Don't even think of using the generator pulley unless it's the same diameter as the alternator pulley. If you slow the alternator rotor down with a big pulley, it won't charge at idle speed. Alternators need to turn at least 2 to 3 times crankshaft speed to be effective.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!