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The recent laptop battery recalls, due to the potential risk of overheating or fire, have inconvenienced millions of mobile professionals. But lithium ion batteries--widely used to power today's laptops--are here to stay, at least for the foreseeable future.

I recently offered tips on how to safely handle lithium ion batteries to minimize the already minimal risks of overheating or fire. This week I've got advice on keeping your notebook's lithium ion battery in top condition and powering your portable PC as long as possible.

Use It or Lose It

If unused for long periods of time, lithium ion batteries can very slowly lose their capacity to hold a charge. Fortunately, lithium ion batteries hold their charge better over time than other rechargeables, including nickel cadmium and nickel metal hydride. But you want your spare to be ready when you need it, so if you've got an extra battery for your notebook, use and then recharge it on occasion to keep it ready to go.

Shut Down Completely

When your notebook is running on battery power, there are things you can do to extend its charge. For one thing, when you're finished working, shutting down your computer instead of putting it into Stand By or Hibernate modes preserves battery power. Though Stand By and Hibernate enable you to restart quickly, both modes continue to draw power from your battery. (Hibernate uses less juice than Stand By, however.)

Turn Off Wi-Fi, Bluetooth and Cellular Modems

Always turn off Wi-Fi, Bluetooth, and cellular modems when they're not needed. These wireless network technologies can be a significant drain on your laptop battery's charge. Many newer notebooks have buttons to turn wireless connections on and off. You can also go to Start, Connect To, "Show all connections," then select the connection you want to enable or disable.

Remove Discs and Devices

When they're not needed, remove CDs, DVDs, flash media cards, PC Cards, ExpressCards, and connected peripherals. When you have media inserted in a computer drive, such as a disc in the CD/DVD drive, the computer continues to try and communicate with that drive. And everything a computer does--including those communication attempts--is a drain on its battery power.

Tweak Power Settings

Your notebook's display is one of its main battery drains. Thankfully, Windows XP notebooks include a utility for adjusting display and other settings that can affect your battery charge.

To open the utility, go to Start, Control Panel, Power Options. Using the Portable/Laptop power scheme, you can opt to have your laptop LCD turn off automatically after a given time. You can also choose to have your hard drive spin down after a period of disuse. And you can opt to have your laptop automatically go into Stand By or Hibernate modes.

But here's a caveat: Don't get too ambitious with your power conservation settings. Your notebook must expend power every time the hard drive and monitor are awakened from their sleep. So for maximum efficiency, make your settings fit your usage patterns. As a general rule of thumb, I recommend that when you're running on battery power you opt to have the hard disk turn off after about 20 minutes and the monitor after about 10 minutes.

Adjust Screen Brightness

You can also save battery power by lowering your laptop screen's brightness. In most cases, this is done using a combination of function keys. For example, on my HP Pavilion dv1000, I hold down the Fn and the F7 keys together to decrease screen brightness and the Fn and F8 keys to increase it. You may be surprised to find that your display is quite comfortable to view at a lower brightness setting than the default.

Get a Long-Life Battery

Many notebook vendors now offer an option for an extended-life battery. Usually, these batteries are heavier, bulkier, and more costly than standard batteries. But they can significantly extend the time your notebook operates away from a wall socket.

Consider a Notebook Battery Booster

Some third-party power products are available that can significantly extend your notebook's battery life.

Xantrex's XPower Powersource Mobile 100 ($130) is like carrying around a wall socket. Plug the AC adapter of your notebook (or other device) into this power brick, and the Powersource's internal battery will keep the notebook running for about 2 hours, according to my informal tests. The Powersource also lets you charge USB devices. And it could come in extremely handy during a power outage. The downside: At 2.4 lbs., the Powersource weighs nearly as much as some ultraportable notebooks. [Correction: The Powersource Mobile 100 actually weighs about a pound, as the Xantrex rep informed us shortly after this article went live. --Editor]

Earlier this year PC World tested two notebook battery extenders: Valence's N-Charge VNC-130 ($250) and Hi-Capacity's PowerPlus 60 ($170). The N-Charge added an extra 9 hours, 8 minutes to a Sharp PC-M4000's battery, while the PowerPlus 60 extended the Sharp notebook's running time by 4 hours and 33 minutes.