How often should UPS batteries be tested and replaced?

Most UPS batteries, whether valve-regulated lead-acid (VRLA) or lithium-ion, should be visually inspected and load-tested at least once a year to ensure they can deliver their rated runtime during a power outage. For smaller UPS, this can be done by disconnecting the mains power supply and using the connected load. For larger systems, with an external UPS maintenance bypass, the same process can be used but with a load bank to simulate a load on the UPS. Most UPS systems will automatically test every 24 hours, and it is important that UPS are connected to remote monitoring systems to ensure alarm conditions are picked up, and corrective action can be taken. For larger UPS systems with batteries on external stands, visually inspect UPS batteries at least monthly, and you may also need a complete battery monitoring system.

Most UPS batteries are VRLA up to 10kVA. VRLA batteries are available with two design lives: 5 years and 10years. It is not uncommon to replace 5year design life VRLA batteries in years 3-4 and 10-year in years 7-8. Lead-acid batteries degrade over time, and the rate of degradation depends on usage and ambient room temperature, which should ideally be within 20–25°C if the design life is not to halve. Lithium-ion batteries are less sensitive to heat and have design lives in the 10-15year range.