Most UPS systems are installed with valve regulated lead acid (VRLA) batteries or battery sets. This is the most commonly used battery due to its cost and performance in a standby power application. The battery is generally only used occasionally to provide power to the UPSinverter and for the most part remains on. A UPS system will check its battery set automatically and typically every 24 hours. This type of testing is on the complete battery set and not each individual battery. For a UPSbattery alarm to occur the battery set must overall. Lithium-ion batteries offer several advantages over lead acid. They are tolerant of higher ambient temperatures (above 25˚C and higher). When it is time to replace a UPS battery set downtime must be planned for as the uninterruptible power supply must be completed powered down. This is easiest if there is either a separate UPSmaintenance bypass. As the established battery technology within the uninterruptible and many other power system markets, recycling methods and facilities for lead acid.
