Here is a really dumb question but worth asking. Is your serpentine belt tight enough? If it is not, the belt will slip and therefore not allow the alternator to work properly.
I run a 90 amp alternator with my 8274 winch, which is one of the highest drawing winches, lights, heater, stereo all that crap and don't have a problem in my YJ.
That's cuz you use lots of belt dressing. A good shot of belt drssing will have your alternator putting out at least 200 amps.