When I read this I understood it as the OP giving a theory of why perpetual motion ISN'T possible, and now people are arguing with him saying it's NOT possible.....? I think at least one of you guys has it backwards
The OP states that he knows it's impossible, and gives his idea of what makes it not work. Yes, alternators make the batteries run longer. We know that. But there is more to the system that meets the eye. That is exactly the point the OP was making. It's not perpetual motion. It's just making something more efficient, which is what scientists are doing today.