Fitbit won't switch on - only showing bar with half colour

I have a fitbit chargeHR. This has stopped working to the extent that the only reaction I can get is a picture of a bar which shows half 'colored in' and half empty.

I have opened the fitbit and a copy of the actual unit is shown here ttps://ibb.co/cp52sa . Any ideas would be greatly appreciated

Sincerity

Harry

harrygrower@hotmail.com