Somehow I have the urge to post "We don't need no stinkin battery light".


AP, the dealer didn't do you any favors. You can also get a battery light if an alternator has a bad diode in some cases, AC volts get into the mix, but the batteries will still charge. But there is a synergism in the electrical power structure, as Mark pointed out post 11, one can hurt the other. Excessive voltage is another to look out for, slowly cooking the batteries to death.