It's called trickle charging. Phone charges to 100% then drops to 90% before starting the recharge. The phone will show 100% though because otherwise, the forums would be flooded with people saying "MY PHONE/CHARGER DOESN'T WORK OMG"
Sent from my HTC Butterfly s using Tapatalk
I totally just realized that the majority of my thanked posts are from where I posted my "3D seatbelt pic".