Bms burning out after connecting balance wires

I have a 60amp bms that i am connecting to a 10s 3p 36v battery pack.i have only a P- and B- plus balance wired with black negative and red positive on each end.

I require a break for charger (and also want to add on/off switch).i have triple checked all soldering and followed diagrams from other builders on this forum however my bms smokes up once i plug in balance cables.any ideas where im going wrong or videos/images i can download.Usually working with bms that have 3 cables including the charge one.


Plenty of info in this thread on wiring…

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The most important diagram is the one of your BMS, link? In general it’s better to fully understand how a BMS works before connecting.

It seems like all your connections are correct (if discharge/charge is same port). Did you measure the increasing voltage from cell 1 to 10 on balance plug to get sure if the order is right?

If you mixed up the order of balance wires the BMS would smoke but it can also be faulty.

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Yes i did follow all balance wires and they all jumped up 4v till end 36v that is from first red working down to the end black…thanks for the reply mate just cant seem to pinpoint the issue

What did you plug in first, balance leads or main leads? Some bms modules can be killed from plugging in the balance leads first

Just now i tried plugging in balance first as i had plugged balance in last and still smoking up.these balance cables are definitely in correctly getting frustrated

Thanks mate have checked these out

Is the first lead of the balance wires connected to the main negative battery lead or the positive one?

And some more photos might help

Black balance wire is connected to battery pack end negative and last red balance wire is connected to start positive red of battery pack. In terms of correct position on actual bms the left has a -negative symbol and the right has the +positive symbol so one assumes this is correct24


Hmm…yes this is correct, I’m not sure what else could be wrong with the wiring. It seems it may actually be a problem with the bms, maybe an internal short

I have now tried 2 of the same bms and same result…perhaps the rating is not correct however it is a 36v bms with 60amp

Thanks for your replys,i appreciate the help…might just have to minus the bms till i figure it out

Do you have a link to the BMS you bought?

Isn’t black supposed to be the first and a red at the end with the full voltage reading of your pack?

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@Rions first black goes to the negative of the first cell group.


It was off ebay will look at purchase history

Looking at your video link and diagram this is the same order as i have my wires in??? Sorry not sure if i understand what it is your refering to.any help is of course appreciated

Oh sorry think getting you- iv started with positive to begin sequence whereas it should start with negative right?

Yes it starts with the negative, the black wire connects to the main negative lead of the battery and then each wire after that connects each series connection in sequence