UPS Battery

UPS Battery Failure Causes

At UPS Systems plc, we offer Uninterrupted Power Supply batteries and also perform impedance tests and all types of power supply maintenance. For more information, click here to contact us.

When an Uninterrupted Power Supply system goes for a long time without being serviced, its chances of failing increase considerably, leaving you open to the possibility of losing crucial data, one of the main reasons this happens is UPS battery failure. In this article, we will be looking at some of the things that cause UPS batteries to fail. Want to learn more about UPS batteries and systems? Give us a call today.

One of the most common failure modes of VRLA batteries is an open circuit, which is often the result of cell dry-out. Uninterrupted Power Supply systems generally make use of connected battery systems to provide the UPS System’s DC Bus with the high current it requires. If one battery cell within the string opens, it breaks the entire string’s flow of current. In short, one faulty battery cell is all that’s needed to bring down a system.

Battery Failure/Temperature

A common reason for uninterrupted power supply battery failure is temperature variances or incorrect temperature. The manufacturer’s average stated life and optimum performance could only be achieved if a battery’s temperature stays at around 22 to 25 degrees Celsius. If the temperature falls below the 22 degrees Celsius mark, the cells could end up sustaining damage or may start to underperform. If the temperature rises above the 25 degrees Celsius mark, their capacity increases but their life reduces. Please note that an 8 degrees Celsius rise in temperature cuts a battery’s life in half. As such, if the batteries in your UPS are operating at 35 degrees Celsius, chances are they’ll only last for half of their expected life, which is 5 to 10 years.

Empty Batteries Do Not Last Forever

No matter how strictly you followed your UPS’ operational guidelines, the batteries in the device still will not last forever. As time goes by, the battery cells in a UPS lose their ability and capacity to deliver power and will, at some point, need to be replaced.

Battery Discharge Cycle

Another major factor that contributes to a reduced UPS battery life is discharge-recharge cycles. It is worth noting that during discharge, the energy a battery delivers to a device directly impacts its life. The reason why this happens can be attributed to battery contacts deterioration. When battery cells undergo too many discharge cycles, they become strained, something that could cause them to reach the end of their lives prematurely. Short uninterrupted power supply activities – like compensating for sags and swell – should be considered as discharge cycles.

Some preventative maintenance measures include battery voltage testing, visual inspection, checking the torque on terminal connections, and performing thermal image scans to test for abnormal or hot conditions. If any of these tests show irregularities, we can help determine how serious the situation is and the best course of action to take.

Regular battery maintenance and service plays a crucial role in guaranteeing the reliability of your system. Apart from removing corrosion and ensuring connections are okay, preventative maintenance also helps identify unhealthy batteries before they fail.


If you do not take good care of your UPS’ batteries, you lower their life by almost half. Replacement of ageing batteries and regular maintenance are both necessary. UPS health checks and maintenance from UPS systems can help provide a clearer picture of how your UPS batteries are faring. Having your UPS system checked regularly can help prevent sudden UPS battery failure, allowing you to enjoy peace of mind knowing your system is in good shape. While you cannot make your UPS batteries last forever, you, on the other hand, can increase their longevity by taking good care of them through regular maintenance and ensuring they are correctly stored. Regular checks can also help ensure failing batteries are identified and replaced before they cause a problem.