Author: CHISEN Battery Team

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  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

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.

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

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.

1. 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.

1. 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.

1. 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.

1. 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.

1. 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.

1. 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.

1. 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 reading: OPzV2-1200 2V1200Ah model page · OPzV2-1000 2V1000Ah tubular gel cell · OPzV tubular gel battery range

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