Here are answers to some common questions about the battery meter.
The battery icon is located in the notification area on the Windows taskbar.
On a desktop computer, the battery icon appears only if you are using a short-term battery, such as a USB uninterruptible power supply (UPS).
The battery icon changes appearance to display the current state of your battery, so that you can view how much charge remains on your battery at a glance.
When the battery charge is above 25 percent, the battery icon is green.
When the battery charge reaches 25 percent, a yellow triangle with an exclamation point (!) appears above the green battery icon.
When the charge reaches the low-battery level, an "X" appears above the green battery icon.
If you hover over the battery icon, you can see the percentage of remaining battery charge, the amount of time remaining before the battery dies, and the power plan that you're using.
If your battery charge is low, and you have customized your power plan settings to notify you when the charge reaches the low-battery level, that notification appears above the battery icon.
When you right-click the battery icon, a menu appears with the following options:
Power Options. Opens the Select a power plan page, where you can change power settings or select a power plan.
Windows Mobility Center. Opens Windows Mobility Center, where you can adjust several of the most commonly used mobile PC settings from a single location. For example, you can change your display brightness, adjust speaker volume, check the status of your battery, and more.
Windows Mobility Center is available only with mobile PCs and is not included in Windows Vista Starter or Windows Vista Home Basic.
Show System Icons. Opens the Taskbar and Start Menu Properties dialog box, where you can hide the battery icon by clearing the Power check box.
When you click the battery icon, the battery meter appears. It lists all available batteries and their remaining charge.
You can also select any of the default power plans from the battery meter. To change a power plan's settings or to select a power plan that isn't shown on the battery meter, click More power options.
Battery life depends primarily on two things: what you do on the mobile PC while it's running on battery power, and the power plan settings that control the computer's use of power. The mobile PC's power consumption varies constantly, depending on your particular activity and how long you spend on that activity. For instance, watching a DVD consumes considerably more battery power than reading and writing e-mail. For these reasons, the battery meter often lags in reporting the charge and the estimated time remaining.
It depends on the mobile PC and battery, and varies according to the manufacturer. To learn more, check the information that came with your mobile PC or battery.
The battery icon changes appearance depending on whether your mobile PC is plugged in or running on the battery. It indicates whether your battery is charging or is fully charged. The battery icon also indicates the remaining battery charge in 10-percent increments and changes appearance if the battery charge reaches low and critical levels. Finally, its appearance changes if no battery is detected.
The following table explains the meaning of the different battery icons.
Your mobile PC is plugged in and the battery is charging.
The battery icon pulses briefly when you first plug in your mobile PC. While the battery is charging, the battery icon fills at 10 percent increments, starting at 10 percent.
The battery in your mobile PC is fully charged.
Your mobile PC is plugged in and the battery is fully charged.
Your mobile PC is running on battery power and the battery is discharging.
When your mobile PC is running on battery power, the icon shows the charge remaining in 10 percent increments until the charge reaches the low-battery level.
The battery charge is at 25 percent.
If you set the low-battery level to greater than 25 percent, you won't see the 25 percent battery alert icon. To change the low-battery level, see Choose low and critical power levels for your battery.
By default, when your battery charge reaches 10 percent, the battery icon shows a critical-battery notification. If you see this warning, plug in your mobile PC or prepare to lose battery power.
A critical-battery notification appears above the battery icon that shows how much battery charge remains.
To change the critical-battery notification, see Choose low and critical power levels for your battery.
Your mobile PC is plugged in and the battery is not charging.
While the battery is charging, the battery icon fills at 10 percent increments. If the battery icon is not filling, the battery may not be reporting a charging state. If your mobile PC is plugged in for a long time and the battery level remains low, there may be a problem with your computer hardware. If you have an older battery, it may be fully charged, but the full charge doesn't appear as 100 percent.
The battery state is unknown.
The percentage of battery charge remaining can't be determined.
Windows can't detect a battery in the battery bay.
Your mobile PC is plugged in, and no battery is detected. The battery might not be installed in the battery bay, or there may be a problem with the battery or computer hardware. To learn more, check the documentation that came with your mobile PC, or go to the manufacturer's website.
If your computer doesn't have a battery bay, you won't see a battery icon.
Open Power Options by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking Power Options.
On the Select a power plan page, click Change plan settings under the selected plan.
On the Change settings for the plan page, click Change advanced power settings.
On the Advanced settings tab, expand Battery, expand Low battery level, click On battery, and then click the arrow to change the number to the percentage of battery charge at which you want to receive the low-battery notification.
Click OK, and then click Save changes.
When the battery charge reaches the critical battery level, Windows does what the critical battery action specifies. By default, the critical battery action is to put your mobile PC into hibernation. In this case, Windows saves your work to your hard disk so that it can be restored when the computer comes out of hibernation. To change the critical battery action, see Choose low and critical power levels for your battery.
Right-click the taskbar, and then click Properties.
Click the Notification Area tab.
Under System icons, clear the Power check box.
If the Power check box is unavailable, your computer may not have a battery installed. Or, some taskbar settings may be managed by your system administrator. For more information, see Why won't Windows allow me to change a system setting?
The battery meter can display three power plans, one representing each plan type:
A plan that balances energy conservation with performance (Balanced)
A plan that conserves energy (Power saver)
A plan that emphasizes system performance (High performance)
Do one of the following:
On the Select a power plan page, click Additional plans, and then select a plan. Any plans that you create, including plans provided by your mobile PC manufacturer, appear under Additional plans.
Create a new power plan based on one of the three default plans. For more information, see Change, create, or delete a power plan (scheme).
By default, the power plan that you select or create becomes the active plan and it then appears on the battery meter. To make the original plan active again, select it from the battery meter.
On the Advanced settings tab, expand Battery, expand Low battery notification, click On battery, click the arrow, and then click Off.
If your computer is part of a network at an organization—such as a school or business—your organization's system administrator might have made certain settings unavailable or even removed them by using Group Policy. Group Policy is a feature of Windows that system administrators use to manage users' access to specific Windows features.
If you think that Group Policy is preventing you from changing a power setting that you need to access, contact your system administrator.
In addition, you might not have the required user rights to select a different power plan because your system administrator may have designated the active power plan for you instead of letting you choose one.
Although the Balanced plan is sufficient for most people's computing needs, you must decide if it's appropriate based on how you typically use your computer. For example, if you travel often and rely on battery power for long periods of time, the High performance plan may not provide the extended battery life that you need. In this case, the Power saver plan may be better. If your computer is always plugged in when you use it, the Power saver plan may not provide the system performance that you need, for example, when you're watching a DVD.
To view the current power plan, hover over the battery meter icon.