In my off grid cabin I want to install a victron smart solar mppt controller 100/30. I noticed on the side of the controller there is a screw for grounding. Does this connect to a grounding rod hammered into the ground outside. My small system is 12v, with one 330w panel and two 105ah batteries, in the future I will get a small inverter to run a tv and dvd player. If it does need grounding in the way I have described what size wire should I use. I am in the UK. Simple answers only please. Thanks