Up to 75 percent of the energy used by free versions of Android apps is spent serving up ads or tracking and uploading user data: Running just one app could drain your battery in around 90 minutes, NewScientist.com reported.
Abhinav Pathak, a computer scientist at Purdue University in Indiana and colleagues made the discovery after developing software to analyse apps' energy usage. When they looked at popular apps such as Angry Birds, Free Chess and NYTimes, they found that only 10 to 30 percent of the energy was spent powering the app's core function.