[PSUBS-MAILIST] agm charger

[hank pronk via Personal_Submersibles]

Hi all,
I am tired of buying battery chargers for Gamma.  I think I am over using them and they go haywire.  I read that I can charge my AGM's with an automotive alternator.  I am thinking of building a battery charger with an alternator driven with  a 1hp AC 220 V motor.  The alternator has an internal regulator, so it will stop charging when the battery is full.  
Is there anything wrong with this idea?
Hank