Alternator doesn't have the ability to "react" the way a battery or capacitor does, they just supply, batteries and capacitors are storage units. Alternator is constantly on while the vehicle is running, whereas a cap or battery is only as good as its source. While their idea is cute, one has to take into effect the alternator has to react through a supply line of 20 feet, wheras a capacitor is directly at the amp in the shortest lead possible.Originally posted by taylor thats not what AS&S's july 2002 issue said...."Alternators are the fastest power source meaning they can respond to power needs more quickly than the battery or even a capacitor"