CNET reporter Eric Franklin spent his weekend torture-testing the battery of the new iPad, the iPad 2 and the Android-powered Asus Transformer Prime. He took each device, charged it fully and then drained its juice by continually playing a movie. All these tests were conducted in airplane mode so WiFi, 4G or LTE connectivity would not affect these results.
He discovered that the iPad 2 with iOS 5.1 lasted the longest at 14.2 hours, while the new iPad with its 42.5-watt-hour battery lasted 12.8 hours. The latest version of iOS helps the iPad 2 as the iOS 4.3 version only squeezed out 11.9 hours. The Transformer Prime came in last 9.6 hours, but its performance was bolstered to 15.3 hours when the tablet was used with an external keyboard dock that included a battery.
Original Post: TUAW