Got it under excitement. got totally disappointed by battery issue. Read ms reviews ---- gone under depression. One thing happened that when charged in car, battery backup is excellent.
So changed the oem Nokia original charger with local made one(its impedance is not matching with phone).
Results---1. charging in three to four hours. 2. backup gone to seven to eight hours with average usage.
Changed battery from bl4c to bl5c battery backup gone to ten to eleven hours. My mobile software version is latest ----- no issues of hanging while any apps.
Removed lens protector of camera ----- flash falling into photograph - gone instantly. Extremely happy after few discoveries.
Hope it will help you all.