HIGHLIGHTS

• A new study highlights only 3 to 9 per cent of power-saving on OLED screens in average brightness through the use of dark mode.
• Peak brightness can increase this to battery saving to about 39 to 47 per cent.
• The research has been conducted across the six most downloaded apps on Google Play on several smartphones.

The smartphone ecosystem is fast adopting dark mode like the one big saviour for battery life. Be it Android or iOS, we see more and more apps offering the choice to users in recent times. Though a new study questions this use of dark mode as an effective measure of reducing battery drain.

In a new study, a team of scientists from Purdue University have developed new tools to measure the effects of a dark mode on a smartphone’s battery. The development now helps effectively monitor the battery drain caused by lighter colours on the screen vis-a-vis a dark mode.

Surprisingly enough, findings from the study reveal that dark mode is unlikely to impact the battery life of a smartphone significantly. Though it does use less battery than a regular light-coloured theme, the difference is unlikely to be noticeable “with the way that most people use their phones on a daily basis.“

In numbers, dark mode on an OLED smartphone is likely to save only 3 to 9 per cent of power as compared to a regular mode. These findings, however, apply to a phone’s use at 30 to 50 per cent of brightness, usually the range followed by an auto-brightness setting.

The new study says that these battery gains can be significantly higher at 100 per cent brightness of the display. A smartphone can save about 39 to 47 per cent of battery power at peak brightness by operating on dark mode. This is close to an additional half of the battery life delivered in one charge cycle.

It was thus found that the dark mode can significantly save battery life in peak brightness, usually employed by smartphone users in outdoor conditions under sunlight. Note that these gains were found to exist on OLED screens, thanks to the lack of backlight as found on the LCD (liquid crystal display) screens. With this, OLEDs draw less power when displaying dark-coloured pixels.

The dark mode research

For the study, scientists from Purdue University tested six of the most downloaded apps on Google Play, including Google Maps, Google News, Google Phone, Google Calendar, YouTube and Calculator. The apps were tested on dark mode for 60 seconds of activity on smartphones, including Pixel 2, Moto Z3, Pixel 4 and Pixel 5.

Even though the tests were conducted on Android apps and phones, scientists say that the findings are likely to hold true for iPhones with OLED screens as well.

The team created new power modeling technology for the test, which is now pending patent. As claimed, the new tool is able to determine the power draw of OLED phone displays more accurately than the existing techniques.

That is because the new tool measures the effects of a dark mode on battery life, a feature that is amiss in Android’s in-built feature as of now. It is expected to be available to platform vendors and app developers as Android Battery+ in the coming year.