iFixit

If you have never soldered before, we have a guide that makes it easy to learn. We suggest brushing up before proceeding.

We're now ready to begin the soldering process. You'll need a soldering iron, solder, and desoldering wick. You should be able to find these items at a Radio Shack if you don't already have them.

Clean the solding iron by melting a small amount of solder directly onto the soldering iron's tip and then wiping the tip of the soldering iron on a damp sponge.

Place the desoldering wick on top of the existing solder ball.

Place the soldering iron on top of wick above the existing solder ball.

Hold the soldering iron in place until the solder melts into the wick.

Repeat the same procedure on the remaining two connectors.

Lift the old battery out of the iPhone. Be sure that all the solder has been removed before pulling the wires away from the board. The wires should come free with little to no resistance.

We recommend that you clean the exposed surface of the board with a soft cloth or sponge and a small amount of rubbing alcohol.

Melt a small solder bead directly onto the metal connector on the board by placing the soldering iron onto the metal connector and then pressing solder against the tip and the board.

Once a small amount of solder has melted onto the board, lift the solder away first and then the soldering iron.

The solder bead should look like a small dome or hemisphere. If it is flat or jagged, simply place the soldering iron back on the solder to re-melt it and then pull the soldering iron away. It may require a little more solder if this does not work.

Attach the red lead first, followed by the white lead, and finish with the black lead.

Place the wire from the new battery onto the new solder bead.

Press the tip of the soldering iron onto the solder bead until it melts.

Slide the wire lead into the liquid solder until it is in the center of the bead, then remove the soldering iron.

Continue with the other two connections the same way, taking special care not to solder two of the connectors together.