On the PCB of the CleanJuice itself, there are 2 LEDs.
Green means the USB cable is providing power to the system. This will mean you can power you console from the USB without draining the battery.
Orange means the USB is charging the battery. When it goes off, the battery is fully charged.
So the usual lights are green + orange when charging, and green only when fully charging.
If you connect a USB cable and the LED does not turn green, your cable or power supply are faulty.
Source: RetroSix Knowledge Base