How to Set Low Battery Warnings on a Windows 7 or Vista Laptop
All Windows laptops can be configured to provide you with various low-battery warnings. Furthermore, you can configure Windows to automatically hibernate or shut down your laptop when the battery gets way too low. In Windows 7 and Windows Vista, you can follow these nimble directions to set the low-battery-power warnings:
Open the Control Panel.
Choose Hardware and Sound, and then choose Power Options.
By the selected power plan, click the Change Plan Settings link.
Click the Change Advanced Power Settings link.
The Power Options dialog box shows up.
Click the plus sign (+) by Battery.
You see five items for consideration, each with settings available for when the laptop is plugged in or on battery power. The items are in chronological order:
Low Battery Notification: Turns on a warning for when the battery power gets low, as set by the Low Battery Level item.
Low Battery Level: Determines at which percentage the Low Battery Notification warning appears. The value is set as a percentage of battery life.
Low Battery Action: Specifies what happens when the battery reaches the Low Battery Level warning. Options are Do Nothing, Hibernate, Sleep, and Shut Down.
Critical Battery Level: Determines at which percentage the critical battery action takes place. Values are set as a percentage of battery life and must be lower than the Low Battery Level values.
Critical Battery Action: Specifies what happens when the battery reaches the percentage set by the Critical Battery Level. Options for On Battery are Hibernate, Sleep, and Shutdown. The additional option of Do Nothing is available for when the laptop is plugged in.
Additional items might be available, which would be specific to your laptop. For example, my Lenovo laptop has a Reserve battery level, which sits between the Low and Critical levels.
Set the values for the various warnings, levels, and actions.
Click OK and (optional) close the Edit Plan Settings window.
The visual warnings you specify appear. Obey them!
It might make no sense to have options for low and critical battery levels when the laptop is plugged in, but consider what happens when the battery is charging: If you plug in a laptop when its battery is low and the Plugged In setting for Critical Battery Action is set to Shut Down, the laptop turns itself off even when it’s plugged in.