new LiFePO4 cells are here

jstept's picture

I ordered two new 20Ah LiFePO4 cells from Sam at Yesa on Tuesday to replace the two that were damaged (see "Fire is Bad"). Cost was $70 per cell and shipping from Hong Kong was $45. The cells arrived last night along with an individual cell charger. Sam asked me to send him a picture of the cell arrangement in the pack so he could have the tabs soldered in the correct orientation.

36V_20Ah.jpg
The red arrows indicate the bad cells.

Yesa's website gives pretty good instructions for replacing cells in a battery pack. I will apparently need use the single-cell charger on the new cells to adjust their voltage to match the older cells before the BMS can take over. I've also got some other fire-related damage to deal with, like replacing one of the charger wires with melted insulation, and finding some HDPE sheets and building a case for the repaired battery pack. Unfortunately my work schedule will probably not allow me to get this done until next weekend or later.

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