StuInFH said:
Battery arrived with digital display on battery showing 88%.
Voltage at terminals was 41V.
What specifically is this battery supposed to be?
Is it a 52v (14s), 48v (13s), 72v (20s), or what?
Knowing what it is supposed to be helps tell you something about it's present state.
For instance, 41v is close to full for a 36v pack, but is beyond completely dead for a 72v pack, and would imply a destroyed battery, too discharged to ever be safe to recharge. For a 52v pack it's very discharged, but typically not unsafe to recharge. For a 48v pack, it's almost empty but not quite. But there's no way that is 88% full for any pack size listed above (far too high for 48-72v, too low for 36v).
But...it's more likely given the other behavior that the BMS has shutdown to protect the battery from overdischarge or overcharge, so any voltage you read on the output is just a leakage of the actual voltage.
To find out what the *real* pack state is, you would have to open it up and check the voltage at the main cell block + and - wires, before the BMS.
Then you can also measure the individual BMS cell sense wire voltages, measuring between every two of them. (and possibly between the main negative and the first one, and the main positive and the last one). If all are the same voltage, the cells are balanced and the wires are good. If not, something is wrong with that cell group or it's wiring (or both), or the channel on the BMS (sometimes the balancer gets stuck on and drains the connected cells).
Did rough handling likely cause physical damage to one or more cells/the pack?
You'd have to open it completely up and examine it carefully to determine that.
May also require continuity tests between the cell interconnects and the cells, or voltage readings between them with an applied load on the pack, to ensure none of the interconnects have disconnected from cells.