Wiring Cap pack parallel to ESC wires?

[BrianG]

I'll try to explain. You want the least amount of resistance between the caps and the ESC. This is why you use low-ESR caps. Shorter and/or larger wires have less resistance. Any resistance will introduce voltage drop, which causes ripple. Very short 20GA wire can have the same resistance as long 10GA wire, but shorter and larger wire is the best.

Smaller wires to the caps can be ok if you use good cells since there is less ripple for the caps to filter to being with.

Weaker cells means more ripple, which means those added caps will have to filter more, which means more current is flowing through the wires, which means more voltage drop on the wires, which results in more ripple.

In short, it's best to use the largest gauge you can without becoming cumbersome and unwieldy. Larger wires may not help, but it certainly won't hurt. Just keep the wires as short as possible and as close to the ESC as possible.