One way of conserving battery life on your mobile devices is by selecting the correct wallpaper. If you look at the battery statistics on your phone (Settings > Battery for most Android phones), you will find that what consumes the most battery life is your display.
This is true for most users, except those who have their display on for just a few minutes each day. Lowering display brightness is one way of saving battery life, but really, you should lower it only to the point that is still comfortable. At some point, carrying a spare battery or external battery pack is better than having a hard time reading your smartphone’s display. But there is a way to conserve the amount of battery life consumed by a display, without causing discomfort. Selecting the correct wallpaper.
There is this old notion that selecting a black background conserves energy. According to this theory, using a black background should result in longer battery life. On most mobile devices though, using a black background won’t save you any battery life.
Most devices use a Liquid Crystal Display. These displays have a white backlight with red, green, and blue LED’s in front of it. Using the different combinations of red, green, and blue, your display is able to produce 16 million different colors. When your typical LCD displays black, it uses the red, green, and blue LED’s to block the white backlight. The result is that using a solid black background on your typical LCD display will actually consume about 5% more power than using a white background.
Some recent phones where displaying white saves more power:
- Apple iPhone 5
- BlackBerry Z10 and Q5
- Google Nexus 4
- HTC One
- Motorola Droid mini
- Nokia Lumia 520, 620, 720 and 920
- Samsung Galaxy S4 Active
- Sony Xperia Z and Z Ultra
This does not apply if you’re using a mobile device with an AMOLED, Super AMOLED or OLED. AMOLED screens do not have a solid backlight. Each pixel on an AMOLED screen produces its own light. When a pixel displays black, it simply does not produce any light. In any other color, the pixel produces white. In other words, if you use a black background on an AMOLED display, your display will produce light to display anything on it which is not black, like shortcuts, widgets and device notification icons.
Some recent phones where displaying black saves more power:
- BlackBerry Q10
- Google Galaxy Nexus
- Motorola Moto X, Droid Ultra and Droid Maxx
- Nokia Lumia 820, 925 and 928
- Samsung Galaxy S III, S4 and Note II
In this day and age, I think few will find using a completely white or black background as a great option. Instead, you can follow this rule of thumb: On typical LCD’s, use lighter themes and on AMOLED devices, darker themes.