I'm guessing you shorted something. I have had 3 quad cell MT's and never fried one. I've made my brother and his friend tri cells too.... we have never had a problem.

I'm guessing you shorted something out when you hooked up the battery. The excessive current is not the problem because, as previously stated, the truck will only draw as much current as it needs. THe fact that I have run 7 trucks with that high or higher voltage with regular motors leads me to believe it was a mistake when hooking up the battery.

Do you remember what color smoke it was? A blueish color usually means a capacitor. Most of the the other components on there can burn up, but none of them should really smoke.