Different size packs, same battery manufacturer question

[rflournoy]

I'm looking for advice from people more knowledgeable than I: I have three 3kW battery packs, each NMC cell is 68 ah being used as a powerwall. I would like to add in parallel three DIY 5kW packs, each NMC cell is 96 ah. All the packs are 60v, each has its own BMS, and all cells are from the same manufacturer. My solar inverter has a built-in charger for the batteries. My question is whether to set the charger to charge at the rating of the smaller packs or the larger packs, or should I have a separate charger for the larger packs? If a separate charger is needed I don't know how to set it up to charge the batteries and then be able to use them as well.

 

[mschaus]

I would double-check that all of the packs are a compatible voltage. 60V is the max or nominal voltage? Or? A 14s lithium-ion NMC, for example, is nominally 52V and max 58.8V. With many in parallel, assuming same number of series strings in each, I think you just need to adjust the charging termination current.

 

[rflournoy]

Thank you. My packs are 58v max.