Aagh... my son pushed buttons on the keyboard...
Anyway, Interesting comments. I reallize it is not going to charge the system and was not the goal behind this idea. The goal was to simply stablize the voltage of the system when the engine isn't running fast enough to do it. Not an attempt to create so called "perpetual motion", but just somehow keep the voltage up when the engine isn't spinning fast enough to do the job.

I really like that 2 speed drive idea.

On the dual battery setup mentioned... you mean to separate the fans from the ignition so that the ignition is running off of the battery with the least load?