So I'm wondering if installing an underdrive pulley on the alternator without screwing with the crank pulley would increase amperage noticeably at idle? I've finely gotten fed up enough with electrical woes to fix the problem

 

What kind of electrical problems are you having ?. Take the time to fix the issues your having, adding an under drive pulley will give you a little more out put from the alternator, but not a whole lot.

 

The stock alternator isn't putting out enough juice to power the e-fan at idle. I've been looking at 200 amp alts, but unless the output is on the low end it won't do me that much good.

 

What kind of fan setup are you running?

 

I'm running the kit from TCP. It works amazingly when I'm not idling for long periods. the fans are 16" SPAL. The secondary never kicks on at idle but even just the one is drawing enough to drain the battery if I'm not careful.

 

What kinda battery Ya got? New old small large?

Do you have the 16in high output ones? This site says they can draw over 25 amps at times.

http://www.a1electric.com/spal/faninfo.htm

 

Those would be the ones. They aren't kidding about high output, it took a 105* day sitting in traffic to engage the second fan...
If I remember correctly from talking with SPAL directly they draw 25-27 on start up and 19 continuous


The battery is about 2 years old, Large, 680 CCA if I remember correctly. Its whatever OReilys says should be in these trucks. It worked great until I drained it using the winch when the fans kicked on.

 

Is that at 0 or 32 degrees? If at 32 that is way too small IMO. Mine is 875 at 32. 700 at 0. And I dont even have electric fans.

You probably do need a bigger alt with those fans.

I would get your battery checked also.

 

Thats at 0. I know the battery is shot, (it really didn't like the whole winch and efan combo). I've been toying with adding a second battery but have been having trouble finding a left side battery box

 

Look for the parts from a diesel truck.