[Samsung Galaxy S8 Questions and Answers] keboom:
Hi,

I tried to find this exact problem, but not. I have serious problems with battery on my unlocked european Galaxy S8.

First I just tried some basic stuff like clearing the cache, diagnostics of Google services and so on. Then I installed BBS and GSAM, but nothing serious here. I monitored it like three days very often. Only thing that havnt made me any sense, is Android OS (something to do with kernel). It had more drain, than screen.

Second I tried some apps that I was suspicious to. Google Fit, Chrome, Facebook,... Nothing.

Okay, I tried Safe mode and even factory reset and nothing. So I was that angry, that I paid that much money for something, that even doesnt work properly, that I ordered a repair (they came to my home, took my S8, rent me another one and than after week or so they returned it).

I finally thought that it was bad piece, because they found the issue and swap daughterboard, charging cirquits, battery and reflashed OS. I didnt used Smart Switch or Google restore. I manually installed all my apps and I think, that battery drain started after I launched preinstalled Chrome. So of course I immediately disabled it, but battery drain didnt stop.

Now I was on vacation on place, where is like one bar of 4G or no signal, nothing else. In that place, battery was dying very fast. I turned on airplane mode and guess...

With my usual drain that Iam trying to figure out, I have about 2-3 hours of SOT only checking mails and browsing web with Spotify. With airplane mode on I played movie at evening. I had 89% after 2h of continuous playing HD movie with airplane mode. After I disabled it, battery started dying fast again.

I could not figure out, what is causing this, because in GSAM, BBS and setting is only "Android OS" and nothing more suspicious. I tried to turn off WiFi and Bluetooth scanning even when they are off, but nothing.

There is all my apps that I have installed in my S8:

Google Drive, Duo, Photos, Play Movies and TV, MS Excel, OneDrive, Power Pint, Skype, Word, Samsung Email, Galaxy Apps, Internet, My files, Samsung Connect, Samsung Gear, Samsung Health, Smart Switch, Voice recorder, 4G switcher, Adblock Plus for Samsung Internet, Airbnb, Google Analytics, Android Auto, Apshalt 8, Bakalari (my school app), Boldbeast recorder PRO, Calculator, Calendar, Camera, Clash of CLans, Clock, COntacts, CPU-Z, CZC.cz (app for local IT eshop), eBay, ES File explorer Pro, Facebook, Flixbus, Flud, Gallery, Gmail, Golf Clash, Google, Google Trips, Hangouts, Google Home, IDOS (czech app for time tables of trains and buses), Instagram, IP Tools, Google Keep, Letuška.cz (app for buying airplane tickets), Google Maps, Mapy.cz (local maps app), Messages, Messenger, MX Player, My Vodafone, NaVlak (another app for timetables wih widget, thats always synchronized ony my screen), Phone, Play Games, Play Music, Play Store, QRbot, Samsung Members, SD Maid Pro, Settings, SledovaniTV (app for watching TV online), UniCredit Smart Banking, Speedtest, Spotify, Steam, Strava.cz (school app for ordering meals), Stream (local youtube), Tenda WiFi, Tik-App, Translate, Trello, Wifi Analyzer, Wifi File transfer Pro, YouTube, Zaslat.cz (local app for ordering couriers to deliver packages).

Could you guys pleas give me some advices? I even tried disable Always On display, but nothing. Iam very shattered about this. At least we know, that it is software related issue, not hardware.

Thank you very much guys and sorry for my bad english skills :D

EDIT: It is caused by SW 1000%, because I experienced same issue on rented S8 when mine was at warranty repair.