I’ve a relatively new Fairphone 2, which I’ve equipped with Fairphone Open, Xprivacy and AFWall+ (these are the relevant apps, I think).
The battery really drains fast and the phone is getting hot for no reason – I even cannot carry it in my Jeans pocket any more (Not because it is too hot for my skin, but too warm to be comfortable)!
Yesterday, I was browsing this forum, and it sucked up the entire battery in about an hour.
This is a screenshot I took a few minutes ago:
95% “Sonstiges”!!! I’ve read something about this yesterday, but unfortunately I got so frustrated that I cannot remember which thread I’ve already read and which I didn’t. 
I’ve tried “another monitor”, and it shows the CPU being used >60%.
Is there any kind of guide one can follow to get rid of this seemingly common problem?