In my previous phone (Lenovo P780, battery 4000 mAh) battery held about 4 days for the same use !!!
Blackview BV5000 has a larger battery, should be sufficient quietly for 5 days.
On the day in normal use the level of the battery drops from 100% to 80% (about 12 hours) to overnight (approximately 80% to 50% for about 8 hours).
My Famous is a problem with power management, you need to improve the software.
Very disappointed on the phone
Sorry for spelling, poorly I know English well.