Yep, I Agree with Danny - I would not run the stock cable (looks like about 6 AWG), especially since they are old and suffer IR.
I would use a 2 AWG myself, though 4 AWG might suffice. Be sure to fuse it appropriately for the weakest link (read the cable used, unless you go for the gusto with your new cable).
Danny, am I misreading prices or are they cheap there?
Good luck.