Pixel Battery Saver turns off some of your AMOLED display's pixels to conserve energy

As you probably know, AMOLEDs don't have a backlight, and they accomplish the deep blacks they are known for by actually turning off the required pixels. This is where PBS comes into play. It superimposes a black mesh on the screen and lets you adjust its density, therefore rendering half or more of the pixels off and not leeching energy. Obviously, this will degrade the image quality as removing pixels takes away detail, but with proper adjustment, you can still enjoy the content you're looking at while saving a bit of electricity for a rainy day. 

The approach makes sense. Today's high-end smartphones, which objectively struggle the most with battery drain due to their demanding displays and fast chipsets - they have, to put it mildly, overkill pixel densities. Thus, you can safely shave off a respectable number of pixels per inch and still end up with a quality image. As for tablets, we believe their nature of being not-on-the-go devices that also have ample battery packs doesn't call for an app like PBS as much as a smartphone does.

Of course, due to the nature of its workings, PBS is not an app to constantly have running. It is best used in times where your battery is steadily going South, as a supplement to manually dimming the display. The app is being developed with new features in mind, such as automatically enabling the mesh at specific battery levels, so definitely keep an eye on it if your device has an AMOLED screen. 

PBS is free, with a premium version in the works.