Demand for electricity requires vast amounts of sophisticated solar collection. Also known as photovoltaics (PV), solar electric technology features large arrays of collectors made up of silicon-coated cells. When sunlight strikes the surface of a PV cell, electrical fields are directed to electrons, resulting in a flow of current. PV electric systems require major components to properly conduct, control, convert, distribute, and store the energy produced by the array – items such as a power inverter, battery bank, system and battery controller, auxiliary energy sources and sometimes the specified electrical load (appliances). Photovoltaic systems can be designed to provide DC and/or AC power service, can operate interconnected with or independent of the utility grid, and can be connected with other energy sources and energy storage systems.