Roversa can be charged using the USB micro port in the rear using a 5V power supply and it should last for several hours of use. You cannot overcharge the robot, it has built-in battery protection. The robot can be charging while in use and the micro:bit supports connecting to USB and having a battery connected at the same time. Here are what all of the colors mean for Roversa’s status:
Green: Roversa is on and in normal operation
Red: Roversa is off and charging
Blue: Roversa is off and fully charged
Yellow: Roversa is on and charging
Blue-Green: Roversa is on and fully charged
Battery level is steady and Roversa is ready to use!
Battery level is getting low, try to charge your Roversa soon.
Battery is low or you only have the USB powering the robot through the micro:bit and the robot is not powered on. If powered by battery and you get this sad face, you need to charge your Roversa.