Researchers from the United States and Finland have launched free iOS and Android smartphone\/tablet software that singles out which apps take the biggest toll on your device batteries and also visualizes fragmentation of Apple and Android mobile OSes.\n\n\nThe NODES research group at the University of Helsinki's Department of Computer Science has joined forced with the University of California at Berkeley to deliver the Carat app (download here for iOS and Android) and has published live stats based on some 2 terabytes of data extracted from Carat, which has been downloaded by about 750,000 users who employ more than 300,000 apps.\n\n\nI'm now among those downloaders, on my iPhone 5, but haven't had it installed long enough yet to get my personal "Hog Report" or "Bug Report." The app will take measurements of app energy use on my device every so often and mix that data in with that of the hundreds of thousands of other users' data.\n\n Carat project \n\nAccording to the current stats, 2% of iOS apps and 12% of Android apps are deemed energy hogs, and about half the devices run at least one app with "an anomalously high level of power consumption."\n\n\nAn Android app dubbed Superuser, if turned off, can save you 203 minutes on your battery, according to Carat. One called Advanced Task Killer chews up 148 minutes of battery life during a battery's normal stretch, according to the app. The general Maps app, as you might imagine, also does a number on the processor and battery.\n\n\n \n\n\nThe researchers finger inefficient code or programming errors as well as compatibility issues between OSes and apps for the energy-draining nature of some apps.\u00a0\n\n\nAs for the fragmentation numbers, Apple's exclusive ownership of iOS naturally makes for a less varied user based than Android and its many phone\/tablet\/phablet vendors. The iPhone 5 leads the way with 47% of the share in this survey of iOS users, while the Samsung Galaxy S2 is tops among Android devices with a 17% share.\n\n University of Helsinki \n\nThis chart displays how users are distributed between platforms, operating system versions and device models.