Increasing of PV solar panels installations on buildings which are already been connected to the electricity grid has grown in recently. It has been stimulated by demand ant with government subsidy programs and green pricing policies of utilities or electricity service providers. The desire of both companies and individuals to use electricity from a clean, non-polluting, renewable source drives the demand. They usually willing to pay only a small premium for renewable energy
As the grid supplies only for any extra demand then the batteries are not required for a residential grid connected system. While the PV solar panels system supplies electricity to the building and any daytime excess may be exported to the grid. For some cases, battery storage is needed to provide power at night to be independent of the grid supply.
Homes at a remote area can obtain reliable electricity to meet basic needs with a simple system comprising of a PV panel. In this case a rechargeable battery is neded to store the energy captured during daylight hours as well as a regulator and the necessary wiring and switches. This kind of systems are commonly called SHS (solar home systems)