Opinions welcome 4p 16s configuration

[Paintedsky]

I am getting ready to complete my off grid solar power system on the Big Island of Hawaii...I have 64 brand new 280 amp grade A matched LiFePO4 batteries, and will be configuring them in a 4P, then 16S bank for 48 volts, I am planning on using the single Overkill Solar 16s BMS to manage each group of 4 batteries that are in parallel. do you think this should work alright? .......Also, I have been trying to complete a top balance on the entire pack of 64 all connected in parallel. all of the batteries were at 3.29 volts when unpacked, and after two weeks of charging from my 10 amp charger, they have increased to 3.35 volts, so I am wondering how big of a risk I might be taking by putting them into service without bringing them all up to 3.65 volts. I have the Growatt 12k charger/inverter, and am thinking about setting the Growatt charge max absorption to 56.4 volts, float to 55 volts, and cutoff to 48 volts....Also, not sure what gauge of wire I should use to connect the positive side of the battery bank to the Growatt.....Your thoughts on this would be greatly valued.

Thanks.....

 

[MisterSandals]

do you think this should work alright?

It will help quite a bit if they are in fact matched.

so I am wondering how big of a risk I might be taking by putting them into service without bringing them all up to 3.65 volts.

I think since you are going 4P first, a good top balance is even more important.

I have the Growatt 12k charger/inverter, and am thinking about setting the Growatt charge max absorption to 56.4 volts, float to 55 volts, and cutoff to 48 volts.

Your Growatt has absolutely no idea if any of the cells, or even groups of cells go over 3.65V. If you do bring them to a higher state of charge, make sure you have a BMS.
If you want to become the BMS and monitor all of your cells (or cell groups), that can work. But you are the BMS and must be attentive all the time. When any cell groups get above 3.4V, its very possible that the lower capacity cell groups will increase in voltage quickly.

 

[MisterSandals]

Also, not sure what gauge of wire I should use to connect the positive side of the battery bank to the Growatt.

This is all dependent on volts (which we know), amps and length of wire.

 

[Paintedsky]

This is all dependent on volts (which we know), amps and length of wire.

I have the Overkill Solar 16s BMS, and it uses a pair of 24 inch 8 gauge cables crimped together going to and from the BMS on the negative side...If two 8 gauge wires combined are equal to a 5 gauge wire, then, I am thinking a 48 inch 4 gauge wire on the positive side would be sufficient.