Battery life on AMOLED screen mobiles improved by simple tweak

Mobile phones with AMOLED screens can be tweaked so the display uses less battery power. We've seen the maths that proves it.

Andy Merrett
Andy Merrett has been using mobile phones since the days when they only made voice calls. Since then he has worked his way through a huge number of Nokia, Motorola and Sony Ericsson models. Andy is a freelance writer and is not an employee of CNET.
Andy Merrett
2 min read

With AMOLED screens becoming increasingly popular on mobile phones, particularly Samsung models such as the Nexus S and Galaxy S 2, it's useful to know there's a way of reducing the impact they have on battery life.

Using Android's built-in system analysis tools, blogger Steve Mould set about discovering how much his battery was being drained by the screen itself. He then went on to find out whether using darker wallpapers, themes and apps would help to reduce power usage.

Guess what? It did. 

It's worth mentioning this only works on OLED-based displays and not the currently predominant LCD/LED displays. That's because the backlight is always lit, regardless of what's being displayed. To achieve a black pixel, the light is blocked rather than turned off. In an OLED system each pixel is self-powered, which means black pixels are unlit, saving power.

The most significant results were found by measuring the difference in battery usage between a Nexus S left for two hours displaying either a white or black screen. The bright screen caused the battery to drop 71 per cent compared to just 12.2 per cent for the dark screen.

If you like looking at a lot of equations, head over to the SHIFT_beeb blog and take a look. It's not an exact science, and in any case every user will get different results based on how they use their phone. If you're running a load of processor-intensive apps it don't matter if your wallpaper is black or white.

There are plenty of other ways of improving battery life. Reducing the display brightness below 50 per cent will work regardless of the screen type, as will turning off features you're not using at the time, such as Bluetooth and Wi-Fi, and ensuring background apps are behaving themselves. Let us know any other power-saving mobile tips you've come across in the comments section below.