0V on BMS P- terminal  


Street cred = 10 mAh
Joined:2 years  ago
Posts: 3
09/11/2019 11:15 am  

I've got a commercially manufactured 36v battery that has 0 v on the  outgoing power terminals.  I took the cover off and found 38v on the actual battery terminals and of course 38v going into the BMS.  I figured it had to be a BMS failure so I replaced it with one of your BMS's.  Same problem.  Call this BMS A.  I figured I must have gotten unlucky and had two bad BMS's so I opened up a working  DIY battery and took the BMS out of it (call this BMS B) and swapped it with BMS A.  BMS A worked fine when I attached it to my DIY battery; 38v on the output side just as I would expect.  I hooked up BMS B to the manufactured battery and it had 0V on the output side!  As you know the wiring is simple.  I have the wire from the ground side of #1 bank of the battery going to B- on the BMS and I'm looking for voltage between the positive terminal of battery bank 10  and the P- terminal on the BMS.  I've tried the setup with the balancing wires connected AND disconnected.  No change.   Any ideas?


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