Marinco Stainless Steel DayNight Solar Vent The Marinco Stainless Steel Solar Vent is used to circulate fresh air into the boat cabin, eliminating mold, mildew, and musty air. These vents are equipped with a built-in replaceable battery. The solar array keeps the battery charged during daylight hours so that it can run the fan at night and during low light situations. On a fully charged battery, these vents will run for up to 24 hours without sunlight. The DayNight vents feature two switches loc