I took it off the charger yesterday morning before I went to work and when I got home it was still at 100% with Wifi on. I used it for around one hour or perhaps two but I forgot. I woke up this morning and been using it for around four hours now watching youtube videos, and surfing the web using Safari and Firefox and in total around five-six hours of usage at full brightness I am only down to 26% battery life. I really do wonder how does Apple do this with using CPU's that aren't low voltage cpu's and use really bright and high res screens.