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