The Game Boy Color CleanJuice uses USB-C charging.

Firstly, remove the DC charging port from the Game Boy Color. The simplest way is to apply plenty of solder on the underside pads and use tweezers to gently bend the port away from the board while applying the soldering iron to the pads.

Alternatively use a hot air gun.

Now solder the USB-C power board in place, aligning the two holes with pins 3 and 2 of the original port.

Use 28AWG / 0.2mm Enamel or Kynar wire or thicker. Solder a single wire on the remaining pad of the USB-C board.

Pass it through the battery positive hole and solder it to the USB-C pad on the CleanJuice.

The RetroSix shells will soon come pre-moulded with a USB-C hole.

Until then the only option you have is to drill out a hole. The USB-C port is perfectly centered over the original DC hole, so it is easy to drill two 3.5mm holes to the left and right of the DC hole, and finally drill the center hole out to 3.5mm.

If required, you could drill it slightly larger with a more common 4mm drill bit.

Now you have the USB-C installed, it is pretty simple.

Plug in any USB-C charger into the USB-C, and the CleanJuice will start to charge.

The green USB-C light will light up when the USB-C is simply providing power. If that does not light up, check your soldering to the USB-C port and the USB-C cable and charger.

The orange charge LED will light up while the battery is charging, and go off once charging is complete, which takes up to 3 hours if completely flat.