This article provides suggestions for reducing power consumption, thus extending the life of your PowerBook computer's battery.

General Information

Some load items that affect battery usage:

• Amount of RAM installed
• Screen brightness
• Hard disk drive usage
• Peripherals (including internal modem or PC cards)

Note: Depending upon the version of Mac OS system software you are running, the energy conservation settings may be in the PowerBook control panel or the Energy Saver control panel. Refer to the Owners Guide for your PowerBook or the documentation for your version of the Mac OS for the location of the PowerBook energy features.

Before Using Your PowerBook the First Time After Purchase

• Shut down your PowerBook and charge its battery overnight. This ensures that both the main and backup batteries get a full charge.
• Reduce the number of extensions and control panels that load by using an extension manager program.

• Turn down the brightness.
• Turn Backlighting down to minimum. Set the shortest delay before dimming (move the slider in the PowerBook Display, or Energy Saver control panel to the left). Use this dimming feature instead of a screen saver program. Screen savers access the hard drive and keep backlighting turned on (which uses battery power) but dimming does not.
• In bright light, you can even turn backlighting off, greatly increasing battery life. Some people use a booklight with no backlighting, but this is an extra accessory to carry. Also, the PowerBook File Assistant software offers the PowerBook Display control panel that provides controls over automatic screen dimming.
• Avoid desktop patterns with many black pixels or solid dark areas. (These don't consume more power, but they tend to make you turn up the backlighting, which does consume more power. For Color displays it is good to use darker colors, like black, that reduce the use of Red, Green, or Blue pixels. All pixels are on make white which uses the most battery power.
• Use the Chooser to turn off AppleTalk. This saves power and lets the PowerBook wake up faster. You may wish to have AppleTalk turned on when you restart and then turn it off. That way you can turn AppleTalk on and off without restarting. If AppleTalk is turned off when you start up a computer, certain system code doesn't get loaded, and a restart is necessary to get it loaded again. If you have the PowerBook File Assistant Toolkit extension installed, AppleTalk is always available, thus avoiding the need to restart the system to load the AppleTalk drivers.
• Turn the sleep wait period down to a minimum using the PowerBook control panel, or set the Battery Conservation slide control to Maximum Conservation.
• Set system and hard disk sleep to their minimum settings.
• Select Reduced Speed in the Battery Conservation Options section of the PowerBook control panel.
• Use Sleep in the Special menu as often as practical. If the PowerBook File Assistant is installed, you can also use the Sleep Fkey sequence, Shift-Command-0.
• Enable "Allow Processor Cycling" to reduce the power draw of the microprocessor.

• Use the Memory control panel to set up a RAM disk. Use the Installer to create a minimal System Folder on the RAM disk, and then use it as the startup disk.

The Tech Info Library article 12259: " PowerBook: Setting Up to Run from a RAM Disk " documents how to set up a RAM disk for your PowerBook.

• Use the Memory control panel to turn off Virtual Memory as it runs the hard drive more frequently.
• Use third-party RAM cards that contain low-power RAM chips.

• Under battery power, don't use applications or features (such as spell checking or QuickTime) that require lots of hard drive access.
• Instead of a full-featured word processor, use SimpleText, or a program designed specifically for PowerBooks. Many word processors constantly access the hard drive, which uses battery power.
• When you're near an AC outlet, and you're planning to use battery power later, launch your applications and open data files with AC power, then put the PowerBook to sleep. Your work will be in RAM when you come out of sleep.

• Quit any program that uses a modem as soon as you're finished with it.
• Turn off features such as "wake on ring" and "fax receive" for modems.
• Don't use external devices when operating the PowerBook from battery power.
• If any SCSI devices are connected to the computer, make sure they're turned on, even when you're using the AC adapter. Power can drain from your battery through attached power supplies.
• Use the disk drive as little as possible and eject any floppy disks you're not using.
• Use only low-power ADB devices that are designed for PowerBook computers.
• Remove any PC (PCMCIA) cards from the PC card expansion slot(s). Some cards draw power even when they are not in use.

Other Tips

• If you're near an electrical outlet, use the AC adapter.
• Travel with a spare battery.
• Regularly "exercise" the battery by running it completely down and recharging it.

To maximize battery life, with the exception of the sealed lead acid battery in the PowerBook 100, discharge them completely once every 90 days. Just 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 the computer goes to sleep automatically, recharge the battery completely before using that battery again.