Alternator spikes

[Chiefdan]

Ok, this isn't for my Chevy C10 but this is the only automotive board I subscribe to so maybe you guys can help me. 1964 Nova Gasser, 383 stroker, 4 speed. I put a 1 wire chrome alternator in with battery in the trunk. 10 guage wire from alternator to cut-out switch in the trunk and then to the battery. The other night the voltmeter read all the way to the right (18+ volts). When I stopped the car it would not start because of blown 40 amp fuse in the wire from alternator to cut-out switch. New fuse and it started and ran normally with meter reading around 13 v. Am I looking at an alternator problem or possibly something else? Thanks for the help. Chief

[Pontiac1976]

Most likely Volts Regulator, If your alt is older then 72 it Reg. is on the body motor bay. If it 73 and newer in the ALT. The Reg maybe starting to go bad on it's way out. I would keep eye on and get it tested, could blow up the Batt for over charging at worst melt wiring or burn up ALT, or ruin batt. Pretty easy to fix or if you can't get a new ALT if that part bad.