hi.. i just bought myself a 15" powerbook.. ive never owned a notebook before.. so im trying to follow the initial instructions carefully. according to the manual.. in order to calibrate your battery correctly, you need to fully charge it until the power adapter plug changes to green and the onscreen meter is at 100%.. then you use it till the battery is fully discharged.. charge it once more.. and you are good to go. my problem is that the onscreen meter says 100%.. but the plug is not green yet.. is my unit defective? or is this common with the initial charge. how long does the initial charge usually take? thanks.. in advance.