OPzS2-100 2V100Ah Flooded Tubular Battery: Published Specs, 48 V String Sizing and Sibling Comparison

Answer First

The OPzS2-100 2V100Ah is a 2 V, 100 amp-hour flooded tubular vented lead-acid cell rated at the 10-hour rate — 10 A for 10 hours down to 1.80 V per cell at 20 °C — and it is the correct cell for a telecom DC plant, a roadside substation or a solar-powered cabinet that needs a 48 V bus holding about 4.8 kWh nominal per string, on a site where somebody will still read the electrolyte level and top up distilled water every quarter.

It is not a sealed block. Hydrogen venting, acid-proof flame-retardant vent plugs, scheduled water top-up and periodic equalisation are part of the product, not optional extras, and a project that treats the OPzS2-100 2V100Ah as a drop-in sealed cabinet battery discovers the difference in the first hot season.

The complete published data set for this cell sits on the OPzS2-100 2V100Ah model page, and the rest of the flooded range is listed under tubular flooded lead-acid batteries.

Key Takeaways

• Capacity is rate-dependent. The nameplate figure is 100 Ah at C10 (10 A to 1.80 V/cell at 20 °C). At longer rates the cell delivers more: 107 Ah at C24, 111 Ah at C48, 115 Ah at C72, 120 Ah at C100, 122 Ah at C120 and 130 Ah at C240 (Datasheet).
• Charging setpoints are fixed by the datasheet. Float 2.23 V/cell at 25 °C, equalising 2.35 V/cell at 25 °C, temperature compensation −3 mV/°C/cell, designed float life 20+ years at 20 °C (Datasheet). Solar and wind sites use the 2.27 ± 0.005 V/cell float and 2.40 ± 0.01 V/cell equalising setpoints (Datasheet).
• Mechanical data is what decides the rack. Body 103 × 206 × 354 mm, 409 mm total height over the terminals, 8.0 kg without electrolyte and 12.6 kg with electrolyte (Datasheet).
• Two limits protect the cell. Maximum charging current is 20 A (0.20 × C10) and internal resistance is about 1.0 mΩ fully charged at 20 °C, with a 1500 A short-circuit current (Datasheet / Model page).
• A 48 V string is simple arithmetic. 24 cells give 4,800 Wh nominal, 302.4 kg with electrolyte (24 × 12.6 kg) and 24.0 mΩ of internal resistance (24 × 1.0 mΩ) (Arithmetic).

§1 — OPzS2-100 2V100Ah Published Specifications

Every row above is traceable: values taken from the manufacturer’s OPzS2-100 datasheet are marked Datasheet, values taken from the published English product page are marked Model page, and derived figures are marked Arithmetic wherever they appear in the text. If a supplier cannot tell you which of the three a given figure is, treat the figure as unverified.

§2 — The Pain: Where 2V 100Ah Projects Go Wrong

The first failure is a specification failure. Buyers routinely receive a quote that says only “2V 100Ah tubular” and treat every 2V 100Ah cell in the world as interchangeable. The published OPzS2-100 data makes the differences explicit: capacity at C10 is 100 Ah, but capacity at C24 is 107 Ah and at C240 is 130 Ah. A bank sized on the C10 number for a slow-discharge backup duty is undersized; a bank sized on the C240 number for a five-hour discharge duty is over-purchased. Both mistakes trace back to a quotation that never stated the rate and the end voltage.

The second failure is thermal. A 48 V string of 24 OPzS2-100 cells accepts a maximum charging current of 20 A per cell, so a charger set to deliver more — which happens when the charger is sized for the string’s nominal power rather than for the cells’ acceptance — pushes the electrolyte into gassing and dries the separator faster than the topping-up interval can repair. The same string on a solar site needs the higher 2.27 ± 0.005 V/cell float and the 2.40 ± 0.01 V/cell equalising setpoint; on a mains-float site the correct values are 2.23 V/cell and 2.35 V/cell at 25 °C. These are not interchangeable, and a controller left on the wrong setpoint is the classic cause of premature capacity loss.

The third failure is weight and access planning. The OPzS2-100 is 8.0 kg without electrolyte and 12.6 kg with electrolyte, and the full height over the terminals is 409 mm, not the 354 mm body height. A 24-cell string with electrolyte weighs 302.4 kg (24 × 12.6 kg, Arithmetic). Cabinets, plinths and lifting plans are usually drawn against the body height and a lighter shipping weight, and the result is a string that does not fit the rack and a handling plan that understates the load.

The fourth failure is assuming sealed behaviour. This cell vents hydrogen during overcharge, needs acid-proof flame-retardant vent plugs, needs distilled water, and needs a scheduled equalising period. Those four obligations are why the OPzS2-100 2V100Ah wins in cabinets with a permanent operator and loses in unmanned roadside or container sites.

§3 — The Choice: The OPzS2-100 Against Its Published Siblings

Buyers comparing cells inside the 100 Ah to 200 Ah window are usually choosing between a flooded cell and a gel cell, or between three flooded capacities. The table below uses published values only — no qualitative claims.

Sources: OPzS2-100 and OPzS2-150 from their datasheets; OPzS2-200 weight from its datasheet, with internal resistance, charging current and short-circuit current from its model page; OPzV2-100 from the model page and its datasheet (Arithmetic for the comparison itself).

Four numbers drive the decision. First, dry weight: 8.0 kg, 10.5 kg and 13.0 kg for the three flooded cells — a cell that must be carried up a ladder or into a pit should be chosen with the wet weight in mind, not the dry one. Second, the charging current limit of 20 A, 30 A and 40 A, which must be matched to the charger output. Third, internal resistance, which falls from 1.0 mΩ to 0.95 mΩ as capacity rises, so a 24-cell string of the 200 Ah cell presents 22.8 mΩ (24 × 0.95 mΩ, Arithmetic) against 24.0 mΩ for the 100 Ah cell (24 × 1.0 mΩ, Arithmetic) — a 5 % difference in string voltage drop under the same load, which matters when the string is long and the load is heavy.

The fourth number is the maintenance profile, and here the published data is unambiguous. The flooded OPzS2-100 carries 12.6 kg of electrolyte in an open container that must be topped up and periodically equalised. The gel OPzV2-100 carries the same 103 × 206 mm footprint with a 390 mm total height, weighs 13.2 kg with the electrolyte immobilised in the gel, and needs no watering — the price of that is a 1.1 mΩ internal resistance, a 30 A charging limit and a shorter life under deep cycling. For a manned substation with a technician on call, the flooded cell usually delivers the lower cost per usable year; for a sealed container with no access, the gel cell removes a whole maintenance category. Both routes are legitimate, and the published figures above are what the comparison should be built on.

The same discipline applies further up the size range. If your string is larger than 200 Ah per cell, move to the OPzS flooded range overview rather than scaling the numbers in this table proportionally — plate thickness, internal volume and electrolyte quantity change non-linearly with capacity.

§4 — The Framework: Seven Hard Checks Before You Sign

Q1. Match the charger to the cell’s acceptance, not to the string. The maximum charging current of the OPzS2-100 is 20 A (0.20 × C10, Datasheet). A 24-cell string therefore accepts at most 480 A (24 × 20 A, Arithmetic). Most telecom float rectifiers are sized well below that, which is correct; a solar controller set to the array’s full output is where the limit gets breached.

Q2. Apply temperature compensation to the setpoint, not to the battery. The published compensation is −3 mV/°C/cell (Datasheet), so a cell at 35 °C needs its 2.23 V/cell float reduced by 0.036 V. Controllers that ignore this are permanently overcharging the string in the hot season and permanently undercharging it in winter.

Q3. Design for the float life at the site’s real temperature. The 20+ year design figure is quoted at 20 °C (Datasheet). A cabinet in the tropics, on a roof in Chennai or an outdoor enclosure in Lagos will not deliver that figure, and the honest way to plan a replacement interval is to take the 20 °C number and treat every 10 °C of ambient uplift as a materially shorter service life. Projects that publish a 20-year asset life for a string sitting in a 35 °C room have not done the arithmetic.

Q4. Plan the watering interval from the real charging regime. A cell that is floated at 2.23 V/cell at 25 °C and never equalised loses water slowly; a cell that is equalised at 2.35 V/cell twice a month in a hot climate loses water fast enough to need attention on a monthly cycle. Put the interval in the maintenance contract, and put the electrolyte density check (1.24 g/cm³ at 20 °C, Datasheet) on the same schedule.

Q5. Size the interconnects and torque them correctly. The terminal is a copper female insert M8 with a published torque of 10–12 N·m (Datasheet). Under-torqued terminals generate heat at the joint; over-torqued ones damage the insert. For a 24-cell string the interconnect carries the full string current, so the cable cross-section is set by that current and the 1500 A short-circuit current (Model page) determines how quickly the fault must be cleared.

Q6. Decide how many strings run in parallel, and how they will be equalised. Two parallel strings of 12 cells in series each will drift apart unless the charger has an equalising stage and the operator runs it. Parallel strings also multiply the water-top-up workload and the total string weight: 24 × 12.6 kg = 302.4 kg per 100 Ah string with electrolyte (Arithmetic).

Q7. Confirm the standards the cell is built to. A 2 V vented cell for stationary duty is normally specified against IEC 60896-11 and the equivalent DIN 40736-1 envelope. CHISEN production runs under ISO 9001 and ISO 14001, and the range is supplied with CE, RoHS and REACH documentation, so the paperwork trail should exist before the first container is booked.

§5 — The Trust: What a Datasheet Must State — and What to Reject

The single most useful question a buyer can ask a supplier is: “which document is this number from?” A published datasheet answers five questions that quotations never answer. What is the capacity rate and the end voltage? For the OPzS2-100 it is 100 Ah at C10 to 1.80 V/cell at 20 °C, and the full curve to 240 hours is published alongside it. What is the weight with and without electrolyte? 8.0 kg and 12.6 kg — both numbers, because a shipping weight quoted without electrolyte tells you nothing about handling. What is the total height over the terminals? 409 mm, not the 354 mm body height, and the difference is exactly the kind of detail that stops a cabinet from being delivered. What is the maximum charging current? 20 A. What is the reference temperature for the internal resistance and for the float life? 20 °C for both, and both references matter more than the numbers themselves.

Against that standard, reject any quotation that quotes a float voltage of 2.24 V per cell for this model, or one that quotes temperature compensation of −3.3 mV/°C/cell, or one that claims a 20-year design life at 25 °C. The OPzS2-100 datasheet set points are 2.23 V/cell float, 2.35 V/cell equalising and −3 mV/°C/cell compensation, with the 20+ year design figure referenced to 20 °C. A supplier who quotes different numbers for the same model is either reading a different revision or inventing them.

Two further quality signals are worth checking on site. First, ask for the plant audit trail: paste mixing, grid casting, group assembly, formation and sealing are the process steps that decide whether a 100 Ah cell really holds 100 Ah in year five, and they are the difference between a manufacturer and a packer. Second, ask for the certification package — ISO 9001, ISO 14001, CE, UL and IEC documentation should arrive with the quotation, not three weeks after the deposit. CHISEN runs eight production bases with roughly 70 million kVAh of annual capacity, and the company profile is published on the CHISEN company page if you want to check the manufacturing scale behind a quotation before you commit a container.

§6 — FAQ

Q1. What is the rated capacity of the OPzS2-100 2V100Ah? 100 Ah at the 10-hour rate (10 A to 1.80 V/cell at 20 °C). The published table also gives 107 Ah at C24, 111 Ah at C48, 115 Ah at C72, 120 Ah at C100, 122 Ah at C120 and 130 Ah at C240 (Datasheet).

Q2. How many cells does a 48 V string need, and how much energy does it hold? 24 cells. 48 V × 100 Ah = 4,800 Wh nominal (Arithmetic). The string weighs 302.4 kg with electrolyte (24 × 12.6 kg) and 192.0 kg dry (24 × 8.0 kg).

Q3. What float and equalising voltage should the charger use? Float 2.23 V/cell and equalising 2.35 V/cell, both referenced to 25 °C. On solar and wind sites use the higher 2.27 ± 0.005 V/cell float and 2.40 ± 0.01 V/cell equalising setpoint (Datasheet).

Q4. What temperature compensation does the cell need? −3 mV/°C/cell (Datasheet), applied to the float setpoint. At 35 °C the float setpoint falls by 0.036 V per cell.

Q5. How long is the designed float life? 20+ years at 20 °C (Datasheet). Higher ambient temperatures reduce achievable service life, so site temperature has to be part of the replacement plan rather than a footnote.

Q6. What is the maximum charging current? 20 A per cell, which is 0.20 × C10 (Datasheet). For a 24-cell string the theoretical ceiling is 480 A (24 × 20 A, Arithmetic), and the charger should normally deliver far less.

Q7. Can this cell be installed without a permanent operator? It can be installed, but not forgotten. Flooded tubular cells need distilled-water top-up, electrolyte density checks, ventilation and periodic equalising. For an unmanned site, compare the published gel alternative instead.

Q8. What is the internal resistance and short-circuit current? About 1.0 mΩ fully charged at 20 °C (Datasheet) and a 1500 A short-circuit current (Model page). The string resistance of a 24-cell arrangement is 24.0 mΩ (24 × 1.0 mΩ, Arithmetic), and the 1500 A figure is what your DC fuse and disconnection arrangement must be able to interrupt.

Q9. How does the OPzS2-100 compare with the gel OPzV2-100? Same 103 × 206 mm footprint, different overall height and different maintenance regime. The flooded cell: 354 mm body, 409 mm total height, 12.6 kg with electrolyte, 20 A charging limit, 1.0 mΩ internal resistance, with watering required. The gel cell: 390 mm total height, 13.2 kg with electrolyte, 30 A charging limit, 1.1 mΩ internal resistance, with no watering. The OPzV2-100 2V100Ah model page carries the gel data set.

Q10. Which standards and certifications apply? The flooded 2 V stationary cell is built to the IEC 60896-11 and DIN 40736-1 envelope, and CHISEN supplies the range with CE, RoHS and REACH documentation under ISO 9001 and ISO 14001 management systems.

Expert Summary

The OPzS2-100 2V100Ah is a 2 V flooded tubular vented lead-acid cell with a published 100 Ah capacity at the 10-hour rate (10 A to 1.80 V/cell at 20 °C), rising to 130 Ah at the 240-hour rate; float 2.23 V/cell and equalising 2.35 V/cell at 25 °C with −3 mV/°C/cell compensation and a 20+ year design float life referenced to 20 °C; a body of 103 × 206 × 354 mm with 409 mm total height; a weight of 8.0 kg without electrolyte and 12.6 kg with electrolyte; a 20 A maximum charging current; about 1.0 mΩ internal resistance at 20 °C; and a 1500 A short-circuit current. A 24-cell 48 V string of these cells holds 4,800 Wh nominal, weighs 302.4 kg with electrolyte and presents 24.0 mΩ of internal resistance. The cell is the correct choice where a manned telecom DC plant, substation or renewable cabinet benefits from long float life and low cost per usable year; where site access is unattended, the published gel alternative trades a higher charging limit and slightly higher internal resistance for the removal of the watering cycle.

Contact CHISEN

If you are quoting a 2 V 100 Ah cell for a 48 V DC plant, a substation in Rotterdam or a solar cabinet outside Nairobi, ask for the complete OPzS2-100 datasheet, the string layout drawing and the certification package, and ask for them in writing: email sales@chisen.cn, or message the export desk on WhatsApp at +86 131 6622 6999 (https://wa.me/8613166226999). One line describing your bus voltage, backup time and site temperature is enough for us to return the string arithmetic, the charger setpoints and the nearest capacity in the flooded range — or the gel equivalent if nobody will ever top up water on that site.

Browse the full CHISEN lead-acid range and technical data at https://leadacidbattery.cn.

Related CHISEN Product Pages

• OPzS2-150 2V150Ah tubular flooded cell — the next capacity step, 150 Ah
• OPzS2-100 2V100Ah model page — full published specification set
• Tubular flooded battery range — 2 V cells from 100 Ah to 3,000 Ah

CHISEN Battery Team

Engineering and export team at CHISEN Battery, Hangzhou, China. Lead-acid and lithium battery manufacturer, ISO 9001 / CE / UL certified, exporting to 50+ countries.

See Full Bio