The off grid solar power generation system uses solar panels to convert solar energy into electric energy when there is light, and supplies power to the load through the solar charge and discharge controller, while charging the battery; In overcast weather or no light, the battery pack supplies power to the DC load through the solar charging and discharging controller. At the same time, the battery also supplies power directly to the independent inverter, which inverts the current to supply power to the AC load.

Off grid solar power generation systems are widely used in remote mountainous areas, power-free areas, islands, communication base stations and other applications. The system is generally composed of photovoltaic array composed of solar cell modules, solar charge and discharge controller, battery pack, off grid inverter, DC load and AC load. The photovoltaic array converts solar energy into electric energy when there is light, and supplies power to the load through the solar charging and discharging controller, while charging the battery pack; When there is no light, the battery pack will supply power to the DC load through the solar charging and discharging controller, and the battery will also directly supply power to the independent inverter. The current will be generated through the independent inverter inverter to supply power to the AC load.

1. Solar cell module

Solar cell module is the main part of the solar off grid power generation system, and it is also the most valuable component in the system. Its function is to convert the solar radiation energy into DC energy. According to the different requirements of users for power and voltage, solar cell modules can be made for single use, or several solar cell modules can be connected in series (to meet the voltage requirements) and in parallel (to meet the current requirements) to form a power supply array to provide greater electrical power. Solar cell modules have the characteristics of high area specific power, long service life and high reliability. Within the service life of 20 years, the reduction of output power is generally no more than 20%. With the change of temperature, the current, voltage and power of battery components will also change, so the negative temperature coefficient of voltage must be considered in the series design of components.

2. Solar charging and discharging controller

Solar charging and discharging controller, also known as "photovoltaic controller", is used to regulate and control the electric energy generated by solar cell modules, charge the battery to the maximum extent, and protect the battery from overcharge and over discharge. In places with large temperature difference, the photovoltaic controller should have the function of temperature compensation. Appropriate photovoltaic controllers are configured according to the DC voltage level of the system and the power of solar cell modules. Common photovoltaic controllers have different voltage levels of DC12V, 24V, 48V, 110V and 220V.

Battery pack

3. Solar battery

Its main task is to store energy, so as to ensure the load power consumption at night or in rainy days. The number of series and parallel storage batteries can be configured according to the requirements of the DC voltage level of the system. The principle of the same model and specification, the same manufacturer, the same batch, and the same installation and use of batteries in series and parallel connection should be followed.

4. Off grid inverter

Off grid inverter is one of the core components of off grid solar power generation system, which is responsible for converting DC power into AC power for AC load. In order to improve the overall performance of photovoltaic power generation system and ensure the long-term stable operation of power station, the performance index of inverter is very important. The inverter selection is based on the characteristics of the load (such as resistance, inductance or capacitance) and the load power.