Which Batteries Are Used In UPS System?

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24th Mar, 2021

After understanding the ratings of the UPS itself and the ratings of other components such as the battery and the load, the type of the battery must be addressed as well. There are two broad categorisations of the battery along with some important sub-categories that need to be considered when buying a battery for a UPS. Each offers something different along with its core features.

The two main types of batteries are starting, lighting and ignition (SLI) batteries and deep cycle batteries. The SLI battery is commonly known as an automotive battery and its primary function is to provide a short burst of high magnitude current needed to start the engine of a car.

On the other hand, a deep cycle battery is capable of providing a steady current of relatively lower magnitude over longer durations. Based on this differentiation, the deep cycle battery is the best type of battery for a U.P.S.

Another key point of differentiation which makes the deep cycle battery the best option is its discharge capacity. A deep cycle battery has a longer charge/discharge lifecycle compared to a SLI battery which means it will have a longer lifespan when used in a UPS system. The SLI battery can be permanently damaged if it is discharged frequently below a certain level of charge (usually 70%).

Within the deep cycle classification, there are different sub-categories. The most common and popular option is the Lead-acid battery. It is cheap and easily available but has a comparatively short lifespan. There are sealed or maintenance free Lead acid batteries as well which offer similar performance with lower need for maintenance.

There are more expensive options as well such as the AGM (Absorbent Glass Mat) and Gelled electrolyte batteries. They have longer lifespans and are capable of providing higher magnitudes of currenT.