Doesn't make any difference. The solar I assume is grid tied. Both granny lead and the Rolex will draw more than the Solar could at max theoretical produce.
Therefore both draw the extra from the grid. The 7kw is simply guicker at filling the battery. Do you have the car at home during the day to make use of the solar? If so you probably used all your panels generate before you plug the car in.
Sorry if its not what you wanted to hear. How often do you charge, daily then go E7.