You don't have to have an internal combustion engine to charge a batter, you have 4 rolling points on electric wheels, that you can actually attach small high output generators to, that is what we used to charge car batteries with, my first car had a Generator, not and Alternator. Anytime you have a rotating mass, such as a generator in a Dam, you can generate electricity and it can be stored if it is DC. Would not be difficult, the efficiency of these little high output generators is amazing. Coupled with a small regulator, you would have a car that could drive just about anywhere.