Fun fact: my Android phone battery was being sucked at a fast pace last month. I don't remember exactly how it presented itself in the UI, but I ended up figuring out that the Google app was the culprit, because it was using the GPS... which I had explicitly disabled.

An internet search showed I was not alone with such problems, and that the solution was to manually revoke some permissions for the app (thankfully it was possible).

I find it amazing that an app can make use of the GPS when it's disabled! I'm actually seriously pissed about it, but there's not much I can do about it.