Dude I did not go to school for this stuff but some others here did... I am sure they will correct me if I am incorrect..
The way I understand the charging system is that you will need a GOOD battery. The battery takes care of the ups/downs varying amps and the alt follows as needed. This keeps the alt from jumping around from that 30 to 80 amps back and forth. I think the alt allows the battery to discharge slightly and creeps it's amp output up to compensate for the AVERAGE of the amp draw on the system..
You can google alternators (police ambulance, high output) and find the GREEN and others at prices you might like.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />