It is a widget not an app. You can add this widget on your home screen using two methods:
Method1:- Menu -> Add -> Widgets -> Battery Meter Widget
Method2:- Long tap on an empty space of home screen -> Widgets -> Battery Meter Widget
Method3 (Honeycomb and above):- Go to All Apps, switch to Widget tab and drag battery meter widget to your desired homescreen.
Clicking on the Battery Meter Widget will show you the Battery Usage.
If you like our widget, then you can help us in development by contributing through our donate app (Battery Widget Plus), which comes with 4 themes and more customization.
- If you have task killer or app killer then please add battery meter widget to ignore-list otherwise battery status in the widget will not update.