An off-grid photovoltaic power station, also known as an independent photovoltaic power station, is a power generation system that operates independently without relying on the power grid. It is mainly composed of solar panels, energy storage batteries, charge and discharge controllers, inverters and other components. The electricity emitted by the solar panel directly flows into the battery and is stored. When it is necessary to supply power to the electrical appliance, the DC current in the battery is converted into 220V AC by the inverter, which is a repetitive cycle of charge and discharge. The advantage of this kind of power generation is that it is not limited by the region, and can be installed and used as long as there is sunlight. , isolated islands, fishing boats, outdoor breeding grounds, areas with frequent power outages.
 
The disadvantage is that this kind of system must be equipped with a battery, and the battery occupies 30%-50% of the cost of the power generation system, and the service life is 3-5 years, and it has to be replaced after that, which increases the cost of use. From an economic point of view, it is difficult to get a large-scale promotion and use, so it is not suitable for areas with easy access to electricity.
 
The difference between the two is obvious, but it can also be integrated to make a compromise. This is the intelligent micro-grid system, that is, the grid-connected inverter in the grid-connected system is replaced by a smart micro-grid inverter (on-grid and off-grid hybrid inverters) , In addition, a controller and a battery need to be added. During the day, the controller stores the electricity generated by the photovoltaic in the battery, and at night, the controller releases the electricity stored in the battery for lighting. In this case, even in the event of a power outage, the power station can still operate normally and supply electricity for households, but the cost is too expensive and is not widely used at present.