How to Ground DC 12V Battery, Charge Controller and Solar Panel?
I would say it depends on your height vs surroundings. If you are up on a hill and are likely to draw lightning, I would recommend grounding.
More importantly, you should place spikes slightly away from the panels and slightly above them so that they draw charges from the air and attract a lightning before it hits the panels.
Those spikes should be connected with a very thick wire, but usually the rails made for that purpose. The panel frames should be connected together with thick wires, but you should know that having a contact between 2 different metals causes galvanic reaction when there is any moisture, and one metal gets spent.
It depends where you are at and what do you have available.
I would suggest reading up on lightning protection and lightning arresters/surge protectors. You will give yourself the best protection hen you know a little more about those subjects and understand how (and why) they work.