Frequently Asked Questions

Does room temperature (ambient temperature) affect battery life?

Yes. As a battery heats up, it draws more current, which causes overcharging.

Overcharging causes numerous problems, such as sulfation, positive plate growth, and plate shedding, all of which contribute to decreased battery life and performance.

Is the weight of a battery a factor in determining its quality?

Yes. If you compare the same size battery (in ampere-hours), the heavier battery has more lead (usually thicker plates), providing better performance and longer life.

What is a true “online” UPS?

A true online UPS protects from problems related to power failure, power sag, power surge, under voltage, over voltage, electrical line noise, frequency variation, switching transients, and harmonic distortion.

Are maintenance-free batteries really maintenance-free?

Sealed batteries are sometimes called “maintenance-free,” which refers to the fact that they do not require fluid. These batteries still require scheduled maintenance, though, to maximize service life.

When referring to a UPS battery, what does “end of useful life” mean?

This term describes a battery that can no longer supply 80% of its rated capacity in ampere-hours. At this point the aging process accelerates, and the battery is no longer capable of supporting a load for the design duration.


How do you choose the size of a UPS?

  • To correctly size a UPS, you need to understand the relationship between the load level, the run time, and the capacity of the UPS unit.
  • The load level is the sum of the volt-ampere (VA) ratings of all the equipment to be protected.
  • The run time is the number of minutes that the UPS will be able to provide power from the battery for a given load level.
  • The capacity of a UPS unit is the VA rating.
  • Choose a UPS unit with a VA capacity that is at least as large as your systems total requirement.
  • Note: You may want to multiply your load level by 1.2 to take into consideration any future expansion needs.

What is the life expectancy of a battery?

  • Design life is the life of the battery as expected by the batterys manufacturer.
  • Actual life is the life of the battery as experienced by the user.
  • With proper maintenance, a battery operating in a temperature-controlled environment specified by the manufacturer (77° F, for example) can be expected to last its design life (i.e., 5, 10, or 20 years).
  • For every 18° F increase in the operating environment above the specified design life temperature, the life of the battery is de-rated by 50%.