alternator

First you wouldn't increase the size of the pulley, you would decrease it to get it to turn faster at any given engine RPM. Amplifiers and auxillary lighting could cause a problem for an alternator since they are used frequently, but a winch actually pulls more load off the batteries because it is so high of a draw and you typically use it when the motor is idling. However, a stock 100 amp alternator is still pretty low. Even if it puts out 14 volts it will still only provide a max of 1400 watts (remember, volts X amps = watts).

For high load applications, I would recommend installing a second battery, using a high-output alternator like Leece-Neville, and consider a high-idle kit that would bump up your truck's idle RPM up to 1000-1200 depending on the load it senses (we use all of this stuff on ambulances and rescue trucks in the fire department). The high idle kit only works when the vehicle is stopped and in park or neutral, and drops the idle when you put your foot on the brake to shift into gear. The extra battery is to give you the extra capacity that you need when you are idling along at a stoplight or someplace else where you don't have the truck in park and your foot off the brake for the high idle to kick in but you are still drawing a large amount of power.

Cheers - Jonathan

Look at Power Master they also make a 200 amp model for most trucks. You can also go to "2" altenators if you really think you are going to load them up. But I would do a second or 3rd or 4th battery before that route if you have the room. I myself, run the 200amp PM altenator, and got a driver side try for my Sierra from a disel in a wreckling yard and added a second battery. Now, I am going to swap out my two large batteries for 4 optima batteries (they fit side by side in a normal try) so I will have 4. This of course requires so isolators and some wiring but is fairly easy.