For my schools new car we are going to use 7 10lb 12v batteries, our old number #80 car uses 6 of those and it works great, but we are having trouble getting a 72v motor. Or would it be worth it using the same 60v system?
The reason we use these smaller batteries is because if we used the full size yellow top about 90% of the weight would be on the single back wheel.
We use two 12 volt yellow tops. In looking at the car in your picture I see the a big difference in how we construct our car and yours. Our cars are meant for short tracks with lots of turns and we have found in that style of trace you need a fairly short wheelbase. Ours are typically between 45 and 55 inches between the front and rear axle. Because of this our cars will turn well--think Cadi vs Porsche on a slalom course. To do this we have longer nose cones. Our knees are right above the axle (and oar bent up) so our nose cones are ~2' long for the lower legs and feet to fit. This allows us to drop one battery just in front of the axle on a very well supported battery box between the drivers legs. This also brings the drivers weight most to the front of the car. The 2nd battery is behind he driver along with the Etek 24 volt motor. With this configuration we almost always end up with just over 50% or more on the front axle. If the driver needs to add ballast then they can put that where needed so that all 3 wheels support about 1/3rd of the total weight.
The couple of cars we have for longer tracks like our Indy track race have a longer axle but again the drivers knees are above the axle we just go to a 65-75 inch wheelbase for a little more stability where we did not need to corner as much. Still we want about 1/3rd of the weight on each wheel
If you want some pictures etc. contact me by email and I can send them to you.
Mike
