Download and use Taskiller and make certain maps,gps wifi all are off. Sometime Bluetooth activates itself. Charge it 100% before turning it off (not sleep) at night. After startup in the morning check battery level. If its below 100 %, there is a leakage of some sort,probably the phone,not the battery. Exchange the phone. To double check,charge the battery to 100 % at night,and take the battery out of the phone. Reinsert in the AM and see if the battery is still at 100%. If,not it's a battery problem. Good luck.