I don't think it's that simple. These circuits are already a thing in the form of solar powered security lights, and shed lighting kits. I suspect the dividing

I don't think it's that simple. These circuits are already a thing in the form of solar powered security lights, and shed lighting kits. I suspect the dividing line is voltage? >50v systems in cars are treated differently, so maybe the same for houses, you probably don't need that much for lighting anyway.