BatteryBot Pro

Shows your battery charge level (percent) as an icon in your status bar, with temperature, health, voltage, and time since plugged / unplugged in the notification area. It also has user-configurable alarms, logs, and widgets.

* Automatic time-remaining estimates based on recent usage * Several icon sets (including fully configurable green, amber, red, and black icons) * Small (1x1) and large (4x1) app widgets * Notification (with status bar icon) is now optional -- can be used as just a desktop widget * Battery logging. You can log the battery state (charge, status, voltage, temperature) and browse the logs on the phone or export to CSV. * Manually or automatically disable / re-enable device lock screen / lockscreen / keyguard * Alarms (full, charge above X, charge below X, temperature above X, or health failure) * Control the notification priority on Android 4.1+ (For example, you can set to "minimum" to hide the icon but keep the notification in the tray.)