|A UK-based electronics testing and recommendation magazine and website, Which, has rated the tablet battery life of various sized tablets -- and found that the iPad and iPad mini ran away with the competition, besting its rivals by very significant scores. While scores were closer between the iPad 2 and the better 10-inch tablets, the Retina fourth-gen iPad model's score was well over 50 percent better than the combined average of the competitor tablets, with all screens set at equal brightness.
Which set every screen to a standard 200 nits of brightness, and then tested various aspects of real-world use, thought for this article only web-browsing as a task was tested. The magazine, which is similar to the US' Consumer Reports in that it accepts no advertising and makes purchase recommendations after thorough test procedures, rates tablets using both Wi-Fi and 3G (or LTE if available), though the report includes on the Wi-Fi test results (the full review of each tablet has further information on other tasks, charging time, quality of components and features and other details).
For Wi-Fi-based web browsing, the iPad was the runaway winner among tablets 9.4 inches in size or larger, lasting a remarkable 13 hours and 31 minutes, with the nearest non-Apple contender being the Sony Experia Tablet S in third place at 8 hours 54 minutes (the iPad 2 offered 9 hours, 50 minutes in the test). The Samsung Galaxy Tab 2 10.1 came in fourth, just two minutes behind the Sony. The newly-released Microsoft Surface RT rounded out the top five with 8 hours, 21 minutes, making this one of the first battery-life comparisons between the Surface RT and its competitors.
Overall, the average of the 16 10-inch-class tablets tested was a respectable 7h31m, qualifying most models as being able to claim "all day" performance in typical work or school use. The worst battery of the lot was the Asus Eee Pad Transformer Prime (without keyboard), which barely managed 5h35m, two hours behind the average. Even with the additional battery provided by its keyboard dock, the Transformer Prime only reached 11 hours -- better than the iPad 2, but still 2.5 hours behind the latest iPad. The combined weight of the Transformer Prime plus the keyboard was more than double the average for other tablets.
In the 7-to-8-inch category, Apple's customized battery again won the day handily, with the iPad Mini offering 13 hours, 3 minutes of Wi-Fi web browsing. In this category, second place went to the 7-inch version of Amazon's Kindle Fire HD, which fell just short of 10 hours (9h51 minutes). Google's Nexus 7 took third at 9h10m, and the overall average of the 10 tablets tested in the 7-inch category was 7 hours, 58 minutes. The two worst performers tested were Amazon's Kindle Fire (at 7h17m) and the Samsung Galaxy Tab 2 7-incher at 7h5m.
Various factors and design decisions played a role in how each model perform -- making a tablet significantly lighter than the iPad, for example, would cut into the amount of battery available, affecting the score -- but Apple's extraordinary lead is likely due mostly to its effort on making custom batteries that take up every available millimeter of available space rather than using standard batteries. The company has invested significantly in battery technology and makes a point of talking extensively about the effort that goes into creating the batteries for its various device designs, usually narrated by former Senior Vice President of Hardware (now SVP of Technologies) Bob Mansfield.