Is it worth building a DIY LiFePO4 battery for a van?

For large banks (300Ah+), DIY can save $200–$500 vs assembled batteries. For smaller builds (100–200Ah), the savings are marginal given that assembled LiTime batteries now cost ~$280/100Ah. DIY requires more research, cell sourcing, BMS selection, and assembly time — worth it for experienced builders who want maximum capacity for minimum cost.

What cells should I use for a DIY LiFePO4 van battery?

EVE 280Ah prismatic cells are the most popular choice for van DIY builds — widely available from suppliers like Amy Wan (AliExpress) or US distributors, well-documented specs, and a large community sharing build experience. Four cells in series = 12V 280Ah battery. Each cell is approximately 3.2V × 280Ah = 896Wh per cell.

DIY LiFePO4 Battery Build for a Van (Cells + BMS)

Building your own LiFePO4 battery from prismatic cells and a separate BMS is a growing trend in the van build community. Here's the realistic picture of cost, complexity, and whether it makes sense for your build.

Why build DIY vs buy assembled?

Cost: Assembled batteries include the cost of a completed BMS, marketing, brand support, and retail markup. With the right cells and a solid BMS, you can build 280Ah for roughly the cost of a quality assembled 100–150Ah battery.

Capacity: Standard assembled batteries come in 50, 100, 200, 300Ah. DIY lets you build exactly 280Ah (4× EVE cells) or 560Ah (8× EVE cells, or 280Ah in 24V) without paying for a non-standard size.

Learning: Understanding what's inside the battery helps you maintain and troubleshoot it.

Common cell choices

EVE 280Ah prismatic cells (~$70–$90/cell from US suppliers; $50–$65/cell from AliExpress with proper vetting):

3.2V nominal, 280Ah = 896Wh per cell
Four cells in series = 12V, 280Ah = 3,360Wh (~$280–$360 in cells alone from US)
Grade A cells from reputable suppliers match or exceed assembled battery specifications

CATL 200Ah prismatic cells: Higher quality but harder to source; popular in electric vehicle applications; used by some serious van builders.

LiTime/LISHEN 100Ah cells: Some builders buy pre-matched cells from battery suppliers rather than extracting cells from assembled batteries.

Where to source: Docan (US distributor), Amy Wan (AliExpress — order from her specifically, she's vetted in the community), Alibaba with careful vetting. Avoid random AliExpress sellers without community verification — misrepresented capacity is common.

BMS selection

The BMS is the most critical component. For a 280Ah DIY bank:

JK BMS (Jikong): Most popular in the van DIY community. Active balancer, Bluetooth monitoring, reliable over-current protection. 100A–200A versions for van loads. ~$60–$120.
Daly BMS: Cheaper, adequate for many builds, but passive balancing only and less refined app. ~$30–$60.
Victron Smart BMS: Premium option for Victron-ecosystem integration. $150+.

Choose a BMS rated for at least 100A continuous, with active cell balancing for a 280Ah bank. Active balancing prevents capacity drift between cells in a large pack.

Build steps (overview)

Source cells — verify grade and capacity before buying
Top-balance cells — charge each cell to 3.65V individually to match state of charge before assembly
Assemble in series — connect positive of cell 1 to negative of cell 2, etc. (4 cells in series for 12V)
Install bus bars — compress cells together, install aluminum or copper bus bars between terminals
Install BMS — connect to cell terminals for monitoring; connect main positive and negative through BMS
Configure BMS — set cell count, voltage thresholds, current limits via app
Enclose and secure — wood, aluminum, or plastic enclosure; label terminals clearly