Alternator question...


Senior Member
Jan 1, 2011
Reaction score
Medford, OR
Guys, back when I got my '68 Newport I installed a 90 amp Powermaster alternator with an adjustable solid state voltage regulator. Krautmaster had already ran a charge lead to the starter relay, and bypassed the ammeter. All this works fine. What puzzles me now is if the 90 amp will keep up with future plans. I have Hella low and high beams now, operated off of a custom harness with 10 gauge power feeds and grounds, allowing 100w high beam bullbs in the high beam lights. Just running 55w in the low beam only lights. I'm planning on installing a Mercedes electric fan controlled with one of these: Micro Autonomations Now the fan can draw 50 amps on startup, but I'm thinking as this controller operates the fan in steps, I won't see a 50 amp instantaneous draw. I will installed a 6 gauge charge lead from alternator to starter relay inplace of the one Kraumaster installed. Will a 90 amp alt keep up with this, and have room for expansion should I ever lose my grasp on reality and add fuel injection, or should I rethink the alternator too? As an aside, all interior and taillights are LED, the only incandescent lights are front turn and markers besides the headlights. Your thoughts? Anything else I should step up?
Last edited:
I would say no. I had a powermaster and it failed. I bought a tuff stuff 130amp as a replacement. I have fans, efi, vacuum pump for brakes, upgraded lights...
I believe it was always operating on or at near max output but ultimately some diodes failed and it started charging at 17volts. Every now and then I did have a drained battery. This has not happened with the tuff stuff alternator and even that drags the voltage down to barely above 12v sometimes with heavy loads.