Apple Macintosh PowerBook 150 - Manual (Page 81)

The table shows approximate recharging times for fully depleted batteries.
80% charge 100% charge
In the recharger:
1 battery 2.5 hours 5 hours
2 batteries 5 hours 10 hours
In the computer (shut down): 2–3 hours 6–8 hours
Removing or replacing the battery
You can remove or replace a battery only while the computer is asleep or
shut down. To remove or replace the battery, follow these steps:
1 Save your work, and then choose Sleep or Shut Down from the Special menu.
2 Close the display.
Doing so will prevent you from inadvertently pressing any keys and waking
the computer.
3 Open the battery door by sliding the door in the direction indicated by the arrow.
The door is physically attached to the battery.
WARNING If you choose Sleep, and the power adapter is not plugged in,
the backup battery will protect open programs and documents for only
about 4 minutes after you remove the battery.
72 Chapter 6