I found this on a previous laptop forum post: 10 tips for extending battery life
I ran across these tips, hopefully they help some of you guys/gals:
1. Think small
If extralong battery life matters to you, forget about that huge, 17-inch-screen laptop with the top-speed processor--it probably won't run for more than two hours. When you're buying your next laptop, think small and consider an ultraportable or a thin-and-light laptop. An Intel Pentium M processor uses about half as much power as a Pentium 4, a 12.1-inch screen uses 50 percent less juice than a 17-inch model, and getting a 4,200rpm hard drive instead of the 5,400rpm model can mean an extra 15 to 20 minutes of battery life.
2. Control your power
Adjust your laptop's power settings to find a comfort zone where you're using as little power as possible with no interference in your computer tasks. The path to the control panel will vary according to your operating system and setup, but for Windows XP Home and Pro users, follow these steps: Go to Start > Control Panel > Performance And Maintenance > Power Options. Set the LCD screen to go off after 5 minutes of inactivity, let the hard drive stay active for 20 minutes, and store the system's contents in RAM when it shuts down. If your laptop goes to sleep too soon, adjust the settings.
3. Dim all the lights
Your LCD's backlight uses up to 10 watts of power, a huge battery drain. Lower the screen's brightness to where it's comfortable to view without squinting. In addition to the Power Options settings detailed in tip 2, most laptops have convenient function keys for controlling brightness. Look for the function key with the brightness icon and a down arrow next to it. (This is the F6 key on many laptops.) Also, some new laptops, such as the Apple 17-inch PowerBook, adjust the screen's brightness to suit the conditions.
4. Be battery smart
Know how much power remains by checking the battery power icon in the system tray. Or buy a laptop with a battery that features a charge-level LED gauge on the battery itself so that you can just flip over the notebook to see how much battery life remains. If you really want to see tons of detail on what your battery is doing and how much life is left, take battery monitoring to the next level with PassMark's $15 BatteryMon 1.3 program.
5. Double or triple your pleasure
Some laptops, such as Fujitsu's LifeBook S series, let you double up with a second battery that fits into a modular bay, nearly doubling runtime. A few laptops can even take as many as three batteries, if you include the docking station, also called a media slice. The IBM ThinkPad X40, for instance, can be fitted with a large-capacity battery in place of its standard battery, and it has a connector for an additional bottom-mounted external battery.
6. Charge when you can
Before leaving the home or the office with your laptop, fully charge all of your batteries. If you're traveling, look around for a wall outlet to give your batteries a refresher charge when you can, because every little bit helps. Some third-party devices will help you charge on the road, such as iGo's Juice 70 ($120). This versatile device does it all: it's a regular AC adapter, as well as a car converter, and it will work on many airplanes. With the right plug, it can even charge your phone or PDA.
7. Check the CMOS battery
If you have to reset your laptop's clock or your system BIOS, you may have a bad backup battery. Also called the CMOS battery, this secondary battery, which powers the clock when the system is not in use, can sap the main battery power if it's dead. The good news is that this battery is inexpensive. The bad news is that you'll likely have to dig around inside the laptop to find it. Some vendors put the backup battery under the memory chip slots, while others stash the CMOS battery under or next to the main battery. Check your manual or the vendor's technical support Web site for details.
8. Shut down unnecessary programs
When you're running your laptop on battery power, turn off devices and programs you don't need. When not connected to a wireless hot spot, turn off the Wi-Fi hardware. If you access wireless networks with a PC Card, remove it when not connected. Listening to music via the CD-ROM drive and watching DVDs are also big battery drains.
9. Start with complete battery drains
To ensure long-term battery vitality, do the following: When first using your laptop on battery power, let the battery completely drain before you recharge it. Don't recharge when the battery is only half drained. Do that for at least the first two sessions. Also, avoid temperature extremes. Don't leave a laptop in a hot car or use it outdoors in extremely cold weather; hot batteries discharge very quickly, and cold ones can't create as much power.
10. Terminal care
Make sure the battery contacts that connect your cells to the laptop are straight and clean and free of grime, because the last thing you need is a bad connection. Most contacts are flat, copper-colored metal strips, but they might be hidden between pieces of protective plastic. Every six months or so, give the contacts a cleaning with a cotton swab and rubbing alcohol to remove electron-sapping dirt and grime. A bad connection can keep you from getting the most out of a battery.