The Stovebolt Site Forums The Shop Area The Electrical Bay Voltage problem

You've received two excellent answers, Alex. Please let me add my personal note: First, I'd concentrate more on amperage than voltage. For decades I've told people to think of voltage as the size of your arm and amperage as the strength of your arm. I also have 2 electric fans, HEI ignition and I have a 100 amp alternator...or that is to say it is rated at 100 amp. The HEI ignition uses around 20 amps briefly at startup and after that settles back to around 7 amps. I haven't had the alternator checked for actual maximum output. I expect if it is a true 100 amp unit it will be ~80-90 amps given the pulley ratio I have and the rpm range at which my engine normally runs. One fan is a Spal puller fan (17") and one is a Spal pusher fan (16") which operates only when the A/C is on. The 17" fan is thermostatically controlled so it only runs when needed. When both fans are running I'll lose about 50 amps according to Spal's tech data. While that is happening, anything like the headlights, turn signal lights, etc will be seen as a reduction on my ammeter gauge (in the dash cluster). Hope this is helpful.