Thanks for your reply. I have charged both units for quite a few hours without connection to Wio terminal. Green LED comes on during charging. I am using it to power the Wio terminal(using firmware for LoRaWAN Field Tester) and the LoRaWAN chassis. When it is connected between the two units the LED cannot be seen because of the LED location(mounted on rear) as it is hidden by the LoRaWAN chassis so I cannot see if it is on or off or any colour.
Thanks