How to tell if a bms is fried

My bms got very hot and after it finished charging o checked all the voltages and all seemed fine but when I plugged in my antispark thought I heard a pop but not sure if I did. There are no burn marks on the bms.

How hot? Can you leave your finger on it indefinitely, or how long until you have to pull your finger off because it’s burning you? What parts are hot? Circle them in a photo please

The whole thing gets hot and I can only put my finger on it for a few seconds.

I can post a pic when I get home from schools

Immediately unplug it from your battery pack.

Do you own a multimeter? If so, can you read off the voltages from the battery connector after plugging it into your charger?

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4.0, 8.2,12.4,16.6,20.8,25.0,29.2,33.4,37.6,41.8,46.0,50.2

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Your first pack is out of balance. It’s POSSIBLE that the BMS was hot because it was balancing. Is this the first time you charged the pack?

What parts are hot? Circle them in a photo please

It’s the first time balancing the pack. And the whole bms got very hot not just one spot

Also only the first cell is out of balance

Well if the BMS is outputting the right voltages, and isn’t dangerously hot, I guess there isn’t an issue.

Most BMS’s have a balance limit of a few mA so it shouldn’t get hot when balancing. When charging it could be pushing several amps, but again I’d expect it to get warm not hot. :confused:

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No it gets hot. Should I just use a heatsink and call it a day or is it a problem?

Should I be concerned

Leave it on the charger for a long time if it’s the first charge. See if the low P-group rises. It may take a long time or days if it’s the first charge. Report back with findings