Nowadays, for many, the computer is a source of income. And a power outage even for a second can cause a crash. Therefore, most have a source uninterruptible power supply(UPS). I bought not only a powerful UPS, but also an inverter, since the UPS operating time is relatively short.

I will tell you how to increase the power and operating time of an uninterruptible power supply by about 2 times. Of course, a lot depends on the specific model.

Budget uninterruptible power supplies cannot work for a long time in stand-alone mode, not only because of the low battery capacity, but also due to the lack of cooling of the power units. Let's remake my spare low-power uninterruptible power supply with a real power of no more than 150W. We disassemble it to make sure that it is suitable for such a rework. Typically, consumer-grade UPSs have a power reserve.

We find power transistors, usually located next to each other on the radiators. We see that there are seats for additional transistors.

FETs drive the transformer at 50Hz, which is a typical 2-cycle push-pull boost converter.

In uninterruptible power supplies use n-channel field-effect transistors(MOSFET) with a drain-source voltage from 40 to 60V from the IRF or IRFZ line. Mine has an IRF3205, one in each shoulder, but there is room for a second one of the same key. Therefore, I solder the second pair of keys. First we install the leads into the holes, then we screw it to the radiator and then we solder it. In my case, the radiators are separate for each arm, so there is no need to insulate their cases. If the heat sink is common, an insulating gasket is required!

What does this alteration give? When the transistors are connected in parallel, the resistance of the open channel is halved, and the lower the resistance, the less heating of the keys. That. by distributing power between 2 transistors, we enable the UPS to work much longer without overheating.

Naturally, by increasing the number of keys, we also raise the power of the UPS as a whole by almost 2 times. But the power depends not only on the transistors, but also on the power transformer. Unfortunately, in mine there is a transformer of at least 200-250W. It is clear that it will not be possible to remove more of this, but the power is greater than before the rework.

2nd stage - revision to increase the operating time. Many people ask: "Is it possible to use a car battery instead of a standard battery?" The standard battery is also lead, only sealed, with a voltage of 12V and a capacity of 7-9A * hour in budget devices. So, the UPS can be powered from auto-accumulators, provided that additional cooling is provided, taking the heated air from the case.

The power switches and the transformer are heated, operating at the limit of possibility. We take the fan from the computer power supply unit, cut out a hole in the case and install the cooler.

Remember that the UPS must also charge the battery. In an uninterruptible power supply, the built-in charger is designed for a standard battery and this is approximately a current of 1A. This is not enough for a car battery, but considering that it is recharged almost all the time, this is quite enough. Of course, if you wish, you can assemble a separate charger in the UPS case, but this is not part of the task of this alteration.

To connect a car battery, you will need alligator clips and terminals. I miscalculated the height of the cooler and the UPS board with a metal frame, I had to fix it at a slight angle, but this will not affect the operation. The cooler is connected directly to the battery through a separate switch, although ideally it is advisable to use the thermostat for automatic on / off.

A small calculation: let's say an auto-accumulator has a capacity of 60A * hour, therefore, it can supply a load of 720W for an hour. Usually the average is not gaming computer consumes within 250-300W, which means that the capacity is enough for 2.5 hours of work. Here we did not take into account the efficiency of the uninterruptible power supply (70-75%), at best, the battery will last for 1.5-2 hours. But, you see, this is a good reserve.

The UPS is a very cost effective device. As long as it works, the user has no problem with the power supply. But the functionality of this device does not end there. The simplest modification of an uninterruptible power supply makes it possible to create on its basis such devices as a converter, a power supply unit and a charger.

How to convert an uninterruptible power supply into a 12/220 V voltage converter

A voltage converter (inverter) converts a direct 12-volt current into an alternating one, simultaneously increasing the voltage to 220 volts. The average cost of such a device is 60-70 US dollars. However, even owners of worn-out uninterruptible power supplies with a battery start function have a very real chance to get a workable converter for nothing. To do this, you need to do the following:

Open the UPS enclosure.

Dismantle the battery by removing two wires from the drive terminals - red (for plus) and black (for minus).

Dismantle the speaker - an audible alarm device similar to a centimeter washer.

Solder the fuse to the red wire. Most designers advise using 5 amp fuses.

Connect the fuse to the "input" contact of the UPS - the socket where the cable was inserted that connects the UPS to the outlet.

Connect the black wire to the free contact of the "input" socket.

Take a standard cable for UPS connections to the outlet, cut off the plug. Plug the connector into the input socket and determine the wire colors corresponding to the red and black pins.

Connect the wire from the red contact to the positive of the battery, and from the black to the negative.

Switch on the UPS.

Inside the Eaton 5P 1150i UPS

Such a transformation is allowed only by uninterruptible power supplies with a battery start function. That is, the UPS must initially be able to turn on from, without connecting to an outlet.

If the UPS has a standard outlet - 220 volts can be removed from its contacts. If there is no such outlet, it will be replaced by an extension cord connected to the “output” socket of the UPS. The extension plug is removed, after which the wires are soldered to the contacts of the "output" socket.

The main disadvantages of such converters:

• The recommended operating time for such an inverter is up to 20 minutes, since UPSs are not designed for long-term operation on batteries. However, this disadvantage can be eliminated by cutting a computer fan operating from 12V into the UPS case.
• Lack of battery charge controller. The user will have to periodically check the voltage at the drive terminals. To eliminate this drawback, an ordinary car relay can be embedded in the converter design by soldering the red wire behind the fuse to pin 87. If properly connected, such a relay will open the power supply when the voltage on the battery drops below 12 volts.

How to make a power supply from an uninterruptible power supply

In this case, from the entire structure of the uninterruptible power supply, only one is needed. Therefore, a user who decides on such a modification of the UPS will have to either gut the entire UPS, leaving only the case and the transformer, or remove this part, having prepared a separate case for it. Then they act according to the following plan:

Using an ohmmeter, determine the winding with the highest resistance. Typical colors are black and white. These wires will be the input to the power supply. If the transformer remains in the UPS, then this step can be skipped - in this case, the input to the homemade power supply will be the "input" socket on the end of the UPS, which connects the device to the outlet.

Next, an alternating current of 220 volts is supplied to the transformer. After that, voltage is removed from the remaining contacts, looking for a pair with a potential difference of up to 15 volts. Typical colors are white and yellow. These wires will be the exit from the power supply.

The input to the power supply is formed from wires, on one side of the core. The exit from the block is formed from wires located on the opposite side.

A diode bridge is installed at the exit from the power supply.

Consumers are connected to the contacts of the diode bridge.

Transformer

The typical voltage at the output of the transformer is up to 15 V, but it will drop after connecting to homemade block load supply. The designer of such a device will have to select the output voltage through experiments. Therefore, the practice of using a UPS transformer as the basis of a power supply for a computer is far from the best idea.

Converting an uninterruptible power supply for charging

In this case, a minimal transformation like the one described in the paragraph above is not needed. After all, the uninterruptible power supply has its own battery, which is charged as needed. As a result, to turn the UPS into Charger you need to do the following:

Locate the primary and secondary circuits of the transformer. This process is described in the paragraph above.

Apply 220 volts to the primary circuit by cutting a voltage regulator into the circuit - as such, you can use a rheostat for light bulbs, replacing a traditional switch.

The regulator will help to calibrate the voltage at the output winding in the range from 0 to 14-15 volts. The insertion point of the regulator is in front of the primary winding.

Connect a 40-50 ampere diode bridge to the secondary winding of the transformer.

Connect the diode bridge terminals to the corresponding battery poles.

The battery charge level is monitored by its indicator or voltmeter.

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Before every car owner someday the question arises of how to charge a dead battery. He also appeared in front of me once. And it happened, as always, unexpectedly, on a weekend, in the village, and as luck would have it, no one nearby had anything similar to charging. I had to strain my convolutions and quickly make a simple but powerful charger from available tools. And the burned-out UPS helped me with this - an uninterruptible power supply for computers. Without going into deep details, I will just note that this device powers the computer from a built-in 12-volt battery in case of a power outage in the outlet.

The most important thing is taken from a broken uninterruptible power supply - a powerful transformer, which usually remains intact, we do not need all the other spare parts from it.

So, to make a simple charger you will need:

1. Transformer from a burnt out uninterruptible power supply
2. Diode bridge (rectifier) ​​2-4 pcs.
3. Capacitor 100 ... 1000 microfarads with a voltage of at least 25 V
4. Medium-sized radiator
5. Board, plywood, plastic
6. Thermal paste KPT-8
7. Tester
8. Soldering iron, pieces of wire

Using the tester, we determine the winding leads that have a higher resistance (from 10 to 50 Ohms), this will be a 220 V network winding. The 12V secondary winding leads are thicker, it is wound with a thicker wire, so the resistance of the secondary winding is practically zero.

The conclusions that went to the output connectors of the uninterruptible power supply will now be connected to the network, and the wires through which 12V was supplied from the board will be connected to the rectifier.

You will also need several rectifier diode bridges GBU406, GBU 605, GBU606, and a filter capacitor, a capacitor from 100 to 1000 uF for a voltage of at least 25V (from a burnt out computer unit food). A small radiator for diodes will also come in handy. Of course, you can make a rectifier on ordinary diodes with a maximum current of at least 10 A and a reverse voltage of at least 25 V, but at that moment they were not at hand, and later I also used ready-made rectifier bridges, because it is convenient to mount them on a radiator ... The rectifier bridges are stacked, coated with heat-conducting paste and pressed against the radiator with a long bolt. All pins of the same name are connected in parallel. Pluses with pluses, minuses with minuses, etc.

A transformer, a radiator with diodes is attached to a suitable sized wooden board, plywood, or a piece of plastic, the entire circuit is mounted, a cord with a plug from an old soldering iron is connected - and charging is ready!

The options for mounting and layout of the charger assemblies can be any, based on what is at hand.

With a rectified output voltage of about 18 V, the charger freely gives a current of up to 5 A. An ordinary battery is charged in an hour, a heavily loaded battery - in 3 ... 4 hours. Many motorists in our village now have such a charge.

Moreover, for better battery charging, I came up with the idea of ​​connecting the charger in a pulse mode. Impulse, of course, is said loudly, it only means that it is connected to the socket through an electromechanical time relay.

This is a simple daily electromechanical relay, it comes from the Middle Kingdom, the store sells for 150 rubles.

For many of us, a personal computer is a way to earn our bread. People whose business is closely related to a computer need an uninterrupted power supply. Otherwise, even a momentary power outage can cause a serious crash. It is very uncomfortable when the lights are suddenly turned off. To avoid such unpleasant surprises, the master purchased not only a powerful uninterruptible power supply, but also a separate inverter, since the UPS operating time is relatively short. You can buy an inverter from this Chinese store (in the search, specify New Car Charger 1500W WATT DC 12V to AC 220v) In his video, the wizard will help those who have this problem often figure out this issue and tell you how to increase the power of the UPS.

Watch the video from the blogger's channel Aka Kasyana.

Budget uninterruptible power supplies cannot operate in an autonomous mode, not only because of the low battery capacity, but also because of the lack of normal cooling of the power units. Today we will teach how to operate a UPS to work for hours on end in stand-alone mode. Due to a small modification, it will also be possible to increase the power of the UPS by almost 2 times. But it all depends on the specific brand of UPS. After alterations, the UPS will be able to work in autonomous mode for about 1.5-2 hours. Its power will also increase.

Let's start with the fact that the conversion will be done on a spare uninterruptible power supply. Its real power is no more than 150 watts.

At the very beginning, you need to disassemble the device to make sure that it is suitable for rework. Typically, these custom category devices have a headroom. If you look closely at the power transistors, which are easy to find on the diagram, you can see the seats for an additional pair of transistors. Field-effect transistors are driven by a transformer with a frequency of 50 Hertz. Typical push-pull boost converter circuit. As a rule, the UPS uses n-channel field-effect transistors with a voltage of 40 to 60 Volts from the IRF or IRFZ line.

As mentioned earlier, next to each key there is a place for a second of the same key. Therefore, first of all, we will free the board and solder the second pair of keys, which were purchased in advance.

First, the transistor is installed, then screwed to the radiator. Only after that the leads are soldered to the board. the dress. We carry out the same operation with the second transistor. It should be noted that in this case the radiators are separate. There is no need to isolate the transistors from the heat sink in this example. In the case of a common heat sink, it is imperative to isolate the transistor cases from the radiators.

What does such an alteration with an increase in strength give us? By connecting the resistor in parallel, the resistance of the open channel is reduced by 2 times. The lower the resistance, the less heating of the keys. That is, we evenly distributed the power between the two switches and reduced their heating, which will allow the UPS to work for a long time without overheating.

Naturally, by increasing the number of keys, we increase the power of the UPS as a whole, almost twice. But power does not depend on transistors. As mentioned above, the existing UPS has a small problem and it is related to power transformer, which has a power of 200-250 watts. Therefore, it will not be possible to remove high power. But of course, the power is now definitely a little more than it was before the rework.

Extending UPS Runtime

The second stage of the rework is to increase the operating time of the UPS. Can a car battery be connected to it instead of a native one? The native battery is also lead, but of a sealed type. The voltage is 12 volts with a capacity of 7-9 amperes. We are talking about budget devices with one battery. An uninterruptible power supply can be easily powered from a car battery, but in the event that additional cooling is organized and the exhaust air is blown out from under the case. The fact is that in the UPS, not only the power transistors heat up, but also the transformer, which literally works at its limit. Therefore, it is highly desirable to take a cooler from a computer power supply, make a corresponding window in the case and adapt the cooler. The latter will blow warm exhaust air from under the body.

Don't forget that the uninterruptible power supply must also charge the car battery. They have for these purposes a separate charging unit with a current of about 1 Ampere. This is not enough for charging a car battery, but taking into account the fact that the battery will almost always be recharged, then the specified current will be enough. If you wish, you can make a separate charger in the UPS case.

A car converter (12-220) is a very useful thing, especially if you are going on a long journey. Powerful converters in stores are quite expensive, and not everyone can buy them, but many can do it themselves. An inverter can be made from an uninterruptible power supply, in other words from a UPS.

The UPS is an automatic electronic device with rechargeable battery... To convert an uninterruptible power supply into a converter, we need only a few parts - the simplest socket, crocodiles or a dad from a cigarette lighter, I bought all this for only 50 rubles.

Keep in mind that the inverter must have an independent start without 220 volts, this is necessary to start the inverter from the battery.

Let's move on to manufacturing, for this you first need to connect the outlet to the rear outlet on the UPS.

To do this, we prepare the filling of the socket, drill special holes for wires and sockets on the body, and install the socket.

Next, we solder the contacts of the old battery, and instead of them we connect the cigarette lighter wires. Uninterruptible power supplies are designed to operate on a battery from 15 to 20 minutes, and we intend to use it for a longer time, for this we need a cooling system.

We drill holes on the case for the cooler and for the decorative grille. We insert the cooler in the same way as in computer power supplies, that is, so that hot air is blown out of the case.