If the task is to connect a device powered by a conventional 12 volt battery to the truck's electrical network with a voltage of 24v.
There are two ways.
The best thing is to power such devices through a special converter. The voltage at the input of the device, in one way or another, decreases and at the output we get the desired 12v.
This method has its drawbacks:
1. The simplest step-down converters are characterized by huge losses in the form of heat. So, for example, when the radio consumes 10W of power, exactly the same amount (10W) will be lost in the converter. His body will start to heat up. If you turn on a 250W kettle at the output of the converter, then the converter will also heat up at exactly the same power. In total, by turning on the kettle through such a converter, the load on the batteries will be the sum of these values, i.e. 500W! So that the converter does not overheat and burn out, its case is made in the form of a powerful radiator.
2. If the converter does not have a protection circuit, then in the event of an accidental short circuit of the device output, a thermal breakdown of the power elements may occur and the input voltage will be applied to the output, i.e. all 24v. Naturally, in such an accident, it is almost guaranteed that all devices connected to the converter (walkie-talkie, radio, etc.) will fail.
From the above, it is clear that the converter must have enough power to power all your devices, be foolproof and accident-proof, and be as economical as possible.
All these requirements are met by converters made according to a special scheme. They are called so, PULSE converters. These devices have appeared quite recently, thanks to new technologies for the production of a number of components. More and more of them appear on the market, and the price decreases every day.
When choosing a converter, you should estimate the power consumed by the expected load.
For example: Kettle 250W + Radio 20W + Radio 50W
We get the maximum power consumption = 320W.
Now you need to find out what current consumption these devices have, turned on simultaneously and to the fullest. To do this, we divide the power by the supply voltage of these devices and get 320/12=26.67Amperes
This means that the converter that we must buy to power these devices must provide a rated output current of at least 26A.

The second way is NOT to go is to connect your 12 volt devices directly to the battery by removing 12 volts from the middle of the battery.

At first glance, everything is great and simple. But this is just an illusion. Irreversible processes begin in the battery, which will quickly disable it.
Let's look at the drawing. As a load, to make it more understandable and spectacular, we take a heating "goat" with a power of 1.2 kilowatts at 12v. In this case, the current in the power supply circuit will be 100 amperes. The engine is off and the alternator is not charging.

As can be seen from the figure, a huge current will flow through b1, discharging the battery and heating the heater. The path of this current is highlighted in orange. In this case, for both batteries, nothing dangerous happens. One simply gives its energy to the load (heating goat), while the voltage on it drops quickly, and the other, b2, is not connected to anything at all and remains charged. The voltage at its terminals will not change.
Now change the situation and start the engine.
From this moment on, unacceptable conditions begin for the battery, which will quickly disable it. See for yourself how you kill her!

Part b1 is discharged, the voltage on it is minimal, the charge current is eaten by the "goat" connected in parallel with it. She is slowly but surely dying.
Part b2 is fully charged. Since she now works both for her friend (b1) and for that guy (goat), the voltage and charging current on her are much higher than the allowable one (highlighted in blue). Reloading starts. There is a lot of gas production. The electrolyte decomposes and bubbles of oxygen and hydrogen rise to the surface, forming explosive gas in the jars. Half an hour of such extreme sports and ... The b2 battery simply shatters into smithereens, piercing with pieces of torn plastic and burning with acid everything that it has time to get into.
Doubt? Try it!
I specially modeled such an example so that the physics of the processes occurring in the battery would be clear to the most obtuse. Naturally, when the middle point of the battery is turned on to a low-power load (walkie-talkie, radio tape recorder), there can be no talk of any explosions, since the electrolyte decomposition procedure will stretch over time. However, this process is inevitable and the battery will fail in the very near future.

This voltage converter is perfect for turning on a computer fan from 24 V when the standard rotation speed from 12 volts is not enough. The proposed circuit discussed below is borrowed to power the UV lamp in one of the scanners.

The main component of the design is a transformer on a ferrite core with a diameter of 30 mm. If you take an armored ferrite magnetic core in its design, then the circuit will work much better. An armored ferrite magnetic circuit can be taken from an old personal computer power supply, or in a burned-out fluorescent lamp circuit.



You will have to spend quite a bit of copper wire on the core, and the turns can be wound with a fairly thin wire. The primary winding consists of only four turns, the two secondary windings are wound with 13 turns each. The primary winding is laid in the opposite direction to the secondary windings. The beginning of the first one secondary winding is connected to the end of the second. In the diagram, dots near the "spirals" show the beginning of the windings.

Since, for our tasks, the output current does not exceed 500 mA, then bipolar transistors of the type can be used: 2N3904, 2N4401, PN2222, MPS2222, C945, NTE123AP. If you need more output current, then you need to take more powerful transistors, for example D965, (They can be borrowed from the flash of an old camera). If the output needs a current above 5 A, then you should use power switches on composite transistors, say TIP120 or TIP3055. But in this case, the diodes used in the circuit must be designed for a flowing current of more than 10 A, and the keys themselves are recommended to be placed on cooling radiators.

Diodes in the usual version will fit any, the main thing is that they can be locked with reverse current polarity in 35 nanoseconds or faster. You can take diodes 1N914 and 1N4148, but keep in mind they are designed for direct current not higher than 4 A. When connecting to a low-resistance load converter, you should use SUF30J, UF510, UF540 rectifiers, which are capable of operating at high currents of 15 - 20 A.

We choose any capacitors with an insulating lining. Capacitances of 100 pF and 470 pF are used for high-frequency filtering. The capacitor at the output of the circuit, with a capacitance rating of 1.5 microfarads, is electrolytic. The capacitance voltage should be chosen twice as high as the operating voltage in the circuit.

Needed at a nominal value of about 1 mH. There are a lot of such coils ready-made in various radio equipment.

Resistors are taken with a small margin of power. Optimally for this design, resistances of 0.5 W are suitable.

This DC-DC converter is suitable for those who do not care about high output current. Because in this version on, the output is only 50 mA.

When you need to connect standard automotive electronics to a 24V vehicle, you need to know how to choose a 24-12 voltage converter to buy a device that can solve your problems.

If we consider various electrical and electronic devices precisely by their supply voltage, we can find several standardized voltages for which these devices were developed. The first and most popular is, of course, the supply voltage of a standard power supply, which we get in a regular outlet. The second is the voltage of the car's on-board network, which is 12 V. It is for these two supply voltages that the most number of devices and devices are produced.
Moreover, products that can run on a conventional car battery can be classified as mobile, which you can always take with you on the road and use to create comfort. In addition, a lot of modern electronic gadgets have standard adapters for power and charging from the on-board network, and the number of different devices for a car is very large. However, today you can find many models of vehicles, as a rule, these are trucks or special equipment, on which a network connected to two series-connected batteries is used to power on-board electronics and electrical devices and the voltage in its network is 24 V.
Of course, this gives certain advantages in the operation of such equipment, but it deprives the driver who controls it of many opportunities associated with the use of familiar automotive electronics and other electrical appliances powered by a standard voltage of 12 V. Of course, a way out can be found, for example, by connecting a tap from one battery to a separate cigarette lighter, however, this solution:

  • Requires intervention in the existing power supply system of the car, and this may simply be prohibited by its owner;
  • Leads to a decrease in the safety of vehicle operation;
  • It causes a faster discharge of one battery, as a result - a decrease in the service life of both batteries.

In any case, being able to connect directly to the standard supply voltage in such a car, you degrade its performance. This will not happen if you use a modern, efficient solution that will allow you to power any devices designed to operate from 12 V from an on-board network, the voltage of which is 24 V. This can be done using a compact electronic converter that can be bought on the market today .

What you need to know when choosing a converter from 24 to 12 V

Answering the question how to choose a 24-12 converter, we can say that only one of its parameters is key for you - the rated conversion power, which determines what load you can connect to it. However, the market for such devices offers both domestic and imported products that differ in their performance characteristics, so it is desirable that your converter from 24 Volts to 12 Volts provides protection against:

  • input voltage reversal;
  • prolonged excess of the rated power;
  • overheating and short circuit in the load circuit.

The presence of these functions allows you to protect the device from user errors and damaged devices, which can lead to the failure of the voltage converter.
You should also pay attention when comparing such indicators as the level of the output signal ripple and tolerances, they can cause interference in the operation of, for example, a car stereo.

IA "". When using the material, a hyperlink is required.

We also recommend