The off-grid photovoltaic power generation system is widely used in places where there are frequent power outages, or where the photovoltaic power generation for self-use cannot be fully transmitted back to the grid, or where the price of self-generated electricity is much higher than the grid electricity price, or where the peak electricity price is much higher than the off-peak electricity price.

The system consists of a photovoltaic array composed of solar cell modules, a solar power generation and off-grid integrated unit, a battery bank, and loads. When there is sunlight, the photovoltaic array converts solar energy into electricity, and through the solar power control inverter integrated unit, it supplies power to the loads and charges the battery bank; when there is no sunlight, the battery supplies power to the solar power control inverter integrated unit, and then supplies power to the AC loads.

Compared with the grid-connected power generation system, the off-grid system adds a charge-discharge controller and a battery. The system cost increases by about 30%, but the application range is wider. Firstly, it can be set to output at the rated power during the peak electricity price period to reduce electricity expenses; secondly, it can charge during the off-peak electricity price period and discharge during the peak electricity price period, making money by taking advantage of the price difference between peak and off-peak; thirdly, when the grid is out of power, the photovoltaic system can continue to work as a backup power source, and the inverter can switch to the off-grid working mode. The photovoltaic and battery can supply power to the loads through the inverter.