What battery is the best choice to use in a UPS system

What battery is the best choice to use in a UPS system giving emergency backup power to critical loads?

The world of batteries is so vast now days that one has many choices in the type or make of battery to use.

There are many advancements in battery technology with a multitude of advantages and disadvantages for different applications.

A UPS system is there to protect ones loads from power fluctuations and occasional complete blackouts.

Most UPS applications be they online double conversion or even line interactive, rack mount or tower mount, modular or stand alone, parallel or not, are installed in situations where they are subjected to occasional power failures and thus designed for what is known as a float application battery pack.

Any site where regular power failures occur daily will require a completely different approach and design when it comes to battery choice.

For a float application, the normal choices are the lead acid battery products.

Factors determining your choice of battery to use with your UPS in a float application are as follows:

      1)  Reliability
      2)  Safety
      3)  Recyclability and the environment
      4)  Pricing
      5)  Maintainability

When it comes to mission critical equipment then reliability is of utmost importance. A lead acid battery offers very good reliability.

All lead acid and NiCad batteries generate hydrogen all the time. Hydrogen is explosive. A Valve Regulated lead acid battery (VRLA) prevents the hydrogen from being released and keeps hydrogen levels in a battery environment very low under float conditions.

Typical examples of VRLA battery makes are ELITE, CSB, Enervision E Guard, all of which are available in high rate discharge and normal rate cells.

Although deep cycle and MF batteries do have a very basic valve they do gas and will generate much higher levels of hydrogen in a room than VRLA and will leak acid if they are laid on their side.

Typical examples of MF and deep cycle battery products are Delkor and Deltec. Another problem with this technology is the environmental factor as ALL lead acid cells are recyclable, but MF technology cells are filled with free running electrolyte which is harmful to the environment if a cell breaks and will cause safety problems to personell and their well being.

VRLA products are no an environmental problem when it comes to electrolyte as they use a starved electrolyte technology and will not leak litres of acid if the break.

All lead acid products are comparatively well priced, MF are the most competitive, but that’s because they use an old flooded battery technology. The saving on an MF battery means a blind eye is turned on health, safety, environment and can bring in many legal arguments if there is a problem as the design is not for standby by rather for automotive application.

VRLA technology has the smallest maintenance requirement.

With the above in mind the best technology to use for a UPS float application is VRLA