Last Updated Aug 19, 2009 12:27 AM EDT
Lower the Brightness. In much the same way that the worldwide market for those tiny dogs that fit in a woman's purse is limited rich blond heiresses, the lion's share of the demand on your laptop battery comes from the screen. (Yes, even I agree that was something of a tortured metaphor.) The first thing you should do when on battery power is make sure the screen's brightness is cranked way down. You can set this up as a default in Windows' power management Control Panel.
Disable Aero Glass. Another screen tweak: If you run Windows Vista or Windows 7, this a huge way to recover lost battery life. Rather than changing it manually whenever you go off the grid, though, install a utility like Aerofoil or BatteryCare.
Turn Off Wireless. If you need Internet access, fine. But if your laptop is always searching for a Wi-Fi connection even when you're out of reach of one, or if you simply don't need to connect, you're wasting battery. Flip the wireless toggle to off (most laptops have a switch to easily disable Wi-Fi) so you don't burn power on something you don't need.
Don't Use the CD/DVD Drive. Running your internal CD/DVD drive consume a lot of battery power. Remove any discs so the drive doesn't spin up[ and don't play audio CDs or try to install something from disc when you're not on wall power.
Mute the Sound. You need sound on a laptop like cats need motorcycles. I leave the sound on my laptop muted all the time so it doesn't beep or alarm in the middle of a meeting, but sound uses power, too - so there are several practical reasons to keep it turned off.