You can charge the battery on a PC or Laptop directly:
1. PLease remove the bracelet where the USB-Logo is. The USB-port becomes visible then. Connect the device with the port to a PC or Laptop. The USB connection is needed only for charging, no data will be transferred. The MX3 can also be charged with a fitting adapter(for example the one of your phone) per outlet.
2. The batterysymbol on your display indicates how much power is left.