Design life is how long a UPS battery will last for assuming perfect operating conditions, while service life is the length of time before the battery needs replacing.
What is battery service life?
Battery service life considers how application, installation, real-world operating conditions and maintenance practices impact battery aging. Failure to understand the difference between design life and service life can lead to improper battery maintenance and less than optimal battery performance.
Design life can range from 8 years for a standard AGM battery or 20 years for a top-of-the-line Gel battery. But does the design life refer to how long your battery will actually last? And what can you do to ensure you get the maximum service life from your batteries? At Valen, we get asked these types of questions quite often.
Why does battery service life never measure up to design life?
This is one of the principal reasons battery service life never measures up to design life, even when tem-perature and number of discharges are scrupulously controlled. On most occasions, when batteries fail, manufacturers, design engineers, and end users are not at fault.
Europe took a different tack. The Eurobat Guide for the Specification of Valve Regulated Lead-Acid Stationary Cells and Batteries defines design life as follows: “The design life is the estimated life determined under laboratory conditions, and is quoted at 20°C using the manufacturer's recommended float voltage conditions.” 6
How long does a battery last?
This resulted in a 20-year, 10-year, or possibly other stated design life. In Europe, design life is applied to components used in the battery and the limiting factors that might affect lifetime as established from endurance 3. Endurance values are the result of combining standardized and accelerated testing results.
Do data center managers understand the difference between battery design and battery aging?
It is imperative that data center managers understand the difference in order to avoid unplanned downtime. Battery design life is determined by the manufacturer and takes into account cell design and battery aging under controlled conditions in the manufacturer's lab.