Individuals who seek to get work done away from an external power source cite usable battery life as one of the key factors involved in how much work they can get done while on the go. Yet many of those same individuals don't know how much latitude they have in controlling power consumption while operating on battery power, nor do they always take the steps necessary to maximize battery lifetime. Over the long term, proper storage of your battery when not in active use can also extend its lifetime significantly.

Checking the battery

You can check the level of charge on your laptop PC battery by clicking the power icon in your system tray, as shown in Figure 1. The battery charge level is indicated by the height of the green area inside the battery container in the icon.

Many of the figures and examples in this quick lesson focus on the Microsoft Windows Vista operating system.

Figure 1: The power icon looks like a battery with a wall plug to its left.

When you click this icon, an information window opens, as shown in Figure 2. This window indicates how much charge remains in the battery and enables you to select a power plan to manage how your laptop PC uses battery power.

Figure 2: The power icon provides information about battery charge and power plan in use.

Another option is to use the HP Battery Check utility. You need to download this tool, and then run it with your laptop PC plugged into an AC power source.

Understanding power plans

Windows Vista includes three default power plans:

• Balanced: Offers as much power as the laptop PC can deliver during periods of activity but significantly reduces power consumption during idle periods.
• Power saver: Saves power by reducing system performance whenever possible. Use this setting if you want to squeeze as much life out of your battery as possible.
• High performance: Maximizes system performance and responsiveness to user input. Battery life can be reduced by as much as 50 percent from Balanced values when the PC uses this power scheme while running on battery power.

HP notebooks generally ship with the following power plans defined, among others:

• HP Recommended: Offers slightly different settings from those for Power saver when running off the battery but with faster time-outs when running plugged in to an external power source. See Table 1 for the details.
• Power saver: Same as the Windows Vista default power plan of the same name.
• High performance: Same as the Windows default power plan of the same name.

The HP Recommended plan replaces the Windows default Balanced power plan. It makes sense to select HP Recommended for most situations in which the laptop PC switches between plugged-in and battery-powered usage. The following table lists default power plan settings.

Table 1: Key settings for default HP power plans.

There are many other settings associated with individual power plans users may want to investigate. These include time-outs for hard disks, wireless network adapters, USB (universal serial bus) devices, processor power management, and more. To dig into this level of detail, select Start > Control Panel. In Classic view, double-click Power Options. For any of the power plans shown, click Change plan settings, and then click Change advanced power settings. The Power Options dialog box opens, displaying individual power plans in complete detail, as shown in Figure 3.

Figure 3: The Power Options dialog box.

Optimizing battery life

Typical lithium ion or NiMH (nickel metal hydride) batteries last longest (that is, accept the greatest number of full charges before displaying diminished charge retention) if not stored in your laptop when it's plugged into a wall socket. You can achieve optimal battery life by storing the battery at temperatures between 35 and 45 degrees Fahrenheit (typical refrigerator temperatures) at a 40-percent charge level. Before you take the laptop PC on the road, charge the battery up to 100 percent. When you return to your home or office, discharge it until the level reads 40 percent, and then place it in a waterproof bag and put it back into the refrigerator.

HP provides a well documented website focused on mobile PC battery care and usage. Visit Wireless and mobility -- maximize your battery life and browse the links for more information.

Next, learn how to address storage issues on a laptop PC.