Most photovoltaic systems feed the generated power into the public grid. This is called grid operation. By connecting the solar installation to a large grid (e.g. the public power grid), you can make sure that there are always enough consumers using the solar energy directly. There is no need for intermediate storage. Power supply is guaranteed at all times and normal alternating current appliances can be used.
Remote objects, such as mountain cabins, holiday homes, SOS phones and parking meters, can use power provided by stand-alone solar installations with batteries (power storage). This is called isolated operation.
These are the features of a stand-alone system:
a cost-saving alternative to connecting remote consumers to the grid;
- operation is generally based on continuous current with a 12 V or 24 V voltage;
- this operation requires special devices and lamps if no inverter is used;
- this type of PV system generally consists of three components: the solar generator, the charge controllers and the batteries.