Plug in the power adapter and fully charge the battery of PowerBook until the indicator light or LED on the plug of the power adapter turns green and the screen indicator light in the menu bar shows that the battery is fully charged.
Don't use the battery, let it be fully charged for at least two hours. In the meantime, you can still use the computer, but you need to plug in the power adapter first.
When the computer is still running, unplug the power adapter and start using battery power to run the computer. You can use the computer during this time. When the battery power decreases, a warning dialog box of low battery power will be displayed on the screen.
Save your work at this time. Continue to use your computer; When the battery becomes very low, the computer will automatically go to sleep.
Turn off the computer or let it sleep for at least five hours.
Connect the power adapter until the battery is fully charged again, then unplug it.
Tip: When the battery is "exhausted", the computer will be forced into sleep mode. In fact, the battery power is not really "empty", but some will be reserved for the computer to sleep for a period of time. Once the battery is really exhausted, the computer will be forced to shut down. At this time, the PowerBook G4( 15 inch, double-layer SD) computer will start the safe sleep function, and the contents in the computer memory will be saved to the hard disk. After the power is restored, the computer will automatically return to the pre-sleep state using the safe sleep image on the hard disk.