Battery Guru

Maximize your battery life, and optimize your BlackBerry® PlayBook™ usage.
Battery Guru reveals your battery's secrets!  No longer are you limited to the simple "percent remaining" estimate.  Watch battery voltage, check power when using or when charging, and view a plot of past activity, with readings updated every two minutes (30s when charging).
You can even see the "health" of your battery, relative to the manufacturer's claimed capacity, and monitor changes over time so you'll know when it needs to be replaced.
The app keeps a record of all past readings, for as long as you want.  Keep weeks, months, or years of history, with an option to automatically purge older readings.
An export feature lets you retrieve the historical data in CSV form whenever you want, for viewing and analysis in a spreadsheet program.  Exported files are available in documents/BatteryGuru, from any file browser, or from the PlayBook network share over WiFi.
Battery Guru is carefully engineered to use no measurable extra power, so rest assured that you will not drain your battery by leaving Battery Guru running.  It works even when "inactive" or when your tablet goes to sleep.
Bonus feature!  Select "Allow Sleep" (default) or "Keep Awake" to prevent the tablet from going to sleep.  Use Showcase mode and keep any part of Battery Guru's window visible (even minimized) for this to work properly.  Useful when running other apps which don't properly handle the standby state (e.g. web-based streaming music players), or just when you want to observe the battery drain caused by another app, over a period longer than the standby timeout allows.
Change History:
• 1.0.4 (2011-12-05): fix graph tick labels, problem with file exports on 1.0.8 and 2.x, add Keep Awake guidance
• 1.0.3 (2011-08-16): bug fix: graph was actually showing 12h of data instead of 10h
• 1.0.2 (2011-07-19): first release