Using an active balancer in a 2 4s with 2 bms config

[dodaly]

The photo is halfway through taking it apart to top balance the cells, but I'm using 2 bms with 8 cells and was just wondering if I should use one 8s active balancer for all the cells or if I should use 2 separate 4s active balancers when I put it back together

 

[sunshine_eggo]

If the two 4S are in parallel, no. You'll need two 4S balancers. If the two 4S are in series for 24V, yes, you could use an 8S.