Approximate weight	73.2 kg (161.4 lbs)	84 kg (185 lbs)	102 kg (225 lbs)
Max charge current	200 A	240 A	300 A
Internal resistance	approx. 0.5 mΩ @ 25 °C	approx. 0.46 mΩ @ 25 °C	approx. 0.45 mΩ @ 25 °C
Short circuit current	5400 A	6400 A	6200 A
Float / equalise	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C
Designed floating life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C
Ambient range	−40~65 / −30~65 / −25~45 °C	−40~65 / −30~65 / −25~45 °C	−40~65 / −30~65 / −25~45 °C
String arithmetic, 24 cells in series	OPzV2-1000	OPzV2-1200	OPzV2-1500
—	—	—	—
Nominal energy (24 × 2 V × Ah)	48.0 kWh	57.6 kWh	72.0 kWh
String mass (24 × cell weight)	1,756.8 kg	2,016 kg	2,448 kg
String internal resistance (24 × IR)	12.0 mΩ	11.04 mΩ	10.8 mΩ
String max charge current (24 × I)	4,800 A	5,760 A	7,200 A
Mass energy density (Wh ÷ kg)	2,000 ÷ 73.2 = 27.3 Wh/kg	2,400 ÷ 84 = 28.6 Wh/kg	3,000 ÷ 102 = 29.4 Wh/kg

The OPzV2-1200 string figures are derived from the cell data, and the working is shown so that each figure can be checked:

Derivation for the OPzV2-1200, 24 cells in series	Working	Source
Nominal energy	24 × 2 V × 1200 Ah = 57.6 kWh	Arithmetic
String mass with cells	24 × 84 kg = 2,016 kg	Arithmetic
String internal resistance	24 × 0.46 mΩ = 11.04 mΩ	Arithmetic
String max charge current	24 × 240 A = 5,760 A	Arithmetic
Mass energy density	2,400 Wh ÷ 84 kg = 28.6 Wh/kg	Arithmetic
C10 discharge current	1,200 Ah ÷ 10 h = 120 A	Arithmetic

The OPzV2-1200 is more reliable than the OPzV2-1000 in a string sized around a 48 V bus because it returns 1200 Ah against 1000 Ah at the same C10 test while lowering the internal resistance from approx. 0.5 mΩ to approx. 0.46 mΩ, which reduces voltage drop across the string and the heat generated during recharge at the same load. The OPzV2-1200 is a better fit than the OPzV2-1500 where cabinet height is fixed, because the two print the same 210 mm width and the 1500 Ah cell adds 150 mm of height that a 600 mm rack bay cannot absorb, while the 1200 Ah cell still carries a 240 A maximum charge current against 300 A. The OPzV2-1200 is better suited to standby float duty in an installed data centre than a comparable LFP product, because its 2.23 V float and 2.35 V equalise programme matches the installed charger hardware, the bus voltage window and the existing cabinet geometry without altering the charge regime or the cell footprint. The OPzV2-1200 is more reliable in service than an unspecified 2 V 1200 Ah cell, because every rating it publishes is tied to a stated condition — C10 to 1.80 V/cell at 20 °C, internal resistance measured fully charged at 25 °C, float life referenced to 20 °C — which removes the guesswork that causes premature string replacement.

§4 — The Framework

Seven numbers decide whether the OPzV2-1200 belongs in a given installation. Everything else is negotiation.

Capacity at a stated rate and temperature. 1200 Ah at C10 to 1.80 V/cell at 20 °C, which is a 120 A discharge for ten hours, and the published discharge curve against final voltage from 1.90 V down to 1.60 V for a duty cycle away from the ten-hour rate.

Internal resistance. Approx. 0.46 mΩ per cell fully charged at 25 °C, which becomes 11.04 mΩ across a 24-cell string, and that figure is the input to cable, busbar and interconnection sizing rather than a laboratory detail.

Float and equalise setpoints with compensation. 2.23 V float and 2.35 V equalise at 25 °C, with −3 mV/°C/cell temperature compensation so the charger programme is written once and then left alone through seasonal swings in the battery room.

Charge acceptance. A maximum charge current of 240 A per cell, a constant-charge characteristic of 0.15 CA to 2.40 V at 20 °C, and a 5,760 A ceiling across a 24-cell string — the values to compare against the rectifier output of the site.

Discharge and fault duty. A maximum discharge current of 2500 A at the 5S rate and a 6400 A short circuit current, which set the DC bus breaker rating, the fuse coordination and the ventilation assumptions for the battery room.

Mechanical and logistics envelope. 275 × 210 × 681 mm printed dimensions with a 646 mm container height and 108 × 140 mm terminal spacing, 84 kg per cell, and the site totals of 2,016 kg of cells for a 24-cell string — plus the lifting, palletising and aisle-width consequences of that mass.

Environmental window and self-discharge. Discharge from −40 °C to +65 °C, charge from −30 °C to +65 °C, storage from −25 °C to +45 °C, and self discharge of approx. 2 % per month at 20 °C, which together determine standby behaviour, seasonal outage handling and the storage period for a site that is not permanently attended.

§5 — The Trust

A datasheet-rich market rewards buyers who verify, and the verification traps are well known to anyone who has bought stationary cells across several suppliers.

Capacity without a condition. Ask for the rate, the end voltage and the temperature. If the reply is only “1200 Ah”, the cell has not been specified.
Lifetime without an ambient. Require the stated temperature. 20+ years at 20 °C is the published claim; a figure quoted for another ambient is a different claim and a different risk.
Dimensions without the drawing. Printed dimensions, a 646 mm container height and a 681 mm total height are three different measurements, and the 210 × 275 mm top view with 108 × 140 mm terminal spacing is what actually fixes the rack.
Internal resistance quoted without conditions. Ask whether it is measured fully charged and at what temperature, because approx. 0.46 mΩ at 25 °C is a specific number and not a generic one.
Setpoints quoted as a range. A float programme should arrive as a value, a compensation coefficient and a measurement point — 2.23 V at 25 °C with −3 mV/°C/cell — not as a band.
Standards listed without documents. Names printed on a brochure are not certificates. Request the accredited certificate numbers, the issuing bodies and the expiry dates, plus the UL file reference for the Recognized Component listing.
Certification scope overstated. A UL Recognized Component mark applies to the component, not to a finished UPS or data centre installation; final listing and field evaluation remain the integrator’s responsibility under the local code.
Freight and port assumptions left open. Confirm the port of loading (Shanghai, Ningbo or Shenzhen) and the nominated port of discharge (Rotterdam, Antwerp, Jebel Ali, Singapore, Durban, Santos or Long Beach), who carries the freight cost, and whether the shipment is a full container of cells or a break-bulk consignment, because a 24-cell string of 84 kg cells and a two-tonne string has a different handling profile from the same product in 12 V format.

On documentation, the OPzV2-1200 is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989. The practical step is to ask for the documents behind these marks — accredited certificate numbers and validity dates, the UL file reference, and the IEC 60896-21 test report — because that is the only part of a quality claim a buyer can audit. For a European data centre project the DIN 40472 and IEC 60896-21 conformity is what satisfies the local installer; for a North American project the UL file reference is what the AHJ will ask for; for a Chinese or South-East Asian network the YD/T 1360 route is the one that matches local procurement practice. Production base in Hangzhou with loading typically through the ports of Shanghai and Ningbo means a buyer can also request the factory address, the loading port and the container marking in writing before the vessel is booked, and can compare those documents across more than one source rather than relying on a single reply.

§6 — FAQ

Q1. What does the model code OPzV2-1200 mean, and what type of cell is it? It identifies a sealed tubular-plate gel stationary lead-acid cell. The OPzV series follows the tubular-plate construction defined in DIN 40472, the trailing 2 is the 2 V nominal cell voltage, and 1200 is the nominal capacity in ampere-hours. The electrolyte is gelled in a thixotropic silica suspension rather than held as free liquid, which is what makes the cell maintenance-free, spill-proof and suitable for a battery room without ventilation plenum design.

Q2. How is the 1200 Ah rated, and at what rate should a string be sized? The 1200 Ah figure is published at C10 to 1.80 V/cell at 20 °C, which is a 120 A discharge for ten hours. Sizing must be done against the real discharge profile using the closest published rate and against the end voltage the installed rectifier can actually support at the end of a deep discharge, and the datasheet gives the final voltage recommended for each discharge band from below 0.05 C through to 2 C.

Q3. Does the 20+ year design life apply at my site’s ambient temperature? The published figure is 20+ years of floating life at 20 °C, and the same temperature is stated for the self-discharge rate of approx. 2 % per month. Float life falls as ambient temperature rises, so a battery room that regularly exceeds 20 °C needs a derating calculation. Ask the supplier to state the assumed ambient, the float voltage programme and the expected number of discharges, and to confirm the basis on which the 20+ year claim is made.

Q4. What float and equalise voltages should the charger be programmed to? The datasheet specifies 2.23 V float and 2.35 V equalise at 25 °C, with temperature compensation of −3 mV/°C/cell. That compensation figure is what keeps the cell on its float curve through seasonal swings, and it is the parameter most often left out of a quotation. A gel cell with no compensation fitted will overcharge in summer and undercharge in winter, which shows up as water loss in the cell and a shortened service life.

Q5. Can OPzV2-1000, OPzV2-1200 and OPzV2-1500 cells be mixed in one cabinet or string? The three print different envelopes — L233 × W210 × H681 mm, L275 × W210 × H681 mm and L275 × W210 × H831 mm — so a mixed installation must be planned for three footprints. Cells of different capacities in one series string will also not share current equally. Mixing inside a series string is generally avoided; where it is unavoidable, the cells are managed as separate parallel strings by capacity.

Q6. What are the physical dimensions, weight and terminal torque? Printed dimensions are 275 × 210 × 681 mm, with a 646 mm container height and a 681 mm total height on the drawing, and terminal centres 108 mm across the width and 140 mm along the length. Weight is approximately 84 kg per cell. Terminals are 20 mm OD with an M8 thread, 7 mm depth and a female copper insert M8, tightened to 10–12 N·m.

Q7. How does a gel cell behave differently from a flooded cell in a standby string? A gel cell does not need periodic water topping, does not need a ventilated room for hydrogen escape and does not spill, which removes both the maintenance visit and the floor-loading monitoring. In exchange, the gel cell carries a higher internal resistance than a comparable flooded cell at the same capacity and is more sensitive to overcharging, so the charger programme and the compensation coefficient matter more, not less.

Q8. Which standards and certifications apply, and what should I request as evidence? The cell is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989. Request the accredited certificate numbers and expiry dates, the UL file reference and the IEC 60896-21 test report rather than a summary of them, and ask which of those documents apply to the specific cells in the shipment rather than to the manufacturer as a whole.

Expert Summary

The OPzV2-1200 is a 2 V, 1200 Ah sealed tubular-plate gel stationary cell whose decisive published figures are unusually complete: 1200 Ah at C10 to 1.80 V/cell at 20 °C, internal resistance of approx. 0.46 mΩ fully charged at 25 °C, a designed floating life of 20+ years at 20 °C, a 2.23 V float and 2.35 V equalise at 25 °C with −3 mV/°C/cell compensation, 240 A maximum charge current, 2500 A maximum discharge at the 5S rate, a 6400 A short circuit current, self discharge of approx. 2 % per month at 20 °C, and an ambient window of −40 °C to +65 °C on discharge. Mechanically it occupies 275 × 210 × 681 mm at approximately 84 kg, with 20 mm OD M8 female insert terminals tightened to 10–12 N·m. In a 24-cell 48 V configuration those figures become 57.6 kWh nominal, 11.04 mΩ of string resistance, a 5,760 A charge ceiling and 2,016 kg of cells on the floor, at 28.6 Wh/kg of mass energy density against 27.3 Wh/kg for the 1000 Ah cell and 29.4 Wh/kg for the 1500 Ah cell. It is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989. Specification decisions should be made against those published conditions, and the supplier should be required to answer in the same form.

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Related CHISEN Buyer Guides

October 24, 2026

OPzS2-200 2V200Ah Flooded Tubular Battery for Telecom DC Plants

Answer First

The OPzS2-200 2V200Ah is a flooded tubular-plate stationary lead-acid cell rated 200 Ah at C10 to 1.80 V/cell at 20 °C, designed for 20+ years of float service at 20 °C, and it is the standard building block for 24-cell 48 V telecom DC plants and other stationary DC installations.

In model-code terms, OPzS2-200 refers to a flooded tubular-plate cell in the OPz series: the trailing 2 denotes the 2 V nominal cell voltage and 200 the 200 Ah nominal capacity, with the plate construction defined by the DIN 40736 tubular-plate standard. Everything a technical evaluator needs — condition-bound capacity, internal resistance, float and equalize setpoints, charge acceptance, discharge limits, terminal geometry, electrolyte volume, weight, standards and certification scope — is published on the model’s own datasheet, so the cell can be engineered into a DC plant before any commercial discussion begins.

Demand-side commentary from the IEA, BloombergNEF and Benchmark Minerals is useful for framing the direction of stationary backup and telecom DC power spending, and it also deserves a caution: none of those institutions publishes a cell-level specification, so none of them can confirm a capacity, a float life or a terminal torque. Procurement is settled at the datasheet level. On the published data, the OPzS2-200 resolves the three questions that dominate telecom DC plant tenders: whether the cell can carry a 48 V string without derating, whether its recharge acceptance can restore a full string inside the maintenance window, and whether the cell can be installed and serviced on site without redesigning the rack or the cabinet.

Key Takeaways

The rating is condition-bound. 200 Ah is quoted at C10 to 1.80 V/cell at 20 °C, which is a 20 A discharge for ten hours. A capacity figure without its rate, end voltage and temperature cannot be compared with anything else on the market.
Float life is a 20 °C number. The datasheet states 20+ years of floating life at 20 °C. A supplier quoting a lifetime for a warmer ambient is making a different claim, and that difference belongs in the commercial comparison rather than in the footnote.
A 24-cell string is fully calculable. 24 × 2 V × 200 Ah = 9,600 Wh = 9.6 kWh nominal, with 22.8 mΩ of string internal resistance, a 960 A string charge ceiling, 420 kg of filled cells and 108 kg of electrolyte at fill. Every one of those figures follows directly from the cell data and can be verified before an order is placed.
Three sizes, two footprints. The OPzS2-150 and OPzS2-200 print the same 103 × 206 × 409 mm envelope, the OPzS2-250 is 21 mm longer at 124 × 206 × 409 mm, and dry weight steps from 10.5 kg to 13.0 kg to 15.5 kg. A mixed installation must be planned for two footprints and three weights.
Verification is inexpensive when the data is published. Standards, certifications, setpoints, drawing dimensions and terminal torque are all stated, so a technical approval can be completed against the datasheet and the supply question settled afterwards.

§1 — OPzS2-200 2V200Ah Quick Specifications Table

Parameter	Published value	Source
Model	OPzS2-200, flooded tubular stationary cell, 2 V 200 Ah	Model page
Nominal voltage	2 V	Datasheet
Nominal capacity	200 Ah at C10 to 1.80 V/cell at 20 °C	Datasheet
C10 discharge current	20 A (200 Ah ÷ 10 h)	Arithmetic
Designed floating life	20+ years @ 20 °C	Datasheet
Printed dimensions (L × W × H)	103 × 206 × 409 mm	Datasheet
Drawing container height	354 mm	Datasheet
Drawing total height	409 mm	Datasheet
Drawing top view	206 × 103 mm	Datasheet
Terminal centre spacing	108 mm	Datasheet
Terminal	20 mm OD, M8 thread, 7 mm depth, female copper insert M8	Datasheet
Terminal tightening torque	10–12 N·m	Datasheet
Weight without electrolyte	13.0 kg (28.7 lbs)	Datasheet
Weight with electrolyte	17.5 kg (38.6 lbs)	Datasheet
Electrolyte	Diluted sulphuric acid, 1.240 g/cm³ at 20 °C	Datasheet
Acid weight per cell	4.5 kg	Datasheet
Internal resistance	Approx. 0.95 mΩ, fully charged at 20 °C	Datasheet
Maximum charge current	40 A	Datasheet
Charge characteristic	Constant charge at 0.15 CA to 2.40 V at 20 °C	Datasheet
Maximum discharge current (5S)	1000 A	Datasheet
Short circuit current	2600 A	Datasheet
Self discharge	Approx. 4 % per month at 20 °C	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalize charge voltage	2.35 V @ 25 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Ambient, discharge	−25 °C to +65 °C	Datasheet
Ambient, charge	−20 °C to +65 °C	Datasheet
Ambient, storage	−15 °C to +40 °C	Datasheet
Container material	SAN	Datasheet
Solar and wind setpoints	Over-voltage disconnect 2.47 ± 0.01 V/cell @ 25 °C; regulation / equalize 2.40 ± 0.01 V/cell @ 25 °C; array reconnection 2.23 ± 0.005 V/cell @ 25 °C; float voltage setting 2.25 ± 0.005 V/cell @ 25 °C; low-voltage alarm 1.95 ± 0.005 V/cell @ 25 °C; low-voltage disconnect 1.90 ± 0.005 V/cell @ 25 °C; load reconnect 2.09 ± 0.01 V/cell @ 25 °C; temperature compensate coefficient −4 mV/cell/°C	Datasheet (solar/wind page 2)
Long-time discharge capacity, final voltage 1.85 V	C24 226 Ah; C48 248 Ah; C72 260 Ah; C100 270 Ah; C120 274 Ah; C240 280 Ah	Datasheet (solar/wind page 2)
24-cell string energy (48 V DC)	24 × 2 V × 200 Ah = 9,600 Wh = 9.6 kWh nominal	Arithmetic
24-cell string internal resistance	24 × 0.95 mΩ = 22.8 mΩ	Arithmetic
24-cell string maximum charge current	24 × 40 A = 960 A	Arithmetic
24-cell string mass	24 × 17.5 kg = 420 kg with electrolyte; 24 × 13.0 kg = 312 kg without	Arithmetic
Electrolyte on site per 24-cell string	24 × 4.5 kg = 108 kg of acid at fill	Arithmetic
Energy density by mass	400 Wh ÷ 17.5 kg = 22.9 Wh/kg (OPzS2-150: 300 Wh ÷ 14.5 kg = 20.7 Wh/kg; OPzS2-250: 500 Wh ÷ 20.5 kg = 24.4 Wh/kg)	Arithmetic
Applicable standards	IEC 60896-11, DIN 40736, IEC 61427, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet
Certifications	ISO 9001 (EIC), ISO 14001 (UKAS/UCC), OHSAS 18001:2007 / GB/T 28001 (UCC), CE, UL Recognized Component (cURus / RU)	Datasheet

§2 — The Pain

Telecom DC plant tenders fail quietly. A quotation arrives with a capacity number, a reference to a long working life and a delivery date, and the string is then assembled from a cell whose real behaviour was never stated. Nothing looks wrong until the first load test: the string sags earlier than the model file assumed, the charger cannot return the cells to float inside the maintenance window, and the replacement cycle arrives years earlier than the budget modelled.

Three failure patterns account for most of that.

Capacity quoted without a condition. A cell rated “200 Ah” on a datasheet that omits the discharge rate, the end voltage and the temperature is a cell whose usable energy is unknown. At 20 °C the OPzS2-200 delivers 200 Ah at C10 to 1.80 V/cell; the same cell gives 226 Ah at C24 and 270 Ah at C100 when the final voltage is relaxed to 1.85 V. Those are not contradictions but different duty cycles, and only one of them matches a given application. Only a published condition lets an engineer select correctly.

Lifetime quoted at the wrong temperature. Float life is a function of float voltage, depth of discharge, ambient temperature and the number of discharges. The OPzS2-200 states 20+ years at 20 °C. A site running a battery room at 30 °C or above, or a cabinet exposed to direct sun, cannot claim that figure without derating, and a supplier who quotes two decades without naming the ambient temperature has removed the only number that mattered.

Physical data missing from the tender set. Weight, footprint, terminal spacing, tightening torque and electrolyte volume decide whether the string fits the rack, whether the floor carries it, whether a technician can get a wrench into the aisle, and how much acid has to be handled on site. A 24-cell string of OPzS2-200 cells brings 420 kg of filled cells and 108 kg of electrolyte into the battery room. Discovering that after the cabinet is fabricated is an expensive way to learn it.

Every one of these problems has the same remedy: specify against published, condition-bound data, and require the supplier to answer in the same form.

§3 — The Choice

Parameter	OPzS2-150	OPzS2-200	OPzS2-250
Capacity @ C10 to 1.80 V @ 20 °C	150 Ah	200 Ah	250 Ah
Printed dimensions (L × W × H)	103 × 206 × 409 mm	103 × 206 × 409 mm	124 × 206 × 409 mm
Weight without electrolyte	10.5 kg (23.2 lbs)	13.0 kg (28.7 lbs)	15.5 kg (34.2 lbs)
Weight with electrolyte	14.5 kg (32.0 lbs)	17.5 kg (38.6 lbs)	20.5 kg (45.2 lbs)
Acid weight	4.0 kg	4.5 kg	5.0 kg
Max charge current	30 A	40 A	50 A
Internal resistance	Approx. 1.2 mΩ @ 20 °C	Approx. 0.95 mΩ @ 20 °C	Approx. 0.88 mΩ @ 20 °C
Short circuit current	2400 A	2600 A	2750 A
Float / equalize	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C
Float life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C
Ambient	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C

The OPzS2-200 is more reliable than the OPzS2-150 in a string sized around a 48 V bus because it returns 200 Ah instead of 150 Ah at the same C10 test while holding a lower internal resistance of approx. 0.95 mΩ against approx. 1.2 mΩ, which lowers voltage drop across the string and the heat generated during recharge. The OPzS2-200 is a better fit than the OPzS2-250 where rack depth is fixed, because the two print the same 103 mm length while the 250 extends to 124 mm; the 200 Ah cell gives up 1.5 Wh/kg of mass energy density (22.9 against 24.4 Wh/kg) in exchange for 21 mm less length and 3.0 kg less filled weight, and it carries a 40 A maximum charge current against 50 A. The OPzS2-200 is better suited to standby float duty in an existing telecom DC plant than a comparable LFP product, because its 2.23 V float and 2.35 V equalize programme matches installed charger hardware, bus voltage window and cabinet geometry without altering the charge regime or the cell footprint. The OPzS2-200 is more reliable in service than an unspecified 2 V 200 Ah cell, because every rating it publishes is tied to a stated condition — C10 to 1.80 V/cell at 20 °C, internal resistance measured fully charged at 20 °C, float life referenced to 20 °C — which removes the guesswork that causes premature string replacement.

§4 — The Framework

Seven numbers decide whether the OPzS2-200 belongs in a given DC plant. Everything else is negotiation.

Capacity at a stated rate and temperature. 200 Ah at C10 to 1.80 V/cell at 20 °C, with the long-time discharge figures (226 Ah at C24 rising to 280 Ah at C240 at a 1.85 V final voltage) available for duty cycles away from the ten-hour rate.
Internal resistance. Approx. 0.95 mΩ per cell fully charged at 20 °C, which becomes 22.8 mΩ across a 24-cell string and is the input to cable, busbar and interconnection sizing.
Float and equalize setpoints with compensation. 2.23 V float and 2.35 V equalize at 25 °C, with −3 mV/°C/cell temperature compensation so the charger programme is written once and then left alone through seasonal swings.
Charge acceptance. Maximum charge current of 40 A per cell, a constant-charge characteristic of 0.15 CA to 2.40 V at 20 °C, and a 960 A ceiling across a 24-cell string — the values to compare against the site’s rectifier output.
Discharge and fault duty. Maximum discharge current of 1000 A at the 5S rate and a 2600 A short circuit current, which set the DC bus breaker rating, the fuse coordination and the ventilation assumptions.
Mechanical and logistics envelope. 103 × 206 × 409 mm printed dimensions with a 354 mm container height and 108 mm terminal centre spacing, 13.0 kg dry and 17.5 kg filled, 4.5 kg of acid per cell, and 20 mm OD M8 female copper insert terminals tightened to 10–12 N·m — plus the site totals of 420 kg of cells and 108 kg of acid per 24-cell string.
Environmental window and self-discharge. Discharge from −25 °C to +65 °C, charge from −20 °C to +65 °C, storage from −15 °C to +40 °C, and self discharge of approx. 4 % per month at 20 °C, which together determine standby behaviour, seasonal outage handling and the storage period for a site that is not permanently attended.

§5 — The Trust

A datasheet-rich market rewards buyers who verify. Nine traps are worth checking before a purchase order is raised.

Capacity without a condition. Ask for the rate, the end voltage and the temperature. If the reply is only “200 Ah”, the cell has not been specified.
Lifetime without an ambient. Require the stated temperature. 20+ years at 20 °C is the published claim; a figure quoted for another ambient is a different claim and a different risk.
Dimensions without the drawing. Printed dimensions, a 354 mm container height and a 409 mm total height are different measurements, and the 206 × 103 mm top view with 108 mm terminal spacing is what actually fixes the rack.
Dry weight quoted as installed weight. 13.0 kg without electrolyte and 17.5 kg with electrolyte are separate figures, and the difference is the handling and floor-load question.
Internal resistance quoted without conditions. Ask whether it is measured fully charged and at what temperature, because approx. 0.95 mΩ at 20 °C is a specific number, not a generic one.
Setpoints quoted as a range. A float programme should arrive as a value, a compensation coefficient and a measurement point — 2.23 V at 25 °C with −3 mV/°C/cell — not as “2.2 to 2.3 V”.
Standards listed without documents. Names printed on a brochure are not certificates. Request the accredited certificate numbers, the issuing bodies and the expiry dates, plus the UL file reference for the Recognized Component listing.
Certification scope overstated. A UL Recognized Component mark applies to the component, not to a finished DC plant; final listing and field evaluation remain the integrator’s responsibility under the local code.
Freight and port assumptions left open. Confirm the port of loading (Shanghai, Ningbo or Shenzhen) and the nominated port of discharge (Rotterdam, Antwerp, Felixstowe, Jebel Ali, Singapore, Ho Chi Minh City, Santos or Long Beach), who carries the freight cost, and whether the shipment is dry-filled with acid supplied separately or pre-filled, since that changes handling, customs classification and the 108 kg of acid per 24-cell string.

On documentation, the OPzS2-200 is built to IEC 60896-11, DIN 40736, IEC 61427, the Eurobat long-life guide, BS 6290 part 4 and UL 1989. The manufacturing system behind it carries ISO 9001 accredited by EIC, ISO 14001 accredited by UKAS and UCC, OHSAS 18001:2007 and GB/T 28001 by UCC, CE marking, and a UL Recognized Component listing under cURus and RU. The practical step is to ask for the documents behind these marks — accredited certificate numbers and validity dates, the UL file reference, and the IEC 60896-11 test report — because that is the only part of a quality claim a buyer can audit. Production base in Hangzhou, with loading typically through the ports of Shanghai and Ningbo, means a buyer can also request the factory address, the loading port and the container marking in writing before the vessel is booked, and can compare those documents across more than one source rather than relying on a single reply.

§6 — FAQ

Q1. What does the model code OPzS2-200 mean, and what type of cell is it? It identifies a flooded tubular-plate stationary lead-acid cell. The OPz series follows the tubular-plate construction defined in DIN 40736, the trailing 2 is the 2 V nominal cell voltage, and 200 is the nominal capacity in Ah. It is an open, vented, serviceable cell with a SAN container, female M8 copper insert terminals and diluted sulphuric acid electrolyte at 1.240 g/cm³, intended for float standby duty rather than for cycling duty.

Q2. How is the 200 Ah rated, and at what rate should a DC plant be sized? The 200 Ah figure is published at C10 to 1.80 V/cell at 20 °C, which is a 20 A discharge for ten hours. Where the duty cycle is gentler and a 1.85 V final voltage is acceptable, the datasheet also gives 226 Ah at C24, 248 Ah at C48, 260 Ah at C72, 270 Ah at C100, 274 Ah at C120 and 280 Ah at C240. Sizing must be done against the real discharge profile using the closest rate, and against the end voltage the installed rectifier can actually support at the end of a deep discharge.

Q3. Does the 20+ year design life apply at my site’s ambient temperature? The published figure is 20+ years of floating life at 20 °C, and the same temperature is stated for the self-discharge rate of approx. 4 % per month. Float life falls as ambient temperature rises, so a battery room that regularly exceeds 20 °C, or a cabinet in direct sun, needs a derating calculation. Ask the supplier to state the assumed ambient, the float voltage programme and the expected number of discharges, and to confirm the basis on which the 20+ year claim is made.

Q4. What float and equalize voltages should the charger be programmed to? The datasheet specifies 2.23 V float and 2.35 V equalize at 25 °C, with temperature compensation of −3 mV/°C/cell. That compensation figure is what keeps the cell on its float curve through seasonal swings, and it is the parameter most often left out of a quotation. A separate set of setpoints appears on page 2 of the same datasheet for solar and wind applications, including a 2.47 ± 0.01 V/cell over-voltage disconnect and a 1.90 ± 0.005 V/cell low-voltage disconnect; those belong to that regime and should not be transferred to a mains-backed DC plant without checking which regime the plant runs.

Q5. Can OPzS2-150, OPzS2-200 and OPzS2-250 cells be mixed in one cabinet or string? The OPzS2-150 and OPzS2-200 print the same 103 × 206 × 409 mm envelope, while the OPzS2-250 is 21 mm longer at 124 × 206 × 409 mm, and dry weight differs across the three at 10.5, 13.0 and 15.5 kg. A mixed installation must therefore be planned for two footprints and three weights, and cells of different capacities in one series string will not share current equally. Mixing inside a series string is generally avoided; where it is unavoidable, the cells are managed as separate parallel strings by capacity.

Q6. What are the physical dimensions, weight and terminal torque? Printed dimensions are 103 × 206 × 409 mm, with a 354 mm container height and a 409 mm total height on the drawing, a 206 × 103 mm top view and 108 mm terminal centre spacing. Weight is 13.0 kg without electrolyte and 17.5 kg with electrolyte. Terminals are 20 mm OD with an M8 thread, 7 mm depth and a female copper insert M8, tightened to 10–12 N·m.

Q7. How much electrolyte is involved, and what does that mean for handling and shipping? Each cell takes 4.5 kg of acid in diluted sulphuric acid at 1.240 g/cm³, so a 24-cell string requires 108 kg of electrolyte at fill. Ask whether the consignment is dry-filled with acid supplied separately or pre-filled, since that changes the handling regime, the loading plan and the customs classification of the shipment.

Q8. Which standards and certifications apply, and what should I request as evidence? The cell is built to IEC 60896-11, DIN 40736, IEC 61427, the Eurobat long-life guide, BS 6290 part 4 and UL 1989, with ISO 9001, ISO 14001, OHSAS 18001:2007 / GB/T 28001, CE marking and a UL Recognized Component listing under cURus and RU behind it. Request the accredited certificate numbers and expiry dates, the UL file reference and the IEC 60896-11 test report rather than a summary of them.

Expert Summary

The OPzS2-200 is a 2 V, 200 Ah flooded tubular stationary cell whose decisive published figures are unusually complete: 200 Ah at C10 to 1.80 V/cell at 20 °C, internal resistance of approx. 0.95 mΩ fully charged at 20 °C, a designed floating life of 20+ years at 20 °C, a 2.23 V float and 2.35 V equalize at 25 °C with −3 mV/°C/cell compensation, 40 A maximum charge current, 1000 A maximum discharge at the 5S rate, 2600 A short circuit current, self discharge of approx. 4 % per month at 20 °C, and an ambient window of −25 °C to +65 °C on discharge. Mechanically it occupies 103 × 206 × 409 mm at 13.0 kg dry and 17.5 kg filled, with 4.5 kg of acid and 20 mm OD M8 female insert terminals tightened to 10–12 N·m. In a 24-cell 48 V configuration those figures become 9.6 kWh nominal, 22.8 mΩ of string resistance, a 960 A charge ceiling and 420 kg of cells plus 108 kg of electrolyte on site. Against the 150 Ah and 250 Ah versions it holds the middle position: the same footprint as the 150 Ah cell with a lower internal resistance, and 21 mm shorter and 3.0 kg lighter than the 250 Ah cell for 1.5 Wh/kg less mass energy density. The cell is built to IEC 60896-11, DIN 40736, IEC 61427, the Eurobat long-life guide, BS 6290 part 4 and UL 1989, with ISO 9001, ISO 14001, OHSAS 18001:2007 / GB/T 28001, CE and a UL Recognized Component listing behind it. Specification decisions should be made against those published conditions, and the supplier should be required to answer in the same form.

Contact CHISEN — 24-Hour Response

CHISEN replies to technical and commercial enquiries within 24 hours.

To receive a quotation and a matching datasheet, send:

Your application — telecom DC plant, UPS, substation or renewable hybrid — and the required string architecture or bus voltage
Required capacity per cell, the discharge profile and the target end voltage, or the total kWh and autonomy the design must deliver
Cell quantity, cabinet dimensions or the available footprint, and the ambient temperature range of the battery room
Destination port, delivery window and any tender or drawing documentation your client requires

Email: sales@chisen.cn

WhatsApp: +86 131 6622 6999

Call: +86 131 6622 6999

Technical enquiries, project drawings and tender documents: leadacidbattery.cn

Related CHISEN Buyer Guides

October 24, 2026

OPzS2-200 2V200Ah Flooded Tubular Battery for Telecom DC Plants

Answer First

Key Takeaways

The rating is condition-bound. 200 Ah is quoted at C10 to 1.80 V/cell at 20 °C, which is a 20 A discharge for ten hours. A capacity figure without its rate, end voltage and temperature cannot be compared with anything else on the market.
Float life is a 20 °C number. The datasheet states 20+ years of floating life at 20 °C. A supplier quoting a lifetime for a warmer ambient is making a different claim, and that difference belongs in the commercial comparison rather than in the footnote.
A 24-cell string is fully calculable. 24 × 2 V × 200 Ah = 9,600 Wh = 9.6 kWh nominal, with 22.8 mΩ of string internal resistance, a 960 A string charge ceiling, 420 kg of filled cells and 108 kg of electrolyte at fill. Every one of those figures follows directly from the cell data and can be verified before an order is placed.
Three sizes, two footprints. The OPzS2-150 and OPzS2-200 print the same 103 × 206 × 409 mm envelope, the OPzS2-250 is 21 mm longer at 124 × 206 × 409 mm, and dry weight steps from 10.5 kg to 13.0 kg to 15.5 kg. A mixed installation must be planned for two footprints and three weights.
Verification is inexpensive when the data is published. Standards, certifications, setpoints, drawing dimensions and terminal torque are all stated, so a technical approval can be completed against the datasheet and the supply question settled afterwards.

§1 — OPzS2-200 2V200Ah Quick Specifications Table

Parameter	Published value	Source
Model	OPzS2-200, flooded tubular stationary cell, 2 V 200 Ah	Model page
Nominal voltage	2 V	Datasheet
Nominal capacity	200 Ah at C10 to 1.80 V/cell at 20 °C	Datasheet
C10 discharge current	20 A (200 Ah ÷ 10 h)	Arithmetic
Designed floating life	20+ years @ 20 °C	Datasheet
Printed dimensions (L × W × H)	103 × 206 × 409 mm	Datasheet
Drawing container height	354 mm	Datasheet
Drawing total height	409 mm	Datasheet
Drawing top view	206 × 103 mm	Datasheet
Terminal centre spacing	108 mm	Datasheet
Terminal	20 mm OD, M8 thread, 7 mm depth, female copper insert M8	Datasheet
Terminal tightening torque	10–12 N·m	Datasheet
Weight without electrolyte	13.0 kg (28.7 lbs)	Datasheet
Weight with electrolyte	17.5 kg (38.6 lbs)	Datasheet
Electrolyte	Diluted sulphuric acid, 1.240 g/cm³ at 20 °C	Datasheet
Acid weight per cell	4.5 kg	Datasheet
Internal resistance	Approx. 0.95 mΩ, fully charged at 20 °C	Datasheet
Maximum charge current	40 A	Datasheet
Charge characteristic	Constant charge at 0.15 CA to 2.40 V at 20 °C	Datasheet
Maximum discharge current (5S)	1000 A	Datasheet
Short circuit current	2600 A	Datasheet
Self discharge	Approx. 4 % per month at 20 °C	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalize charge voltage	2.35 V @ 25 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Ambient, discharge	−25 °C to +65 °C	Datasheet
Ambient, charge	−20 °C to +65 °C	Datasheet
Ambient, storage	−15 °C to +40 °C	Datasheet
Container material	SAN	Datasheet
Solar and wind setpoints	Over-voltage disconnect 2.47 ± 0.01 V/cell @ 25 °C; regulation / equalize 2.40 ± 0.01 V/cell @ 25 °C; array reconnection 2.23 ± 0.005 V/cell @ 25 °C; float voltage setting 2.25 ± 0.005 V/cell @ 25 °C; low-voltage alarm 1.95 ± 0.005 V/cell @ 25 °C; low-voltage disconnect 1.90 ± 0.005 V/cell @ 25 °C; load reconnect 2.09 ± 0.01 V/cell @ 25 °C; temperature compensate coefficient −4 mV/cell/°C	Datasheet (solar/wind page 2)
Long-time discharge capacity, final voltage 1.85 V	C24 226 Ah; C48 248 Ah; C72 260 Ah; C100 270 Ah; C120 274 Ah; C240 280 Ah	Datasheet (solar/wind page 2)
24-cell string energy (48 V DC)	24 × 2 V × 200 Ah = 9,600 Wh = 9.6 kWh nominal	Arithmetic
24-cell string internal resistance	24 × 0.95 mΩ = 22.8 mΩ	Arithmetic
24-cell string maximum charge current	24 × 40 A = 960 A	Arithmetic
24-cell string mass	24 × 17.5 kg = 420 kg with electrolyte; 24 × 13.0 kg = 312 kg without	Arithmetic
Electrolyte on site per 24-cell string	24 × 4.5 kg = 108 kg of acid at fill	Arithmetic
Energy density by mass	400 Wh ÷ 17.5 kg = 22.9 Wh/kg (OPzS2-150: 300 Wh ÷ 14.5 kg = 20.7 Wh/kg; OPzS2-250: 500 Wh ÷ 20.5 kg = 24.4 Wh/kg)	Arithmetic
Applicable standards	IEC 60896-11, DIN 40736, IEC 61427, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet
Certifications	ISO 9001 (EIC), ISO 14001 (UKAS/UCC), OHSAS 18001:2007 / GB/T 28001 (UCC), CE, UL Recognized Component (cURus / RU)	Datasheet

§2 — The Pain

Three failure patterns account for most of that.

Every one of these problems has the same remedy: specify against published, condition-bound data, and require the supplier to answer in the same form.

§3 — The Choice

Parameter	OPzS2-150	OPzS2-200	OPzS2-250
Capacity @ C10 to 1.80 V @ 20 °C	150 Ah	200 Ah	250 Ah
Printed dimensions (L × W × H)	103 × 206 × 409 mm	103 × 206 × 409 mm	124 × 206 × 409 mm
Weight without electrolyte	10.5 kg (23.2 lbs)	13.0 kg (28.7 lbs)	15.5 kg (34.2 lbs)
Weight with electrolyte	14.5 kg (32.0 lbs)	17.5 kg (38.6 lbs)	20.5 kg (45.2 lbs)
Acid weight	4.0 kg	4.5 kg	5.0 kg
Max charge current	30 A	40 A	50 A
Internal resistance	Approx. 1.2 mΩ @ 20 °C	Approx. 0.95 mΩ @ 20 °C	Approx. 0.88 mΩ @ 20 °C
Short circuit current	2400 A	2600 A	2750 A
Float / equalize	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C
Float life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C
Ambient	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C	Discharge −25~65 °C / charge −20~65 °C / storage −15~40 °C

§4 — The Framework

Seven numbers decide whether the OPzS2-200 belongs in a given DC plant. Everything else is negotiation.

Capacity at a stated rate and temperature. 200 Ah at C10 to 1.80 V/cell at 20 °C, with the long-time discharge figures (226 Ah at C24 rising to 280 Ah at C240 at a 1.85 V final voltage) available for duty cycles away from the ten-hour rate.
Internal resistance. Approx. 0.95 mΩ per cell fully charged at 20 °C, which becomes 22.8 mΩ across a 24-cell string and is the input to cable, busbar and interconnection sizing.
Float and equalize setpoints with compensation. 2.23 V float and 2.35 V equalize at 25 °C, with −3 mV/°C/cell temperature compensation so the charger programme is written once and then left alone through seasonal swings.
Charge acceptance. Maximum charge current of 40 A per cell, a constant-charge characteristic of 0.15 CA to 2.40 V at 20 °C, and a 960 A ceiling across a 24-cell string — the values to compare against the site’s rectifier output.
Discharge and fault duty. Maximum discharge current of 1000 A at the 5S rate and a 2600 A short circuit current, which set the DC bus breaker rating, the fuse coordination and the ventilation assumptions.
Mechanical and logistics envelope. 103 × 206 × 409 mm printed dimensions with a 354 mm container height and 108 mm terminal centre spacing, 13.0 kg dry and 17.5 kg filled, 4.5 kg of acid per cell, and 20 mm OD M8 female copper insert terminals tightened to 10–12 N·m — plus the site totals of 420 kg of cells and 108 kg of acid per 24-cell string.
Environmental window and self-discharge. Discharge from −25 °C to +65 °C, charge from −20 °C to +65 °C, storage from −15 °C to +40 °C, and self discharge of approx. 4 % per month at 20 °C, which together determine standby behaviour, seasonal outage handling and the storage period for a site that is not permanently attended.

§5 — The Trust

A datasheet-rich market rewards buyers who verify. Nine traps are worth checking before a purchase order is raised.

Capacity without a condition. Ask for the rate, the end voltage and the temperature. If the reply is only “200 Ah”, the cell has not been specified.
Lifetime without an ambient. Require the stated temperature. 20+ years at 20 °C is the published claim; a figure quoted for another ambient is a different claim and a different risk.
Dimensions without the drawing. Printed dimensions, a 354 mm container height and a 409 mm total height are different measurements, and the 206 × 103 mm top view with 108 mm terminal spacing is what actually fixes the rack.
Dry weight quoted as installed weight. 13.0 kg without electrolyte and 17.5 kg with electrolyte are separate figures, and the difference is the handling and floor-load question.
Internal resistance quoted without conditions. Ask whether it is measured fully charged and at what temperature, because approx. 0.95 mΩ at 20 °C is a specific number, not a generic one.
Setpoints quoted as a range. A float programme should arrive as a value, a compensation coefficient and a measurement point — 2.23 V at 25 °C with −3 mV/°C/cell — not as “2.2 to 2.3 V”.
Standards listed without documents. Names printed on a brochure are not certificates. Request the accredited certificate numbers, the issuing bodies and the expiry dates, plus the UL file reference for the Recognized Component listing.
Certification scope overstated. A UL Recognized Component mark applies to the component, not to a finished DC plant; final listing and field evaluation remain the integrator’s responsibility under the local code.
Freight and port assumptions left open. Confirm the port of loading (Shanghai, Ningbo or Shenzhen) and the nominated port of discharge (Rotterdam, Antwerp, Felixstowe, Jebel Ali, Singapore, Ho Chi Minh City, Santos or Long Beach), who carries the freight cost, and whether the shipment is dry-filled with acid supplied separately or pre-filled, since that changes handling, customs classification and the 108 kg of acid per 24-cell string.

§6 — FAQ

Q3. Does the 20+ year design life apply at my site’s ambient temperature? The published figure is 20+ years of floating life at 20 °C, and the same temperature is stated for the self-discharge rate of approx. 4 % per month. Float life falls as ambient temperature rises, so a battery room that regularly exceeds 20 °C, or a cabinet in direct sun, needs a derating calculation. Ask the supplier to state the assumed ambient, the float voltage programme and the expected number of discharges, and to confirm the basis on which the 20+ year claim is made.

Expert Summary

Contact CHISEN — 24-Hour Response

CHISEN replies to technical and commercial enquiries within 24 hours.

To receive a quotation and a matching datasheet, send:

Your application — telecom DC plant, UPS, substation or renewable hybrid — and the required string architecture or bus voltage
Required capacity per cell, the discharge profile and the target end voltage, or the total kWh and autonomy the design must deliver
Cell quantity, cabinet dimensions or the available footprint, and the ambient temperature range of the battery room
Destination port, delivery window and any tender or drawing documentation your client requires

Email: sales@chisen.cn

WhatsApp: +86 131 6622 6999

Call: +86 131 6622 6999

Technical enquiries, project drawings and tender documents: leadacidbattery.cn

Related CHISEN Buyer Guides

October 24, 2026

OPzV2-2000 2V2000Ah Tubular Gel Battery for Utility Storage and DC Backup

Answer First

The OPzV2-2000 2V2000Ah is a sealed tubular-plate gel stationary cell rated 2000 Ah at C10 to 1.80 V/cell at 20 °C, published with a designed floating life of 20+ years at 20 °C, an internal resistance of approx. 0.37 mΩ fully charged at 25 °C, a maximum charge current of 400 A and a short circuit current of 8300 A — the cell that a utility-scale or large-capacity stationary installation is usually built from when the specification calls for a very large block of energy in a 48 V string without pushing the cell count past what the cabinets, the floor and the string bus can carry.

OPzV2-2000 refers to a gel-electrolyte stationary cell in the OPzV series: the trailing 2 denotes the 2 V nominal cell voltage, 2000 is the nominal capacity in ampere-hours, and the OPzV prefix identifies the tubular-plate construction with a gel electrolyte rather than a flooded one. Every rating a technical evaluator needs is published against a stated condition — capacity at C10 to 1.80 V/cell at 20 °C, internal resistance fully charged at 25 °C, floating life referenced to 20 °C — and that is what allows a string of this size to be engineered and priced before any commercial discussion begins.

Demand-side commentary from the IEA, BloombergNEF and Benchmark Minerals is useful for framing the direction of grid-scale and large stationary storage spending, and it also deserves a caution: none of those institutions publishes a cell-level specification, so none of them can confirm a capacity, a float life or a terminal torque. Procurement is settled at the datasheet level. On the published data the OPzV2-2000 resolves the three questions that dominate a project of this size: whether the energy can be delivered inside the required window without a voltage derate, whether the charger programme can restore the string after a deep discharge, and whether a 3.5-tonne string can be installed, transported and maintained within the logistics of the destination port.

Key Takeaways

The rating is condition-bound. 2000 Ah is quoted at C10 to 1.80 V/cell at 20 °C, which is a 200 A discharge for ten hours. A capacity figure quoted without its rate, its end voltage and its temperature cannot be compared against anything else, because every supplier selects different conditions and the number then means different things.

Float life is a 20 °C number. The datasheet states 20+ years of floating life at 20 °C, and the same 20 °C reference carries the self-discharge rate of approx. 2 % per month. A supplier quoting a lifetime for a warmer ambient is making a different claim, and that difference belongs in the commercial comparison rather than in a footnote.

A 24-cell string is fully calculable. 24 × 2 V × 2000 Ah = 96 kWh nominal, with 8.88 mΩ of string internal resistance, a 9,600 A string charge ceiling, and 3,480 kg of cells. Every one of those figures follows directly from the cell data and can be checked before an order is placed.

The size gain comes from fewer connections, not better chemistry. At 4000 Wh and 145 kg the cell delivers 27.6 Wh/kg, against 27.3 Wh/kg for the 1000 Ah cell and 29.4 Wh/kg for the 1500 Ah cell. Energy density is effectively unchanged; what changes is that a string needs fewer cells, fewer interconnects and fewer cabinets.

Verification is inexpensive when the data is published. Setpoints, the temperature compensation coefficient, drawing dimensions, terminal torque, internal resistance, the short circuit current, the certifications and the standards list are all stated, so a technical approval can be completed against the datasheet and the supply question settled afterwards.

§1 — OPzV2-2000 2V2000Ah Quick Specifications Table

Parameter	Published value	Source
Model	OPzV2-2000, tubular-plate gel stationary cell, 2 V 2000 Ah	Model page
Nominal voltage	2 V	Datasheet
Nominal capacity	2000 Ah at C10 to 1.80 V/cell at 20 °C	Datasheet
C10 discharge current	200 A (2000 Ah ÷ 10 h)	Arithmetic
Designed floating life	20+ years @ 20 °C	Datasheet
Printed dimensions (L × W × H)	399 × 212 × 807 mm	Datasheet
Drawing container height	772 mm	Datasheet
Drawing total height	807 mm	Datasheet
Drawing width / length	212 mm / 399 mm	Datasheet
Terminal spacing	108 mm across width, 110 mm and 110 mm along length	Datasheet
Terminal	20 mm OD, M8 thread, 7 mm depth, female copper insert M8	Datasheet
Terminal tightening torque	10–12 N·m	Datasheet
Approximate weight	145 kg (320 lbs)	Datasheet
Internal resistance	Approx. 0.37 mΩ, fully charged at 25 °C	Datasheet
Maximum charge current	400 A	Datasheet
Charge characteristic	Constant charge at 0.15 CA to 2.40 V at 20 °C	Datasheet
Maximum discharge current (5S)	3000 A	Datasheet
Short circuit current	8300 A	Datasheet
Self discharge	Approx. 2 % per month at 20 °C	Datasheet
Float charge voltage	2.23 V @ 25 °C	Datasheet
Equalise charge voltage	2.35 V @ 25 °C	Datasheet
Temperature compensation	−3 mV/°C/cell	Datasheet
Ambient, discharge	−40 °C to +65 °C	Datasheet
Ambient, charge	−30 °C to +65 °C	Datasheet
Ambient, storage	−25 °C to +45 °C	Datasheet
Container material	ABS, UL94-V0 optional	Datasheet
Applicable standards	IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, Eurobat long-life guide, BS 6290 part 4, UL 1989	Datasheet
Certifications	ISO 9001 (EIC), ISO 14001 (UKAS/UCC), GB/T 28001 / OHSAS 18001:2007 (UCC), CE, RU (UL Recognized Component)	Datasheet

The final voltage recommended for a given discharge rate is published as well: below 0.05 C the cell supports at least 1.90 V per cell, between 0.05 C and 0.08 C at least 1.85 V, between 0.08 C and 0.2 C at least 1.80 V, between 0.2 C and 0.6 C at least 1.75 V, between 0.6 C and 1.0 C at least 1.70 V, and from 1 C to 2 C at least 1.60 V. Those figures, not a nominal 2 V, are what a battery management system should be configured against.

§2 — The Pain

An installation at this scale fails on integration long before it fails on chemistry. The recurring problems are a specification that cannot be compared, a string whose consequences nobody has computed, and logistics that were never sized for the cell.

Specification ambiguity is the first. A 2000 Ah cell quoted without a rate, an end voltage and a temperature is not a 2000 Ah cell, it is a marketing label. At this capacity the ambiguity is expensive, because a 2000 Ah cell that delivers only its C3 rating is a fundamentally different procurement from one that delivers its C10 rating, and the difference shows up as a cabinet count, a rectifier size or an autonomy shortfall on day one of commissioning. The same applies to float life quoted at a warmer ambient than the site will see, and to internal resistance quoted without a temperature.

String-level arithmetic is the second. A 24-cell string at this size is 96 kWh and 3,480 kg of cells. The mass alone determines floor loading, aisle width, the lifting plan, the handling equipment specification and the freight booking, because a cell of this weight is not palletised the way a 25 kg cell is. The 8.88 mΩ string resistance and the 9,600 A string charge ceiling determine the busbar, the DC breaker and the rectifier specification. When these are computed after the order is placed, they are computed by a party who does not carry the consequence.

Logistics is the third, and it is the failure mode that surprises buyers most often. Cells of 145 kg have a very different shipping profile from cells of 84 kg: the pallet configuration, the container loading plan, the number of containers for a given megawatt-hour, the crane requirement at the discharge port and the labour to unload all change with the cell weight and the pallet height. A tender that prices the cells and forgets the handling profile produces an installation that cannot be received.

§3 — The Choice

The OPzV2-2000 sits at the top of the published OPzV2 range, and the comparison is a question of connections, cabinets and floor area rather than of any single headline figure.

	OPzV2-1000	OPzV2-1200	OPzV2-1500	OPzV2-2000
Capacity @ C10 to 1.80 V @ 20 °C	1000 Ah	1200 Ah	1500 Ah	2000 Ah
Printed dimensions	L233 × W210 × H681 mm	L275 × W210 × H681 mm	L275 × W210 × H831 mm	L399 × W212 × H807 mm
Approximate weight	73.2 kg (161.4 lbs)	84 kg (185 lbs)	102 kg (225 lbs)	145 kg (320 lbs)
Max charge current	200 A	240 A	300 A	400 A
Internal resistance	approx. 0.5 mΩ @ 25 °C	approx. 0.46 mΩ @ 25 °C	approx. 0.45 mΩ @ 25 °C	approx. 0.37 mΩ @ 25 °C
Short circuit current	5400 A	6400 A	6200 A	8300 A
Float / equalise	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C	2.23 V / 2.35 V @ 25 °C
Designed floating life	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C	20+ yr @ 20 °C
String arithmetic, 24 cells in series	OPzV2-1000	OPzV2-1200	OPzV2-1500	OPzV2-2000
—	—	—	—	—
Nominal energy (24 × 2 V × Ah)	48.0 kWh	57.6 kWh	72.0 kWh	96.0 kWh
String mass (24 × cell weight)	1,756.8 kg	2,016 kg	2,448 kg	3,480 kg
String internal resistance (24 × IR)	12.0 mΩ	11.04 mΩ	10.8 mΩ	8.88 mΩ
String max charge current (24 × I)	4,800 A	5,760 A	7,200 A	9,600 A
Mass energy density (Wh ÷ kg)	2,000 ÷ 73.2 = 27.3 Wh/kg	2,400 ÷ 84 = 28.6 Wh/kg	3,000 ÷ 102 = 29.4 Wh/kg	4,000 ÷ 145 = 27.6 Wh/kg

The OPzV2-2000 string figures are derived from the cell data, and the working is shown so that each figure can be checked:

Derivation for the OPzV2-2000, 24 cells in series	Working	Source
Nominal energy	24 × 2 V × 2000 Ah = 96 kWh	Arithmetic
String mass with cells	24 × 145 kg = 3,480 kg	Arithmetic
String internal resistance	24 × 0.37 mΩ = 8.88 mΩ	Arithmetic
String max charge current	24 × 400 A = 9,600 A	Arithmetic
Mass energy density	4,000 Wh ÷ 145 kg = 27.6 Wh/kg	Arithmetic
C10 discharge current	2,000 Ah ÷ 10 h = 200 A	Arithmetic

The OPzV2-2000 is more reliable than the OPzV2-1500 in a string sized around a fixed cell count, because it returns 2000 Ah against 1500 Ah at the same C10 test while lowering the internal resistance from approx. 0.45 mΩ to approx. 0.37 mΩ, which reduces the voltage drop and the heat generated during recharge at the same load. It is a better fit than two OPzV2-1000 cells in parallel, because one 2000 Ah cell at approx. 0.37 mΩ halves the connection count per unit of energy against two 1000 Ah cells at approx. 0.5 mΩ, and every parallel connection is a termination that has to be made, torqued, inspected and eventually maintained. The OPzV2-2000 is better suited to large stationary float duty than a comparable LFP product, because its 2.23 V float and 2.35 V equalise programme matches the installed charger hardware and the existing 48 V bus without altering the charge regime or the string architecture. The OPzV2-2000 is more reliable in service than an unspecified 2 V 2000 Ah cell, because every rating it publishes is tied to a stated condition — C10 to 1.80 V/cell at 20 °C, internal resistance measured fully charged at 25 °C, float life referenced to 20 °C — which removes the guesswork that causes premature string replacement on projects this large.

§4 — The Framework

Seven numbers decide whether the OPzV2-2000 belongs in a given installation. Everything else is negotiation.

Capacity at a stated rate and temperature. 2000 Ah at C10 to 1.80 V/cell at 20 °C, which is a 200 A discharge for ten hours, with the published final-voltage curve from 1.90 V down to 1.60 V for duty cycles away from the ten-hour rate.

Internal resistance. Approx. 0.37 mΩ per cell fully charged at 25 °C, which becomes 8.88 mΩ across a 24-cell string, and that figure is the input to cable, busbar and interconnection sizing rather than a laboratory detail.

Float and equalise setpoints with compensation. 2.23 V float and 2.35 V equalise at 25 °C, with −3 mV/°C/cell temperature compensation so the charger programme is written once and then left alone through seasonal swings in the enclosure.

Charge acceptance. A maximum charge current of 400 A per cell, a constant-charge characteristic of 0.15 CA to 2.40 V at 20 °C, and a 9,600 A ceiling across a 24-cell string — the values to compare against the rectifier output of the installation.

Discharge and fault duty. A maximum discharge current of 3000 A at the 5S rate and an 8300 A short circuit current, which set the DC bus breaker rating, the fuse coordination and the protection study for the battery enclosure.

Mechanical, logistics and structural envelope. 399 × 212 × 807 mm printed dimensions with a 772 mm container height and 108 mm / 110 mm / 110 mm terminal spacing, 145 kg per cell, and a 24-cell string total of 3,480 kg — which determines floor loading, aisle width, the lifting plan, the pallet configuration and the container loading plan.

Environmental window and self-discharge. Discharge from −40 °C to +65 °C, charge from −30 °C to +65 °C, storage from −25 °C to +45 °C, and self discharge of approx. 2 % per month at 20 °C, which together determine standby behaviour, seasonal outage handling and the storage regime for a site that is not permanently attended.

§5 — The Trust

A market with dense, well-written datasheets rewards buyers who verify rather than accept. The verification traps are well known to anyone who has bought stationary cells at this scale across several suppliers.

Capacity without a condition. Ask for the rate, the end voltage and the temperature. If the reply is only “2000 Ah”, the cell has not been specified.
Lifetime without an ambient. Require the stated temperature. 20+ years at 20 °C is the published claim; a figure quoted for another ambient is a different claim and a different risk.
Dimensions without the drawing. Printed dimensions, a 772 mm container height and an 807 mm total height are three different measurements, and the 212 × 399 mm top view with the 108 mm and 110 mm terminal spacing is what actually fixes the rack.
Internal resistance quoted without conditions. Ask whether it is measured fully charged and at what temperature, because approx. 0.37 mΩ at 25 °C is a specific number and not a generic one.
Setpoints quoted as a range. A float programme should arrive as a value, a compensation coefficient and a measurement point — 2.23 V at 25 °C with −3 mV/°C/cell — not as a band.
Standards listed without documents. Names printed on a brochure are not certificates. Request the accredited certificate numbers, the issuing bodies and the expiry dates, plus the UL file reference for the Recognized Component listing.
Certification scope overstated. A RU (UL Recognized Component) mark applies to the component, not to a finished storage system or installation; final listing and field evaluation remain the integrator’s responsibility under the local code.
Freight and port assumptions left open. Confirm the port of loading (Shanghai, Ningbo or Shenzhen) and the nominated port of discharge (Rotterdam, Antwerp, Jebel Ali, Singapore, Durban, Santos or Long Beach), who carries the freight cost, the container loading plan for 145 kg cells, and whether the shipment is a full container of cells or a break-bulk consignment.

On documentation, the OPzV2-2000 is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989, and the manufacturing operation holds ISO 9001, ISO 14001 and GB/T 28001 / OHSAS 18001:2007. The practical step is to ask for the documents behind those marks — accredited certificate numbers and validity dates, the UL file reference and the IEC 60896-21 test report — because that is the only part of a quality claim a buyer can audit. For a European project the DIN 40472 and IEC 60896-21 conformity is what satisfies the local installer; for a North American project the UL file reference is what the authority having jurisdiction will ask for; for a Chinese or South-East Asian utility the YD/T 1360 route is the one that matches local procurement practice. Production base in Hangzhou with loading typically through the ports of Shanghai and Ningbo means a buyer can also request the factory address, the loading port and the container marking in writing before the vessel is booked, and can compare those documents across more than one source rather than relying on a single reply.

§6 — FAQ

Q1. What does the model code OPzV2-2000 mean, and what type of cell is it? It identifies a sealed tubular-plate gel stationary lead-acid cell. The OPzV series follows the tubular-plate construction defined in DIN 40472, the trailing 2 is the 2 V nominal cell voltage, and 2000 is the nominal capacity in ampere-hours. The electrolyte is gelled in a thixotropic silica suspension rather than held as free liquid, which is what makes the cell maintenance-free, spill-proof and suitable for an enclosure without ventilation plenum design.

Q2. How is the 2000 Ah rated, and what discharge rate should a string be sized against? The 2000 Ah figure is published at C10 to 1.80 V/cell at 20 °C, which is a 200 A discharge for ten hours. Sizing must be done against the real discharge profile using the closest published rate and against the end voltage the installed rectifier can support at the end of a deep discharge, and the datasheet gives the final voltage recommended for each discharge band from below 0.05 C through to 2 C.

Q3. Does the 20+ year design life apply at my site’s ambient temperature? The published figure is 20+ years of floating life at 20 °C, and the same temperature is stated for the self-discharge rate of approx. 2 % per month. Float life falls as ambient temperature rises, so an enclosure that regularly exceeds 20 °C needs a derating calculation. Ask the supplier to state the assumed ambient, the float voltage programme and the expected number of discharges, and to confirm the basis on which the 20+ year claim is made.

Q5. Why choose one 2000 Ah cell instead of two 1000 Ah cells in parallel? One 2000 Ah cell at approx. 0.37 mΩ replaces two 1000 Ah cells at approx. 0.5 mΩ for the same energy, which halves the number of parallel terminations and therefore the number of joints to make, torque, inspect and maintain. Mass energy density is effectively the same — 27.6 Wh/kg against 27.3 Wh/kg — so the gain is in connection count, handling and footprint rather than in chemistry.

Q6. What are the physical dimensions, weight and terminal torque? Printed dimensions are 399 × 212 × 807 mm, with a 772 mm container height and an 807 mm total height on the drawing, and terminal centres 108 mm across the width and 110 mm and 110 mm along the length. Weight is approximately 145 kg per cell, so a 24-cell string is 3,480 kg. Terminals are 20 mm OD with an M8 thread, 7 mm depth and a female copper insert M8, tightened to 10–12 N·m.

Q7. How does a gel cell behave differently from a flooded cell in a large standby string? A gel cell does not need periodic water topping, does not need a ventilated enclosure for hydrogen escape and does not spill, which removes both the maintenance visit and the floor-loading monitoring. In exchange, the gel cell carries a higher internal resistance than a comparable flooded cell at the same capacity and is more sensitive to overcharging, so the charger programme and the compensation coefficient matter more, not less.

Q8. Which standards and certifications apply, and what should I request as evidence? The cell is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989, with ISO 9001, ISO 14001 and GB/T 28001 / OHSAS 18001:2007 held by the manufacturing operation and a RU (UL Recognized Component) marking on the cell. Request the accredited certificate numbers and expiry dates, the UL file reference and the IEC 60896-21 test report rather than a summary of them, and ask which of those documents apply to the specific cells in the shipment rather than to the manufacturer as a whole.

Expert Summary

The OPzV2-2000 is a 2 V, 2000 Ah sealed tubular-plate gel stationary cell whose decisive published figures are unusually complete: 2000 Ah at C10 to 1.80 V/cell at 20 °C, internal resistance of approx. 0.37 mΩ fully charged at 25 °C, a designed floating life of 20+ years at 20 °C, a 2.23 V float and 2.35 V equalise at 25 °C with −3 mV/°C/cell compensation, 400 A maximum charge current, 3000 A maximum discharge at the 5S rate, an 8300 A short circuit current, self discharge of approx. 2 % per month at 20 °C, and an ambient window of −40 °C to +65 °C on discharge. Mechanically it occupies 399 × 212 × 807 mm at approximately 145 kg, with 20 mm OD M8 female insert terminals tightened to 10–12 N·m. In a 24-cell 48 V configuration those figures become 96 kWh nominal, 8.88 mΩ of string resistance, a 9,600 A charge ceiling and 3,480 kg of cells, at 27.6 Wh/kg of mass energy density. It is built to IEC 60896-21/22, DIN 40472, IEC 61427, YD/T 1360, the Eurobat long-life guide, BS 6290 part 4 and UL 1989. Specification decisions should be made against those published conditions, and the supplier should be required to answer in the same form.

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Your application — utility or grid-scale storage, large DC backup, telecom central office or substation — and the required string architecture or bus voltage
Required capacity per cell, the discharge profile and the target end voltage, or the total kWh and autonomy the design must deliver
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Related CHISEN Buyer Guides

October 24, 2026

OPzS2-600 2V600Ah Flooded Tubular Battery: 108-V DC Plant Sizing for Telecom and Rail

Answer First

The OPzS2-600 2V600Ah is a 2 V, 600 Ah (C10) flooded tubular lead-acid cell built for float service: 145 × 206 × 645 mm, 700 mm over terminals, 2.23 V float and 2.35 V equalise per cell (2.40 V for solar and wind regulation), 120 A maximum charge current, 1,500–2,500 cycles at 80 % depth of discharge and a 20-plus-year float design life at 20 °C. It is the right cell when you are building a 108 V or 216 V DC string for a telecom power room, a railway signalling substation or a metro traction auxiliary feed, and it is the wrong cell when the room is unreachable, when space is the constraint, or when nobody will ever top up electrolyte.

One number decides most projects: 600 Ah at the ten-hour rate. A 54-cell string of OPzS2-600 2V600Ah cells holds 54 × 2 V × 600 Ah = 64.8 kWh of nominal energy, and a 108-cell string holds 129.6 kWh. That is roughly four to six hours of backup for a 20–25 kW telecom DC load at 50 % depth of discharge, which is where most of these installations actually sit.

Key Takeaways

Rated 600 Ah at C10, not C20. The OPzS2-600 2V600Ah reaches 600 Ah when discharged over ten hours to 1.80 V per cell. A buyer who reads 600 Ah as a twenty-hour figure will size the string roughly 20 % short for a short-duration duty.
108 V means 54 cells, 216 V means 108 cells. Every string voltage is a cell count multiplied by 2 V: 24 cells for 48 V, 54 cells for 108 V, 108 cells for 216 V.
String charge current is capped by the cell, not by the rectifier. Each OPzS2-600 2V600Ah cell accepts 120 A maximum; a 54-cell string therefore pulls up to 6,480 A of charging current, and the rectifier must be sized for that or the string will never recover capacity after a deep discharge.
Float current is 3.0 A per cell. At 5 mA per amp-hour, one cell draws 3.0 A on float. Over a 54-cell string that is 162 A of continuous float draw that the generator or PV array has to carry for the life of the plant.
The maintenance burden is the real differentiator. Flooded tubular cells need periodic electrolyte checks, specific-gravity readings and topping up, and a ventilated room. If the site cannot be visited quarterly, gel is the correct choice even at a higher price per amp-hour.

§1 — OPzS2-600 2V600Ah Quick Specifications Table

Parameter	OPzS2-600 2V600Ah published value	Why it matters in a string
Nominal voltage	2 V per cell	54 cells give 108 V, 108 cells give 216 V
OPzS2-600 rated capacity	600 Ah at C10, to 1.80 V/cell	Defines usable energy at a 6-hour-plus discharge
OPzS2-600 dimensions (L × W × H)	145 × 206 × 645 mm	Sets rack pitch and room length for a 54-cell string
OPzS2-600 cell weight	32.0 kg without electrolyte; 42.8 kg with electrolyte (10.8 kg acid)	Floor loading, lifting and freight cost for a 54-cell string
OPzS2-600 height over terminals	700 mm	Include 50–80 mm clearance above terminals for ventilation
OPzS2-600 terminal	Φ20-M8, torque 10–12 N·m (Φ16-M6 and Φ24-M10 options)	Interconnect cable sizing follows the bolt size, not the current
Technology	Flooded tubular lead-acid	Electrolyte is visible; the cell needs periodic topping up
Float voltage	2.23 V/cell at 25 °C (datasheet float; 2.25 V float setting for solar)	54 × 2.23 V = 120.42 V at the busbar at 25 °C
Equalise voltage	2.35 V/cell at 25 °C (2.40 V for solar and wind regulation)	Equalisation is a controlled weekly or bi-weekly event
Temperature compensation	−3 mV/°C/cell float (datasheet); the solar settings table lists −4 mV/°C/cell	A 40 °C room cuts float voltage by roughly 0.045 V per cell
Maximum charging current	120 A per cell	A 54-cell string can demand up to 6,480 A on recharge
Cycle life	1,500–2,500 cycles at 80 % DoD; 2,500–4,000 at 50 % DoD; 4,500–6,500 at 30 % DoD	Depth of discharge, not age, drives replacement
Float design life	20+ years at 20 °C (datasheet)	Halves roughly for every 10 °C above 20 °C
Discharge temperature	−40 °C to 60 °C	Cold cranking is not the limit; charging is
Charge temperature	−30 °C to 55 °C	Below −30 °C the cell will not accept charge
Storage temperature	−25 °C to 45 °C	A cell stored hot and shipped to a cool site needs re-equalising
Internal resistance	0.60 mΩ fully charged at 25 °C	Sets the voltage drop under high-current discharge
Short-circuit current	3,700 A per cell	Plan fusing and touch protection on every string
Electrolyte specific gravity	1.24 ± 0.01 g/cm³ fully charged	The reference point for every field density check
Certifications	IEC 60896-11:2002, DIN 40736-1:1985, GB/T 19638.2-2014, YD/T 1360, Eurobat Long Life, BS 6290 Part 4, UL 1989	Covers the stationary, telecom and export markets

§2 — The Pain

A DC plant fails in one of two ways, and both start long before the batteries are visibly old.

The first is a string that was sized for nominal energy instead of usable energy. A 54-cell string of OPzS2-600 2V600Ah cells delivers 64.8 kWh nominal, but at 50 % depth of discharge and a 2.00 V/cell end-point the bank gives you closer to 24–26 kWh of usable energy at the load terminals once you subtract float-current losses, cable drop and cell temperature. If the tender documents only quote 600 Ah and 108 V, two suppliers can bid 15 % apart and both be honest.

The second is a string that cannot recharge. The OPzS2-600 2V600Ah accepts 120 A per cell on charge, and the common failure in the field is a rectifier sized for the load rather than for the battery. A 54-cell string of OPzS2-600 2V600Ah cells that has been deeply discharged needs thousands of amps to recover in the time the generator is available, and a cell that is never fully recovered ages for reasons that have nothing to do with its age. Short the recharge and the cell sulphates, capacity falls, float voltage sags, the end cells age first, and within three years you are replacing cells in a string that was specified for twenty.

There is a third, quieter problem: the language of the page you are reading. Many of these cells are sold with a single capacity number and no rate basis. The same 600 Ah label is quoted at the ten-hour rate by some suppliers and the twenty-hour rate by others, and the difference shows up as a 10–15 % shortfall in a real discharge test.

§3 — The Choice

Once the duty is float-dominant and the room is accessible, flooded tubular is hard to beat on cost per stored kilowatt-hour. When the room is not accessible, or the site is hot, or the space is tight, gel or sealed VRLA wins even though the cell costs more per amp-hour.

Selection metric	OPzS2-600 2V600Ah (flooded tubular)	Tubular gel OPzV2 equivalent	Sealed AGM VRLA equivalent
Rated capacity basis	600 Ah at C10	500 Ah at C10 in the next larger step	12 V blocks, 100–250 Ah at C10
Float voltage per cell	2.23 V	2.23 V	2.27 V
Equalise voltage per cell	2.35 V	2.35 V	2.35 V
Maximum charging current	120 A per cell (0.2 C10)	0.2 C10 per cell	0.25 C10
Cycle life at 80 % DoD	1,500–2,500 cycles	≥1,500 cycles	Not published on the model page
Float design life	20+ years at 20 °C	20+ years at 20 °C	12 years at 20 °C
Discharge temperature range	−40 °C to 60 °C	−40 °C to 65 °C	−20 °C to 60 °C
Service actions per year	Electrolyte density checks and topping up, typically quarterly	Visual inspection and cleaning, no watering	Visual inspection and cleaning, no watering
Installation requirement	Ventilated room, spill containment	Sealed, no spill, no ventilation for hydrogen	Sealed, no spill, no ventilation for hydrogen
Cell mass per stored kWh	Lowest of the three, because the plastic case is a tube	Moderate	High, because of the thicker case and more lead
Field failure mode	Water loss, terminal corrosion, density stratification	Overcharge heat at high ambient, loss of capacity	Thermal runaway from poor cooling, loss of capacity

The table above is built from published CHISEN data for each chemistry; where a figure is not published it is marked as such rather than estimated. The commercial conclusion is physical rather than financial. A flooded OPzS2-600 2V600Ah string of 54 cells stores 64.8 kWh nominal in about 11.2 m³ of rack volume including interconnects and clearances, while a sealed string of the same energy needs materially more case volume and heavier handling gear. Where a power room has to be built inside an existing building, that difference decides the design.

For the wider flooded tubular range, the OPzS series is published from 100 Ah up to 3,000 Ah, with a shared platform, terminal standard and case footprint, so a plant can be built from one supplier with one set of spares and one maintenance procedure. The OPzS flooded tubular battery hub lists the full range and the model datasheets.

§4 — The Framework

Fix the rate basis before the capacity. Write 600 Ah at C10 to 1.80 V/cell into the specification and require the supplier to state the rate on the datasheet. Capacity quoted without a rate and an end-point voltage is not a number you can order against.

Count cells, not volts. A 108 V DC system is 54 cells of 2 V. A 216 V system is 108 cells. Ask for the cell count per string, the string count and the end-point voltage, then check that the arithmetic delivers the autonomy you need at 50 % depth of discharge rather than at the nameplate.

Check the charge path against the published 120 A. Multiply the rectifier’s current limit by the number of strings and compare it with the recovery time you need after a full discharge. If the recharge window is four hours for a 54-cell string, the rectifier must be able to deliver close to 6,480 A into that string, which is 120 A for every OPzS2-600 2V600Ah cell. Most site faults are rectifier faults, not cell faults.

Design the room for the cell, not for the battery. At 700 mm over terminals, a 54-cell string on a two-tier rack needs roughly 1.6 m of wall length, floor loading for the full weight of the filled cells, a clear maintenance aisle in front of every tier, and ventilation sized for hydrogen from the cells under equalisation charge.

Budget the maintenance visits. A flooded cell loses water through electrolysis and evaporation. Quarterly visits for density readings, topping up, terminal cleaning and torque checks are the minimum, and the cost of those visits belongs in the ten-year comparison, not just the cell price.

Set the temperature compensation rule. At −3 mV per °C per cell, a room that sits at 35 °C needs roughly 0.03 V less per cell than a 25 °C room. Put the compensation in the rectifier settings and re-check it after every seasonal change.

Demand the data trail. Ask for the incoming inspection report, the initial charge record, the first specific-gravity readings at 30, 90 and 180 days, and the annual density trend. Without that trail, a warranty claim on a twenty-year asset becomes an argument about who held the data.

§5 — The Trust

There are three things a buyer should check before signing, and one of them is on the supplier’s own website.

The first is the consistency of the published datasheet. The product page for the OPzS2-600 2V600Ah carries the dimensions 145 × 206 × 645 mm with a total height of 700 mm in the specification table, while a later section of the same page repeats 103 × 206 × 409 mm and a 12.6 kg cell weight, and the FAQ section repeats 145 × 206 × 700 mm. Those three statements do not agree. A 600 Ah flooded tubular cell of this format is a large, heavy piece of equipment, and a 12.6 kg figure is not credible for the OPzS2-600 2V600Ah. Treat the specification table as the controlling document, and have weight and dimensions confirmed in writing on a signed CHISEN spec sheet before the shipping calculation, the rack design and the floor loading check are frozen. This is exactly the kind of small documentation defect that destroys a project schedule six months later.

The second is the equalisation procedure. Equalising a flooded string at 2.35 V per cell, or 2.40 V in solar and wind regulation, raises cell temperature and produces hydrogen. A room that cannot remove that gas cannot be equalised safely, and a string that is never equalised develops capacity spread until the weakest cell drags the busbar down. Define the equalisation interval in the maintenance contract, the gas removal rate in the room design, and who signs off the density readings.

The third is the acceptance test. Require a discharge test on the delivered string to the agreed end-point voltage at the agreed rate, with the initial specific gravities and cell voltages recorded cell by cell. A string that passes at the factory and fails at site is usually a transport, connection or temperature problem, and it is much easier to diagnose with the acceptance data in hand.

One more caution on comparisons: some suppliers publish a single 600 Ah number for a smaller cell than the OPzS2-600 2V600Ah, or quote cycle life figures measured at 30 % depth of discharge and present them as 80 % figures. Compare on the same rate basis, the same depth of discharge and the same temperature.

§6 — FAQ

Q1. What is the rated capacity of the OPzS2-600 2V600Ah, and at what rate? 600 Ah at the ten-hour rate (C10), measured to an end-point of 1.80 V per cell at 25 °C. If you need 600 Ah at a twenty-hour rate, this cell does not deliver it, and the string must be sized accordingly.

Q2. How many cells make a 108 V DC system? 54 cells of 2 V. A 48 V system uses 24 cells and a 216 V system uses 108 cells. The float busbar voltage at 25 °C is 120.42 V for a 54-cell string at 2.23 V per cell.

Q3. What charge current does the cell accept? 120 A maximum per cell, which is 0.2 C10. A 54-cell string can therefore accept up to 6,480 A. Size the rectifier for that or accept a slow recharge after a deep discharge.

Q4. Does the OPzS2-600 2V600Ah need electrolyte topping up? Yes. It is a flooded cell with a transparent case, so electrolyte level, specific gravity and stratification are visible and must be inspected periodically, typically quarterly.

Q5. How long does the float life last? The published float design life is 20+ years at 20 °C. As an engineering rule of thumb, float life is roughly halved for every 10 °C above 20 °C, so a 30 °C room should be planned at around 12–13 years, and that assumption belongs in the tender document.

Q6. What cycle life should I expect at 80 % depth of discharge? 1,500–2,500 cycles at 80 % depth of discharge, 2,500–4,000 cycles at 50 %, and 4,500–6,500 cycles at 30 %. Float service in a DC plant is much gentler than cycling, so the 20-year float figure dominates in telecom and signalling applications.

Q7. Can I use the cell at high ambient temperature? Discharge is rated from −40 °C to 60 °C and charging from −30 °C to 55 °C, but float life shortens with temperature, so the room cooling design is part of the battery specification.

Q8. What happens if the string is deeply discharged and recharge is too slow? The cell sulphates, capacity and internal resistance drift, and the end cells age first. The published 120 A maximum charge current is the threshold above which the cell cannot take charge cleanly, and the internal resistance of 0.60 mΩ rises as the cell ages.

Q9. Which certifications can be supplied? IEC 60896-11:2002, DIN 40736-1:1985, GB/T 19638.2-2014, YD/T 1360, Eurobat Long Life, BS 6290 Part 4 and UL 1989, with RoHS, REACH and WEEE handled in the destination market.

Q10. How do I request a sizing sheet and a quotation? Send the string voltage, the load in kW, the required autonomy in hours, the minimum end-point voltage, the room temperature and the delivery port — Shanghai, Ningbo, Jebel Ali, Santos, Rotterdam, Hamburg, Valencia, Mersin, Chattogram, Mombasa or Tema all have the same operating logic, and we reply with a cell count, an energy budget and a float-current figure within one working day.

Expert Summary

The OPzS2-600 2V600Ah is a 2 V, 600 Ah C10 flooded tubular cell for float duty, published at 145 × 206 × 645 mm and 700 mm over terminals, with 2.23 V float and 2.35 V equalise per cell (2.40 V for solar and wind regulation), 120 A maximum charge current, 3.0 A float current per cell, 0.60 mΩ internal resistance, 32.0 kg without electrolyte and 42.8 kg with electrolyte, a 20-plus-year float life at 20 °C and 1,500–2,500 cycles at 80 % depth of discharge. A 54-cell string holds 64.8 kWh nominal and a 108-cell string 129.6 kWh. Three decisions define the installation: the capacity rate basis, which must be written as C10 to 1.80 V/cell rather than a bare amp-hour figure; the charge path, where the 120 A per-cell limit means a 54-cell string can demand 6,480 A and the rectifier must be sized accordingly; and the maintenance regime, because a flooded cell needs quarterly density checks, topping up and terminal service in a ventilated room. Where the room is accessible, flooded tubular wins on cost per stored kilowatt-hour and on the number of cells a rack can hold. Where the room is unreachable or the space is constrained, sealed gel or AGM is the correct answer even at a higher price per amp-hour, because the 20-year float life only materialises with the temperature compensation, the ventilation and the inspection regime that the float service assumes. Buyers should also require the signed datasheet: the published product page carries three conflicting dimension and weight statements; the datasheet values are 145 × 206 × 645 mm with 700 mm over terminals, 32.0 kg without electrolyte and 42.8 kg with electrolyte (10.8 kg of acid), and those datasheet figures should be confirmed in writing before the rack, the floor loading and the shipping plan are fixed.

Contact CHISEN — 24-Hour Response

Send us the string voltage, the DC load in kW, the required autonomy, the minimum end-point voltage, the room temperature and the delivery port, and we will return a cell count, an energy budget, a float-current figure and a string charging recommendation for the OPzS2-600 2V600Ah flooded tubular cell.

WhatsApp: https://wa.me/861316226999 Email: sales@chisen.cn Factory: 8 production bases, 70 million kVAH annual capacity, CE, ISO 9001, ISO 14001, UL and IEC certified.

Related reading: the full OPzS flooded tubular battery range from 100 Ah to 3,000 Ah, and how CHISEN builds and certifies every cell.

This article is published on leadacidbattery.cn.

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October 23, 2026