LFP (lithium iron phosphate) cells are more available and cheaper than they've ever been. The question is knowing where to buy them, what to expect from different sources, and how to pick the right cell for your project. Start with Battery Hookup with code CS5 — it's the best US source for most applications.

Battery Hookup: the main recommendation

Battery Hookup is a US-based battery surplus and overstock retailer. They buy tested cells and packs from manufacturers and OEMs, test them before listing, and sell a mix of new and overstock inventory. What makes them the right call for most builders:

  • US-based shipping: Ships from domestic warehouses. No customs, no long waits, no import headaches.
  • Tested and graded: They don't just relist what they receive. Cells are tested and graded before listing, with capacity and IR specs noted.
  • Variety: They regularly carry large-format LFP prismatic cells (EVE, CALB, CATL), cylindrical LFP, pouch cells, and pre-built modules.
  • CS5 discount: Use code CS5 at checkout for a discount on most orders.

The inventory changes frequently — what's in stock today may be gone next week. The Cell Database LFP page has specs for the cell models they commonly carry, so you can know what you're looking at before you buy.

New vs overstock cells

Battery Hookup sells both new and overstock cells. Here's what to expect from each:

New cells

Cells that haven't been used. Spec'd at rated capacity and typical IR for the model. These are safe to use directly in a pack without extensive testing, though testing a random sample is still good practice.

Overstock/surplus cells

Cells that were originally bought for a commercial project and didn't get used, or that came from a system that was disassembled early. Overstock LFP prismatic cells often have very low cycle counts — sometimes under 50 cycles — and test close to rated capacity. Battery Hookup lists capacity and cycle count data when they have it.

Overstock is usually cheaper per Wh than new. The main gotcha: capacity can vary between lots. If you're building a pack from overstock cells, test and sort them before assembly and try to get cells from the same lot.

Choosing the right LFP cell for your project

LFP cells come in multiple form factors, and the right one depends on what you're building.

Powerwall / home storage

Large-format prismatic LFP cells (EVE 280Ah, CALB 314Ah, CATL 280Ah). These are the standard for home storage in 2026. Wire 16 in series for a 48V system. Each cell has threaded terminal posts for bus bars — no spot welding required.

Use the Powerwall Planner to size your system and see current Battery Hookup pricing with the CS5 discount.

E-bike or EV

Smaller LFP prismatic cells or cylindrical LFP cells. LFP is heavier than NMC for the same capacity, so it's less common for e-bikes, but some builders prefer it for the cycle life and safety margin. Battery Hookup sometimes carries suitable formats — check their current inventory for LFP cylindrical or smaller prismatic cells.

12V system (van, camper, marine)

4S LFP gives you a 12.8V nominal system (13V charged). Options include bolt-together 38120 cylindrical cells (see the 38120 battery guide) or prismatic cells in a 4S configuration with a compression frame. Prismatic cells are easier to work with at this scale.

For a simple 12V LFP drop-in replacement, buy a pre-built 12V LFP battery rather than building from cells — the cost difference is minimal at small capacities and the pre-built units include a built-in BMS.

What to look for when buying

  • Capacity: Listed in Ah. For large prismatic cells, 280Ah is the most common size. 314Ah cells are available but less widely stocked. Verify the listed capacity against a test sample if buying overstock.
  • Grade: Grade A cells are full-spec, tested to rated capacity. Grade B cells are tested but have minor cosmetic issues or slightly lower capacity. Avoid unlabeled grade cells — you don't know what you're getting.
  • Terminal type: Threaded vs non-threaded posts. Prismatic cells with M6 or M8 threaded posts connect cleanly with bus bars. Cells with flat pads or non-standard terminals require more creative bus bar work.
  • Cycle rating: Quality cells specify 3,000 to 6,000 cycles to 80%. Cheaper cells may list higher cycle counts without data backing it up — check what the discharge depth and test conditions are.

Other sources worth knowing

For AliExpress / direct from China: you can get cells cheaper if you're buying a large quantity and willing to deal with shipping times, import duties, and more variable QC. For most US buyers doing a single build, Battery Hookup is more practical. Direct Chinese suppliers make more sense if you're buying 50+ cells at a time and can test a sample on arrival.

eBay and local surplus: occasionally a good deal on pulled EV cells or datacenter backup packs. Capacity and condition are unknown unless tested. Good for experienced builders who can test and grade cells; risky if you're building your first pack.

FAQ

Are Battery Hookup cells real grade A?
Based on community testing, yes — their grade A listings match spec. They've built a reputation in the DIY energy storage community over several years. That said, always test a sample if you're building a large pack.
Can I buy LFP cells locally?
Rarely. Industrial battery suppliers occasionally carry LFP cells for commercial applications, but they usually sell in quantities and at prices that don't make sense for DIY builders. Online ordering is the practical approach for most people.
What's the CS5 discount code for Battery Hookup?
Use code CS5 at checkout on the Battery Hookup site. It applies to most cell listings. The discount percentage varies by product, but it's consistent and works on large-format prismatic cells.
Are prismatic LFP cells safe to ship?
Yes — LFP cells are classified as less hazardous than NMC for shipping purposes. Battery Hookup handles the shipping compliance. Large prismatic cells ship by ground freight for large orders.