In our opinion, the duration of a UPS in battery mode is very relative, an exact time cannot be said because it will always depend on several values, however, one thing that is clear and does not depend on anything are the specifications of the batteries inside, number of batteries, voltage and amperage of each of them.

Knowing the batteries that a sell UPS (จำหน่าย UPS which is the term in Thai) carries, we can say the following:

The formula for calculating the time of a UPS in battery mode is:

Time in minutes of a UPS / UPS = ((N x V x AH x Eff) / VA) x 60

  • N = number of batteries in the UPS
  • V = battery voltage
  • AH = Battery Amps-Hour
  • Eff = efficiency of the UPS (as a rule, it usually ranges between 90% and 98% depending on the UPS)
  • VA = Volti-Amps of the UPS
  • Taking into account everything described here, we explain it with the example of the Offline UPS from Qloudea.com
  • N = number of batteries in the UPS = 2
  • V = battery voltage = 12
  • AH = Amps-Hour of batteries = 9
  • Eff = efficiency of the UPS (as a rule, it usually ranges between 90% and 98% depending on the UPS) = approximately 95%
  • VA = Volti-Amps of the UPS = 1000
  • UPS duration at maximum load= ((2 x 12 x 9 x0.95)) / 1000) x 60 = 12.31 minutes

Once we know that it lasts 12.31 minutes, we have to understand that this time is what the UPS would last at 100% of its capacity.

We know that approximately, a 1000VA UPS provides us with 700W, so if we put the 1000VA UPS with a load of exactly 700W continuously, we would obtain about 12.31 minutes until the UPS shuts down.

Keep in mind that normally we never reach the maximum capacity of the UPS since a 700W power supply does not always consume 700W, it will normally work consuming about 300 or 350 W depending on what we demand, so the UPS  we are talking about , it would last about 25 minutes with this source connected to it.