I got in my truck this morning and turn the key forward to see about 11 volts on the battery. A little bit less than usual. I crank it forward truck starts fine, but as I was driving away I noticed my battery light is on. I'm only seeing about 11 or 11 and a half volts while driving. That is a few volts shy of what I'm normally getting. My completely stock alternator usually gets me around 13.3 to 13.8.
After driving for 10 or 15 minutes, it jumps back up in the normal range and the battery light went off. I'm thinking I may have a problem with the regulator, or the alternator itself. It is still the original factory alternator. Is there a good way to test it? Or should I just go ahead and upgrade it. And if so, what should I use? I just want the longest lasting replacement option. The stock one has done a good job for me for the past 10 years.

 

Check the plug in the back of the alternator with the thin wires. An alternator needs voltage at first to produce the field to start generating electricity. This comes from that plug. If it is loose the alternator will intermittently work.

 

Also check your terminals and grounds- as soon as a ground gets funky (moisture, rust, etc) things go south quickly.

 

Yeah I was suspicious of that but everything looks good. All connections tight and corrosion free.

From what I've read, I'm lucky the stockers lasted 11 years.

I'm contemplating this as an economical replacement. 130 amps.
http://m.summitracing.com/parts/wgl-7776n

Everything Napa has is 110 and that seems far too small. I'm not sure I need a 200 amp aftermarket unit though and they are $250 or more. I don't necessarily want the cheapest option but I don't want to pay more for a beefy unit when it's not really needed.