I fixed it, at least for the short term. I'll tell him to replace the fuse with a correct fusible link. The problem was actually a Mallory coil he had in the car from the first day he started it last year. Since last year he burned up two Mallory Hyfire 6A boxes, blew all his lights out once, and lastly couldn't start it with out a massive amount of current blowing the 30 amp fuse he replaced the fusible link with. Bottom line, the coil was drawing way too much current causing a massive voltage drop from the voltage regulator, in turn making the alternator think the battery was super weak, in turn causing the alternator to "charge" at 18+ volts. I had him replace the Mallory coil with a factory style coil and the problem has been solved. He claims the car hasn't run this good since he first got it running over a year ago. That Mallory coil has been bad since day 1.