BatteryAnalyzer

While all recent iPhones include a battery health indicator in the settings, most Android phones don't have this. The only way was to create a dumpstate log, open it on a PC and check for specific strings. This apps automates the latter. You only need to create the log, the app will analyze it for you and display the results. Running such a check once per week will give you a nice overview in the history graph and allow you to monitor battery degradation.