"Think about an electric motor running an alternator. If you use the alternator output to run the motor, it wont work because of a little word called "efficiency." If it did work, you would have perpetual motion."

At the bottom of my post it says "tanstaafl" That stands for "there ain't no such thing as a free lunch" ROBOT had it right- perpetual motion doesn't work in THIS universe.
You might try running your fans from the battery to use it as a buffer between your alternator and ignition. I'm no electrical expert by a lonnnnng shot, but that might cause less of a drain on your ignition. Be sure to include an inline fuse!