How To Choose A UPS

For the stable operation of equipment in the home or office and maintaining its functioning, an uninterruptible power supply (UPS) is used. It helps stabilize the voltage in the network; for example, if you connect the computer to the device, there will be a specific time to save data in a light outage. The purchase of models with a large battery capacity makes it possible to support even heating systems in a private house. It is essential to understand how to choose a UPS so that it can perform its basic functions.


Structure and principle of operation of the UPS

Before deciding which UPS to choose, you need to familiarize yourself with the device as a whole, as well as the principle of its functioning. Among the main components are various modules:

  • power;
  • distribution;
  • control;
  • management;
  • indications;
  • Batteries.

A similar technique works according to the following principle:

  • In the case of a stable voltage in the network, which meets certain limits, the current is supplied to the output of the UPS. This allows you to maintain the charge of internal batteries from an external power source.
  • As soon as the light is turned off, the power disappears, or it can significantly deviate from the rated capacity, in which case the activation of the output of the equipment to the inverter, which provides current to household appliances from the batteries, begins.

The duration of the operation is determined by the battery capacity and the efficiency of the built-in inverter. In addition, an important factor is the power of the equipment used, which the UPS powers.


UPS selection options

UPS selection options

To understand how to choose an uninterruptible power supply, you should realize its main parameters.


Choosing the power of the UPS, you should focus on a similar indicator, but for all equipment that will be connected. To do this, it should be understood that the power of household appliances is measured in W, and the uninterruptible power supply itself is in the VA.

To understand and simplify the calculations, you will need to multiply the total capacity of the product by 0.8. So, for example, if there is a model for 600 VA on sale, you can connect devices consumed at 480 W.

In addition, the inrush current for equipment should be taken into account. Often, all the equipment will have more power than the connected devices, by about 20-40%. For some people, it is essential to connect several types of equipment at once, so you will need to allocate nominal consumption in total for all equipment.



Due to this indicator, the consumer can understand how effective the UPS will be. If you choose weak devices, the effectiveness will be low, which means there will be costs without efficiency. To calculate, you need to divide the output power by the input and multiply by 100%.

As an example of the effectiveness of the UPS, experts distinguish the following parameters:

  • With the power of the UPS at 800 W and the leading equipment connected to 300 W, the use of equipment will be inefficient. About 70 W is spent on providing equipment, from which 41% of efficiency is obtained.
  • A practical example is that with a similar UPS, the household appliance will consume 650 W. In this case, the coefficient will be 89%.


Battery life

With this value, the user can determine the duration of the device during a light outage. The period of operation directly depends on the batteries’ capacity and a load of consumption. Often, household models can work in a small range of 4-15 minutes, but this is enough to save data on a PC or perform other manipulations.



Choosing a power source for yourself should immediately determine the number of necessary outputs to which the equipment will be connected. In addition, they must coincide with the entrance in household equipment. Many models have the following connectors:

  • For inclusion in the network 220 V.
  • To protect a network or phone lines.
  • To control the module using a PC.
  • For diagnostics or monitoring using USB, COM ports.

There may also be sockets on the case that help to connect to the battery using a standard plug or IEC cable. It is possible to connect to the module, bypassing the batteries.


Other selection options

Among the other recommendations for the choice are the following:

  • When choosing a UPS for a computer or other equipment, you need to select different outlets. They can be of European standard (CEE 7/4) or computer type (IEC-320-C14). Experts recommend choosing combined devices since, at home, this type of technique can be helpful everywhere.
  • In addition, you need to make sure that the case has a removable unit for the possibility of replacing the battery without additional effort. This is because the average period of work is up to 5 years. If there is no such function, the device will need to be sent to the masters for repair.
  • An equally important parameter for choosing an uninterruptible power supply is an indication. It helps to see data about the operation of equipment, the rest of the battery charge, and modes. It is often performed in diode pointers on inexpensive models and a screen with a detailed data display in medium and high-cost models.
  • Having at least one USB jack will help you quickly save personal data on your PC automatically. For this purpose, special software is intended, which is very convenient to use. In addition, the feature helps to keep unfinished work when the lights are turned off, even if there is no person nearby.
  • RJ11 and RJ45 ports help protect your network or phone line from heavy loads. ; often, some people may require this feature. It is available even in budget technology.
  • The “bypass” mode allows you to bypass the inverter inside the UPS and gives power directly from the mains. In this case, users can make repairs without disconnecting household appliances from power. In addition, when the network is functioning normally, the load from the inverter can be transferred to the bypass to reduce current consumption.


Types of uninterruptible power supplies

Types of uninterruptible power supplies

Many ups variants that can be found at points of sale are produced in China. Quality is not always on top, so it is essential to understand the best brands and types of devices. Experts advise using equipment from proven companies that guarantee high quality:

  • APC;
  • Powercom;
  • Ippon;
  • P-Com.

Below are the main types used at home with all the pros and cons. This will make it possible to disassemble which UPS to choose for the computer or boiler.



Such models are the simplest and most common among the possible options. Most of them are used for computers, but you can connect to other devices. Often, it is customary for PCs to use a switched UPS since they can compensate for the shortest drawdowns in the network. This is caused by a small supply of energy in the internal capacitors. Since the minimum delays during the transmission of current from the mains to the battery are not critical, you can use backup models.

When connecting a personal computer to this device, a person receives a few minutes in reserve, allowing you to save important data or unfinished work. In addition, when the lights are turned off, it will be possible to make the proper closure of programs and turn off the PC.

The backup type is suitable for a stable network with no current drops or minimal. However, in applications in networks with constant interruptions, the batteries will quickly discharge and fail. Therefore, they will need to be replaced. On average, the price of such a device is in the range of 2.2-4 thousand rubles.


  • The design is one of the simplest.
  • Affordable price.
  • Low maintenance costs.
  • Almost silent operation.


  • There is no built-in current stabilizer, so it is not recommended to use models in constant network failures.
  • It is impossible to quickly resume battery charge in frequent switches, so the service life is reduced.
  • The button is activated in about 6-20 ms, which can cause negative consequences for some household devices.



These models are considered better than conventional backup sources. They are characterized by stability of functioning. Inside, manufacturers put an automatic transformer that can stabilize the voltage by compensating for its fluctuations. They are also connected to the output channel. Switching between the network and the battery is reduced to a minimum due to the installed inverter with a converter.

The main distinguishing feature of this type is that current consumption does not change during voltage stabilization before it is distributed to connected devices. The principle of operation does not differ from backup devices. In the presence of power supply and voltage, power will be supplied from the network. Management is carried out once the off light is off using an inverter from the battery, and the input switch will be unlocked. In addition, if there is a current, but it does not meet the nominal value, then the equipment makes a switch and stabilizes the current without using the battery.

Linear-interactive options are best suited for those places where the current is not much different from the nominal. However, the price of this device can be completely different, starts from 2500 rubles and reaches 177000.


  • An extensive price range will allow you to choose options for specific parameters for an affordable price.
  • The highest efficiency of the device in comparison with other types. The efficiency of this device is at the level of 96-98%.
  • The output is a sinusoidal voltage, which reduces voltage drops and pulses due to switching charging from the mains and the battery.
  • Provides power to household appliances even with the reduced or increased current in the network without switching to battery operation. This helps to extend the battery life significantly.
  • During operation, minimal heating of the case is made, and a minimum of structural parts is involved. This solution helps to increase the level of reliability and increases the service life.


  • Switching power supplies is carried out within 6 ms.
  • The average degree of protection, if you compare the options for the double conversion.
  • Low performance in case of interference filtering or current suppression.


With dual converter

Such devices allow you to convert energy two times. Initially, the alternating current is wholly restored to DC, after which any distortions are eliminated with the transfer to the alternating current. If the AC voltage parameters do not meet the desired nominal value, the device runs on battery, but the switching is almost instantaneous. The inverter is powered through capacitors, which provide a constant supply of output current to the devices.

In addition, models of this segment can stabilize power. The devices are considered the most expensive on the market. The starting price is 16,000 rubles and ends at 171 thousand rubles.


  • At the output, you can adjust the frequency, as well as make a partial conversion.
  • Small weight and size.
  • Despite the load, power compensation is made.
  • With current solid drops in the network from the standard indicators, the devices rarely run on batteries.


  • High electricity consumption.
  • Significant heat generation, for which it is necessary to think over the removal.
  • Many elements are installed inside, and with an increase in their temperature during the operation of the UPS, the reliability and durability of the devices are reduced.
  • Average efficiency compared to linear-interactive UPS. Based on a specific model, the efficiency is 85-92%.


Which uninterruptible power supply to choose

There are a few simple recommendations for choosing that will simplify the search for a product. So, we prefer a UPS for the boiler, computer and other equipment:

  • In low-power equipment, for example, a PC or fax machine, you can buy backup UPS, which gives a small amount of time after turning off the light.
  • If the PC is gaming or powerful, you should take sources that will be stronger by 30% of the computer’s power.
  • For a boiler powered by gas with electronics needed to maintain all heating, devices with about 40% more capacity for the reserve should be used.
  • It is better to choose products that can quickly replace the battery for comfortable operation without outside help. In addition, their durability is small, often 3-5 years.
  • For heating boilers, pumping equipment, backup models are suitable. Still, in this case, a voltage stabilizer or other devices that protect against heavy loads, for example, a relay, should be used.
  • Dual conversion models can be connected to boilers without the use of stabilizers. The same is permissible with the technique of linear-interactive form since the devices automatically equalize the voltage. The output should be a sinusoidal waveform.
  • It is better to buy a linear-interactive UPS in the country or a private house, where various boilers, pumps, and other equipment are actively used. You can put a permanent action if you correctly calculate the power.


Frequent mistakes of buyers

If you make a mistake with choosing and purchasing an uninterruptible power supply, then there may be a problem with the frequent replacement of the battery. In addition, the voltage is constantly jumping, so inexpensive devices will often switch to functioning from the storm, which reduces its service life. In this case, the person should choose options of the linear-interactive type.

Often, users quickly buy equipment, but you need to calculate the total number of all devices of all de; otherwise, when overloaded, the UPS will not work but turn off.

To avoid being disappointed in the choice, you should remember that models with double conversion are loud to cause trouble after an operation. The UPS’s described tips and basic parameters will help you choose a PC model, pumping equipment, or boilers.

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