Sourcing LiFePo4 cells from China

One of the best ways to source high quality large capacity OEM Lithium cells at an unbeatable price is to buy a battery pack from a 3 to 5 years old salvaged car (*)
 
For instance, it costs ~$4000 for a 24KWh Nissan Leaf pack with a few thousand miles, from long established salvage companies on Ebay, delivered to your house.
 
That's $0.17 per Wh, which is my benchmark for large capacity cells with OEM quality. Getting such cells any other way can cost 30% to 100% more.
 
However, at this time, no high volume car on American roads uses LFP cells. This will change soon, but not an option right now.

Ordering cells directly from the source, China, is the next option. Yes, large capacity LFP cells can be bought from US distributors. Reputable ones test the cells and provide great support and warranty. But at a 50% to 100% markup over the same cells, from the same boat, from the same supplier. Fantastic for peace of mind but, right now, my wallet is reeling from 2 years of runaway inflation and a van build that's a money pit.

So, onward with setting up an Alibaba account, and praying that I find a supplier that can be trusted, with good support, warranty and decipherable instructions in English. Yeah, right 😂

Here is the strategy I used to improve the odds of success:
  •   Nov'22 Update   I can not recommend this seller / company without notable caveats
  •  Used a so-far-reputable seller from a so-far-reputable company. That's Jenny Wu jennywu896@gmail.com from Docan Technology. Thanks to Ray's How to reduce the risks when buying LiFePo4 from Alibaba in-depth experience
  • Got written details on their support model should a cell not meet specs. Their term is to contact them within 15 days after delivery.
  • Bought the proper charging and test equipment, so as to test each cell right after delivery (capacity, resistance, weight, swelling, temp, etc)
  •   Update   should also have considered checking the barcode on each cell, for vendor #, date of prod, etc. Decoding: https://secondlifestorage.com/index.php?threads/how-to-quickly-identify-fake-lfp-battery-cells-part-3-%E2%80%93-qr-code.11266/
  •   Update   should also have considered weighing the cells to ensure they meet the supplier's 5.4kg (11lbs) spec. Fake cells sometimes use less matterial and are consequently lighter
  • Picked a company, Docan Tech, with a US warehouse. Reasons:
    • Freight delivery costs a lot and increases risk. Got some bad freight experiences in the last 2 years, so not doing that for fragile and valuable cells !
    • Getting defective cells from China replaced via return shipment is not realistic. Cells are classified as  hazardous material, so the shipping cost for low quantities is almost as much as the cells (many Alibaba/express vendors ignore that law). It is also prone to risks and delays, and not reimbursed.
    • A credit card company will reimburse a sale gone wrong, but only when the seller receives the defective goods back. That's guaranteed and traceable when doing so at a warehouse.
    • The new LFP system in the van must be ready for the Ouray ice festival in January. Any shipment delay or issue will throw that off.
Luckily, their warehouse is in Houston, Texas, not too far from Northern Colorado. It will cost ~$400 in gas, but that's cheaper than $550 of freight delivery, provides the advantages above, and is a great excuse for another van trip adventure.

For large electrical storage projects this 280Ah prismatic cell type is extremely popular:
Its high capacity allows to minimize the number of cells to wire in parallel, thus reducing the number of connections & cables. The rectangular form factor makes packaging simple and efficient. It is also readily available from several manufacturers and relatively affordable. 
 
Sacrebique, stop stalling ! So what did it cost ???
$132 per LF280 cell, $87 Alibaba trade assurance fee scam, $400 gas. I.e. $4711 total for 32 cells / 28KWh, or $0.164 per Wh. Sweet, same as a salvaged pack, but for brand new cells.
 
Note that this was NOT the lowest price on Alibaba. But now we know why I went with this seller from that supplier.

Was it the right choice ? I don't know yet. Cells are supposed to arrive in a couple of weeks. In the meantime:

(*) Granted that one then has to spend hours disassembling the pack, for used cells. However, an OEM pack with 30.000 miles will still deliver most of its rated capacity in stationary applications, as those are way less demanding than a driving usage. And when you need 24KWh the savings are worth it.

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