✅ E-bike battery shows 54V at the terminals but BMS cuts out under load. Is the pack dead?
@spokes_n_sprockets
Oct 15, 2026 · 1.3k views
48V 13S pack, about 400 cycles. Charges to 54.6, rides for 30 seconds then dead, recovers after a minute. One cell group reading 3.1V while others are 4.1.
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2 replies
✅ Accepted solution
One group at 3.1 with the rest at 4.1 is a failed group, not a failed pack. The BMS is doing its job cutting out when that group sags under load. You can replace the group if you can spot-weld; if not, a battery shop can for well under the price of a new pack. Do not charge it in the house until then.
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Figured. Going to try the rebuild, will post it in Show & Tell if it does not catch fire.
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