That being said, one of the battery saving features of Android M is called Doze. It basically puts your phone into a deeper sleep which helps improve battery and recently according to some tests, it turns out that Doze is quite the battery saver especially on the Nexus 5. According to the test, standby time on the Nexus 5 saw a drain of 4% after 8 hours, 12% after 24 hours, and 24% after 48 hours.
Those are pretty decent times as it is, but upon installing the Android M developer preview, the tests found that battery drain after 8 hours was 1.5%, 4.5% after 24 hours, and 9% after 48 hours. These are some amazing numbers! Especially when you compare previously where the Nexus 5 with Android 5.1.1 was projected to have 200 hours of standby, which has since jumped to 533 hours with Android M.
Best of all? Android M is currently in developer preview meaning that things are subject to change, further improvement, and optimization, meaning that upon its final release, Android M’s Doze feature could be even better than it is now. Fingers crossed!