[BrianG]

Actually, I was shooting for two 2s2p 8Ah Maxamps Lipos. Nothing else will give me the runtime I want, with the size and weight I need. Plus, a continuous discharge of 120A will ensure the voltage won't drop much at all when I anticipate peaks of about 100A. which will be better for the batteries and I can squeeze more of that 8Ah out on each cycle.

According to the site, each 2s2p pack is 44mm X 137mm X 26mm. I figure if I make the trays adjustable from 130mm up to 150mm long, it should allow me to use pretty much anything within reason. I also plan on making the tray 50mm wide to again allow room for future packs and/or a little extra side padding. 26mm high is just right so it won't touch the body - even with the raised platform.

I also thought about moving the diff forwards more, but that would mean cutting a new groove in the chassis for the bottom of the spur, moving the steering servo, modding or getting new bones, etc. I'd rather keep it looking nice without too many extra holes and such.

I made little 150mm X 50mm cardboard cutouts (to simulate the packs) for test fitting. It's tight, but I think it will work.