Managing Battery Life
Sometimes you want the full power of your PC, especially if you're trying to accomplish a resource-intensive task on a tight schedule and you know that you'll be back within range of AC power well before your battery is in danger of running out of juice. Under other circumstances, when the workload is light and you know it will be many hours before you'll be able to recharge your device, you want to make that battery last as long as possible.
Being able to accomplish either goal requires mastering one essential skill first: the ability to quickly assess how much power capacity remains in the current session.
For a quick estimate of remaining battery life, click the battery icon in the notification area. That opens a flyout menu that shows the remaining battery life, expressed as a percentage. (On a portable PC with more than one battery, such as the Surface Book line from Microsoft, each battery gets its own percentage, beneath an overall percentage that estimates the remaining battery life overall.) When the laptop is plugged into a charger, this menu also estimates the amount of time before the battery is fully charged.
Click the battery icon in the taskbar to display this flyout menu, which shows remaining battery life and offers a slider to control how Windows uses the battery.
When the portable PC is plugged in, this flyout also displays an estimate of the time remaining before the device is fully charged. When running on battery power, Windows displays an estimate of the time remaining. (If you don't see either detail, just wait; Windows needs a few minutes of charging or discharging time to make an estimate, and it sometimes takes a few extra minutes to make an accurate estimate.)
For a more complete display of information about the current battery status, click the Battery Settings link at the bottom of that flyout menu (or take the long way around by going to Settings → System → Battery). On that page, you'll find a similar display of remaining battery life and, if available, estimated charging time. But that Settings page also includes some additional controls.
This Settings page shows the same information available on the Battery flyout menu, but it also includes a Battery Saver switch to help keep your PC running longer.
For the most important troubleshooting tool on the Battery page in Settings, scroll down to the section headed Battery Usage Per App. After running your portable PC on battery power for at least a few hours (and preferably at least a day).
Use the options on the Time Period menu to change the scale of activity to 24 Hours or 1 Week; the values returned show activity on a per-app basis for all times during the selected period when your device was running on battery power. That's pretty powerful diagnostic information. Used properly, it can help you diagnose which apps are most responsible for draining your PC's battery. Armed with that information, you can either choose not to use those apps when power saving is high on the agenda, or you can look for configuration changes in the apps at the top of the list to help reduce their hunger for power.
Don't forget to check the batteries on your peripheral devices
If you carry essential add-on devices when you travel, be sure to check their battery level before you leave, unless you want to experience the frustration of having your noise-canceling Bluetooth headphones stop working one-hour into a trans-Atlantic flight. Recent additions to the Settings → Devices → Bluetooth & Other Devices page make it possible to check battery life at a glance for modern Bluetooth devices.
Battery Saver and other power management options
To quickly change the way in which Windows uses the battery during the current session, open the Battery flyout menu and use the slider to choose one of the options ranging from Best Performance (on the right) to Best Battery Life (on the left). Moving the slider all the way to the left turns on the Battery Saver feature; you can also turn on Battery Saver using its Quick Actions button at the bottom of Action Center.
While Battery Saver is on, Windows automatically adjusts the following settings:
- The Mail, People, and Calendar apps no longer sync automatically.
- Most apps that normally run in the background are blocked from doing so. OneDrive, for example, sends a notification that it has temporarily stopped syncing local changes to the cloud. You can override this action by clicking the Sync Anyway button in Action Center, as shown in the graphic.
- Display brightness (one of the biggest factors in battery usage) is reduced by 30 percent. Hardware manufacturers can change this default setting, and you can override it using the Lower Screen Brightness While In Battery Saver check box.
- All noncritical telemetry uploads are blocked.
- All noncritical downloads from Windows Update are blocked.
While Battery Saver is enabled, Windows displays an overlay of a leaf on the battery icon in the taskbar, in Settings, and in the Battery flyout menu.
By default, Windows 10 automatically turns on Battery Saver when remaining battery life falls below 20 percent. Use the drop-down menu on the Battery page in Settings to change that threshold to a round percentage between 10 and 50; choose Always to make Battery Saver mode the default, or choose Never to continue running at your chosen power mode until you reach the Low or Critical battery level. At those two settings, you can ask Windows to show a notification or perform an action. For example, you might ask to see a notification when remaining battery level drops to 10 percent and have Windows automatically hibernate when it reaches 5 percent.
You'll find these settings for the current power plan in the old Control Panel, in the Power Options category, under the Advanced Settings tab for the current power plan. Expand the Battery heading to expose options for setting Low and Critical levels and defining notifications and actions for each level.
Monitoring long-term battery life and capacity
Over time, if you're paying attention, you develop an instinctive sense for how long your battery will last and when you should begin looking in earnest for a power outlet. Windows 10 allows you to generate a battery report that gives you a more precise measurement of your battery's history. The report also allows you to observe the decline in battery capacity that inevitably occurs over time. To generate a battery report, open a Command Prompt or PowerShell window and run the command powercfg /batteryreport. That action generates a file in the current folder called Battery-report.html; double-click that file to view the report in a browser window.