SOK SK48V100 questions

[wheeto]

Hello,

I currently have two of these battery packs connected to a Victron MultiPlus-II 48/5000. They're connected together via CAN for closed-loop operation and work perfectly for Victron's ESS system with AC coupled solar.

Except

They discharge very unevenly, and cut out even when the BMS says that there is 20% capacity remaining. In order to start to get to the bottom of this problem, I removed one of the packs and have just one now connected to the inverter. Straight away I'm getting the battery BMS going into OCP and shutting down, even though there is no way the inverter can pull more than the 100A the pack is (should be?) capable of and the inverter thinks it's pulling way less than this anyway. See screenshots. Any ideas where I go from here?


Thanks,

 

[MiSh]

I would charge both batteries up individually, reconnect together, then see if the problem persists. From what I found with my SOK 48v server rack bank, sometimes the BMS would indicate 99% charge, but the batteries were almost depleted. I wouldn't rely on the BMS SOC meter for any kind of reliability.

 

[sollap]

Is this OCP happening during inverter startup? I noticed that the current is going down each time you try it, so I'm wondering if you went through the precharge procedure.

 

[wheeto]

Is this OCP happening during inverter startup? I noticed that the current is going down each time you try it, so I'm wondering if you went through the precharge procedure.

Thanks for the reply. I religiously follow the procedure (BMS off, all CBs on, BMS on) if I've ever powered everything on, so I think that's not the problem here.

 

[wheeto]

I would charge both batteries up individually, reconnect together, then see if the problem persists. From what I found with my SOK 48v server rack bank, sometimes the BMS would indicate 99% charge, but the batteries were almost depleted. I wouldn't rely on the BMS SOC meter for any kind of reliability.

I have tried that, and 4mV cell-to-cell (across all the cells in both packs!) and no change.