My Blazer has a 105A alternator. The alternator is PCM controlled, just one wire.

The stock alternator output wire looks to be 10 gauge. From the charts, a 10 gauge
cable, less that 4 feet is rated 65-85 Amps @ 13.8 volts. I find it hard to believe the
alternator would get close to this "105A"


When the alt is excited,

What is the average AMP output at idle ?
What is the average AMP output at X - RPM's ?

I'm replacing the Alternator to Battery Terminal cable with a 4 gauge
cable and a ANL fuse holder ( versus the stock cable with fuse-link.)

I am unable to find out what the fuse-link amp rating is, so I'm hunting for
a fuse value,

 

By "one wire" I'm assuming you mean the output wire? Because there's another connector on it, 3 wires I believe, that control the internal regulator. The alternator will output various amps based on the electrical load. Could be just 30-40 amps when the battery is good and the truck is just idling with nothing on, could be 70-80 amps with the headlights and everything else on. However I will say that the single output wire from the alternator that runs to the battery is barely adequate for a stock truck, which is why anyone with a stereo, auxillary lights, electric fans, or anything else, should really look into doing the big 3 upgrade.

 

Fusible links aren't rated in amps, they're rated in wire gauge. So, if you have a 10-gauge wire, that should be a 10-gauge fusible link.

If I were you, I would use a fuse rated at the full rated output of the alternator, plus a little bit. Probably something like 125A. You don't want it to blow unless there's a short circuit.

 

Yes, I'm doing the big three, just wanted to fuse the alt.
I had read about fuse-able material but I may as well
fuse it like mentioned 125a. My fuse holder came
with a 150a, but I'd be more comfortable with 125a.

 

There is a aftermarket alternator that has just one single wire, Internally regulated. The single wire is hooked to a switched positive and when the regulator senses a voltage drop exciting the alternator it back feeds the charge thu the system.