AC cycles

I've noticed with my 98 XJ my ac compressor will cycle on and off every few seconds when im at an idle. It always blew cold until yesterday i noticed it blew warm/maybe cool air. I also noticed the cycling had longer intervals so I checked the ac system to see if it was charged and it was. Anyone know what it could be? I'm not sure if its relevant but I recently had my alternator checked at advanced auto and it read 13 amps(lowwww). I didnt believe it and just kept driving it and now my needle rests just below 14 volts, when it used to be at 14. The reason I asked, I read an older thread on the ac might cycle like that if its not getting enough power.. I duno..

fsm says rapid compressor clutch cycling (ten or more times per minute) is most of the time caused by low refrigerant system charge. the alternator thing seems like a possibility but Im no A/C expert so Ill leave it at that...

had the same problem on mine. worked fine for a couple of weeks, then one day it just quit blowing cold and started cycling a ton. Recharged it and all is good now.