hey there! im a newbie and i dont post often but always looking around!
so anyways, i have been having the problem with quick battery discharge, phone turning on by itself and continous restarts for the last 2 weeks it seems. i was going crazy! tried all the resets and battery pull stuff, nothing worked.
only thing that has worked for me for the last 2 days and havent had any reoccurences.
plug in the phone to charge> go to "USB debugging connected> "uncheck" the stay awake> youre done!
for some reason i did an update on something but it caused this option to pop-up on screen, which i had "checked" before the update, so i re-selected it. had these problems ever since. the phone was staying awake even when the screen was off and running everything. it also seemed to hiccup everytime i turned the screen on and started doing the reset thing. something must be wrong with the program that controls this, especially since it only started after that option came up.
im not saying this will fix everyones problem but it fixed mine!!! hope this helps!