A free program for Android, by Sam Lu.

2 Battery – Battery Saver is a simple and easy-to-use app that allows you to extend the battery life of your Android device. It is the best and most efficient way to keep your phone running for a longer period of time.

How to use this app?

Open the app and install it on your device. After that, you need to open the app and configure it.

Now, you need to enable the background service. You can do that by opening the Settings menu of the app and then selecting the Battery Management option.