I have the east coast ultra mini and it seems to do the job. 2 weeks ago at Keystone I round robin the car using electric fan, water pump, fuel pump and head lights 7 rounds in about an hour and half with one 12v battery never used a battery charger and no problems. I think the car's wiring is a major factor along with the pulley ratio. Oh and when that little alternator really has to work it gets hot and takes a few hp to turn it, belt has to be tight or it will slip. just my 2 cents.