A system with as little power as yours will not affect the life of the alternator. And it should have very little effect if any on the battery life. If your the type who continuously turns off your car and listens to the radio for long periods of time and drains the battery down to barely enough power to start your car....then you will hurt your battery life.

2000 SVT Black/Tan #1633/2150 (a few mods) Alpine: CDA-9835, MRV-F540, MRD-M550 PG: TANTRUM-X 6.5 COMP all around. Some people wear Superman pajamas. Superman wears Chuck Norris pajamas. CEL currently: Off