About Fortress Power Fortress Power is a trusted U.S.-based manufacturer of advanced lithium battery storage systems, known for their safe, scalable, and easy-to-install LiFePO4 batteries. Designed for both residential and commercial use, Fortress Power batteries deliver high performance, long cycle life, and seamless compatibility with top inverter brands. With a strong focus on reliability and customer support, Fortress Power is a leading name in energy storage innovation.