My thought exactly. The MH has a 60+ amp generator, and although the convertor is quite large, I am not sure what kind of charging current goes to the battery. In this case, we used the generator which worked well. I was thinking that if we had needed some AC, I might have used the coach AC at the same time. That thought passed quickly as I realized that alternator output is dependent on engine speed, whereas the generator is speed regulated depending on load. If I was going to be driving, then yes, the alternator charge is probably faster.