Lifepower4 unbalanced SOC and won’t charge

[Jack Rabbit Off Grid]

I have 6 Lifepower4 48v. they are not discharging or charging at the same rate. I just noticed this today. I may have caused this problem with my conservative charge profile. 55.20 bulk absorption and 53.60v float. Now I have to figure out a way to fix this.


1. 98%
2. 75%
3. 87%
4. 100%
5. 75%
6. 64%

I isolated 6 to charge it separately with the Eg4 charger and it won’t charge. It starts to charge the the battery voltage gets to 56.8 and it stops charging.

any ideas?

 

[niktak11]

One of the cells is likely hitting 3.65V

 

[TacomaJoe]

Basics: Is each of these batteries connected to a common bus with the same size/length cable? If the wires are set up correctly, I'd think cell balance. Each battery has to be at the same voltage but I'm thinking the lower ones have some higher voltage cells messing up the BMS.

 

[Jack Rabbit Off Grid]

You are both correct.

I turned off and disconnected those 3 batteries from the buss bars. Turned them back on and pushed the reset on ea.
reconnected the charger to ea. Separately. The charger would run for about 10 sec. then all the cell voltages went up from 3.3ish to 3.5ish. and the charger would shut off. After that all 3 batteries had one cell in each that had a cell over voltage alarm at 3.560 to 3.564 and said (BAL) in front of the voltage of that cell.

I guess my conservative charging profile won’t let the packs balance correctly. So I set the Victron back to its factory settings of 56.8 absorb and 54.0v float.

Guess I’ll see what happens.

 

[Kornbread]

At what voltage does the basic eg4 bms begin the balance process?

 

[Jack Rabbit Off Grid]

I should have taken more photos.

 

[Jack Rabbit Off Grid]

I also forgot to mention that the SOC inductors jumped strait to 100% in the matter of seconds of the charger being connected. Like the BMS had a brain fart. My SCC let them sit at absorption 56.8v for the rest of the day until I lost adequate sun. The few times I checked the 3 packs were still in balance.

So I guess trying to charge them so conservative won’t let them balance. Ive read several posts where people charge at such low voltage but not sure if they were retail made rack batteries.

 

[TacomaJoe]

The idea is to sneak up slowly at the top end to give the BMS time to balance. I'm running 4S and at 14.2 float I was getting a BMS cutout for high cell voltage (3.65V). Dropped it down to 14.0V and no more over voltage. You don't want the BMS to cut out on one battery because when it re-connects then it will get a flush from the other batteries.