Apple PowerBook G3 - Manual (Page 53)

Recharging the battery
To recharge the battery, plug in the power adapter. Your computer’s batteries
may be charged inside the computer. You may also use an external battery
charger designed specifically for your model of the Macintosh PowerBook.
Note: It is normal for the computer to start up when power is applied and the
PowerBook has been in storage or the battery is discharged or has been
removed from the computer.
A lightning bolt icon appears in the battery monitor portion of the Control
Strip when the power adapter is plugged in and a battery is recharging.
The battery is recharged regardless of whether you are using the computer, or
the computer is off or in sleep; however, it will recharge more quickly if the
computer is off or in sleep.
WARNING Use only the external power adapter that came with your
computer or one made specifically for this PowerBook model. Adapters
for other electronic devices (including other portable computers) may
look similar, but they may damage your computer.
Power cord
Power adapter
Power adapter plug
¯ Power adapter port
53 Power Management