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How Does Temperature Affect UPS Batteries?

High ambient temperature is the most important factor that influences the deterioration of UPS batteries and can cause premature battery failure.

Higher temperatures result in faster chemical reactions inside the battery, which increases water loss and corrosion.

Valve Regulated Lead-Acid (VRLA) batteries have a rated design life capacity based on an optimum ambient operating temperature of 20-25°C.

For every 10°C constant increase in temperature above this recommendation, it is generally accepted that battery service life will halve (reduce by 50%). Please note that short-term fluctuations in ambient temperature have relatively little effect on UPS battery lifespan. 

See the below image for an indication of how rising ambient temperature can impact service life.


Adjusting the float voltage according to the ambient temperature can mitigate the impact of higher temperatures, but this only has a marginal impact.

Without effective control of the ambient temperature around a battery set, the likelihood of a premature battery failure increases significantly. This could result in both a costly battery replacement and damaging system downtime.

A UPS battery failure due to over-temperature can also lead to a complete system failure that only becomes apparent when the battery set is placed under load during a mains failure.


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Lifespan of UPS batteries

Batteries are essential for UPS correct functioning. In this whitepaper we explain the main important factor that affect their duration and we provide some recommendations for optimizing the UPS + batteries system, in order to maximize its lifespan and general availability.