How to tackle power-hungry Android apps and improve battery life for free

A new, free tool could cut Android battery loss significantly by controlling unused app functions in smartphone sleep mode.


Researchers have developed a free tool which may improve Android battery life by at least a sixth, with hope to eventually reduce battery drain by half.

In the first large-scale study of smartphones and application battery drain, researchers from the University of Perdue say some apps are responsible for draining 28.9 percent of battery power -- while the screen is turned off and the smartphone is not in active use.

Applications which constantly check for updates and wake themselves up when not required are most at fault, the team say. Charlie Hu, a professor of electrical and computer engineering at Perdue who led the research says:

"During screen-off, the phone hardware should enter the sleep state, draining close to zero power. Apps wake the phone up periodically during screen-off to do useful things, but then afterward, they should let the phone go back to sleep.

They are not letting the phone go back to sleep because of software bugs and, specifically, due to the incorrect use of Android power control application programming interfaces called wakelocks."

In a study of 2,000 Samsung Galaxy S3 and S4 phones served by 191 mobile operators in 61 countries, the team -- together with Intel and Mobile Enerlytics -- discovered that out of the 45.9 percent of daily battery drain where the screen is off, 28.9 percent is due to apps that frequently wake up and run in the background.

The study could assist app developers and mobile device manufacturers to address battery drain issues in a different light, and perhaps new stipulations or settings could one day be given to users to help preserve their battery life further.

In the meantime, however, the Perdue team have developed a free tool which can reduce energy drain by about 16 percent, and eventually may be capable of doubling life.

The free tool, called HUSH and available for download at Github as an implemented framework -- with an app due soon -- monitors the background activities of individual applications. To prevent turning off useful functions, the app learns which apps and what functions the user frequently accesses -- such as checking Facebook news feeds -- and takes these factors into the equation.

Turning off Facebook's update checker can help save battery life, but for frequent users, this is likely to hamper user experience. As such, background activities are only suppressed on a per-app and usage basis depending on which apps are most commonly used.

Hu said:

"Being able to reduce the total daily energy drain by about 16 percent is rather significant because you can extend the battery charge by one-sixth. The big picture is that we want to double the battery life for smartphones.

This is going to be a non-trivial journey because much of the battery drain is caused by various apps when the screen is on and also legitimate maintenance functions."

The team will present their findings this week at the ACM MobiCom 2015 conference in Paris.

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