My first question on StackExchange - I was not able to find sufficient information anywhere else, so far.

I got a bunch (~150) of used Li-Ion battery cells (see picture 1). Chemistry is LiFePO4; cell type seems to be 40138 (40mm diameter, 138mm length without connector screws); imprint on cell says "9 A 0 5 - H"; barcode reads "4BF1M331-0720"; the batteries come from electric go-carts and weight is ca. 360g +/- 5g.

LiFePO4-battery cell

Unfortunately, I have no reliable information about these battery cells concerning capacity, nominal/(dis-)charge voltage etc. I was told, the cells are not produced any longer; the follow-up model is blue.

So, my question is: Does anyone out there know exactly this battery cells and can provide reliable specifications - perhaps even a data-sheet?

I started to characterize each single cell using a battery tester and a tailored test procedure, but the first cells show highly deviating results. Since I found also a lot of different specifications online about similar (but not the same) cells, I would like to assure myself with reliable information.

Thanks a lot!

  • \$\begingroup\$ I don't have enough reputation to comment. You mention that they are from "electric go-carts", do you know the exact brand/model it might help identify the cells used. \$\endgroup\$
    – Pop24
    Commented Sep 26, 2017 at 7:36
  • \$\begingroup\$ You can approximate capacity from similar new cells. But highly variable results from used cells is probably to be expected, you'll probably have to screen them into batches with similar characteristics. \$\endgroup\$
    – user16324
    Commented Sep 26, 2017 at 9:23
  • \$\begingroup\$ Thanks a lot for your feedback. @Pop24: I have not seen the go-carts, but I was told the were manufactured by the Swiss company Tomkart (www.tomkart.ch). I already contacted Tomkart, but until now I got no response. Since I do not know the exact model and their current models use newer types of batteries, I was not able to find out more in this direction. \$\endgroup\$
    – phyfficus
    Commented Sep 26, 2017 at 12:38
  • \$\begingroup\$ Thanks a lot, too. @Brian Drummond: My measurements show capacities between 10.000mAh and 12.000mAh. But since all the cells are used, I am very uncertain, whether the original capacity is 12.000mAh, 14.000mAh or even higher. \$\endgroup\$
    – phyfficus
    Commented Sep 26, 2017 at 12:43

1 Answer 1


This is a 40138 LifePO4 made by PSI Taiwan. 10 Ah, 3.3V. Later sold by LifeBatt as 40138F1.


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