Hello this is my first xperia smartphone. I'm impressed about the battery of z2 but I have question about battery life, I have auto brightness auto, Sleep 30 seconds, mobile data on, nfc off, Wifi Always on, stamina mode off. I looked into may battery usage and the screen usage is using 62 percent? When you charge your z2 phone is it necessary to make the battery turn to 0 percent before charging? Mine was I discharged it to 0 before charging it but when I read about the battery Li-Ion that it doesn't need to be discharged to 0 is this ture? .How to make the battery life of z2 last longer but not damaging the battery itself? Any tips? Thank you!