Power Management

Power management issues are technically no different on the tablet than on any laptop. If there is a difference, it’s simply that you’re more likely to use the tablet on battery power and for longer periods of time. Here are some of the most useful ways for getting your batteries to last the longest. For a detailed discussion of power management under Windows XP, see Chapter 9, “Configuring Shutdown and Power Management Options” in the book, Microsoft Windows XP Inside Out (Microsoft Press: 2001).

Setting Power Options

The default power options settings for the tablet are a compromise between decent power savings and making your tablet behave similarly to a desktop or laptop computer. If you’re willing to adjust these settings in the Power Options control panel, you can often squeeze an extra 15 to 30 minutes out of your battery life. Open the Power Options control panel by right-tapping on the Power/Battery icon in the notification area and selecting Adjust Power Properties or by using Control Panel. The control panel opens with the Power Schemes tab visible, as shown in Figure 1-5, which lets you set time of inactivity before the tablet invokes any of four power-saving actions:

Hibernation must be enabled on the Hibernate tab to appear as an option.
Figure 1-5 Power Schemes organizes four power-saving properties for use in different situations.
Figure 1-5. Power Schemes organizes four power-saving properties for use in different situations.

These power-conservation behaviors are organized for different situations. For example, you can make sure the screen normally turns off after one minute of inactivity but doesn’t go blank at all when you are giving a presentation on battery power. There are quite a few power schemes by default, but none geared specifically for a tablet. Figure 1-5 shows custom settings for my tablet, in which the screen goes off after one minute and standby happens after three when running on batteries. Because the screen comes alive as soon as the pen gets near it, I hardly notice whether it’s on or off, so I want it to happen as soon as possible. I set standby to a wait long enough that I can pause while working for a moment, but short enough that I don’t waste power if I sit and think. Hibernate is set to one hour because I don’t want the tablet to hibernate while I’m working, even during a long break, but I do want it to hibernate if I forget to turn it off. Notice that the settings are different for when I am plugged in and presumably working at my desk. The tablet switches between these two sets automatically when you plug into a power outlet and when you unplug again.

You can quickly switch between power schemes by single-tapping the Power
icon in the notification area and selecting from a menu of all the saved power schemes. Since there are probably more power schemes in the system than you will ever need, deleting the ones you don’t want makes this feature easier to use. If the Power/Battery icon is not visible in the notification area, you can add it by checking the Always Show Icon On The Taskbar check box on the Advanced tab of the Power Options control panel.

The Alarms tab and the Advanced tab are two other tabs in the Power Options control panel worth checking. The Alarms tab determines the actions taken at low and at critically low battery levels. Usually the defaults are fine, but you can adjust how much warning you get before you run out of power. You should ensure that when the tablet reaches a critical battery level, it either hibernates or shuts down to prevent you from losing your work. The Advanced tab has a check box for prompting for a password when resuming operation from standby. If you use standby often, uncheck this box. There is little point in a super-fast resume from standby if you must enter a password each time. Use the tablet security button to password-protect your tablet if you step away for a moment.

If you run on batteries for long periods, the best policy is to have a second battery. To switch batteries quickly, hibernate Windows and switch rather than shutting down and restarting. You should still save your work first.

Here are a few other items that help prolong battery life: