Yesterday night, after over 12hours with no use, the phone was at 92%. I configured it downloading a lot of application and backup data and when I went to bed it was at 84%. I powered it off in order to check if the battery drain with the phone powered off was still present. Tonight, after 24h, the ...

Thank you for your response.
Yes, I did it last night.
Now I just powered on the phone... I will leave it today powered on and tonight switched off in order to check if battery drain is still present.
I will report tomorrow the results.

I just bought a blackview 8000 PRO. As I received the phone I updated succesfully the firmwware to the Oreo BV8000Pro_blackview_2018062921 version. Updated the phone I charged the battery to 100% and powered off the phone (long pressing the power off button and selecting the "power off" op...