Gsam Labs display the battery percentage and the estimated time of battery left on your home screen
Formerly known as Badass Battery Monitor, GSam Battery Monitor still lives up to its former name:
* Status bar notification for battery state and time left estimates
* Overlay the stock battery icon with the icon pack add-on.
* Detailed display of what is using your battery
* Lists showing app usage allowing sorting by things such as CPU usage, Sensor usage, Wake Locks, Wake Time, Kernel Wakelocks, etc.
* Set a custom time reference to see stats over a certain period of time.
* See time remaining estimates based on current and historical usage
* Add a widget to your home screen showing the battery status and time remaining
* Download or create your own icon themes
* Set audible alarms to know when your battery has finished charging
* Share and compare your average battery life with others