# Plug in the power adapter and fully charge your PowerBook's battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged. # Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in. Should I be using my MBP while the battery is being fully charged? Or do I wait until it is fully charged to turn it on?