The ESS system is a high-performance off-grid energy storage system. It uses high-quality lithium iron phosphate cells and is equipped with an intelligent BMS battery management system. It has long cycle life, high safety performance, good sealing, and is equipped with high-frequency off-grid inverter, built-in MPPT controller, provides efficient and reliable energy solutions for PV off-grid power generation systems, homes PV storage systems, and industrial and commercial energy storage systems. The system is equipped with a self-developed APP, supports IOS/Android mobile phones, remotely controls the charging and discharging of the ESS system, and real-time system operation data. When the system fails, it can be quickly eliminated and the effective power supply can be restored efficiently.