Power to the Tablet PC | Tablet PCs for Dummies

Even though docking stations may make a Tablet PC act like a desktop computer, these PCs are really all about portability. They were designed to be lightweight and manage battery power efficiently for those times when you can't be tethered to a wall socket.

I'll be frank: Most Tablet PCs advertise battery life (that is, how long you can run the computer on a battery before it needs recharging) of 3.5 to 4.5 hours, with Standby battery life (battery life when you have the unit in Standby mode) of about three days, but in reality, they usually fall short of that. You want to take best advantage of your battery's potential, but first you have to understand a little bit about power-management and Tablet PC.

A AAA battery this ain't

Like their cousins, laptop computers, Tablet PCs come with a lithium-ion battery (see Figure 3-9), which is the best type of battery for holding a charge the maximum amount of time. The more cells these batteries have (for example six cells versus three cells) the longer they'll hold a charge, but the higher cell models are also a bit heavier to cart around.

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Figure 3-9: A battery will slide right into the body of your Tablet PC.

These batteries aren't cheap (a six-cell battery can cost about $180), so if you buy a second one to carry more charge around with you, be prepared to spend some money.

Tip If you travel a lot, a second battery is worth the price. With two charged batteries, you may get as much as six or seven hours of battery life, which should get you through most plane flights.

Where you're supposed to insert the batteries varies depending on the model of Tablet PC you own. The ViewSonic battery is about 11 inches long and actually runs all along one side of the unit. Many other manufacturers fit their batteries into the body of the Tablet PC on the underside of the unit.

Remember There's often a sliding latch you have to push to release a battery to remove it. See your user manual for specific instructions on how to install and remove the battery.

Charging the battery

Some manufacturers recommend that you charge the battery with the Tablet PC turned off for a few hours (usually two to three) when you first get it out of the box. Others say the battery that comes with the unit is already fully charged and requires no start-up charge at all. Be sure to read your manual for manufacturer recommendations.

You charge the battery with it installed in your Tablet PC by connecting the Tablet PC power cord into a standard electrical outlet. It's always best to plug the AC adapter into the wall and then into the Tablet PC with the Tablet PC turned off. Then turn it on and say, 'Charge this battery.' (Just kidding; it will ignore you and charge the battery anyway.) You can do this whole operation while you're working on the Tablet PC, if you like.

Warning! Some manufacturers warn that if you don't fully charge the battery before using it the first time, you could affect the battery's overall life. It's important that you read your manual regarding charging when you first buy your Tablet PC.

Tip If you leave your Tablet PC turned off or remove a charged battery from it, the battery will keep its charge for anywhere from one to two months.

You can check your power level by following these steps:

Choose StartðControl Panel.

The control panel is displayed.
Double-tap the Power Options icon.

The Power Options Properties dialog box is displayed.
Tap the Power Meter tab (shown in Figure 3-10).

Figure 3-10: Get the exact percentage of charge and current power source here.

The current power source and the current percent of remaining battery power are shown here.
Tap OK to close the dialog box.

Tip You can also hover your pen over the Battery icon on the Windows system tray to get a look at how much battery power you have left.

Choosing a power scheme

Windows XP for Tablet PC includes power schemes. No, they aren't plans for world domination; they're instructions to the computer on how to save electricity. Several power-management settings are saved into schemes that fit your use of the Tablet PC, such as Home/Office Desk, Presentation, and Always On.

You can even make settings manually and save new power schemes that fit the way you use your computer.

To set a power scheme, follow these steps:

Choose StartðControl Panel.

The control panel is displayed.
Double-tap the Power Options icon.

The Power Options Properties dialog box is displayed.
Tap the Power Schemes tab (as shown in Figure 3-11).

Figure 3-11: After you create your own scheme and make individual settings, tap the Save As button to save the scheme.
Tap the arrow on the Power Schemes drop-down list box and select a power scheme.

The individual settings are shown.
When you locate a scheme that fits your needs, tap Apply, and then OK to close the dialog box.

Tip Want a shortcut? You can also tap the Battery icon on the Windows system tray and the saved schemes will be displayed. Just tap another scheme to apply it.

Setting a lower battery warning

Windows XP for Tablet PC displays a battery power indicator in the task tray on the taskbar when you are running off of a battery charge. Check it to see if you're running low.

Windows XP also provides a low battery warning to alert you when a battery is about to be completely drained so you can save your work and attach to a power source if one is available. An LED low battery light on the front of your Tablet PC begins blinking to let you know that the battery is low. You also hear a beep every 15 seconds or so. By default, the Tablet PC is set to alert you when it's got 6 percent of its charge remaining, which translates to about ten minutes of battery life before your power goes phffft.

Warning! There's also a very low battery warning that occurs when you have only 3 percent of your charge left. This warning, quite annoyingly, beeps at you about every four seconds.

You can change this setting to give you more or less notice by following these steps:

Choose StartðControl Panel.

The control panel is displayed.
Double-tap the Power Options icon.

The Power Options Properties dialog box appears. If it's not already displayed, tap the Alarms tab and get the dialog box shown in Figure 3-12.

Figure 3-12: You can make settings for two battery alarms in this dialog box.
Tap the slider for the Low Battery Alarm and drag it left or right to set the first level of battery warning.
Tap the slider for the Critical Battery Alarm and set the second-level alarm - the one that sounds when the battery is almost drained.

You can also set the alarms to function in specific ways; for example, to display a message instead of sounding an alarm. Follow these steps:

From the Alarms tab of the Power Options Properties dialog box (shown in Figure 3-12), tap the Alarm Action button for either the Low Battery Alarm or Critical Battery Alarm.

The Low Battery Alarm Actions dialog box (see Figure 3-13) appears.

Figure 3-13: Choose how an alarm will function by choosing settings in this dialog box.
Choose how you want the alarm to notify you by tapping in the Sound Alarm and Display Message check boxes.

You can choose sounding an alarm, displaying a message, or doing both.
If you want the computer to take an action when the alarm sounds, tap the When the Alarm Goes Off, the Computer Will check box; then select an action from the drop-down list.

Tip To run a program (for example, an executable file that saves an open document and then shuts down the computer), tap in the When the Alarm Occurs, Run This Program check box, and tap Configure Program to select the program to run.
When you've completed your settings, tap OK twice to save them.

Battery pointers and power-saving tips

Tips are free, so I've got a few for you that can help you become a powerful power manager:

If you're installing software or writing files to a CD-ROM, use the power cord to save battery drain.
Put the system in Standby or Hibernate mode if you're not using it for a few minutes (for example, while you take a phone call).
Lower display brightness settings can save battery power.
Don't touch the ends of the battery where they connect with the Tablet PC.
Don't put batteries in very cold or very hot temperatures. Lithium-ion batteries work by converting dry chemicals into electricity and those chemicals don't like extreme temperatures.
Before a trip, plan battery charging time. Don't just get up in the morning to dash for a plane when you may need two hours or so to get your battery up to speed.
Don't keep PC cards that you're not using in the unit. Even if they're not active, they can drain a tiny bit of power from your battery.
Use the Max Battery Power Scheme, which saves the most power of any of the schemes.