Originally Posted by
Frank L
On that charger it would be best to charge them separate because I think it peaks at 6amps. Pumping 6 amps into a 4s would take a lot longer than 6amps in to each 2s and then you don't have to fab up a 4s balance lead.
Could be wrong but 6amps for 4s will charge the same time as 2s. It's still just 6000 mah or whathaveyou. It's if you charged in parallel that it would take longer. 4s is same capacity just higher voltage.