im facing battery drain issue...the phone is fully charged before i go to sleep, and when i wake up 9hrs later, battery is at 50% .... wifi is off, brightness is at 10%, gps off, power saving on, is there problem with the battery? if yes, can i exchange for new 1?

yes, upgraded once when i got the phone.... currently on rooted stock rom...

i ve been using the phone for amonth now, almost 1 charge each day....