I don't know for sure, but I think the solar panel of that size (even at 100% efficiency, which is impossible) would only be able to trickle charge the CT, like to keep the natural battery losses to a minimum. No where near enough power to drive it.
How about towing up and down a steep hill? Where is the breaking point when a heavy load meets a steep hill? In other words, if I know I'm going to have to climb a hill with a load, how do I know the motors can handle it, both up and down.
Our M3 does ok on steep hills, but that's only with...