Starting with Windows Phone 8.1, you can significantly extend the battery life of your handset by enabling a feature called Battery Saver. This feature also lets you monitor your battery usage so you can see which apps are using the most battery and can control which apps are allowed to run in the background.
Note: Battery Saver is coming to Windows 10 for phones, of course, but it is also coming to Windows 10 for PCs and tablets. I’ll be looking at this evolved version of Wi-Fi Sense in a future article, but it works similarly to the version in Windows Phone 8.1 today.
Here’s what you need to know about Battery Saver.
It’s a floor wax and a dessert topping. Battery Saver is somewhat unique in that you can access it from both Settings and in the All Apps list. If you choose the Settings route and are running Windows Phone 8.1.2, you’ll need to check under System.
It can make a big difference in battery life. Microsoft claims that Windows Phone can achieve up to an additional 24 hours of usage when Battery Saver is enabled.
It’s off by default. If you want to take advantage of Battery Saver, you will need to enable it first. To do so, select one of the options below “Conserve battery life”: “When battery is under 20%” or “Always (limits functionality).” I recommend using “When battery is under 20%” since the latter option will indeed make your phone much less useful.
Pinning Battery Saver to the Start screen doesn’t buy you much. The tile just shows you the current battery life as a percentage. That said, if you do go below 20 percent battery life, the Battery Saver tile will display a shield, indicating that it is engaged.
See the remaining battery life. While you can always view battery life as a percentage in the status bar at the top of the Windows Phone screen, Battery Saver’s Settings view will also show you the estimated time remaining based on your current usage.
Get a detailed view of your battery usage. On the Usage view, you can see which apps are using the most battery—the biggest offenders are at the top of the list—and change the view to show only certain kinds of apps (all apps, apps with battery usage, or apps that can run in the background) and a certain time frame (last 24 hours, last 48 hours or last week).
Dive deeper into an individual app. To get more details about a particular app’s battery usage, tap it in the Usage view. Battery Saver will show you its battery usage while you’re using the app and while it’s running in the background.
Prevent an app from running in the background. From the app’s usage view, change “Allow app to run in the background” to Off.
Or … allow an app to run in the background even when Battery Saver is on. Maybe the app is just so crucial that you need it to run in the background no matter what. Battery Saver lets you configure that in the app’s usage view too.
This is what happens when the battery life hits 20 percent. Microsoft says that Windows Phone will disable all non-essential features and background tasks, and will slow the rate at which it allows apps and the system to send push notifications. But it will also tailor how it works based on which apps you use the most. And it will respect the exceptions you create using the instructions above.
If you’re running low on battery, you can enable Battery saver manually. Even if you generally ignore Battery Saver normally, remember that you can always enable it on the fly if you’re out in the world and are running low on battery. Just load Battery Saver and enable the option “Now until next charge.” And then remember to turn it off when you’re charging.