Boondocker's 7 Pin Battery Charger (& two questions)

Roy, here is a wild idea -- solar panels on the roof of your truck!! They would go to a controller in the bed to charge your two extra batteries. I don't know if there is enough real estate on the roof to do the job -- probably not. I guess it depends on how much usage those two batteries would get. But this would avoid putting a big drain on the alternator. Getting stuck in the middle of nowhere with a dead truck battery can ruin your whole day.