6-EVF-50 12V50Ah Solar and Off-Grid Energy Storage Battery

Answer First

The 6-EVF-50 is a sealed 12V 50Ah battery built for solar and off-grid duty: 50 Ah at the C3 rate, twelve volts nominal, six 2 V cells per string, and 600 Wh of stored energy (12 V × 50 Ah = 600 Wh). The published envelope is 230 × 140 × 180 mm at 15.25 ± 0.2 kg, with φ11.8-M6 terminals, a 13.5 V float setpoint (2.25 V/cell), a 14.1 V equalise setpoint (2.35 V/cell), a 10.0 A maximum charge current, and a 1.75 V/cell discharge cutoff. Cycle life is published at 350–600 cycles at 50–80 % depth of discharge, self-discharge is ≤3 %/month at 25 °C, the working range is −15…50 °C, and design life is 2–5 years. Every figure on this page comes from the factory model page or from arithmetic on those figures.

For an off-grid installer, the planning number for one 12V 50Ah battery is not 600 Wh but 540 Wh. Applying a 0.90 usable fraction to the nominal 600 Wh gives 540 Wh of working energy (600 Wh × 0.90 = 540 Wh), which is 1.8 hours against a 300 W continuous load (540 Wh ÷ 300 W = 1.8 h) for one block, and 3.6 hours with two blocks in parallel (2 × 600 Wh = 1,200 Wh; 1,200 Wh × 0.90 = 1,080 Wh; 1,080 Wh ÷ 300 W = 3.6 h). On a mass basis the block reaches 39.3 Wh/kg (600 Wh ÷ 15.25 kg = 39.3 Wh/kg) and 103.5 Wh/L (230 mm × 140 mm × 180 mm = 5.796 dm³; 600 Wh ÷ 5.796 L = 103.5 Wh/L).

This page deliberately carries factory-published numbers and the arithmetic built on top of them, so an importer can size a solar cabinet before the pallet arrives. Values that the factory does not publish — internal resistance, inter-cell connectors, rack wiring diagrams, container assembly ratings — are marked as not published or to be requested from the factory. The complete published data sheet on this model page is sent with any quotation request.

Key Takeaways

• One 12V 50Ah battery, one string: 50 Ah at the C3 rate in a 12 V enclosure, six 2 V cells, 600 Wh nominal (12 V × 50 Ah = 600 Wh) — the arithmetic base for every solar cabinet layout.
• Charge control is fixed: float 13.5 V (2.25 V/cell), equalise 14.1 V (2.35 V/cell), maximum charge current 10.0 A (10.0 A ÷ 50 Ah = 0.2 C), discharge cutoff 1.75 V/cell, which is 10.5 V across a six-cell string.
• Cycle duty is published, not promised: 350–600 cycles at 50–80 % depth of discharge, with ≤3 %/month self-discharge at 25 °C and a −15…50 °C working range.
• Physical build: 230 × 140 × 180 mm, 15.25 ± 0.2 kg, φ11.8-M6 terminals — 39.3 Wh/kg and 103.5 Wh/L.
• Runtime arithmetic: 600 Wh nominal → 540 Wh usable at a 0.90 planning fraction → 1.8 h at 300 W continuous load per block, 3.6 h with two blocks in parallel.
• Array pairing: a 300 Wh/day daytime load spread over 5 peak sun hours needs 60 W of array (300 Wh ÷ 5 h = 60 W), which becomes 78 W after a 1.3 charge-loss factor (60 W × 1.3 = 78 W) — so a 150 W module is the practical step, and a second string doubles the reserve.

§1 — 6-EVF-50 Quick Specifications

The table below is the factory model page reproduced without adjustment. Every line carries its source so that a technical buyer can trace the number back to the original document instead of a brochure summary.

§2 — The Pain: Why Off-Grid Solar Projects Fail at the Battery Cabinet

The panel gets engineered, the inverter gets specified, and the battery cabinet gets ordered from a price list. That sequence is where off-grid projects go wrong, and it fails in five repeatable ways.

Sizing from amp-hours instead of watt-hours. A 12V 50Ah battery nameplate invites a 600 W load, because 12 V × 50 Ah looks like 600 units of something. It is 600 Wh — and usable energy is lower again once a planning fraction is applied. At a 0.90 fraction the block yields 540 Wh (600 Wh × 0.90 = 540 Wh). Against a 600 W load that is 0.9 hours (540 Wh ÷ 600 W = 0.9 h), not the ten hours a nameplate reading suggests.

Ignoring the idle months. Published self-discharge is ≤3 %/month at 25 °C. On a 600 Wh 12V 50Ah battery that is 18 Wh per month (600 Wh × 0.03 = 18 Wh), and 108 Wh across a six-month dry season (18 Wh × 6 = 108 Wh), leaving 492 Wh (600 Wh − 108 Wh = 492 Wh) before any usable-fraction derating — 443 Wh after the 0.90 factor (492 Wh × 0.90 = 443 Wh), which is 1.5 hours at 300 W (443 Wh ÷ 300 W = 1.5 h). A cabinet that sits unloaded through the dry season starts the rainy season with less than the drawing suggests.

Fighting the charge current. Maximum charge current is 10.0 A, which is 0.2 C (10.0 A ÷ 50 Ah = 0.2 C). If the solar controller tries to push 30 A into the string for fast recovery, the block is being charged outside its published window and the controller, not the battery, must limit the current.

Ignoring temperature. The working range is −15…50 °C. Cabinet temperatures above 50 °C in a sealed enclosure are outside the published envelope, and cold mornings below −15 °C reduce usable capacity without reducing the load.

Mixing strings. Parallel blocks of different models, ages, or capacities create unequal current sharing, which is a shortened-life problem rather than a power problem. Every string in one cabinet should be the same model from the same production window.

§3 — The Choice: One Block, Two Blocks, or a 48 V Stack

There are three practical architectures for an off-grid cabinet built on 12 V blocks, and the right one follows from the load profile and the wiring distance rather than from the unit price.

Architecture A — one block per string, 12 V bus. Simplest to install, lowest voltage to service, and appropriate for small daytime loads or single-appliance backup. One 12V 50Ah battery gives 600 Wh nominal, 540 Wh usable at 0.90, 1.8 hours at 300 W.

Architecture B — two identical blocks in parallel, 12 V bus. Capacity doubles without raising the bus voltage: 2 × 600 Wh = 1,200 Wh nominal, 1,080 Wh usable (1,200 Wh × 0.90 = 1,080 Wh), 3.6 hours at 300 W (1,080 Wh ÷ 300 W = 3.6 h), and 100 Ah at 12 V. Parallel wiring doubles current capacity at the same 10.0 A per-block charge limit, so the charge current allowance stays 10.0 A per string, not 20.0 A for the pair — a point that catches integrators who size the controller on the parallel total.

Architecture C — four blocks in series, 48 V DC bus. Four 12 V blocks in series give 48 V (4 × 12 V = 48 V) across twenty-four 2 V cells (4 × 6 cells = 24 cells) and 2,400 Wh of nominal capacity (4 × 600 Wh = 2,400 Wh), while current stays at 50 Ah. Voltage rises at the string: float becomes 54.0 V (4 × 13.5 V = 54.0 V), equalise 56.4 V (4 × 14.1 V = 56.4 V), and the cutoff 42.0 V (4 × 10.5 V = 42.0 V). Fewer conductors, lower current losses over long cable runs, and a single point of connection to a 48 V inverter.

Whichever architecture is chosen, the array has to cover the load plus losses. A 300 Wh/day daytime load over 5 peak sun hours needs 60 W of array (300 Wh ÷ 5 h = 60 W), which becomes 78 W once a 1.3 charge-loss factor is applied (60 W × 1.3 = 78 W) — so a 150 W module is the practical step. If block capacities are to be compared against other 12 V options, the published data for the full product range can be reviewed on request.

§4 — The Framework: A Four-Step Sizing Method for a 12V 50Ah Solar Bank

Step 1 — Build the load ledger before anything is quoted. List every load in watt-hours per day and every continuous load in watts, and put surge loads in a separate column because a pump or a compressor start draws several times its running current. A 12V 50Ah battery bank is sized from that ledger, never from the inverter’s nameplate rating.

Step 2 — Apply the derating factors in writing. The usable fraction used here is 0.90 (600 Wh × 0.90 = 540 Wh). The published cycle life is stated at 50–80 % depth of discharge, so cycle depth must be fixed in the design note. Capacity loss below 0 °C is not published and is to be requested from the factory. Putting the factors on paper is what makes two quotations comparable.

Step 3 — Match the charge side to the published limits. Maximum charge current is 10.0 A per block, the float setpoint is 13.5 V, the equalise setpoint is 14.1 V, and the discharge cutoff is 1.75 V/cell, which is 10.5 V across the six cells of a string. A controller whose absorption stage is set above 14.1 V must be derated or the equalisation step disabled, otherwise the controller is driving the block outside its published window.

Step 4 — Plan the cabinet and the service interval. Ventilation must keep the case inside the −15…50 °C working range, terminals are φ11.8-M6 and must be torqued to the hardware specification, equalisation runs every three to six months, and each string should carry a monthly voltage log so a weak block is found before it drags a whole parallel string down.

The arithmetic behind one design case is set out below so a technical buyer can re-run it with their own numbers.

§5 — Where the 6-EVF-50 Sits Against Its Sibling Blocks

Off-grid projects rarely end up on a single block size, so the useful comparison is between the published values of the neighbouring 12 V blocks. The figures below are taken from the factory model page for each type; the specific-energy column is arithmetic on those published values.

Two practical notes for integrators. First, the 6-DMF-52 is the closest alternative on paper for a 12V 50Ah battery cabinet: 52 Ah with the same φ11.8-M6 terminal and a 10.4 A charge limit, but a shorter 175 mm case height than the 180 mm of the 6-EVF-50, so existing 175 mm shelving fits it without rework; its design life is not published. Second, moving up to 60 Ah adds 120 Wh of nominal energy (720 Wh − 600 Wh = 120 Wh) for 3.55 kg (18.8 kg − 15.25 kg = 3.55 kg), which is often the cheaper move than adding a second parallel string. Published details for the 60 Ah block are on the sibling model page, and the wider 12 V VRLA listing is available on request.

§6 — The Trust: Who Makes the 6-EVF-50 and How Solar Orders Move

CHISEN operates 8 production bases with an annual capacity of 70 million kVAh across three product lines: flooded tubular OPzS2, gel tubular OPzV2, and the 12 V VRLA blocks in the 6-DZF, 6-DMF and 6-EVF series that include this model. The factory holds CE, ISO 9001, ISO 14001, UL and IEC certifications, and the certificate set for the 6-EVF-50 is released with the quotation rather than claimed on a page.

For solar cabinets, the practical question is whether the same block will be supplied on the next order, because a mixed fleet is what causes string imbalance. The production base, the batch policy and the despatch inspection record should be requested with every purchase order, and the export desk in Hangzhou, China issues them.

SHIPPING AND MARKET COVERAGE — Solar cabinets built around this block are supplied to distributors and installers in India, Nigeria, Kenya, Vietnam, the Philippines, Brazil, Mexico, Egypt, Pakistan, Indonesia and Turkey. The export desk in Hangzhou, China handles shipment documentation for these markets, with containers moving out of Shanghai, Ningbo and Shenzhen, and onward routing through Jebel Ali and Rotterdam for European and Middle East destinations. Freight terms, minimum order quantity and production lead time for the 6-EVF-50 are to be requested from the factory, and the same request can carry the certification pack.

§7 — FAQ

Q1: What are the published nominal voltage and capacity of the 6-EVF-50? The 6-EVF-50 is a 12V 50Ah battery: 12 V nominal and 50 Ah at the C3 rate, which is 600 Wh of stored energy (12 V × 50 Ah = 600 Wh). Both values come from the factory model page.

Q2: What float and equalise setpoints does the manufacturer publish for the 6-EVF-50? Float 13.5 V and equalise 14.1 V for the whole 12 V block, which is 2.25 V/cell at float and 2.35 V/cell at equalise (13.5 V ÷ 6 cells = 2.25 V; 14.1 V ÷ 6 cells = 2.35 V). The discharge cutoff is 1.75 V/cell, or 10.5 V across the string. All from the model page.

Q3: What is the maximum charging current for the 6-EVF-50? 10.0 A, published on the model page. In rate terms that is 0.2 C (10.0 A ÷ 50 Ah = 0.2 C), and the controller should be set to respect this limit per block.

Q4: What are the case dimensions and weight of the 6-EVF-50? 230 × 140 × 180 mm and 15.25 ± 0.2 kg per block (model page). Two blocks side by side need 460 mm of rail length, and the pair weighs 30.5 kg (15.25 kg × 2 = 30.5 kg) before cabinet hardware.

Q5: What terminal type and torque does the 6-EVF-50 use? The terminal is φ11.8-M6 as published on the model page. The specified tightening torque is not published and is to be requested from the factory, together with the busbar and inter-connector drawings.

Q6: How many cells does a 12V50Ah string contain and what bus voltage does it give? Six 2 V cells in one block, giving a 12 V bus. Four such blocks in series give a 48 V bus across 24 cells (4 × 6 = 24 cells) with 2,400 Wh nominal and float at 54.0 V (4 × 13.5 V = 54.0 V).

Q7: What is the published design life of the 6-EVF-50 and at what temperature? Design life is 2–5 years and the working temperature range is −15…50 °C, with self-discharge specified at ≤3 %/month at 25 °C and cycle life at 350–600 cycles at 50–80 % depth of discharge. The float-life reference temperature for the published design life is to be requested from the factory.

Q8: How should an importer verify the 6-EVF-50 on delivery? Record the open-circuit voltage of every block against the factory despatch record, check the case for cracks, leaks or terminal damage, confirm the manufacturing date on the label, verify the terminal hardware is φ11.8-M6, and run a sampled capacity test against the 50 Ah C3 rating before the balance of the container is released.

Q9: Which certifications does the CHISEN factory behind the 6-EVF-50 hold? CE, ISO 9001, ISO 14001, UL and IEC. The certificate set and test reports are released with the quotation on request.

Q10: How do I request a quotation or samples for the 6-EVF-50? Send the target quantity, the destination country and port, the load profile and the required certification set to the export desk. Samples for evaluation are arranged with the same request.

Expert Summary

The 6-EVF-50 is a 12V 50Ah battery, a C3 sealed block with six 2 V cells, 600 Wh nominal energy, 230 × 140 × 180 mm case, 15.25 ± 0.2 kg, φ11.8-M6 terminals, 13.5 V float, 14.1 V equalise, 10.0 A maximum charge current, 1.75 V/cell cutoff, ≤3 %/month self-discharge at 25 °C, −15…50 °C working range, 350–600 cycles at 50–80 % depth of discharge and 2–5 years design life. The planning numbers that follow directly: 540 Wh usable at a 0.90 fraction, 1.8 h at 300 W per block, 3.6 h for two blocks in parallel, 3.6 h at 48 V with four blocks in series (2,400 Wh, 54.0 V float, 42.0 V cutoff), 39.3 Wh/kg, and 78 W of array for a 300 Wh/day load over five peak sun hours. Capacity growth across the sibling blocks raises nominal energy but not specific energy (45.5 Wh/kg at the 6-DMF-52 against 36.0 Wh/kg at the 6-EVF-120), so selection should follow the load ledger, the derating factors, the 10.0 A charge limit and the 50 °C cabinet ceiling rather than the amp-hour headline.

Contact CHISEN — 24-Hour Response

• Email: sales@chisen.cn | jack@chisen.cn
• WhatsApp: +86 131 6622 6999
• Website: www.chisen.cn
• Factory: CHISEN Battery, Hangzhou, China — 8 production bases, annual capacity 70 million kVAh, certified to CE, ISO 9001, ISO 14001, UL and IEC.

chisenbattery@gmail.com

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