Use an iPod opening tool to carefully pry the battery connector up from the ends closest to the top and bottom edges of the iPhone.

Do not pry against the contact clip.

Remove the contact clip from the iPhone.

Before reconnecting the battery connector, be sure the pressure contact (shown in red) is properly positioned next to the battery connector.

Before reassembly, be sure to clean all metal-to-metal contact points on the pressure contact as well as its contact point on the rear panel with a de-greaser such as windex. The oils on your fingers have the potential to cause wireless interference issues.