As soon as there is any load on the quad especially with the plow it slips but the belt seems fine.

check and test belt -stretched or worn --

transmission belt is worn out or slipped off pulley somewhere service drive belt then try it out

Check alternator output against specs. I suspect that the issue is with the belt not being properly lined up with the pulleys

INSPECT BATTERY ELECTROLYTE LEVEL
INSPECT BATTERY CABLES/TERMINALS
LOAD TEST BATTERY,_______VOLTS @ 150 AMPS (Min SPEC 10.2 VOLTS @ 150 AMPS.)
INSPECT BELT(s),
TEST ALTERNATOR OUTPUT (ON THE VEHICLE,'NOT' BENCH TESTED),
1 _____AMPS @ 12 VOLTS @ 2500 RPM w/PLOW not ENGAGED
2 _____AMPS @ 12 VOLTS @ 2500 RPM w/PLOW ENGAGED ALT OUTPUT SPEC ????

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Year make and model ??
The belt could be glazed and slipping even if it is tight.
You could have a weak belt tensioner too.
The noise when the ac or heat is turned on can be the extra load from the ac compressor or the alternator. The compressor cycles on and off especially in defrost mode.
The load from the alternator is the first noise of the day. As the belt warms up it becomes better at handling the load of the accessories.
Even tho the belt looks fine, you may have to replace it to get rid of the noise.

I think you have a problem with the plow motor grounding out. when you raise or turn plow in either direction you have to run the plow motor which is grounded out. ( as in hooking the ground and positive together directly ) the plow is on a gravity drop when you let it down by the weight itself and does not require the motor for the plow to operate. It's your plow motor or the positive feed to selonoids.

you could need a bigger tranny cooler, plowing is tough on a transmission, get an after market cooler.

It sounds like your draining your battery with all the accessories. It could be a loose alternator belt or that the belt is just getting wet and slipping or your alternator is not up to the job!
Try going to a good auto parts store like Advanced Auto and ask them if this could be the problem. They may be able to swap up your alternator to one that can handle the load!
Good Luck!

Check and tighten your drive belts / fan belts. The noise you are most likely hearing is the belt slipping on the alternator pulley. Its worse in the morning because the starter takes more out of the battery when the engine is cold. This in turn leaves the alternator with more load to replenish charge. More load = more resistance on the pulley to turn, hence the belt slips if too loose.
Cheers John

Yes It can and It should not void the warranty. Contact your dealer.