battery drain when phone idle

I'm using LG G4 H818 with android 6.0 All of the sudden my battery started to get drained when I'm not using it at all, mostly over night. For example, it goes from 100% to 45% over night when I turned off pretty much everything like wifi, data, location, sync etc. When I turn on the flight mode, everything looks good and I may lose only 2% of my battery, except I can't get calls and since I should be on call for work, that's not a good option. I have also installed some battery usage app and top processes related are: - android/OS - system/android/log.d I also changed battery in case my previous battery was broken, this doesn't helped either. Today, I did a factory reset, wiped cache partition and of course there is no app installed and still the same. And, one more thing, my phone gets hot while using/charging, but not when I'm using it. Any suggestion about how to fix this issue?