Bms pack voltage error  


New Member
Joined:5 months  ago
Posts: 1
30/03/2019 3:46 pm  


I made a 14s pack using the vruzend 1.5 kit and the vruzend bms.

The pack is working fine but i think something is wrong with the bms.

The problem is that when i charge the pack to 100% using the vruzend charger the total voltage measuring after the bms is only 56.4 volts.

When i measure directly at the pack the voltage is 58.8v

Is this normal?




Micah (Vruzend Rep)
Street cred = 5 Ah Admin
Joined:2 years  ago
Posts: 484
02/04/2019 6:20 pm  

No, there shouldn't normally be a gap that large. It sounds like there could be a BMS connection issue. Are you sure you have it connected correctly?

Street cred = 10 mAh
Joined:2 years  ago
Posts: 3
06/06/2019 12:04 pm  

I had a similar problem using cells and a BMS from a defective pack and building it up using a Vruzend V2 kit. 

Each cell was tested at 3.67 volts. Each 2p cell group was tested at 3.67 volts. The 10s2p pack was tested at 36.7 volts. All as expected. However the BMS output tested at 25.7 volts. I guess that the BMS was only taking power from 7 cell groups but I do not know if that was the case or why. I checked the wiring and realised that I'd not wired the balance wires in order. I.e.The first positive balance wire to the first cell group, the second positive balance wire to the second cell group and so on. I reattached the positive balance wires in order of the cell groups. The BMS output voltage now equalled the pack voltage of 36.7 volts. 

Maybe you have one balance wire that isn't in order and the BMS is ignoring the cell group it is attached to.  The BMS neither charges or discharged the cell group which may explain the odd voltage reading you are getting.


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