I have suddenly NO MORE BRAKES

Your -B looks mostly flowed.

But the -P looks like it was tinned, and is mostly sitting on top of the tinned solder pad. Could you reflow that pad?

Cool so it looks like your discharging through the BMS. And that -P joint could be the culprit

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Heating the iron right now

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I have a BMS where C- is used for charge AND discharge…

I soledred into P- because it was already like that with the old BMS

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That’s a first for me

Oh that’s fine man. Was just trying to understand why this could be happening. If it is not that -P joint, then it is the BMS itself limiting current. If the BMS is limiting current it can only be one of a couple things

-BMS is improperly rated(amps) -series connection in the battery pack is weak causing a voltage spike -one of the parallel packs is weak, is not balanced and the BMS cuts off because of the I’m balance for safety, or has very bad(high) internal resistance.

After you reflow that -P can you put a meter on each of your cell connections on the BMS JST plug and verify each series connection reads the same voltage or within 0.02 volts of one another?

I think there’s enough tin :stuck_out_tongue: Yet i still get over voltage fault

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Will need to buy a multimeter to do that, i will check all connections and voltage tomorrow.

It’s weird the thing that bother me the most is that i used my last sheet of heatshrink for nothing hahah

Yea looks fine now

At this point I would suspect it is either a weak group or a bad series connection… verify voltage for me and tag me when you do. Well get it figured out I’m sure.

Will do. Thanks for your help, it’s much appreciated !

Something you wanna know maybe is that i replaced the BMS because last one had 3 mosfets burning during a ride The battery pack is brand new When the bms fried I visually checked all the 18650’s connections and they seemed fine to me but i’m not an expert

Ah yeah. It’s essentially the same as connecting to the -P, the pad is probably shared trace.

Do you have a link to your BMS?

No i don’t. It’s weird because i can still charge the battery no problem

More pics in case it can help

Get a BT module or a UART data logger to pinpoint the error if this happens again.

Yeah i will try with meter app to see… i don’t even know if the battery is the problem eveything seems in perfect shape. I have no clue of what is causing the problem,maybe it’s because i m using 12S ? Never had a single issue with a 10S battery

Btw since you are not using -C I think youre bypassing the balancing function

Unless -C ,-P is the same trace


I can’t tell. Maybe if i solder it into C- it will change something ?