CNET tablet battery life results

(Credit: Xiomara Blanco/CNET)

Editor's note:This list was originally posted on July 25 and is updated regularly.

Battery life testing is one of the last evaluations we subject tablets to at CNET Labs, but by no means is it the least valued. How long you can use your tablet is nearly as important as what it is you do while using it.

Our CNET labs testing standards ensure that all tablets, regardless of size, color, or operating system, are tested as close to equally as possible. Details on how we test tablets are included below the testing results chart. We've also thrown in each tablet's maximum luminosity for good measure.

Expect this list to be updated frequently as new tablets are tested.

To see what tablets are coming down the pike, check our current and upcoming tablets list, which gets updated every week.

How we test tablets

In the CNET Labs, we currently run two different tests to evaluate the performance of non-Windows tablets.

Battery life
We evaluate battery life by continually running a movie file on the tablet until its battery dies.

We set each tablet to Airplane mode and adjust its respective brightnesses to 150 candelas per square meter (cd/M2) or as close to that number as possible.

For the iPad, we run the iPad version of "Toy Story 3." On Android tablets, we run a 720p version of "Toy Story 3." The reason we chose 720p for Android was that not every tablet can run 1080p video just yet, and we wanted to make sure we tested Android tablets under the same methodology.

On the iPads, we ran the movie through the iPod app; for Android, we used the movie player apps mVideoPlayer or DicePlayer, as they provide a much-needed repeat video function that not all native Android movie players include.

*The times for the Amazon Kindle Fire and the Barnes and Noble Nook Tablet reflect continually streaming video through a wireless connection. The router was approximately five feet away with a full signal. We used Amazon Prime to stream "Amadeus" on the Amazon Kindle Fire; for the Barnes and Noble Nook Tablet we used the Netflix application to stream "Amadeus". On both tablets when the movie ended it was manually repeated due to a lack of repeat video function available.

Contrast ratio and brightness
We also tested the maximum brightness, default brightness, and contrast ratio for each tablet. We conducted these tests using the Minolta CA-210 display color analyzer. With each screen at full luminosity, we placed the sensor in the middle of the screen. We used a completely white screen to test the brightness and a completely black screen to test the black level. We then divided the maximum brightness by the maximum black level to get the contrast ratio.