I'll try setting it to GPS only first and see how it goes. I charged my phone before bed and unplugged it. It was at 100 percent and just sat idle for 7hrs. I look at my phone when I wake up and it dropped 10 percent in 7hrs. While sitting doing nothing. Checked Android system gps usage. Almost 2hrs of GPS usage. WTF? It was sitting untouched! I know this isn't a marshmallow issue as I encountered this before the update. Figured a reset would solve it. It did, but the problem seems to be coming back.
EDIT: Well, I've been using my phone for about 30mins at lunch and the GPS usage under Android system has climbed about 30 more minutes. So something has been pinging location this entire time. What I don't understand is I have not see the location/GPS icon on my notification bar at all. Not even once. Does this mean anything? I'm so glad google lumped so many things under Android system. Makes it easy to troubleshoot *end sarcasm*. Seriously, why isn't it just set to show what app requests GPS versus everything lumped into system?