The Transformer Prime has a 25 Wh lithium-ion polymer battery inside its tablet frame, plus another 22 Wh battery in the keyboard dock. This 47 Wh total battery capacity is getting into serious netbook and some notebook territory, all while powering a device that uses a fraction of the juice.
The tablet itself in combination with the dock is easily good enough to last you a day of heavy use and up to three or so days of moderate usage. Right now I haven’t charged the dock or the tablet for a day or so now (with moderate usage) and the dock still has over 20% of its battery still to give up to the tablet.
So, I’ve told you that the average user’s battery life is going to be amazing, so what about an unusual usage scenario. The above screenshot consists of about 7 hours of screen time with automatic brightness on the standard IPS display mode. Furthermore, the tablet was on the balanced power profile and ran Glowball happily for over 90 minutes and spent the rest of the time switching up between internet browsing, Youtube and idle time on the homescreens.
Aside, idle battery life is unsurpassed due to the Tegra 3’s companion core. Following the aforementioned stress test I went to sleep with the tablet on 14% battery life with auto-sync still on; when I woke up at least 8 hours later it had only dropped 3%.
For those wondering about heat, after the Glowball session it had only mildly warmed up my bed and while the back on the tablet was slightly warm to touch, it was nothing that would be considered uncomfortable.