LG G4 battery is draining overnight?

[AC Question]

I've been experiencing some major standby battery drains on my LG G4 recently... I've done everything to try to stop this issue but nothing seems to work... I've performed a factory reset but my battery is still draining like crazy (20% - 30% every night). I waited 24 hours after I reset my phone before I restored it and still had massive battery drains, so I don't think the problem is a rogue app. I've had the phone for around 2 months, and I had no issues the first month. Maybe I have a defective unit?

Using unrooted LG-H811 on T-Mobile