In 1890, the Western Union Telegraph Company utilized a battery storage system consisting of 20,000 zinc-copper cells. The installation was designed to provide power in the event of a utility failure. Modern battery storage systems are designed to meet the same goal. However, the technology has improved significantly -- the cost of batteries, controllers, inverters, and other necessary hardware has decreased to the point where battery storage systems (BSS) are a realistic option for many property owners. There are a number of key factors to explore when considering the purchase of a BSS, including: