What year/model is it? You can always take your car to AutoZone and have the alternator checked for free on the vehicle. You may need a new one, if you do (depending on your application) you can upgrade to a stronger one.
This would probably be your best bet, and get 130 amps out of the deal. I did this on my '73 351C, I'm running an electric fan, A/C, high output halogen headlights, EFI, and other odds and ends and mine has never skipped a beat. I got mine from AutoZone from a '95 Mustang Cobra with a 5.0 with a lifetime warranty.
Hope you get it figured out and good luck, Chris.
That would be located inside the alternator on an '88 mustang.
Take a voltmeter reading across the battery terminals when the engine is running. It should read 14.5 volts. Anything lower indicates a charging problem.
I too like the notion of getting a higher than stock amperage alternator to run modern electrics. How did you get the AutoZone from a '95 Mustang Cobra with a 5.0 with a lifetime warranty to fit your '73? Isn't there the serpentine pulley vs. v-belt pulley difference and what about the mounting ears? I like what you did and would like to try something similar with my Ranchero.
I used this link as reference: http://tinyurl.com/l2vsb
I used (2) 6-10 inch pieces of 12ga fusible link wire (NAPA) in place of the mega fuse (Ford used this for years).
For the pulley, I got a double pulley from the junkyard and swapped it out, you can probably use a single groove, but the double is heavier duty. All the pulleys lined up perfectly, I threw on a new belt, and gave it a try. The voltage went from 12.8V stock to 14.35V, that is always good.
The only major mod to the alt. was on the small ear, I tapped it and put a helicoil in it to reuse the factory alt bolt.
My car came with the small case alt. (no power anything) so the swap was a breeze, and it looks like it belongs there.