What is a UPS Batteries life cycle expectance?

UPS Battery Life cycle expectations can vary dramatically, especially when used in a UPS System. A battery manufacturer will always state the expected life of a battery block. Dependant on a pure DC float voltage and the ambient temperature restricted to 20°C. In reality, adherence within these parameters are rare. The real life of a battery cycle is always less then manufacturers design life. A similar principle as car manufacturers, no one ever achieves the fuel consumption targets they advertise.


Unfortunately, as we do not live in a perfect world there are limitations applied to the battery block. One is the ambient temperature, although a number of rack-mounted UPS systems may luxuriate in ambient temperatures of 20°C or less because of the demands of the IT equipment, due to the nature of the design of the UPS there is generally insufficient space to achieve a significant airflow round the battery blocs and as a result they will fail the UPS system battery test after a mere 2 – 3 years.

knowledgebase-batteries-4In this situation the requirements of Uninterruptible Power Supplies and their installation mean that UPS maintenance is unlikely to detect the failure of the battery pack, often due to the fact that after a very short period of time the UPS system is hidden in a mass of communication cables. The most positive approach under these circumstances is to rigorously implement a two-year battery replacement programme to ensure the integrity of the backup UPS system. This also applies to Generators. Yes, even diesel generators require batteries to crank. Without them they won’t start.

Flat or failed batteries render the generator useless. A regular maintenance regime will avoid call outs and additional charges.
In larger UPS systems the problems arising are often due to location; no-one wants the local radiated noise of Uninterruptible Power Supplies to impinge on their working environment and, as a result the uninterruptible power supply will be located in a basement, where the ambient temperature is not ideal for batteries and maybe the saying,” out of sight is out of mind,” is true. In the case of battery life, ignorance is not bliss. Batteries will fail, so be prepared.

Ambient Temperature Effects

Due to location the ambient temperature can often exceed 25 – 30 °C. This potentially could decrease the expected life of the battery. Prolonged use at 30° can decrease the expected life of VRLA (valve regulated lead acid) batteries by 50%. If the ambient temperature raises to 40°C, the life of the battery will fall by a further 50%. Therefore at an ambient temperature of 40°C, the expected operating life of a 7 – 10 year life battery has fallen to 1.75 – 2.5 years!

In this case even UPS maintenance will not save the battery, all it can do is report on the rapid deterioration of the battery blocks. Fortunately the extremes covered by these scenarios are not too common. On the other hand, they highlight the need to record the operating conditions by regular UPS maintenance. Ensuring there is an 24/7 emergency callout cover in place. Prepare in advance! Carry out regular mains fail tests of your UPS system and look for battery issues.

When you require UPS Batteries that are reliable call Power Continuity on 0845 055 8455

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