Are the 32 Lithium Cells from China any good ?

So how did the LF280 LiFePo4 EVE cells direct from China via Docan Power Tech perform on the capacity test ? Was it worth it ?

Answer: YES and NO. Depends on one's expectations, as explained below.

My take ? I would order them again, seeing the strong price / performance value. Might try another supplier, though, to gain more experience.

Performance of the cells

First, a few words on context so the results can be properly interpreted. Once the initial testing issues were solved, 2 of the cells previously measured at low temperature were retested:

Cell #16 clearly was an outlier at 264AH. After restesting at 25°C it delivered 274AH. That's still a FAIL, clearly out of spec
Cell #6 previously measured 273.3 but then reached 279.4 at 25°C
So, cells above 273 at low temp should reach close to 280AH at 25°C
This ~6AH gain was added to the 15 cells initially tested at low temp. No time to retest them all. But that is probably too simplistic math as it makes them all pass now 🤔

Performance summary:

Only 4 cells actually measured at 280AH or higher. And the average for the cells tested at 25°C is 278.8AH.

The capacity specification for these LF280 cells is as follows, per the EVE spec initially provided by the seller:

No cell came even close to the 285AH typical value. Most failed to reach 280, although not by much as all but one were less than 1% short.

Interestingly, other DIYers, building home solar systems, have measured their LF280 cells from the same supplier between 280 and 284AH. That's almost 2% above my experience.

However, this will definitely meet this van's needs, and the price / capacity value is great. But if the cells don't even meet the most crucial spec (capacity), how can we trust that they meet their other specs: cycles, reliability, longevity... ?

Performance of the supplier and seller

The cells were procured on Alibaba from the seller Jenny Wu at Docan Power Tech.

It was useful to meet their US team at the warehouse in Houston, and be able to inspect and measure each cell on site before signing off on them. Definitely increased my confidence in this supplier's operation and legitimacy. Note: apparently they also carry products from EZeal and EFest.

Jenny was very responsive, even after the money transfer, and provided clear, timely and on topic support on both technicals and logistics. What a breeze of fresh air compared to many online sellers 👍

She offered, unprompted, to replace the out-of-spec cell #16, at no charge and without having to ship it back. The new cell showed up only a few days later. That's one of the benefits from picking a supplier with a warehouse in country.

However, the EVE brand does not appear on the cells, only Docan Power. Though I have not tried to decode the barcode and numbers on the top:

And to repeated questions on why some cells were not meeting the minimum 280AH value, the only response was "There are other factors that can affect the testing result". With no response to "What might those be?" enquiries 🤔

The only hint I found came from learning that Docan also test the cells themselves, instead of simply reselling brand new EVE cells. That's a huge effort, investment, and time sink. Why would they do so if EVE actually manufactures them ? Indeed, cell capacity testing is integral to the manufacturing of Lithium cells, during the weeks-long Formation & Aging production steps(*).

After getting more details on Docan's testing process and a picture of their test racks, it reinforced my (unproven) suspicion that the cells were likely produced by EVE but rejected due to marginal capacity or other reason. Then they might have been sold to suppliers like Docan that sort them out further and sell the ones in the 278-280 range as genuine meet-the-spec EVE cells. Although, I have no proof of that, and other customers have reported 280-284AH across large numbers of cells.

Final conclusion

So, there we have it: was it worth it ? YES ! Great value, and excellent support from Jenny Wu.

Did the cells meet the specs ? Some, yes. But many were close to 1% short. And the seller + supplier did not unequivocally stand behind the claimed specs.

I am completely satisfied with the final outcome, but...