What are the Reasons for UPS Battery Failure?

Without regular servicing, your UPS can fail, leaving you at risk of losing vital data. The biggest reason for this is UPS battery failure. Below, we take a look at what causes a UPS battery to fail.

battery failureTemperature

The most common reason for UPS battery failure is incorrect temperature or temperature variances. Optimum performance and the manufacturer’s average stated life is achieved if the lead acid battery temperature is maintained at between 22-25 ºC. If the temperature drops to below 22 ºC, batteries will underperform or sustain damage; temperatures above 25ºC will result in increased battery capacity but reduced battery life. As a guideline, every 8 ºC rise in temperature cuts the battery life in half. Therefore, if batteries are operating at 35 ºC, they are at risk of lasting only half of their 5-10 year expected life.

UPS-Battery-EmptyBatteries don’t last forever

Even if you follow all the guidelines correctly, UPS batteries won’t last forever. Over time, UPS batteries will lose their ability to deliver power and will eventually need replacing.

UPS Battery Discharge Cycle

A major contributory factor to reduced battery life is the number of battery discharge-recharge cycles. The amount of energy that a battery delivers during a discharge has a direct impact on the reduction of battery life. The main reason for this is the deterioration of the battery contacts.
Constant discharging of batteries will cause them to reach their end of life prematurely. Short UPS activity due to compensating for swells and sags should be considered as battery discharge cycles.



If you don’t look after your batteries they’re much more likely to fail. Regular maintenance and eventual replacement is necessary. A health check from UPS Systems will provide a clear picture of the state of your battery to give you peace of mind and help prevent UPS battery failure. Our maintenance visit video shows you the checks carried out by our engineers to make sure your UPS will not fail:

If you have any questions or queries, please contact us.