P group died, in need of spot welder

I just completed my board a week ago, it’s a 12s4p, dual 6374 on hummies deck with bergimeister wheels. Everything looked good, cells were balanced before charging, perfectly balanced after charging, I bolted it all up and have been riding a few times since, but it seemed like my voltage was dropping faster than it should. Yesterday I took the enclosure off and one of my p groups was dead, reading less than a volt.

Really glad that I purchaced 4 extra cells in case this happened, however I dont have my spot welder, i borrowed it to a friend, the arduino broke and its currently on its was to south korea.

Would someone be willing to spot weld these 4 cells for me? I’ll pay you a couple bucks for your time or i have a few items I’d be willing to trade.

You should contact @hyperIon2

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was it bms that killed it?

To save everyone time, OP is in Utah. I’d offer but I’m in dirty jersey, so shipping would be slow.

Huh I thought It would be @hyperIon1

Benjamin does the batteries, mostly :slight_smile:

I shouldve listed that, I expect that I’ll need to ship these. I doubt theres anyone close buy who could help, but if there is that’d be great!

We Keep @hyerion2 swamped with work, ha. I think its been months since he’s been on the forum, a good thing so he can focus on these badass batteries for you guys. We feed him occasionally and let him out to test builds…


As for your problem, @Colson003 you can’t just throw 4 new cells in a pack. It first has to be conditioned for the addition of the new group. ( bringing all P groups to the same voltage and then adding it to the pack. If you don’t get the volts of each group close to the same you will throw the bms off and the pack will be unbalanced and never reach full charge


I have the tools to get it all balanced. I think the 4 extra cells are all at 3.44 and the rest of the pack is all at 3.25.