This is a #wiki post, please help improve it if you have any further information.
After upgrading to Android 6 some users experience an increased battery drain. For some this goes away after a few days. If it stays and either Wifi or Google Maps show as the main culprit in the battery stats then you suffer the issue described in this topic.
Fairphone Bug Status: Rejected
This issue was reported as Issue #16 in the official bug tracker, but was rejected as it seems to be a known Android 6 bug that can only be fixed by Android developers.
Since I have updated OS to Android 6, my battery life decreased dramatically. Do any of you have similar issues and/or know what the cause is and how to fix it?