12V And 24V Lithium Batteries
12V 400Ah LiFePO4 Deep Cycle Battery
The largest 12V pack in the range: 400Ah in one IP65 ABS case at 38 kg, with a 200A smart BMS and Bluetooth monitoring.
Product Overview
The largest 12V pack in the range: 400Ah in one IP65 ABS case at 38 kg, with a 200A smart BMS and Bluetooth monitoring. It exists because a 400Ah lead-acid bank gives roughly half its rating in usable energy and weighs about three times as much - so an off-grid cabin, a large motorhome or a working boat ends up with four heavy batteries where one pack will do. Published cycle life is 3000+ deep discharge cycles.
Key benefits
Why Buyers Choose This Pack
One Case Instead Of A Bank
400Ah in a single 522 x 268 x 218 mm case removes three sets of interconnects and the voltage drop that comes with them.
200A BMS For Inverter Loads
Enough headroom for a substantial inverter surge rather than a rating that trips when the kettle and the microwave overlap.
38 kg Against Roughly Three Times That
For a vehicle or a small boat, the weight saved is payload that can be used for something else.
Bluetooth Rather Than A Voltmeter
The LiFePO4 discharge curve is nearly flat, so voltage tells you very little. Real state of charge on a phone tells you everything.
Application scenarios
Where It Is Used
- Off-grid cabins running an inverter through the evening
- Large motorhome and expedition vehicle house banks
- Working boats with substantial electrical loads
- Solar systems on a 12V bus needing a full day of autonomy
- Mobile catering, events and film power
- Backup supply for a small workshop
Who it is for
The Buyers This Pack Suits
Off-Grid And Expedition Builders
Where one large pack beats four smaller ones for reliability and install time.
Marine And Vehicle Electricians
Fitting a house bank with a real inverter load behind it.
Distributors Serving Solar Installers
Carrying the top of the 12V range for customers whose loads outgrew 200Ah.
Problems it solves
What It Fixes
Banks Built From Small Batteries
Every parallel connection is a resistance and a maintenance point. One 400Ah pack removes them.
Inverter Surge Tripping The Pack
A 200A BMS is specified for real inverter behaviour rather than average draw.
Weight Over The Axle
38 kg for 400Ah changes what a vehicle can legally carry.
Specifications
Published Figures For This Pack
Every value below comes from our own product specification. Where a figure is not published we leave it out rather than estimating it.
| Nominal voltage | 12.8 V |
|---|---|
| Capacity | 380-400 Ah consistent output |
| Dimensions | 522 x 268 x 218 mm |
| Weight | 38 kg |
| BMS current | 200 A smart BMS |
| Cycle life | 3000+ deep discharge cycles |
| Ingress protection | IP65, ABS case |
| Monitoring | Bluetooth real-time monitoring |
| Certificates | MSDS, UN38.3, CE, ROHS, UL |
| Cells and BMS | Grade A LiFePO4 cells, smart BMS |
Packing and documents
How It Ships And What Comes With It
Packing And Shipping
Packing follows UN38.3 requirements for lithium battery transport, and the carton and pallet arrangement is confirmed with the quotation for your quantity and destination. We do not publish a fixed carton specification here because it changes with order size and freight mode.
Documentation
UN38.3 and the MSDS travel with every lithium shipment, and the certificates listed in the specification table above are supplied for the model you order. Tell us the destination market at the quotation stage so the document set is planned rather than chased after the goods are built. Where a certificate we do not hold is required, we will say so rather than promise it.
Manufacturing
This pack is built at Shenzhen Sike Power Technology Co., Ltd. in Da Peng New District, Shenzhen, with cell grading, assembly, BMS integration, aging test and final inspection carried out in house. Only brand-new grade A LiFePO4 cells and a top-brand smart BMS go into it.
Download the catalogue and datasheets for the specification in PDF form.
Installation guide
Getting It Right First Time
Step 1
Measure the locker against 522 x 268 x 218 mm and check the mounting can hold 38 kg under vibration.
Step 2
Match the inverter's surge rating to the 200A BMS limit - if the inverter can exceed it, the BMS will disconnect.
Step 3
Use a DC-DC charger between an alternator and the pack; a lithium battery will draw everything an alternator can give.
Step 4
Set solar controller and shore charger to a LiFePO4 profile, not an AGM default.
Step 5
Pair the Bluetooth monitor with a shunt-based amp-hour count for the most reliable state of charge.
Comparison
How It Compares In Our Range
The 12V deep cycle range steps by capacity in a fixed set of case sizes - pick the biggest that fits the space.
| 12V 100Ah group 24 or 31 | 9.7 kg, replaces a single lead-acid battery |
|---|---|
| 12V 200Ah | 18.4 kg, 502 x 186 x 240 mm |
| 12V 300Ah | 28 kg, 522 x 268 x 218 mm |
| 12V 400Ah | 38 kg, same case as the 300Ah, maximum 12V capacity |
FAQ
12V 400Ah LiFePO4 Deep Cycle Battery Questions
Is one 400Ah pack better than four 100Ah packs?
Usually yes: fewer connections, no current-sharing imbalance between packs, and a single BMS managing all the cells. Four smaller packs win only where the space is fragmented or the weight has to be distributed.
What inverter can it run?
The 200A BMS is the limit. At 12V that is roughly 2.5 kW continuous before losses, so check your inverter's continuous and surge ratings against it.
Can I charge it from the vehicle alternator?
Through a DC-DC charger, yes. Direct connection risks overheating the alternator because the pack will accept everything it is offered.
How long will it last?
3000+ deep discharge cycles is the published rating - six to eight times a comparable lead-acid battery.
Is the case really IP65?
Yes, IP65 in an ABS case built to take shock and vibration. It is not a submersion rating.
Which certificates apply?
MSDS, UN38.3, CE, ROHS and UL.
Related products
Other Packs Buyers Look At
Applications
Sectors That Use This Pack
RV And Camping Power
12V and 24V LiFePO4 house banks from 100Ah to 400Ah, IP65, Bluetooth monitored, at about a third of the weight of lead-acid.
Marine And Trolling Motor Batteries
12V and 24V deep cycle packs for trolling motors, electronics and house loads, IP65, 3000+ cycles.
Residential Solar Storage
Powerwall, stackable and rack mount 51.2V storage for homes running solar self-consumption, tariff shifting or full off-grid.
Further reading
Guides That Cover This Pack
LiFePO4 Versus Lead-Acid For Deep Cycle Work
Why a 100Ah lithium pack replaces a 200Ah lead-acid bank, what changes about charging, and where lead-acid still makes sense.
What A Smart BMS Actually Does In A LiFePO4 Pack
The five protections, why balancing decides whether a 6000-cycle rating is real, and what current rating to specify.
Quote The 12V 400Ah LiFePO4 Deep Cycle Battery
Send the quantity, the application and the destination, and we will confirm specification, packing and lead time.