How many hours does UPS work?

8th, May 2021

One of the questions that is always raised is how long the UPS stays on during a power outage, or in technical terms, the backup time. Or how much is the power supply UPS.

It is necessary to calculate this problem for each type of UPS only at the time of operation and separately, and in no way depends on the type of UPS or UPS power. which is purchasing; It has nothing to do with UPS batteries and consumers connected to UPS;

The duration of backup or powering of UPS depends on two factors:

1) Capacity or ampere hours of the batteries in the UPS

2) The amount of load connected to the UPS (within the allowed working power range)

Assume that a KVA3 UPS device with PF=0.9 has been purchased. This only means that you are able to load VAx0.9=2700W 300 from the device; In other words, the most consumers who are allowed to connect to the device; It should not be more than 2700 watts, and this has nothing to do with the power supply of the device during a power outage.

Also read: Comprehensive UPS Buying Guide

In order to determine when the power went out; How long does the device stay on? There is a need to provide some explanations:

For each UPS device, a DC voltage number is defined as the battery voltage, which is actually determined by the manufacturer and cannot be changed (although it is possible for some devices strong> can work with several different battery voltages; but once the batteries are installed, it cannot be changed anymore), this voltage is provided by serializing the specific amount of the 12 volt battery; For example, in the Hogun KVA3 UPS, the battery voltage is 96 volts (which means 8 12-volt battery cells that are connected in series).

batteries in terms of capacity have different types which are so called They are defined in ampere-hours. This is while the voltage of all of them is the same 12 volts; For example, 12 volt 7 ampere-hour battery, 12 volt 18 ampere-hour battery, 12 volt 28 ampere-hour battery and…

A 7 ampere-hour battery is discharged much faster than an 18 ampere-hour battery, and thus an 18 ampere-hour battery is discharged faster than a 28 ampere-hour battery and…

In this way, as much as the capacity of the batteries that are prepared for the purpose of the device; be more; The duration of the support or powering of the device will be longer.

But the second issue is the amount of device consumers; In such a way that no matter how many consumers are connected to the device; in range to be more; The batteries are discharged faster and the charging time becomes shorter.

Using the following formula, you can estimate the duration of powering the UPS device. It should be noted that the time obtained in this formula is in hours:

Electrification time (Vbat x AH / P) x 0.7 = )

Assume that a 1000 watt consumer is connected to the mentioned UPS (KVA3 with a battery voltage of 96 volts) and also 8 18 ampere-hour battery cells. It is also included as a backup battery. According to the formula above:

“x18x0.7/1000=1:12’3496

Also read: Why does the UPS not turn on or have no output Doesn’t it?

As you know; The number 2096/1 is in hours and in order to make this number tangible, you can convert it to the decimal part according to what we did. ; Convert to minutes and seconds.

min h x 60 = 0.12.5762096

Now we do the same for the decimal part of the minute.

Second m x 60 = 0.34.56576

It should be noted that this exact number cannot be considered as the duration of backup time; Because according to various factors such as the quality of the batteries and the change in the amount of consumption at different times, it is recommended to count on the amount of about one hour; In addition to the fact that the batteries wear out over time and their capacity decreases, and the power supply time decreases accordingly; For example, batteries that have worked for a year (depending on the type and quality), their capacity is generally up to 70 or 60 percent of the amount they had at first; decreases

In order to make this matter more clear, we also provide some other examples:

<a href="https://fa.wikipedia.org/wiki/%D9%85%D9%86%D8%A8%D8%B9_%D8%AA%D8%BA%D8%B0%DB UPS KVA1 with PF=0.8 and include battery voltage of 36 volts; You can connect a maximum of 800 watts of power to this UPS. VAx0.8=800W (1000) Consider that 800 watts is the maximum power that can be supplied from the UPS. >expected and it is not recommended to use your device on the maximum tolerable power.

If we consider 70 percent of the UPS power; 560 watts will be VAx0.7=560W) 800). Now it is necessary to consider 3 12V battery cells for the UPS, which are connected in series. Assume that the batteries are 7 amp hours; Thus, according to the above formula, we will have:

“x7x0.7/560=0:18’5436