I literally just got my base 13" MBA yesterday, set it to charge when I opened it up, let it stand for a couple of hours while the Time Machine backup loaded up and then when it was done and I disconnected it (the charger indicated a full charge by then) - it was only on 97% even though the light was green! I used it for half an hour before going to bed and it dropped from 97% to around 85% even though I just browsed. Shouldn't the battery last 7 hours?! It only shows me about 1:30 left. Has anyone else had the problem? Thanks.