75% of in-app battery deplition on Android is caused by background data acquisition and the serving of targeted ads. This was the slightly disconcerting discovery made by a team of researchers from Purdue University and Microsoft.
If the rise in aftermarket extended battery cases and the one re-occurring complaint isn't enough, an issue that's been voiced publicly by many Android phone owners is the battery life of their devices. So with this in mind, the team, led by Abhinav Pathak, commenced testing with a developed energy profiler named EProf: capable of performing an in-depth analysis of the battery use of Android apps.
Essentially, they've asked the question: 'Where is the energy spent inside my app?'
They picked five popular Android apps including FreeChess, The New York Times and Angry Birds, used a Google (HTC) Nexus One running 2.3 Gingerbread, and began testing.
Angry Birds only drained 30% of the battery to run the gameplay itself (the only bit we'd want), the remaining 70% was consumed by your user information metrics being uploaded to Google and your location being tracked, to generate a targeted ad for the user. Free Chess was the same case, that magic 70% of drain being caused by the aforementioned processes in mobile ads. The New York Times differs in terms of usage, with 15% of your battery consumption being expended by performing user tracking.
Pathak explain that they didn't do this to shine a light on any particular app, developer or advertising agency for consuming needless amounts of energy (they just exposed everyone instead). They've used this as a tool to bring it to people's attention, concluding that Android ads within apps don't have to eat away at this much of your battery life. The study suggests that this is to do with poor coding and implementation, and the team have announced their plans to open-source the EProf tool and release it for free to help tackle this problem.
Source: EProf (PDF)