A free program for Android, by Lizanfo.

Battery Health Checker is a useful application that shows you the state of your phone’s battery, its capacity, and more. It will display the battery’s level in the notification bar, as well as its capacity and the amount of energy it can store. The application is designed to help you increase your phone’s battery life, so you will be able to play more games and use your device for longer.

The application can be used in different ways. You can set an alarm level and it will alert you when the battery reaches that level. You can also set the level for the percentage of charge that your phone can store.