What amp alternator should I go with?

[69 GTX]

I'm wondering what size alternator I should install in my car. I may have to put a electric fan in so that's a consideration along with the AC. Was going to use LED lighting. Other than that not to many changes from OEM. I was thinking 75-100 amp? Thanks for your input.
Tim

 

[ykf7b0]

75 amp alternator will be plenty.

 

[69a100]

Yea, what he said.

 

[5.7 hemi]

I'd go at least 100 if not 120. When you have everything on (lights, ac, stereo, engine running) you might find that you need a bit more than 75, especially at lower rpm's.

 

[ykf7b0]

A 75 amp Powermaster will be great even at lower rpm's if your wiring is in order as recommended by Mad Electrical.

 

[5.7 hemi]

How many amps does the electric fan(s) pull? They could draw 25-50 amps by themselves. So we need to know that to help figure out the total amp draw your could have with everything on. Better to have a bit more than not enough cause the alt. will supply what is needed according to the draw on the entire system.

 

[Darthomas]

Electric fans are a bad day on the side of the road when it's 90 degrees and you least need such a problem.
Silly to add such a load to the electrical system when you already have a bunch of spinning stuff up there on the front of a motor.
Why not electrify the water pump and AC compressor? Heck, motorize the power steering too, then just put in an alternator the size of a watermelon.
Problem solved, except you're gonna need about three belts on that puppy.
The more transformtions of energy you have, the more losses you incur.
Use free spinning power to run spinning things.
I have little respect for engineers that uselessly add complication.
They only do this for cheapness.
And because the average idiot refuses to maintain a vehicle.
"Oh my god, a BELT broke!"
Whoda thunkit?

 

[miller]

Whoda thunkit?

Ha!

 

[moparjohnny]

Electric fans are a bad day on the side of the road when it's 90 degrees and you least need such a problem.
Silly to add such a load to the electrical system when you already have a bunch of spinning stuff up there on the front of a motor.
Why not electrify the water pump and AC compressor? Heck, motorize the power steering too, then just put in an alternator the size of a watermelon.
Problem solved, except you're gonna need about three belts on that puppy.
The more transformtions of energy you have, the more losses you incur.
Use free spinning power to run spinning things.
I have little respect for engineers that uselessly add complication.
They only do this for cheapness.
And because the average idiot refuses to maintain a vehicle.
"Oh my god, a BELT broke!"
Whoda thunkit?

in total agreement,i want to keep my car on the factory set up as it rolled off the truck for delivery,all those ad ons causes more problems and strain the system and cost money.

 

[ykf7b0]

To each his own but back to the original question. The OP is considering adding A/C and is thinking an electric fan(s) would be a good idea. I too think a pusher fan on a sensor or toggle would not be a bad idea in low rpm traffic light situations. He did mention maybe adding led lights. I'm thinking he may be opting to replace incandescent lights with led lights. All things considered the amp draw and is not that radical and the changes from stock are not extreme except for the most true purists. My 69 road runner with auxiliary (pusher) electric fan and electric fuel pump has no problems with the 75 amp Powermaster even at idle.

 

[SwedCharger67]

I'd say minimum 100 Amps. As already stated, things quickly add up and extra amperage that you don't use doesn't cost you any extra in running costs. And you have the Amperes there when you need them. Myself I have 100 Amps and it's not too big. And the TuffStuff alternator looks original to most people.

 

[ckessel]

Don't forget to up size the charge wire when you increase the amps. And you may want to do the same for the ground.

 

[69 GTX]

So I don't think I'll need a pusher fan but I'm trying to be ready if I do. So looks like I will go for the 100 amp. Thanks everyone for your thoughts!

 

[1968rick]

What about your Amp Meter....still in use? If so get rid of it and run a voltmeter. Up size your wiring.......Want all the modern convienences....buy a modern car.

 

[Darthomas]

Why do people hate ammeters so much?

 

[SwedCharger67]

Why do people hate ammeters so much?

I don't hate them, I in fact like them! It's the only way to know which way the current is going. A voltmeter does not do the trick.

I'm using the original 67 ammeter with my 100 Amp TuffStuff alternator...the ammeter pegs out on the charging side for a few seconds after a heavy start, but it doesn't matter, the internals of the 67 ammeter can handle big currents without problems.

 

[1968rick]

Here is a good read....
http://madelectrical.com/index.shtml

 

[69 GTX]

Just ordered the powermaster 95 amp.

 

[Hemirunner]

Just ordered the powermaster 95 amp.

Which one? Going one wire?

 

[69 GTX]

7018 part # not a one wire. I'll have to upgrade the wiring a little.