As it's name indicates, it is the smart alert for the battery of your device.

It will play alarm on Full Battery Level, when you are charging it. So you can save your phone and battery.

It also play alarm when your battery is low, so that you can come to know that you need to charge your phone.

It is as simple as that. There is no rocket science required to use this app. Just install and you are done. All other stuffs handled by the app itself.