Advice for using 2 24v 280ah banks in series with JBD BMS.

[brandonboosted]

I’m currently waiting on my JK bms to show up but I wired my 2 24v banks in series which have been in parallel for some time now. I’m having a problem with one bank hitting 28.4 and single cell over voltage and the other bank is still at 27. Do I need to top balance these all together? They were working perfect in parallel and both banks were at the same voltage they could have both been at the same soc. Recommendations? Should I just be able to parellel both banks again or top balance them all together and then recon connect in separate banks?

 

[sunshine_eggo]

Before placing batteries in series, they need to be top balanced individually and then in parallel.

 

[brandonboosted]

Before placing batteries in series, they need to be top balanced individually and then in parallel.

Thank you! Do you recommend having balancing only while charging? Unsure if they are more likely to come unbalanced in series like this.

 

[sunshine_eggo]

Thank you! Do you recommend having balancing only while charging? Unsure if they are more likely to come unbalanced in series like this.

yes. 3.40V/cell, 20mV deviation, during charge only

 

[Keith C]

Or use a balancer. Preferably a flying cap version.