I did my software engineering Masters thesis (2012) on Android power management and I learned, as part of my research, that most app developers have no idea how much power their app demands from their Android device’s battery. Some who thought they were looking at power were confusing other metrics with power. At the time, tools for measuring power were not easy to obtain (costly, and hard to measure power inside a phone).
Now there is an app that provides many metrics about what apps are doing on Android, including power.
Go to the Google Play store, search for Trepn Profiler and install that app (from Qualcomm, who makes the Snapdragon processor used in most phones).
For a quick look at battery power in a strip chart format, select Network Activity and see a chart like this:
Then select CPU Usage Monitor and identify what percent of CPU time is being used by each app. Initially the display will show “No applications are running” – wait a moment and gradually, apps will begin to show up in the list, with the % of CPU core they are using, shown at right. This may help you spot apps that are using an unexpected amount of power.
If possible, delete apps that you never or rarely use. Many lurk in the background and periodically run a fraction of a second, infrequently. While each individual app has little impact, the total of all apps may start to have an impact that you notice.
For more information about Trepn and estimating power consumption, read the linked article, below.