No one battery test will tell you exactly how long a phone’s battery will last, so how do we measure battery life in a way that will help you? By performing several tests, of course!

Philosophy

When it comes to smartphones, few people use theirs in the same exact way as someone else. Different models, different apps, and different habits all combine to make battery life tests generally useless. However, the more tests that are performed, the more context we can provide for you. Consequently, we perform three major tests: WiFi browsing, video watching, and a scripted mixed use test. While this doesn’t cover certain use cases, it does meet most users’ needs.

Performing tests

For all of our battery tests, we set the phone’s screen to 200cd/m2 so that the results can be directly compared. Then, after topping off the cell, we run our proprietary app to cycle through the chosen tasks. After all that, we let the battery run out, and log the time.

A photo of a smartphone being tested with a spectrophotometer.

Setting each phone’s screen to 200cd/m^2 allows us to compare each phone’s performance directly.

Currently, we test:

  1. Video playback
  2. WiFi browsing
  3. Mixed use

After the first battery exhaustion, we charge the phones, and let a baked-in utility track how fast the cells are replenished. We then log how much charge the phone has at 15, 30, and 60 minutes of charging. Additionally, we log how long each phone takes to charge fully, and how much power the charger is able to get to the phone per minute.

Scoring results

Because battery life isn’t like most of our scores — in that theoretically there is no point at which improvement is imperceptible — we normalize the scores based on a 16-hour day (assuming 8 hours of sleep, or non-use). If a phone goes over 16 hours in any of our tests, the score will also scale up over 100 points.

Similarly, the less time each phone needs to charge, the more points it will earn. While we don’t see any phone ever getting a perfect 100, if a phone ever comes into existence that takes under a minute to charge, that’ll be the first model with a perfect score.

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