diy solar

diy solar

How bad are these voltages?

I build a 4S, 12V, 272Ah battery bank.

I charged the battery, did a capacity test and charged again.

This is now what the BMS shows:
View attachment 44623
It has total 0.25V difference between cells after loading.
Is this bad?
When I start discharging, the cells quickly equalize and difference becomes around 0.05V (I think about the measuring fault of the BMS).

Should I a top balance? Or is this fine?

One thing that surprised me: the BMS -daly smart 250A, is not activating the balancing: any idea why this is the case?
Balancing seems only active when charging or discharging...

Walter
You should top balance the cells. This is why.

Do NOT expect commodity cells with the same voltage to be balanced, they are not.

You really shouldn't need the balancing to get top balanced packs a lot closer than you show. Daly has a very low balance capacity, and should be set to only activate above 3.4v while charging. If you top balance, between 3.0 and 3.4 your cells should be much closer, above or below that, it's expected to diverge simply because the cells are different capacity.
 
Back
Top