Particularly useful for devices that have official docking attachment with additional battery, such as ASUS PadFone and Transformer Pad series.
Originally, additional battery's percentage is available only from a widget. Thus, a user needs to first turn on the screen, then unlock the device, and finally find the home screen with the widget, just to see remaining battery percentages.
With this app, just turn on the screen and see every battery's percentage in the status bar visible at the lock screen.
Optional notification by sound, flashing lights, or vibration when any or all batteries become fully charged. (Default disabled)
Supports Android version 1.6 and later.
Supports Dynamic Display Switch.
Requested Permission Explained
Run at startup: Automatically showing battery percentages after the device powers on eliminates the need to manually run this app every power on. (Default on, can be turned off in the app's settings)
Control vibration: Enables notification with vibration when a battery becomes fully charged.
By the way, in order for an app to keep showing something in the status bar/notification area on Android, the battery notification can not be dismissed, but can stay below most of other notifications, and can be customized to do nothing, open app, or (for ASUS devices only) open ASUS customized settings when tapped.
ASUS The new PadFone Infinity (T004 A86) with PadFone Infinity Station (T003P)
Sony Xperia Z
Reportedly Working Devices
ASUS PadFone 1, its PadFone station, and keyboard dock
ASUS PadFone 2
ASUS PadFone mini and its PadFone station
EeePad Transformer TF101
HTC Desire S
Since the developer has only 2 devices available for testing, it will be appreciated if people can report bugs by e-mail instead of review to enable further two-way communication.