You may be mystified as to why your phone’s battery can drain in a matter of hours. And while mobiles have a large number of adjustable settings which can be tweaked to prolong battery life, they are often tricky to understand. Now there’s a free app that offers users personalised advice about how to boost their phone’s battery life. A free iOS and Android app called Carat offers frustrated smartphone users personalised advice to boost their phone's battery life. A screenshot showing distribution information is shown left, and a J-Score, which indicates how a device’s battery life compares with others running Carat, is shown right . Called Carat, it uses crowdsourced measurements to work out how much of an impact certain settings and apps are having on a specific battery, before advising users what to do. After using their phone normally for around a week, people who download the app will start to receive personalised recommendations for improving battery life. This is because the app intermittently takes measurements about the device and how it is being used. These measurements are sent to Carat’s servers and ‘thrown into a statistical stew’ so that the measurements can be used as a benchmark to compare how power-hungry a certain device is. Carat uses crowd-sourced measurements (illustrated) to work out how much of an impact certain settings are having on the battery and what users can do about it. Users who download the app can use their phone normally, and after  a week, will start to receive personalised recommendations for improving their battery life . Carat analyses a specific phone's energy use, drawing upon crowd sourced information. It offers users recommendations on how to boost the battery life of their device. For example, it might point out that Twitter is using an unusually large amount of power compared to on other phones, indicating that either an individual is hooked on the social media app, or that it could contain an energy-sapping bug. An ‘action list’ is shown on the main screen of the app, with instructions such as ‘Kill App X’ or ‘Upgrade OS’ along with an estimate of how much battery life will improve if a user takes the recommendation. A J-Score is also given that indicates how a device's battery life compares with other Carat users' devices. A Hog Report section advises which apps to close, while a Bug Report section points out those that are in a bad state. Non-identifiable information from phones is collected to build up the main database used as a benchmark for energy consumption. The results of the analysis are then sent back to the app, in order to give users instructions on what to do to improve the life of their phone. For example, it might point out that Twitter is using an unusually large amount of power compared to on other phones, indicating that either an individual is hooked on the social media app, or that it could contain an energy-sapping bug. An ‘action list’ is shown on the main screen of the app, with instructions such as ‘Kill App X’ or ‘Upgrade OS’ along with an estimate of how much battery life will improve if a user takes a recommendation. ‘The information displayed by Carat changes over time as it learns - the longer you use it, the better the results get,’ according to the researchers behind the app. Users will also see a ‘J-Score,’ which indicates how a device’s battery life compares with others running Carat. It's expressed as a percentage, so a J-Score of 75 means a device has a better battery life than three out of four smartphones - and users can get a score for a comparable model too. Apps listed under the title of ‘Hog Report’ are shown to be energy-hungry and closing them could result in battery  life. Similarly, Carat lists some apps under ‘Bug Report,’ which are associated with increased energy use on an individual user’s phone. ‘In other words, it may be that your instance of the app is caught in a bad state or has a bad configuration,’ the researchers behind the app wrote. Apps and settings listed under the title of ‘Hog Report’ (shown left) are shown to be energy-hungry and closing such apps could result in battery life. The confidence level (shown right) indicates how likely it is that closing an app will make a difference to battery life . ‘Restarting the app may help if it's a transient problem, but, if not, you may need to close and avoid the app.’ As well as being a tool for consumers, Carat is a research project run by computer scientists at the Universities of Helsinki and University of California, Berkeley. ‘We want to know whether it is possible to take sparse, incomplete measurements from a large community of mobile devices and figure out which apps are abusing the battery,’ they said. ‘We want to find bugs and simultaneously help users mitigate their ill effects and help developers fix them. While it's relatively easy to find a link between energy consumption and screen brightness and connectivity, the experts are unravelling the energy impact of the combination of roaming, high operating temperature, and bad signal strength, for example. Recommendations could lead to less charging (stock image) While it is relatively straight forward to find a link between energy consumption and screen brightness and connectivity, the experts are unravelling the energy impact of the combination of roaming, high operating temperature, and bad signal strength, for example. The researches have so far found that Wi-Fi signal strength dropping one bar can cause 13 per cent battery loss, and high temperature can cause 50 per cent battery life loss, even if the heat doesn’t come from the CPU inside a smartphone or tablet. Automatic screen brightness is in most cases better than the manual setting and together, battery temperature and distance travelled,. offer a good predictor of battery lifetime. ‘We believe that, as our dependence on mobile devices increases, energy bugs will rise to prominence, and we want to begin developing tools and techniques for detecting and fixing them.’ Their research is based on a large dataset that currently consists of device usage data gathered from more than 150,000 smartphones and tablets. It covers life daily usage patterns and, together with laboratory based specific high precision measurements, serves as the basis for the research work. While it is relatively straight forward to find a link between energy consumption and screen brightness and connectivity, the experts are unravelling the energy impact of the combination of roaming, high operating temperature, and bad signal strength, for example. The researches have so far found that Wi-Fi signal strength dropping one bar can cause 13 per cent battery loss, and high temperature can cause 50 per cent battery life loss, even if the heat doesn’t come from the CPU inside a smartphone or tablet. Automatic screen brightness is in most cases better than the manual setting and together, battery temperature and distance travelled,. offer a good predictor of battery lifetime.
Carat app, for iOS and Android devices, was produced by University of Helsinki and University of California, Berkeley computer scientists . Uses crowdsourced data to investigate a phones' energy consumption . Monitors phone usage over a week, feeding data to a central server . Information is analysed and personal power-saving tips given to users . Suggestions include shutting certain apps down or upgrading software . The longer the app is used, the more tailored the suggestions become .