original paid application.
Battery Ace is a nice customizable widget to keep track in detail of your battery level percentage.

Widget Features:
- several styles to chose from.
- 3 modes: level, time left and temperature.
- re-sizable widget with high quality graphics
- numerical battery percent in widget
- option to show charge / discharge time left (estimated)

App Features:
- discharge prediction (estimates how long the battery lasts)
- charge prediction (estimates how long until full charge)