Photos show the 12VBK8A-C variant
LiFePO4 battery
12.8 V / 640 Ah
AkuBox LiFePO₄ battery 12.8 V / 640 Ah / 8.0 kWh, 8× EVE MB31-D06-01. Bluetooth. JK BMS active balancer, handmade in the Czech Republic, 4-year warranty on the cells.
- Energy
- 8 kWh
- Capacity
- 640 Ah
- Cycle life
- 8,000 cycles
- Cell warranty
- 4 years
Variants of this pack
Other voltage or capacity · AkuBox
What it's good for.
For installations that need maximum capacity and current handling in a single 12V battery — for example with a Victron MultiPlus 12 V / 5000 VA inverter.
The BAKOM 12.8 V / 8 kWh battery pack is the largest storage unit in our 12V range. Eight EVE MB31 prismatic LiFePO₄ cells (grade A) in a 2P4S configuration provide a usable capacity of 640 Ah (8 kWh) in a robust plastic AkuBox. It is designed for solar (PV) installations, backup power, off-grid systems and more demanding mobile applications that need both high current draw and a large energy reserve from a single 12V block.
Its high current capability makes this pack a suitable source even for powerful inverters: 270 A continuous charge and discharge current and peaks of up to 300 A for 20 s.
- Voltage: 12.8 V nominal, EVE MB31-D06-01 cells, 8 pcs (2P4S)
- Capacity: 640 Ah / 8 kWh of usable energy
- Service life: 8000 cycles (until capacity drops to 70%)
- Currents: 270 A continuous, max. 300 A (20 s) — charge and discharge
- Operating temperature: discharge −22 °C to +55 °C, charge +1 °C to +55 °C
- Charging window: 13.8–14.1 V; end-of-charge voltage 14.15 V (SOC 100%)
- BMS: smart JK BMS with a 2A active balancer, Bluetooth, optional CAN
- Dimensions / weight: 64 × 24.5 × 22 cm, approx. 49 kg
Why LiFePO₄: lithium iron phosphate is one of the safest battery chemistries — it resists thermal runaway, tolerates deep discharge and offers a long service life of thousands of cycles. Safety is handled by an advanced BMS control unit that continuously monitors overvoltage (OVP), undervoltage (UVP), overcurrent (OCP), short circuit (SCP) and cell temperature, and immediately disconnects the relevant circuit if the limits are exceeded. The active balancer continuously equalises the voltage between the cells, extending the life of the whole pack. You can follow all operating data in the BAKOM BMS mobile app via Bluetooth.
AkuBox design: the cells are enclosed in a rigid plastic case, the terminals are protected by covers and the battery is switched on and off with an ON/OFF switch with LED indicator (on LCD variants the switch is built into the display). We recommend placing the battery in a dedicated space with no access for unauthorised persons. Variants with a CAN connector allow data communication with inverters (Victron, Growatt, GoodWe and others). Installation may only be carried out by a qualified person; we recommend connecting the battery to the DC installation while it is switched off, and providing suitable anchoring, fusing and adequately sized cabling. Given its weight of approx. 49 kg, plan for a secure mounting.
This variant (12VBK8A-L): Communication: Bluetooth; external LCD display.
Technical specifications.
Values for the 12VBK8A-L variant. The charge and discharge limits match the BMS settings the battery has when it leaves our workshop.
- Nominal voltage
- 12.8 V (4S2P)
- Capacity
- 640 Ah
- Energy
- 8 kWh
- Chemistry
- LiFePO₄ (lithium iron phosphate)
- Cells
- 8× EVE MB31-D06-01
- BMS
- JK B2A8S20P
- Balancer
- active, 2 A
- Continuous current (charge and discharge)
- 270 A
- Peak current
- 300 A / 20 s
- Cycle life
- 8,000 cycles to 70% capacity
- Charging — temperature
- +1 to +55 °C
- Discharging — temperature
- −22 to +55 °C
- Charging: absorption / float
- 14.1 V / 13.8 V
- Discharge cut-off (recommended)
- 12.0–12.4 V
- Communication
- Bluetooth
- LCD display
- included
- Build
- AkuBox
- Dimensions
- 64×24.5×22 cm
- Weight
- 49 kg
- Production
- handmade, Czech Republic
- Warranty
- 4 years on the cells
Energy = capacity × average discharge voltage (3.125 V per cell), i.e. the energy the battery delivers between the BMS limits. Cycle life is stated by the cell manufacturer for 25 °C; actual life depends on operating conditions. The 4-year warranty applies to the cells; the BMS and other electronics are covered as set out in the warranty certificate.
Ready to connect.
Each battery leaves the workshop with its BMS set up and after a final test. Every battery comes with a report of the measured cell capacity and a warranty certificate.
- Battery with the BMS configuredWe set the protections according to the battery type and the communication according to your inverter.
- Cell capacity reportMeasured capacity and internal resistance of each cell, and the result of the final test.
- Manual and warranty certificateWiring procedure, recommended inverter settings and warranty terms.
- Inverter cableIncluded with 48 and 51.2 V batteries with BMS+ according to the ordered configuration; for other batteries at extra cost.
- BAKOM BMS app and BAKOM CloudBattery status and cell voltages on your phone via Bluetooth, history and settings on the web. Free for BAKOM batteries.
What you ask us.
Didn't find your answer? Call or write to us — we'll help you choose and connect it.
When will I receive the battery?
We build batteries by hand to order and do not keep them in stock. After your inquiry we confirm the current lead time and put you in the order queue — the reservation is free and non-binding. We contact you before production starts.
Do I pay a deposit?
No. We build and test the battery, then send the invoice and dispatch the battery once payment has arrived. Smaller batteries go by PPL, heavier ones on a pallet; the shipping cost is stated in the quote. Collection in person is possible by arrangement near Klatovy or near Ostrava.
Will the battery communicate with my inverter?
CAN variants communicate with Victron, Deye, Growatt, GoodWe, MUST, Luxpower and other inverters, and via RS485 with, for example, Voltronic inverters. With a Victron system (Cerbo GX), it is the CAN variants that communicate. Our batteries are low-voltage — they do not work with high-voltage (HV) hybrid inverters. Send us your inverter type and we will check.
Can I charge the battery in winter?
Below +1 °C the BMS blocks charging to protect the cells and allows it again above +4 °C. Discharging is possible down to −22 °C. For unheated spaces there are variants with HEAT heating (suffix H), which warm the cells before charging.
What charging voltage should I set?
12.8 V: absorption 14.1 V, float 13.8 V · 25.6 V: 27.9 / 27.4 V · 51.2 V: 55.8 / 54.7 V · 48 V (15 cells): 52.3 / 51.3 V. The BMS protection voltage (3.56 V per cell) is not a charging target. For 15-cell batteries, do not use profiles for 51.2 V or for lead-acid batteries.
Is the inverter communication cable included?
For 48 V and 51.2 V batteries with BMS+ (RC variants), yes, depending on the configuration ordered. For 12.8 V and 25.6 V packs we supply it at extra cost or make one to measure.
Can I add another battery later?
Variants with BMS+ (BK8K-RC and the 48/51.2 V RC series) can be connected in parallel; up to 16 batteries with the same BMS version can be addressed. Each battery is connected separately to the DC busbar with cables of the same length and cross-section — daisy-chaining power cables from battery to battery is not permitted. For more than two batteries we go through the set-up with you in advance.
What is the difference between the AkuBox and a compression box?
The compression box keeps the cells clamped, which benefits their life especially under high load; it can stand horizontally or vertically. It is an open design, so it belongs in a lockable technical room. The AkuBox is a closed enclosure that protects the battery from damage and unauthorised tampering — made of plastic for 12.8 and 25.6 V. The metal AkuBox BK16A-RC also has a built-in display and an isolator switch.
How many cycles will the battery last?
Packs built from EVE LF280K and MB31 cells last 8,000 cycles until capacity drops to 70 %, 105 Ah packs 4,000 cycles to 80 % (cell manufacturer's data at 25 °C). Actual life depends on temperature, currents and depth of discharge.
How should I store the battery over winter?
If the battery will be out of use for more than a week, switch it off. Store it in a dry place, charged to roughly 40–80 %, and top it up every three months. Never leave it fully discharged.
How can I monitor the battery remotely?
The BAKOM BMS app connects to the battery via Bluetooth. The BAKOM Cloud web portal then keeps your batteries, measurement history and settings in one place — you add a battery to your account with the QR code on its label. More on the App page.
Am I allowed to change the BMS settings?
We set the protection parameters in the workshop according to the battery type. Normal user functions in the BAKOM BMS app do not void the warranty; changing the protection configuration, changing the administrator password or modifying the wiring does.
Interested in the 12VBK8A-L?
Write to us.
Add the quantity, the type of inverter or appliance and your timing. We check that the pack suits your system and send a quote with a delivery date.
- baterie@bakom.czInquiries, orders and technical questions
- Bronislava Baxová
- +420 737 344 853Orders, lead times, invoices and dispatch
- Petr Baxa
- +420 603 552 577Production, wiring of batteries and Deye inverters
- Michal Komenda
- +420 602 564 571Technical matters, off-grid systems and Victron, BAKOM BMS app
- Workshops
- Svrčovec near Klatovy and Krmelín near OstravaVisits and collection by appointment only