Dark mode, which is a UI based on dark colors, is generally thought to have the effect of reducing eye strain and suppressing power consumption. However, according to an experiment conducted by a research team at Purdue University in the United States using a power consumption measurement tool, the effect of dark mode on extending battery life is very limited. On the other hand, it was also found in the experiment that there are scenes of use where the power saving effect that can be felt by using the dark mode is exhibited.
They say that the dark mode, which uses a lot of dark colors, can extend the battery life because the OLED display, which is recently adopted by many smartphones, does not use a backlight. However, since most of the light mode and dark mode power consumption comparison tests used so far investigated the total power consumption and battery life of smartphones, it was impossible to accurately determine only the display power.
Purdue University research team built a power calculation model that can separate AMOLED display power consumption from other components, and based on this, developed PFOP (Per-Frame OLED Power Profiler), a power consumption measuring tool. We investigated the power consumption when using the dark mode at the most common 30-50% setting for screen brightness and using six Google apps, such as Google Maps, Google News, Google Photos, Google Calendar, YouTube, and Calculator, for 60 seconds.
As a result of the experiment, it was found that the dark mode saves an average of 3 to 9% power compared to the light mode, so that the battery life is not extended enough to feel it. The Pixel 2, 4, 5 and Moto Z3 used in the experiment were Android devices, but the research team is saying that there is a possibility in Apple devices including the iPhone X.
Meanwhile, in another experiment with changing the screen brightness setting, we also confirmed that there are two usage scenes where we can expect dark mode to work. The first is when using dark mode in bright places such as outdoors. For example, if you use your smartphone while watching a sporting event outdoors on a sunny day, the automatic brightness adjustment function makes the screen very bright, so battery consumption is getting worse.
The research team compared the power consumption in the light mode and the dark mode in the case of 100% brightness, and confirmed that the dark mode can save an average of 39 to 47% battery consumption. For this reason, the research team said that if you use the dark mode when the screen is very bright, you are more likely to use the smartphone for a long time if you use the same brightness lighting mode.
Second, as stated earlier, if the brightness is less than 50%, the power consumption is almost unchanged in light mode or dark mode. In fact, when using the Google News app on the Pixel 5, it can be seen that the power consumption is the same in light mode at 20% brightness and in dark mode at 50% brightness.
Therefore, the research team said that there is little need to worry about an increase in power consumption even if the brightness is increased in the dark mode to reduce eye fatigue because the power consumption in the dark light mode and the bright dark mode are the same. The research team will create a power measurement app (Android Battery +) applying PFOP, the measurement tool developed this time, and release it in 2022. Related information can be found here.