Before you begin soldering, note the following safety precautions:

Always unplug, turn off, and remove power sources before soldering.

Do not touch the metal part of the soldering iron! The soldering iron can heat up to over 310°C (600°F).

Be extremely careful when you are soldering/desoldering lithium-polymer battery wires! You can easily short the battery with solder or your tools, resulting in battery damage and a fire hazard.

Plug in the soldering iron and wait 1-3 minutes for it to heat up.

Place the flat side of the soldering iron on the 2 globs of metal for 2-3 seconds as shown.

While the globs are still hot, use your tweezers to carefully detach the black and red wires from the power board.