Battery drain after October security patch!

[SatwikR]

My phone literally had 20% at 1am last night this morning at 11 am, my phone is dead.

My phone is on battery saver, everything turned off and cleared all apps from background. Good guardians sleep mode is even turned on. 

Why is there a steep decline in battery during idle?

I just ran app optimiser in good guardians a few days ago. Restarted the phone a couple of times. Everyday my battery goes dead, help!

The only option I see is to reset the phone.

[yamialex]

You do realize that Wi-Fi cell service sell data they all use battery power as well it's not just background stuff running or apps open maybe before you try to correct someone and tell them to read something you learn exactly what at all is using battery it's always been searching for a cell signal or having a cell signal uses battery using your Wi-Fi will use a little battery using Wi-Fi calling that uses battery it's always on display uses battery there are other things than what you stated that will use your battery so maybe before you try to think you know better than everyone else you actually learn what's going on with any electronics

[SenseiKayJayy]

Check your apps and what uses power in the back ground. Also how many tabs is open and etc.

[TimmA64]

I had this issue for a while and really worked hard at it and this is what I did to fix it.
To get into the menu you have to go to the phone and push on the keypad *#9900#
Once this menu opens you want to delete the logcat dump state after that you'll scroll down further to you see battery stats reset.
This makes your system relearn your usage and your battery should last longer.

[SatwikR · Accepted solution]

I finally found out what was draining my battery. It was my second SIM card (international one). I must have turned it back on by accident, and it was on roaming, which was messing up my battery life. I turned it off again, and now my battery is back to normal, only draining 8-12% overnight. Problem solved, i guess.