I don't know much about the alternator. A junkyard guy said it was a nice one and charged me $20 for it. I got it for something else and never used it. Then I had the idea of using it on a pressure washer someone gave me when the pump went bad. I use the little UPS battery, just to tickle the alternator to get it going. I imagine a big capacitor would work for that too. It was a common trick on old Triumph choppers to get rid of the battery and lower the seat.