Hello, I have recently purchased a MacBook Pro "13 screen. It is great except for the battery life. Apple claims that the battery lasts about 7 hours I think but when I use my computer unplugged, the battery lasts for only 3 hours at the most. I do not suspect that Apple is lying but rather there is something wrong with my battery or that I am doing something wrong. Perhaps I have to calibrate the battery to get the best results. Is this plausible? What do you think?