How much power can I run off a 65amp alt?

[ace_800 5,000+ posts]

Looking at putting a small system in my 66 GTO. The alt thats in it now is rated at 65amps and I'm running a optima red top. About how much power should I be able to run without dimming issues? The car has very little as far as electronics, basic am/fm radio, dome light, very little in terms of the dash lights. The biggest thing is the electric fan I installed.

Basically wanting to see if i can get away with the 65amp.

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[modskwod 10+ year member]

You'd probably be able to get away with up to 500 watts, I had a 65 amp alt in my el camino and it did fine on that power for me.

 

[AQHDC3 10+ year member]

Ya I have an older Mustang with a 65amp and if I run much more 600 the voltage wants to drop pretty bad. Do the big 3 upgrade and that will help a lot