What is the size of the stock alternator on 2000 expy with a 4.6L?

What does it put out at idle?

 

I think that it is probably a 130 Amp unit, but I do not know the output at idle.

 

Your factory alternator should at idle have an out put of about
80 to 100 amps . Now these figures are granted that the entire
charging system is in good condition .From idle to self exciting
point about 2k rpm you may see as much as 150- 180 peak amps. If you have a group 65 battery in your ford keep the water level topped off with di or distilled water only. when you run a bear test or arbst test on it run the first test with no acceories on and you have an out put of about 80 to 100 amps . With acceories
on like a/c,radio,lights,etc is when you will see your peak numbers. good luck ford buddy.

turboted