Off-grid photovoltaic system is mainly composed of photovoltaic modules, controllers, inverters, batteries and other accessories. Off-grid photovoltaic systems operate independently and do not need to rely on the grid. Equipped with a storage battery can ensure the stability of the system power, and can supply load electricity when the photovoltaic system does not generate electricity at night or when the power generation is insufficient on rainy days. It is characterized by high reliability, long service life, no pollution to the environment and independent power generation.