Reason for not balancing properly last group of cells?
- Thread starter robb
- Start date
robb
10 W
Meant to add. As you can see 13th block of cells is not balancing despite the bluetooth BMS measuring voltage. What are the possible reasons for this or is it a faulty bms?
The BMS can only balance at a very low current. Depending on your pack size, it could take weeks. If you manually charge the low cell group, the BMS would have a better chance of keeping it balanced. Balancing can only happen during charging and when the cells are above 3.8v. The problem is the charger will turn off when it sees the current drop at end of charge so balancing stops. Adding just enough load to the pack output to keep the charger going is one way around this. Something like a light bulb or big resistor. Then let it cook for a few days.
Also try looking at the voltages while it's actively charging. If you see much less difference while charging, it could be from a poor pack wiring layout. Voltage drop in the pack wiring might make the end cell look higher than it really is during charging.
Also try looking at the voltages while it's actively charging. If you see much less difference while charging, it could be from a poor pack wiring layout. Voltage drop in the pack wiring might make the end cell look higher than it really is during charging.
CrimpDaddy
1 mW
- Joined
- Apr 22, 2019
- Messages
- 10
Looks like its working fine to me... the BMS isn't going to charge cell group 13. Its going to pull down cell groups 1-12 so its in line with group 13.
In a nutshell, the BMS will not charge group 13, do not expect the voltage to increase. It is going to discharge the rest so it all levels out, which is why the other cell groups show a B, showing that they are discharging.
The B also doesn't stay on all the time, they cycle and flicker on and off. Either way, it takes days and days to balance if the pack is large.
I agree with the other comments, I use this board mainly for monitoring and protection only.
In a nutshell, the BMS will not charge group 13, do not expect the voltage to increase. It is going to discharge the rest so it all levels out, which is why the other cell groups show a B, showing that they are discharging.
The B also doesn't stay on all the time, they cycle and flicker on and off. Either way, it takes days and days to balance if the pack is large.
I agree with the other comments, I use this board mainly for monitoring and protection only.
