The battery performance of my Z2 has just dropped significantly a few days ago. I was able to use it for 4-5 days (mostly standby) in the past and recently, it lasts only for 1.5 and 2 days. Such a sudden decrease in battery performance is very surprising. Can it be battery fault or some kind of "update"? I use "STAMINA mode and have switched off all the battery consuming features and the statistics say that mostly the Cell standby (~30%) and Phone idle (~30%) are spent electricity on. The next one is Screen which is usually between 15-20%. Any tips, what could have happened?
