Hasn't been the case for me, I charged my phone overnight, when I wore up I installed the update, then called 2 automated message numbers and checked the weather. All this took probably 7-8 minutes, and my battery meter read 93%. Now, an hour and a half later after light-moderate use, 80%.
I put mine back on the charger after the update, because after the update I could see that the meter had dropped.
Basically I took it off the charger, noticed the update was available, installed it, used it for a short time, saw the battery down a notch, and put it back on the charger until it was full and the LED was glowing green.
It was after that when I took it off and the point of my post began.



