What happens at night or on a cloudy day?
Your solar panels will only produce electricity when they receive sunlight. You will need electricity, however, even when your panels are shaded. Systems that are grid-tied (connected to the utility electric grid) can draw energy from the grid when electricity is not being produced by the panels. Systems that are not grid-tied usually have battery back up storage. This means that systems that are not grid tied must overproduce during the day and store the energy in a battery. The stored energy can then be used at night or when the panels are shaded.
