Originally Posted by heffer
hey, i was wondering, what does a power supply? and why do a lot of chargers reuire one? thanks
yea....what redwings said. a power supply converts 120 volts, a/c (normal house current) to 12 volts d/c.....which is what those chargers require to operate off of. you can run that type of charger off of your automobile's battery, but with a power supply (at least the goods one anyway), the current is regulated to a constant voltage, unlike your auto's battery.