6-EVF-50 12V50Ah UPS Battery: Complete Buyer Guide for Data Centres and Telecom

Answer First

The 6-EVF-50 is a 12 V, 50 Ah VRLA (AGM) block rated at the C3 discharge rate, and every figure a purchasing team needs is published rather than estimated: 230 × 140 × 180 mm casing, 15.25 ± 0.2 kg, φ11.8-M6 terminals, 13.5 V float, 14.1 V equalise, 10.0 A maximum charging current, a 1.75 V per cell cut-off, self-discharge of no more than 3 % per month at 25 °C, an operating window of −15…50 °C and a design float life of 2–5 years. All of these values come from the manufacturer model page, and every derived figure below is marked “Arithmetic” with the calculation shown in full.

Two conclusions follow immediately. First, the energy content of one 12V 50Ah battery is 12 V × 50 Ah = 600 Wh, and against the published 15.25 kg that is 600 ÷ 15.25 = 39.3 Wh/kg, while the casing volume of 230 × 140 × 180 mm = 5.796 L gives 15.25 ÷ 5.796 = 2.63 kg per litre of envelope. Second, the string arithmetic is fixed by chemistry and published setpoints: 12 V ÷ 2 V per cell = 6 cells, float 13.5 ÷ 6 = 2.25 V per cell, equalise 14.1 ÷ 6 = 2.35 V per cell, and a 10.5 V end voltage at the 1.75 V per cell cut-off.

Key Takeaways

§1 — 6-EVF-50 Quick Specifications

The table reproduces the published data for the 6-EVF-50 12V 50Ah battery exactly as it appears on the manufacturer model page. Nothing here is inferred; where the factory has not published a value it is written as “not published” rather than estimated.

Two points deserve emphasis. The published cycle life of 350–600 cycles applies at 50–80 % depth of discharge, so a runtime promise built on a shallower discharge will not be conservative. The 2–5 year design float life is quoted at 25 °C and is separate from the −15…50 °C operating window; high ambient temperature shortens usable life well before the cell reaches the top of its range. Full technical detail for this block is on this model page, and the wider 12 V VRLA size options are listed in the full product range.

§2 — The Pain: Where UPS Battery Purchases Quietly Lose Money

The specification that arrives as a brochure line. A quote sheet saying only “12V 50Ah battery” hides the four values that decide whether the block fits the job: case footprint, weight, terminal type and maximum charge current. On the 6-EVF-50 these are published as 230 × 140 × 180 mm, 15.25 ± 0.2 kg, φ11.8-M6 and 10.0 A (Source: Model page). Without them a buyer cannot check whether a 230 mm wide module fits the rack pitch, whether the maintenance team can handle the weight, or whether the charger can deliver the specified current.

The runtime figure nobody recomputed. “40 minutes of backup” is a common line in tender documents and it is frequently inconsistent with the battery count that follows. Take a 1 kVA unit at 0.8 power factor: the inverter delivers 1,000 × 0.8 = 800 W to the load. Allowing 94 % for inverter and cabling losses, the battery must supply 800 ÷ 0.94 = 851 W. A two-block parallel string of 6-EVF-50 units stores 2 × 600 Wh = 1,200 Wh, and at 50 % depth of discharge the usable energy is 1,200 × 0.5 = 600 Wh. Runtime is therefore 600 ÷ 851 = 0.705 h, about 42 minutes (Arithmetic). A quotation claiming 60 minutes for the same arrangement is out by about 40 %, and nobody notices until the first outage.

The float-voltage gap. The factory publishes 13.5 V float and 14.1 V equalise for a 6-cell 12 V string (Source: Model page). A charger set to 13.2 V never fully recovers capacity and ages the block early; a charger left at 14.4 V in float boils it. That one line in the cabinet specification decides whether the published 2–5 year design float life is achieved or forfeited.

§3 — The Choice: Selecting the Right Block for the Duty

The 6-EVF-50 12V 50Ah battery sits in the middle of the 12 V VRLA shelf, and the wrong choice is usually made by comparing the wrong attributes. Three selection routes cover almost all real projects.

Route three — match the charger. The published 10.0 A maximum charge current (Source: Model page) is a ceiling, not a target. A charger below it is acceptable but lengthens the recharge window after a deep discharge; a charger above it shortens battery life. Confirm the bulk current is at or below 10.0 A per parallel string and the float and equalise programme against 13.5 V and 14.1 V.

The terminal question. φ11.8-M6 on the 6-EVF-50 matches the 6-DMF-45 and 6-DMF-52, but the 6-EVF-60 moves to φ14-M6 and the 6-EVF-80 to φ16-M6 (Source: Model page). Changing block in an existing cabinet therefore changes the cable set, the ring terminal and the torque value — the most commonly forgotten line in a replacement order, and the one that stops a rack from powering up on day one.

§4 — The Framework: Sizing, Strings, Setpoints and the Arithmetic Behind Them

A UPS battery line should be written as an engineering chain with every link visible to the person signing the purchase order.

Link 1 — load and real power. For a 1 kVA unit at 0.8 power factor: 1,000 × 0.8 = 800 W at the output.

Link 2 — battery-side power. At 94 % inverter and cabling efficiency: 800 ÷ 0.94 = 851 W drawn from the battery.

Link 3 — nominal energy per block. From the published data: 12 V × 50 Ah = 600 Wh (Model page for voltage and capacity; Arithmetic for the product).

Link 4 — usable energy. At 50 % depth of discharge: 600 Wh × 0.5 = 300 Wh per block, so two blocks in parallel give 600 Wh usable.

Link 5 — runtime. 600 Wh ÷ 851 W = 0.705 h, about 42 minutes. Four blocks in parallel give 1,200 Wh usable and 1,200 ÷ 851 = 1.41 h, about 85 minutes (Arithmetic).

String architecture. A 12V 50Ah battery block contains 6 cells at 2 V nominal: 12 ÷ 2 = 6 (Arithmetic). Float is therefore 13.5 ÷ 6 = 2.25 V per cell and equalise 14.1 ÷ 6 = 2.35 V per cell. The 1.75 V per cell cut-off sets the string end voltage at 6 × 1.75 = 10.5 V, the figure the UPS should recognise as “battery exhausted”. A 24 V string for a 2 kVA unit doubles everything: 12 cells, 27.0 V float, 28.2 V equalise, 21.0 V end voltage.

§5 — Comparison with Sibling Blocks on the Same 12 V Shelf

The table uses published values for the sibling models from the same manufacturer model page. The two right-hand columns are derived, and each derivation is shown so a reviewer can check it.

Source for all published values: Model page. Energy and specific-energy columns: Arithmetic.

Three observations follow from the table. The 6-DMF-45 and 6-DMF-52 carry more energy per kilogram than the 6-EVF-50 — 43.9 and 45.5 Wh/kg against 39.3 Wh/kg — so a project constrained by lifting weight or floor area per kWh may prefer the DMF route. The 6-EVF-50 is 10 mm narrower than the 6-EVF-60 but 20 mm taller, and it saves 3.55 kg per block (18.8 − 15.25 = 3.55 kg), which matters where every kilogram has to be carried up a stairwell. Terminal progression is monotonic — φ11.8-M6 for the 6-EVF-50, then φ14-M6 and φ16-M6 as capacity rises — so a mixed fleet means two cable sets and two torque figures. The next capacity step up is documented on the sibling model page.

§6 — The Trust: Documentation, Verification and Delivery

Buying a battery block is a low-value, high-frequency transaction, so the risk sits in paperwork and in what arrives on the pallet. The factory behind the 6-EVF-50 operates 8 production bases with an annual capacity of 70 million kVAh and holds CE, ISO 9001, ISO 14001, UL and IEC certification (Source: company register §D). Those five marks are the audit trail behind every published figure in §1.

Verification on arrival. Weigh three blocks per pallet against 15.25 ± 0.2 kg. Confirm the terminal is φ11.8-M6 and the casing marking matches the model. Measure the resting open-circuit voltage of each block: six cells at 2 V nominal gives about 12.6 V per block when fully charged (Arithmetic), and a reading well below that on arrival points to a transport or storage problem. Check the manufacture date, confirm the float and equalise labels match 13.5 V and 14.1 V, and file a photograph of the pallet label before the cartons are opened.

Delivery and export markets. CHISEN ships 12 V VRLA blocks to distributors and OEM programme customers in India, Nigeria, Kenya, Vietnam, the Philippines, Brazil, Egypt, Pakistan and Turkey, mainly from Ningbo and Shanghai, with onward container routes through Lagos, Karachi, Mumbai, Jebel Ali, Durban and Hamburg (Source: company register §D). Lead time, packing method and shipping terms are quoted per order — to be requested from the factory with the model and destination confirmed.

§7 — FAQ

Q1: What are the published nominal voltage and capacity of the 6-EVF-50? 12 V and 50 Ah at the C3 discharge rate for the 12V 50Ah battery (Source: Model page). Stored energy is 12 V × 50 Ah = 600 Wh per block (Arithmetic).

Q2: What float and equalise setpoints does the manufacturer publish? Float 13.5 V and equalise 14.1 V for the 6-cell string, which is 2.25 V and 2.35 V per cell (Source: Model page; Arithmetic).

Q3: What is the maximum charging current? 10.0 A, equal to 0.2 C (Source: Model page; Arithmetic: 10.0 ÷ 50).

Q4: What are the case dimensions and weight? 230 × 140 × 180 mm and 15.25 ± 0.2 kg (Source: Model page). Casing volume is 5.796 L (Arithmetic).

Q5: What terminal type and torque does the 6-EVF-50 use? φ11.8-M6 (Source: Model page). The tightening torque is not published — to be requested from the factory with the model and terminal specification.

Q6: How many cells does a 12V50Ah string contain and what bus voltage does it give? Six cells at 2 V nominal (12 ÷ 2), float 13.5 V, equalise 14.1 V, and 10.5 V at the 1.75 V per cell cut-off (Source: Model page; Arithmetic).

Q7: What is the published design float life and at what temperature? 2–5 years at 25 °C, with 350–600 cycles at 50–80 % depth of discharge, and self-discharge of no more than 3 % per month at 25 °C (Source: Model page).

Q8: How should an importer verify the 6-EVF-50 on delivery? Weigh sampled blocks against 15.25 ± 0.2 kg, confirm φ11.8-M6 terminals and the model marking, measure resting open-circuit voltage per block, and check the manufacture date plus the CE, ISO 9001, ISO 14001, UL and IEC documents before releasing payment.

Q9: Which certifications does the CHISEN factory behind the 6-EVF-50 hold? CE, ISO 9001, ISO 14001, UL and IEC (Source: company register §D), delivered from 8 production bases with 70 million kVAh of annual capacity.

Expert Summary

The 6-EVF-50 is a mid-size 12V 50Ah battery whose published data removes most of the guesswork in a UPS purchase: 50 Ah at C3, 230 × 140 × 180 mm, 15.25 ± 0.2 kg, φ11.8-M6 terminals, 13.5 V float, 14.1 V equalise, 10.0 A charge current, 1.75 V per cell cut-off, ≤ 3 % monthly self-discharge, a −15…50 °C operating window and 2–5 years of design float life. From those figures a buyer derives 600 Wh per block, 39.3 Wh/kg, 2.63 kg per litre of envelope, 0.2 C charge acceptance, a 10.5 V string end voltage and — for a two-block parallel string behind a 1 kVA unit — about 42 minutes of runtime at 50 % depth of discharge. The procurement discipline that follows is simple: write the arithmetic chain on the quotation, keep the charger inside the published setpoints, and verify weight, terminals, voltage and date on every pallet before payment.

Contact CHISEN — 24-Hour Response

Sales enquiries for the 6-EVF-50, including pricing, lead time, packing and OEM programme terms, are answered within 24 hours.

• Email: sales@chisen.cn
• Export desk: jack@chisen.cn
• WhatsApp: +86 131 6622 6999
• Website: www.chisen.cn

chisenbattery@gmail.com

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