Board ruining slow when still charged?

so i was just out riding i have 4 zippys running in seares so 44.4v+ and they where all charged a little over 11v i was going up a hill and the amout of tork and speed started reducing when i stoped and started agan it was faster and kept doing this tell it didint realy want to go, and the moter was not to hot when i got home all the batterys where cool to

i figured it out

What was the issue and how did you solve it?

One of the batterys where charged a little less than the rest so all the others where putting all the loltege through that one to keep up and it killed it, this wasn’t the first time this has happened and I didn’t know why before the solution it to have all batterys fully charged before riding so they all drain evenly but I’m also gonna get a bms to help with this

11V is not enough charge… you need to charge each pack to at least 12V, 12.6V max

and charge all the packs to the same level. don’t have different voltage packs in series.