Apple Macintosh PowerBook 150 - Manual (Page 83)

Replacing the backup battery
In addition to its main battery, your computer has a small backup battery that
maintains the contents of RAM while you replace the main battery.
The backup battery usually lasts for several years. You may need to have it
replaced if you notice that some of your system settings changed after you
removed or replaced the main battery. (You may notice, for example, that the
clock time is different.) By replacing the backup battery you ensure that the
contents of RAM will be preserved the next time you change the main
battery.
Your computer’s backup battery must be replaced by an Apple-authorized
service provider.
Reconditioning the battery
To maximize battery life, you should recondition the battery once every
30 days. Reconditioning means letting the battery run all the way down before
you recharge it. By regularly reconditioning your battery, you help it maintain
its maximum charge. Follow these steps:
1 Use the computer as you normally would, but ignore the low-power messages that
appear on the screen.
Make sure to save your work when you see the low-power messages.
2 Allow the computer to go to sleep automatically after the third low-power message.
3 Recharge the battery completely before using it again.
See “Recharging the Battery” earlier in this chapter for instructions.
74 Chapter 6