With default settings, when the battery level comes down to 20%, the built-in battery saver mode automatically gets turned on. When the battery saver is turned on, Windows 10 does several things to improve the battery life, including lowering the screen brightness.
While dimming the screen is a good way to let users know that only 20% of the battery life is left, many users might not want Windows to automatically reduce the screen brightness. The other problem is that once the screen brightness is lowered, you cannot manually increase the screen brightness to the highest level.
If you do not want Windows to interrupt you by lowering the screen brightness, you can turn off the same under Settings.
NOTE 1: This will not change the default auto screen brightness feature. If you do not Windows 10 to automatically adjust the screen brightness, please refer to our turn off automatic or adaptive screen brightness feature in Windows 10 guide.
NOTE 2: When the battery saver gets activated, Windows 10 lowers the screen brightness to improve the battery life. Turning this feature off will impact the battery life big time as the screen consumes more energy than anything else on your computer. Lowering the screen brightness is the best way to improve the battery time.
Turn off auto screen dimming when on battery saver
The automatic screen dimming when the battery saver is turned on can be disabled by following the given below directions.
Step 1: Open the Settings app. As you likely know, you can open the Settings either by clicking on the gear/settings icon in the left pane of the Start menu or simultaneously pressing the Windows logo and I keys.
Step 2: In the Settings app, navigate to System > Battery. In the Battery saver section, turn off Lower screen brightness when in battery saver option.
That is all you need to do! From now on, Windows 10 will not automatically lower your device’s screen brightness when the battery level comes down to 20%, when the battery saver gets activated or when you manually turn on the battery saver.
As said earlier, this might impact the battery time.