Would I have to disconnect the XT90 connector between to two batteries when charging individually?
You can connect two batteries in series, which will add voltage (V of pack1 + V of pack2) or you can connect them in parallel. Here are two simple rules: when connecting in series, each pack should be made out of same cells and each group should have same capacity (same number of cells in parallel). When connecting in parallel, each pack should have same Voltage (samo S count and charged to same level).
When connecting in parallel you connect - in one battery with - on second battery with - on vesc. Also, + on + on +.
And yes, 12s3p wirh 12s2p in parallel will be 12s5p.
When you charge one battery and that battery is connected to second one in parallel, they will both charge at same speed (both batteries will have same voltage or % of their capacity). You can also disconnect them and charge them separately, each with its own charger. But if you are going to separate them, take care that they are at same voltage (aka same % full) when connecting them back in parallel
1 Like
Genius, Genius I tell you! or maybe this is common knowledge and Iām a virgin to battery building either way thanks for the advice.
2 Likes
It is kinda common knowledge, so try to read a little bit more about those stuff 
anyway, we are always here to help with details or advices! 
1 Like
I will, now that we have all this free time. lol
I got a p-packs thatās newer and a p-pack thatās olderā¦do I put them in the middle or the ends of spread out in the series order?
@longhairedboy says it is better to build new battery than use new p group with other groups that have more than 10 cycles.
You can disassembe groups and mix cells, so each group would have same number of old and new cells. I would do it this way (actually I already did )
1 Like
Ah fuckā¦they are already welded as a new p-pack. Do I pull them all apart?
Are you gonna use bms?
If you gonna use charger with built in bms (so you have only balance wires out of battery), then I see no problem, charger will balance groups every time.
But donāt hold my word on this, I am talking out of experience with Trampa charger which shows voltage of each group during charge
Itās 2 separate batteries with their own BMS in parallel, Iām pulling maybe half current capacity from it
I guess I can rip a third the side apart, and have 4 parallel packs with a high and a low cell each
Maybe try to use that new p group anyway, but often check if it drifts too much from other p groups
1 Like
Okay, will do. Itās an easy check on this anyways since itās a pop top lid and the BMS is on the top
1 Like
Are we talking about that battery you posted earlier? Why are all other groups blue? Are those just rewrapped 30Q cells or something else?
Yeah, I bought a 12s4p from someone last year, it was really shitty and the welds fell off in transit so I ground the spikes off and replaced the shredded wraps
They look like legit 30Q cells and he said it had 10 cycles at most
1 Like
Well then it should all be alright! Just check voltages after every ride and after you are done with charging. We want to see if bms can balance those groups if there is need for that
1 Like
So Iām not sure if this is ācorrect procedureā but likeā¦itās working? I need a longer clamp though to connect them all
4 Likes
what adhesive is that?
GE Silicone 2+ā¦the good stuff. I removed all the excess and whatās left comes off the nickel pretty easy when it cures completely
2 Likes
nice. you on another level bro, im still using hot glue 
1 Like