i've finished my stereo install. When the volume is turned up the alternator gauge moves from its normal middle position to one line up on the charge side. I read that to mean that the alternator is having do do a bit of work to keep up and that i have nothing to worry about. Am i reading things correctly. The alternator was replaced about a year ago. I'm not sure what i bought but i'm sure if there were 2 sizes available i would have gotten the larger one at autozone.