Max put the lights in the water about 6 inches down make sure ya get just the green not the one with the spot light. As far as battires goes on the inside just cut the plugs off & wire on some clips to clamp on the batt,s i,ve got the big maxx batt,s from wally world & can go all night you want even need your depth finder once your on the fish.we only use 1 light inside most of the time i never hook anything to the cranking batt. try 1 large batt to start with nothing but your lights should last several hours.