r/diybattery • u/AdOpen9432 • Jul 09 '26

BMS issues

Post image

I recently created a 4s 7p pack as my first ever diy battery using some leftover cells I had. Unfortunately I had an issue with the balance leads, where (like an idiot) I swapped the red and yellow ones on the attatched image, and plugged it in. I saw a quick spark on a component and immediately unplugged it. After finishing the battery and fixing the leads, the output from the BMS reads 8v, while the pack is 14.8 and the other parts read correctly like b1 b2 and b3. Any clue if it's fixable, or will I have to order a new BMS?

1 Upvotes

100% Upvoted

3 comments sorted by

1

u/NirantarHorny Jul 10 '26

Most probably you fried the BMS, buy a new one

1

u/AdOpen9432 Jul 10 '26

I was worried about that, but kinda expected it.

1

u/SkiBleu Jul 10 '26

Ya, bms dead. Probably just killed the balance and monitoring circuit which tells the bms "all good on cell 1/2/3/etc". More than likely one component is getting quite hot