The power of dark mode: Boosting battery life with OLED
Is dark mode just a trendy addition, or does it truly save battery? Smartphone users are increasingly switching to a dark background, hoping for longer battery life. Does it actually affect energy consumption, or is it just a myth? Find out how dark mode works and in which situations it can extend battery life.
The screen is an essential component of smartphones, but it's also one of the largest energy consumers. While manufacturers often highlight that a device can remain in standby mode for many weeks, actively displaying content often drastically reduces this time, sometimes to just a few hours.
So, how can you reduce battery consumption? The simplest way would be to avoid using the screen, but we purchase smartphones to use them after all.
By analyzing what exactly the display shows, you can reach some interesting conclusions. In the screenshot, key elements such as graphics, texts, and icons occupy less than 30% of the screen's surface. The rest is mostly a white background.
This background primarily serves a visual purpose, meaning that up to 70% of the screen lights up to make other elements visible. Wouldn't it be better if this background didn't require energy?
It turns out that managing the screen surface can be more efficient. In the case of LCD screens, they are entirely backlit evenly, regardless of the colours displayed. However, OLED displays work entirely differently, using organic diodes that allow each pixel to operate independently. The brightness of the pixels can be adjusted separately.
OLED panels stand out not only for their image quality but also for their energy efficiency. Pixels responsible for deep black are not activated at all, meaning they don't consume energy.
Remember the mentioned 70% of the screen's surface that lights up unnecessarily? If you were to change the colours and switch the white background to black, only the displayed elements on the OLED screen would consume energy, occupying less than 1/3 of the screen's surface.
Dark mode and smartphone battery savings
In an experiment, a smartphone with a 4.5-inch OLED screen and a 4500 mAh battery was used to create two different sets of screenshots of a website. The first had a white background:
the second a black background:
Each set was transformed into a slideshow, which was displayed until the battery was exhausted.
The tests began with a fully charged battery at 100%. During the experiment, the smartphone operated in airplane mode, with no additional applications, and at maximum brightness, so any differences in energy consumption were due only to the background colour.
The smartphone ran out of power:
- in light mode after 10 hours and 25 minutes;
- in dark mode after 13 hours and 31 minutes.
The results are clear. Enabled dark mode allowed the smartphone to operate for 3 hours and 6 minutes longer, which constitutes a 29% increase in operating time.
Let me remind you that both times the display was showing the same text and identical graphics. The difference in performance was solely due to the background colour.
How does dark mode impact the environment?
Longer battery life means less frequent charging. Fewer charges mean energy savings, which reduces emissions linked to coal usage.
It is predicted that up to 75% of new smartphones entering the market will have an OLED screen.
In computers, the energy-saving advantages of dark mode are smaller due to the less frequent use of OLED screens, but they are not insignificant. Dark backgrounds are less straining on the eyes, which is beneficial when working in low light at night.
As a result, dark mode can lead to significant energy savings if widely adopted by smartphone users.
