How to handle to inrush currents with 2 large parallel 48v lifepo4 batteries

[Henderson]

Hello, I'm building 2x 48V batteries (each 3P16S using 280ah lifepo4). Each battery will have its own BMS and will be in parallel and connected to the inverters (either MPP or Growatt....still deciding). I know under normal circumstances the 2 batteries will be balanced between each other but my concern is, if something were to happen and I need to take one of the batteries offline, then by the time I'm ready to connect it, it will have a different SOC than the battery that remained online thus causing a potential inrush when they are connected again. Is there a way to deal with the inrush safely?

 

[DThames]

Hello, I'm building 2x 48V batteries (each 3P16S using 280ah lifepo4). Each battery will have its own BMS and will be in parallel and connected to the inverters (either MPP or Growatt....still deciding). I know under normal circumstances the 2 batteries will be balanced between each other but my concern is, if something were to happen and I need to take one of the batteries offline, then by the time I'm ready to connect it, it will have a different SOC than the battery that remained online thus causing a potential inrush when they are connected again. Is there a way to deal with the inrush safely?

If the batteries are at the same voltage, there will be no current flow. I use the JBD BMS with bluetooth. You can turn each of the batteries off with the BMS software. You can load or charge one of the batteries until it matches the other and then turn the second one on.

 

[Henderson]

If the batteries are at the same voltage, there will be no current flow. I use the JBD BMS with bluetooth. You can turn each of the batteries off with the BMS software. You can load or charge one of the batteries until it matches the other and then turn the second one on.

Ahhh, this makes sense. Thank you.

 

[Henderson]

If the batteries are at the same voltage, there will be no current flow. I use the JBD BMS with bluetooth. You can turn each of the batteries off with the BMS software. You can load or charge one of the batteries until it matches the other and then turn the second one on.

By the way, if you're using more than 1 JBD BMS, can it give me a total view of SOC of both batteries combined or do you need to look at both cells individually?

 

[DThames]

By the way, if you're using more than 1 JBD BMS, can it give me a total view of SOC of both batteries combined or do you need to look at both cells individually?

One would need to look at both. I do have a Smartshunt on the busbar where both batteries are connected together, so I can monitor the bank as a whole.

 

[Henderson]

One would need to look at both. I do have a Smartshunt on the busbar where both batteries are connected together, so I can monitor the bank as a whole.

Ok nice, thanks.