Hi Gilbert, you say you have no electric when your not connected to the mains "all the electrics work fine on mains electricity.However,when I try to run the electrics of battery only nothing works the battery is fully charged and also brand new I have reset the mains box is there something im missing?"
The electric wont work if your not connected, or do you mean your 12 volt system?
If you do and this is not meant to be funny or sarcastic, have you got it switched on? normally on your control panel a rocker switch
car - van - middle is normally off you need it set to van
hope this helps