bottom balance with bms

[John Frum]

I saw a post recently and the author mentioned that he was using a commodity fet based bms with his bottom balanced pack.
Typically BMS's only balance on the high knee.
Is the BMS balance feature at cross purposes with the bottom balance?

 

[FilterGuy]

I saw a post recently and the author mentioned that he was using a commodity fet based bms with his bottom balanced pack.
Typically BMS's only balance on the high knee.
Is the BMS balance feature at cross purposes with the bottom balance?

Yes, if the BMS balances at the top, starting with a bottom balance is rather counter productive.

 

[Zil]

It is generally recommended to bottom balance for such deep cycle as in a EV. Top balance for fractional C rate discharge as in a house bank.

 

[opticalcarrier]

It is generally recommended to bottom balance for such deep cycle as in a EV. Top balance for fractional C rate discharge as in a house bank.

what about for home solar uses where you expect to discharge to very low SoC every daily cycle? For instance, in my case here in AL it makes zero sense to try to sell any power back to the POCO, so my best path is to use battery as much as possible when the sun's not shining.

Or, and this is assuming none of the 32x of the 3.2v@280ah lifepo4 cells that I got are too terribly far different in capacity, do I just top balance and then just make sure I never drop below 20% SoC?

(this is now a zombie thread)