Insert the battery connector onto the connector on the printed circuit board, and press down onto the board.

Bend the battery wires to arc the connection route better.

The manufacturer may have glued down the battery cable onto the circuit board's connector. If the connector is not secure, reinforce with electrical tape or pressure on top of the connector.

Now, test that the controller can be powered via USB for a couple minutes, then unplug and attempt to turn on the controller.

Once the connection is established, place thick double-sided adhesive onto the replacement battery opposite the rubberized part, and insert the battery into its chamber on the handle.

Carefully insert! There are sharp corners around the handle, which could puncture the battery and cause a fire!

The battery wires should be nested on the side of the battery, not over, under, or in the way of the housing edges.