Here we go… the wiring diagram for putting together 20 4s packs.
The basic concept? Everything is paralleled. All the balance tabs, and all the main + – leads from the individual packs. (NOTE: You MUST make sure all the packs are fully charged and balanced before paralleling the balance leads, to avoid any severe current flow between unbalanced packs/cells.)
Then, you series the modules:
DISCLAIMER: First, mostly all of this is from RemoteContact, AKA Adam Bercu. He gives credit over to Endless Sphere, but I know for a fact he’s learned all this stuff himself, the hard way – by building such badass robots they won’t let him play in their sandbox anymore… but that’s a tale for another day.
Second, lipo is dangerous, and you take anything I say here at YOUR OWN RISK. If your lawyer thinks I have some deep pockets he can go after if you blow your silly ass up doing anything I say here… well, your lawyer is delusional. Do your homework. I may be totally full of crap.
(edit: Please see the updated wiring plan here, due to me realizing that you have to charge through the main power leads. Duh.)