dont use 1/8" plywood. one humid day and your precision cut car body turns into a picasso...(dont ask how i know )
if you have any parm stores aroudn they sell 6V batteries. thier ment for some tractors that wire them in series to make 12V but crapload of amps. (i picked up one that fits my model A ford.) and thier liek $40 a piece with a 2-3 year warranty
Just a (hopefully) helpful thought- if youre going above 40 mph I think you may want to do a little bit of aerodynamic upgrading. The short wheelbase combined with a flat rear drop just looks to me like it will be very unstable on the highway. I think it needs a longer rear slope, or at least some sort of roof spoiler to help a little bit. Below 45 mph it's probably not a problem. My sister had a Geo Metro and that was scary enough on the highway, even at only 55 mph we were struggling to keep it in our lane when other cars were around- and if a tractor trailer passed us we had our hands full big time.
I took my other electric car out today, very similar body style and had it going nearly 45mph and it handled just fine, but to get that speed I had to have a full battery and go down a hill, so I don't see that happening alot.
Sorry to barge in on your thread (I did do an intro first).
If you go the aluminum route, you could use surplus highway signs. They would be cheap (relatively) and very visible at night! The alloy is usually 6061. Might not bend a 90 without crazing or cracking, but would probably do a tight radius OK. Pop rivits and 3M VHB tape!
was also thinking about coroplast or 1/8" plywood, or aluminum plate, coroplast being the lightest, plywood being easy to work with, and aluminum being stiff enough that it would make the frame more ridgid, and because they are all self suporting they could simply be glued in place, and have sound dampening pads stuck to them.[/QUOTE]