There are two kinds of electrical photovoltaic solar systems: off-grid and on-grid. The off-grid system works totally independent of the regular power company feed. It requires batteries. The grid system incorporates your solar electrical supply directly into the power system that receives electricity from the power company grid. Batteries are not required in the grid system. They are used by some for a backup system in the event of emergencies. Your own supply from your solar panels makes it possible for you to reduce your need of electricity from the power company. You can even produce a surplus that is turned back onto the grid for which the power company credits your account. The power company will even pay you when your system produces a surplus.
The electrical photovoltaic collection solar panel is the first of the four components necessary to collect sunlight and transform it into usable electricity in an off-grid system. An electrical solar panel consists of individual like silicon cells that generate electricity from sunlight. Light particles of sunlight, or photons, hitting the silicon cells produce electrical current. The average solar panel, two feet by four and one-half feet, with at least 36 cells can at peak generate approximately 24 volts of electricity.
You calculate how much electricity will be needed from any system and match that calculation to the number of solar panels needed to produce that much electricity. This is then matched to the number of batteries needed to store your electricity. Usually, eight to ten solar panels with 17-19 twelve volte batteries will supply on an average 15 to 18 hundred square foot house on a continuous basis with all the most common electricity needs. This is just an estimate, mind you, and each house will have its own unique considerations requiring more or less batteries.
There are three kinds of electrical photovoltaic solar panels: monocrystalline, polycrystalline, and amorphous. The best, and most expensive of these, is the monocrystalline which cells are composed of pure silicon involving sophisticated crystal development. Less efficient is the polycrystalline, which is derived from large blocks of numerous crystals. Polycrystalline solar panels have a shattered glass appearance.
By far the least expensive and the least efficient is the amorphous solar panel not made from crystals but merely silicon spread over metal or glass. This does not yield the same amount of electrical power as monocrystalline and polycrystalline cells. Vastly more square footage of the amorphous solar panels is required to generate the equivalent output of monocrystalline or polycrystalline panels. The advantage of amorphous photovoltaic cells is that they are now made into roofing shingles which mount right on the roof and replace asphalt shingles. They thereby serve the dual purposes of protecting the house or building from the weather and providing electricity.