Off Grid or Standalone power system uses battery for energy storage and they do not depend on grid or any other electric power supply. That is why they are called off-grid PV System. Off-Grid Solar PV Systems are recommended for small electrical loads or at remote places where grid supply is not present. It works by generating electricity from solar panels and using it to charge a solar battery via charge controller. Electricity is then may be converted using inverter so that it can provide AC power to the home or appliances. By saving the electricity in a battery designed for solar application, it is possible to run home with solar energy, even at night or during times when there is less sun exposure.
The simple reason of introducing a battery bank is to enable the use of solar power in absence of grid supply or no source of electricity. The main purpose of battery storage is to keep the critical load circuits operating.
These systems are self sufficient in themselves. They do not depend on any other source of energy to supply electricity.
The example of stand-alone solar PV systems includes a solar lantern, a solar PV home lighting system.
This kind of system does have option to charge the battery with normal electricity. Off-grid system by Nova Energie are customised, cost effective and designed for longer life.