Put your fingernail in the notch on the bottom-left corner and pry the back cover off. Pry the battery up and remove it. Connect metal contacts well. Put the battery in place. Put back back cover. Press the power button to power on the phone. In terms of battery capacity,this phone can hold 2300 mAh. The K10 has an advertised talk time of 16 hours. The 2300mAh battery in the K10 LTE lasted for 10 hours and 24 minutes in our test, which is quite good considering its capacity. Charging the phone and observe the battery life.