Maximizing battery life under OS X

There are a few simple tips that can make major improvements in battery life on a PowerBook running under OS X, and many of these tips are the same tips that applied under Mac OS 9.x.

1) Dim your LCD screen as low as you can stand it. The LCD is a major draw on the power resources for your PowerBook, and although it can be harder to read or to work with graphics with the brightness turned way down, the payoffs in battery time can be significant.

2) Turn off hard drive intensive apps. The simple rule when trying to maximize battery time is that if you aren't currently using the application and you won't need to use it soon, then quit the application. Everyone knows that playing a DVD while on battery power is going to drain your battery quickly, but the same goes for browsing Web sites that constantly hit your hard drive (like the Lycos site I work on...) or doing intensive work with image editing applications like PhotoShop that require constant hard disk use.

3) Turn off AppleTalk if you don't need it. AppleTalk is a useful networking protocol, but even now it remains a "chatty" protocol that makes frequent networking calls to see what new resources are available on the network. You can make turning AppleTalk off an easy process by creating different Location profiles with different Network settings. Create one with no network settings live at all and run that when you need to maximize your battery life. And create another profile with AppleTalk turned off and other networking resources that you need, such as AirPort, turned on. Then you can change using the Location item in the Apple Menu.

4) Run only the applications you need. This cuts down on the need for OS X to juggle system resources to keep those idle applications running.

5) Avoid using the CD or DVD drive while on battery power, and especially avoid doing things like burning CDs while on battery power. Burning is a double hit on battery life, since it uses the hard drive and the burner drive in conjunction.

6) Turn off Classic. Running two OSes at once is a sure way to suck a battery dry in no time at all. If you want to stretch the battery life, turn off the old OS.

Using these six simple steps I have been able to squeeze between 2 and 3 hours of life out of the more-than-one-year-old battery in my PowerBook G3 FireWire (Pismo) while running OS X 10.1.x. And while this is still a reduced time from what I once saw under OS 9.x, it is still acceptable enough to get through those times when I need to run without a power connection. Combined with the much improved battery life under Sleep mode in OS X 10.1.x, I don't find OS X to be a major problem running under battery power. And if I ever get my hands on a second battery for this Pismo, I should be good for at least half a day of regular work on my machine without the need to plug into the power jack...

What additional steps do you take to extend the life of your PowerBook batteries under OS X?