EG4 LiFePOWER4 48v undervoltage cell and slow charging

[PhotonsAreNeat]

Buddy has 3 LiFePOWER4s 48v, just updated them today to 3.37 (unrelated to issue). Since mid last week, the top battery of the rack of 3 had all of it's SOC lights on, but it's voltage was about 50v, while the other 2 were at 52v. I checked them today, and they were dead from yesterday's all-day rain. Powered them up, and the top one has a solid alarm light. BMS tools showed one cell at 2.4v (UV). As the solar started charging it, the max cell difference started dropping, so it seems like it's balancing it. I started the generator and chargeverter at 90a, 56.4v, and the other two batteries were taking about 35+ amps, while this one was only taking 10 amps. Will the BMS limit charge current like this? Or is this cell damaged and now it's IR is high, slowing charging of the pack?

 

[MaikaiLifeDIY]

The BMS (naranda type) in the LifePower4 batteries uses MOSFETs to passively balance the charge between the 16 cells as it inflows to the battery. Most likely you need to get the batteries into a float stage for many hours to let the cells gradually balance.

 

[EG4_Jared]

Buddy has 3 LiFePOWER4s 48v, just updated them today to 3.37 (unrelated to issue). Since mid last week, the top battery of the rack of 3 had all of it's SOC lights on, but it's voltage was about 50v, while the other 2 were at 52v. I checked them today, and they were dead from yesterday's all-day rain. Powered them up, and the top one has a solid alarm light. BMS tools showed one cell at 2.4v (UV). As the solar started charging it, the max cell difference started dropping, so it seems like it's balancing it. I started the generator and chargeverter at 90a, 56.4v, and the other two batteries were taking about 35+ amps, while this one was only taking 10 amps. Will the BMS limit charge current like this? Or is this cell damaged and now it's IR is high, slowing charging of the pack?

The cells will need to be balanced. I suggest deep cycling them together at an 80% depth of discharge for 1-2 weeks and this should correct the issues you are seeing.

 

[PhotonsAreNeat]

I checked all three today, and all were reading 100% SOC. And, it appears they are balancing the cells better today, so that's good. I think this firmware update has helped a lot with that.