EEL Battery Box Balancing Issues

[Surferdudemi]

I've got two of the EEL battery boxes. The first was assembled with 271AH cells and I recently built another with the Envision 304 grade B cells. The new one is the latest version of the larger box. It has had strange balancing issues. Groups of 4 or 8 cells are balancing to the same voltage in the group, but the groups balance to different levels between them. And this issue doesn't stay the same cycle to cycle. Cells 1-8 would be balanced, and 9-16 would be balanced, but the two groups would be different, which causes cut-out and overvoltage issues. Then cells 5-8 were balanced, but didn't match other groups of 4.

Tried working on the with Howard a few times, but the reply was basically to wait and the BMS would take care of it (even with the pack turned off, which seems odd). So I've got no resolution to this.

Has anyone else had this problem and solved it?

 

[740GLE]

What brand BMS are in these?

 

[Quattrohead]

Seplos, but V2 or V3 on the newer one ?

 

[solardanman]

I've got two of the EEL battery boxes. The first was assembled with 271AH cells and I recently built another with the Envision 304 grade B cells. The new one is the latest version of the larger box. It has had strange balancing issues. Groups of 4 or 8 cells are balancing to the same voltage in the group, but the groups balance to different levels between them. And this issue doesn't stay the same cycle to cycle. Cells 1-8 would be balanced, and 9-16 would be balanced, but the two groups would be different, which causes cut-out and overvoltage issues. Then cells 5-8 were balanced, but didn't match other groups of 4.

Tried working on the with Howard a few times, but the reply was basically to wait and the BMS would take care of it (even with the pack turned off, which seems odd). So I've got no resolution to this.

Has anyone else had this problem and solved it?

I have a similar issue with older batteries just purchased with Howard and he ignored all my concerns. I am now in dispute with the help of paypal to get my money back. The issue of the imbalance if not for a defective cell could a resistance between the bus bars and the batteries.

 

[Surferdudemi]

I have a similar issue with older batteries just purchased with Howard and he ignored all my concerns. I am now in dispute with the help of paypal to get my money back. The issue of the imbalance if not for a defective cell could a resistance between the bus bars and the batteries.

Resistance between bus bars and battery seems unlikely, when I'm pulling 100A or so into the SkyBox inverter. Likewise when it's pushing 40A into the batteries. The out-of-balance groups switch up over time, too. If it were just resistance, it should be the same cell or group of cells consistently I would think. I kind of got the same thing with Howard. He would reply fairly quickly, but gave me the runaround with no actual solution.

 

[solardanman]

Resistance between bus bars and battery seems unlikely, when I'm pulling 100A or so into the SkyBox inverter. Likewise when it's pushing 40A into the batteries. The out-of-balance groups switch up over time, too. If it were just resistance, it should be the same cell or group of cells consistently I would think. I kind of got the same thing with Howard. He would reply fairly quickly, but gave me the runaround with no actual solution.

Checking here to see if I can find a clue for you.

After watching this with v3 looks like balancing is quite a challenge for the Seplos bms

 

[LikeWithMike]

What batteries and BMS do ya'll have?

I have the larger wall mount DIY on the way and order of the Eve 306k cells from them two via separate orders.

 

[Surferdudemi]

Checking here to see if I can find a clue for you.

After watching this with v3 looks like balancing is quite a challenge for the Seplos bms

I'll have to open it up and ee which version of the BMS I've got. I don't' recall seeing relays when I put it together. The parameters are programmable via USB connection to my laptop with their app.