pic: Too much power?

[Chris is me]

Originally Posted by Andrew Lawrence

More like not enough material. Those thin pieces of sheet wouldn't hold up on their own even without the motors. At a minimum, especially for anything with a CIM attached to it, use 1/4" aluminum plate, or else your gearbox is going to snap before the first miliamp hits your motors.

This isn't necessarily true at all. Tons of gearboxes, including the AndyMark Toughbox, use 1/8" aluminum. The Toughbox Nano mounts a CIM to 1/8" thick material (granted, a box rather than a plate). Lots of teams with sheet metal use gearboxes with plates .125 thick or even lower with appropriate bends. Saying a gearbox with 1/8" plates is going to snap before load is even applied to it is a ludicrous generalization.

...but yeah, I'd step up to .125 if you're not adding bends to that.

I don't know what you're trying to accomplish with an 8 motor drive, but I don't think it will be of much benefit. You're going to really tax your main breaker and the voltage drop you induce in the battery might even offset the gain of the 4th motor to some extent.