My battery light has started doing this, too.
I had it tested at AutoZone, battery is cool, 12 volts, alternator at idle is 14 volts. Here's the problem, the voltage from the alternator spikes to over 16 volts under a load. Under a load, i.e. accelleration.
Everyone says it has to be the voltage regulator, and I agree. This sounds like a pretty common thing and I'm not looking forward to changing the alternator.
