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An Eaton 93E UPS.

An Eaton 93E UPS.

One of the most common questions concerning an Uninterruptible Power Supply (UPS) system is how long the battery supplies power that remains uninterrupted. In other words, how long does a UPS system last?

Although some UPS systems can operate flawlessly for up to 15 years, the fact remains the power systems typically have lifespans that last between six and seven years. If you learn about the components of a UPS system, you should be able to answer the question.


A UPS power system needs to be cooled and with several fans operating at the same time, a standard UPS system should remain at an operable temperature for the entire lifespan of a UPS system. However, UPS system fans can slowly degrade because of several reasons. Prolonged exposure to high heat and humidity levels is the most common reason why UPS system fans deteriorate. Another way for UPS system fans to decline in performance involves the collection of particulates that eventually clog the sir filters.


With the primary objective to filter voltage changes, capacitors play an integral role in delivering superior performance for a UPS system. The important UPS system components usually require replacement once every seven to 10 years, depending on the workload placed on the UPS system. Under less than idea operating conditions, capacitors have shorter lifespans. Less than ideal conditions include operating in moist environments, such as inside of a refrigerator or near a water source located in a basement.

UPS Battery

A large majority of batteries that operate on a UPS application have a standby design of five years. After five years of operation, UPS powered batteries retain 80% of the original power capacity, that is, if the batteries operate under ideal temperature and float charging conditions.


Virtually every battery running on a UPS application optimizes power performance when the battery keeps a temperature between 20 and 25 degrees Celsius. With every 8.6-degree increase over 25 degrees Celsius, a UPS operated battery will decline in performance at twice the normal rate of degradation. For example, a UPS battery exposed to a 40 degrees Celsius temperature for three months can expect to lose one year of its expected lifespan.

Discharge Frequency

Most UPS batteries operated on standby use, instead of deep cycle use that discharges and recharges on a frequent schedule. A standby UPS battery operates mostly on a float charge that discharges a small amount of what is the possible discharge capacity. More volume and frequency of a UPS battery discharge will cause the battery to deteriorate faster than a UPS battery operating on a standby discharge design.


Another factor that can decrease the lifespan of a UPS powered battery is the charging rate of the battery. The standard charging rate for a UPS battery should be between five and 20% of the amp hour rating. Charging a UPS operated battery over 20% of the amp hour rating will produce too much heat and at below the five percent rating, the development of plate sulfation will reduce the charging capacity.

Of course, there are exceptions to the general rule for determining how long does a UPS system last. For example, overcharging a UPS system at 60 degrees Celsius is a recipe for a serious malfunction. A UPS system handled by following the correct operational protocol should last between six and seven years.