Mac OS battery cycle count Im under Yosemite OS X I got a new battery for my mac model a1398 mid 2012 retina, I charged the battery first time to 100% and drained it till it went to sleep mode to calibrate the battery, now I never let it go under 80% and plug the charger, most of time I use the charger but the thing is, I saw that my cycle count is 3 and it was 1 before, I don't understand how this happened? any idea?
From Apple's support note on battery cycles:


  A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could use your notebook for an hour or more one day, using half its charge, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so it may take several days to complete a cycle.


So essentially, as long as you ever run the laptop unplugged at all, your cycle count will slowly increase.