Angry Birds among the high flyers sapping device power.
Research from Purdue University shows that free mobile apps, where developers profit from in-app advertising, are responsible for causing faster smartphone battery drainage.
This has been put down to apps such as Angry Birds, where a fifth of energy use went into gameplay, while half goes to the GPS tech that serves location-based ads.
This much was true for Android and Windows Phones, though the researchers were unable to diagnose Apple due to the complexity of iOS.
The report calls upon developers to be more clued up when it comes to the energy drain of their customers' devices at the hand of advertiser plug-ins.
The testing was carried out across a 3G connection allowing researchers to discover a '3G tail', which means in-app ads will continue to leech onto battery power up to ten-seconds after the app has been closed.
Additionally, Free Chess was highlighted as another offender for energy using in-app ads.