In gauging battery life, it's hard to perfect a methodology that lets you cover all of the various use scenarios without having to test for weeks on end. Whether it be display, audio quality, or camera, the goal with all of our tests is not only to provide you with the clearest, most comprehensive examination of a particular device but also to provide it to you promptly. Our battery test is no exception.
With each battery test you'll see four different numbers, each reflecting a different type of battery-consuming activities. The test revolves around three tasks, performed commonly by smartphone users: making calls, browsing the web, and playing a video.
Our Endurance rating is the result of combining the power draw from these activities in a formula, which at its most basic level assumes a daily usage scenario including an hour of voice calls, an hour of offline video playback, and an hour of Wi-Fi browsing per day, with the rest of the 24 hours taken up by standby power consumption.
We also give you an option to adjust the formula - clicking on the image above will take you to our battery chart where you can adjust the share of these activities in a 24h day.
But even then, our endurance rating may still not match your real-life usage scenario, but remember - this is just an even base for comparing battery performance across devices.
If you are more into eBook reading or social media browsing, for instance, you can give more weight to the web browsing test. If you prefer watching YouTube videos, the offline video playback would also be a good indication of how the phone will perform in this task. If you are into gaming - average the results in the two on-screen tasks and divide it by half or so.
Don't be afraid to work the numbers as you please. No measure is perfect - and the number of apps you have installed, your ambient temperature, and also the available ambient light are also important variables.
So do not look at our numbers as a promised runtimes. The Endurance rating is just an indication of overall battery life. The individual scores are merely indicative of how the phone will perform in any similar category of tasks. The numbers should only be used to compare whether Phone A is better than Phone B and you can't expect to match the same runtimes in your own usage.
The first test is the talk time test, which measures how long it takes to deplete the battery by making voice calls. Bearing in mind that most screens automatically turn off during a call, we've made sure our set up accounts for this. We close all applications which may further strain the battery, too.
The web browsing test is performed using an automated script that reloads a webpage every ten seconds. There are no flash elements on the web pages, so the playing field is even. We use an 802.11n access point placed a few meters away to get full connectivity bars.
In our video playback test we measure how long it takes for a device to run its fully charged battery down to 10%, while looping a standard-definition H.264 video. We stop at 10% since most devices shut their video players at this point or lower their brightness substantially. All radios on the device are switched off (Airplane mode).
Since the beginning of 2016 we also have a fixed brightness level of 200nits of the screen for all of our battery tests. The level of 200nits has become somewhat of an industry standard for indoor day use. But more importantly, it's both the median and average value of the brightness levels at which we've tested all reviewed devices so far. This means that our earlier pre-2016 battery life test results will remain comparable and equally relevant as before.