Under normal operating conditions, the vehicle's electrical system is self-sufficient. We are talking about energy supply - a combination of a generator, a voltage regulator, and a battery works synchronously and ensures uninterrupted power supply to all systems.
This is in theory. In practice, car owners make amendments to this harmonious system. Or the equipment refuses to work in accordance with the established parameters.
For example:
- Operating a battery that has exhausted its service life. The battery does not hold a charge
- Irregular trips. Prolonged downtime of the car (especially during hibernation) leads to self-discharge of the battery
- The car is used for short trips, with frequent stopping and starting of the engine. The battery simply does not have time to recharge
- Connecting additional equipment increases the load on the battery. Often leads to increased self-discharge current when the engine is turned off
- Extremely low temperature accelerates self-discharge
- A faulty fuel system leads to increased load: the car does not start immediately, you have to turn the starter for a long time
- A faulty generator or voltage regulator prevents the battery from charging properly. This problem includes worn power wires and poor contact in the charging circuit.
- And finally, you forgot to turn off the headlights, lights or music in the car. To completely discharge the battery overnight in the garage, sometimes it is enough to close the door loosely. Interior lighting consumes quite a lot of energy.
Any of the following reasons leads to an unpleasant situation: you need to drive, but the battery is unable to crank the starter. The problem is solved by external recharge: that is, a charger.
The tab contains four proven and reliable car charger circuits from simple to the most complex. Choose any one and it will work.
A simple 12V charger circuit.
Charger with adjustable charging current.
Adjustment from 0 to 10A is carried out by changing the opening delay of the SCR. 
Circuit diagram of a battery charger with self-shutdown after charging.
For charging batteries with a capacity of 45 amps.
Scheme of a smart charger that will warn about incorrect connection. 
It is absolutely easy to assemble it with your own hands. An example of a charger made from an uninterruptible power supply.
The vehicle's on-board network is powered by the battery until the power plant starts. But it itself does not generate electrical energy. The battery is simply a container for electricity, which is stored in it and, if necessary, given to consumers. Afterwards, the expended energy is restored due to the operation of the generator, which produces it.
But even constant recharging of the battery from a generator is not able to completely restore the expended energy. This requires periodic charging from an external source rather than a generator.
Design and principle of operation of the charger
Chargers are used to produce. These devices operate from a 220 V network. In fact, the charger is a conventional electrical energy converter.
It takes the alternating current of the 220 V network, lowers it and converts it into direct current with a voltage of up to 14 V, that is, to the voltage that the battery itself produces.
Nowadays a large number of all kinds of chargers are produced - from primitive and simple ones to devices with a large number of various additional functions.
Chargers are also sold, which, in addition to possibly recharging the battery installed on the car, can also start the power plant. Such devices are called charging and starting devices.
There are also autonomous charging and starting devices that can recharge the battery or start the engine without connecting the device itself to a 220 V network. Inside such a device, in addition to equipment that converts electrical energy, there is also one, which makes such a device autonomous, although the battery of the device is also After each release of electricity, charging is required.
Video: How to make a simple charger
As for conventional chargers, the simplest of them consists of only a few elements. The main element of such a device is a step-down transformer. It lowers the voltage from 220 V to 13.8 V, which is the most optimal for charging the battery. However, the transformer only lowers the voltage, but converting it from alternating current to direct current is performed by another element of the device - a diode bridge, which rectifies the current and divides it into positive and negative poles.
Behind the diode bridge, an ammeter is usually included in the circuit, which shows the current strength. The simplest device uses a dial ammeter. In more expensive devices, it can be digital; in addition to the ammeter, a voltmeter can also be built-in. Some chargers have the ability to select voltage; for example, they can charge both 12-volt and 6-volt batteries.
Wires with “positive” and “negative” terminals come out of the diode bridge, which connect the device to the battery.
All this is enclosed in a housing, from which comes a wire with a plug for connecting to the network, and wires with terminals. To protect the entire circuit from possible damage, a fuse is included in it.
In general, this is the entire circuit of a simple charger. Charging the battery is relatively simple. The terminals of the device are connected to the discharged battery, but it is important not to mix up the poles. The device is then connected to the network.
At the very beginning of charging, the device will supply voltage with a current of 6-8 amperes, but as charging progresses, the current will decrease. All this will be displayed on the ammeter. If the battery is fully charged, the ammeter needle will drop to zero. This is the entire process of charging the battery.
The simplicity of the charger circuit makes it possible to manufacture it yourself.
Making your own car charger
Now let's look at the simplest chargers that you can make yourself. The first will be a device that is very similar in concept to the one described.
The diagram shows:
S1 - power switch (toggle switch);
FU1 - 1A fuse;
T1 - transformer TN44;
D1-D4 - diodes D242;
C1 - capacitor 4000 uF, 25 V;
A - 10A ammeter.
So, to make a homemade charger you will need a step-down transformer TS-180-2. Such transformers were used on old tube TVs. Its feature is the presence of two primary and secondary windings. Moreover, each of the secondary output windings has 6.4 V and 4.7 A. Therefore, in order to achieve the 12.8 V required for charging the battery, which this transformer is capable of, you need to connect these windings in series. For this, a short wire with a cross-section of at least 2.5 mm is used. sq. The jumper connects not only the secondary windings, but also the primary ones.
Video: The simplest battery charger
Next, you will need a diode bridge. To create it, 4 diodes are taken, designed for a current of at least 10 A. These diodes can be fixed on a textolite plate, and then they can be connected correctly. Wires are connected to the output diodes, which the device will connect to the battery. At this point, the assembly of the device can be considered complete.
Now about the correctness of the charging process. When connecting a device to a battery, do not reverse the polarity, otherwise you can damage both the battery and the device.
When connecting to a battery, the device must be completely de-energized. You can turn it on only after connecting it to the battery. It should also be disconnected from the battery after disconnecting from the network.
A heavily discharged battery cannot be connected to the device without a means that reduces the voltage and current, otherwise the device will supply a high current to the battery, which can damage the battery. An ordinary 12-volt lamp, which is connected to the output terminals in front of the battery, can act as a reducing agent. The lamp will light up when the device is operating, thereby partially absorbing the voltage and current. Over time, after the battery is partially charged, the lamp can be removed from the circuit.
When charging, you need to periodically check the state of charge of the battery, for which you can use a multimeter, voltmeter or load plug.
A fully charged battery, when checking its voltage, should show at least 12.8 V; if the value is lower, further charging is required to bring this indicator to the desired level.
Video: DIY car battery charger
Since this circuit does not have a protective housing, you should not leave the device unattended during operation.
And even if this device does not provide the optimal 13.8 V output, it is quite suitable for recharging the battery, although after about two years of using the battery, you will still need to charge it with a factory device that provides all the optimal parameters for charging the battery.
Transformerless charger
An interesting design is the circuit of a homemade device that does not have a transformer. Its role in this device is played by a set of capacitors designed for a voltage of 250 V. There must be at least 4 such capacitors. The capacitors themselves are connected in parallel.
A resistor is connected in parallel to the set of capacitors, designed to suppress the residual voltage after disconnecting the device from the network.
Next, you will need a diode bridge to operate with a permissible current of at least 6 A. It is connected to the circuit after a set of capacitors. And then the wires that will connect the device to the battery are connected to it.
We have repeatedly talked about all kinds of chargers for car batteries on a pulse basis, and today is no exception. And we will consider the design of an SMPS, which can have an output power of 350-600 watts, but this is not the limit, since the power, if desired, can be increased to 1300-1500 watts, therefore, on such a basis it is possible to build a starting-charger device, because at a voltage of 12 -14 Volts from a 1500 watt unit can draw up to 120 Amperes of current! well of course
The design attracted my attention a month ago, when an article caught my eye on one of the sites. The power regulator circuit seemed quite simple, so I decided to use this circuit for my design, which is very simple and does not require any adjustment. The circuit is designed for charging powerful acid batteries with a capacity of 40-100A/h, implemented on a pulse basis. The main power part of our charger is a mains switching power supply with power
Just recently I decided to make several chargers for car batteries, which I was going to sell on the local market. There were quite beautiful industrial buildings available; all you had to do was make a good filling and that was it. But then I encountered a number of problems, starting from the power supply and ending with the output voltage control unit. I went and bought a good old electronic transformer like Tashibra (Chinese brand) for 105 watts and started reworking it.
A fairly simple automatic charger can be implemented on the LM317 chip, which is a linear voltage regulator with an adjustable output voltage. The microcircuit can also work as a current stabilizer.
A high-quality charger for a car battery can be purchased on the market for $50, and today I will tell you the easiest way to make such a charger with minimal expenditure of money; it is simple and even a novice radio amateur can make it.
The design of a simple charger for car batteries can be implemented in half an hour at minimal cost; the process of assembling such a charger will be described below.
The article discusses a charger (charger) with a simple circuit design for batteries of various classes intended to power the electrical networks of cars, motorcycles, flashlights, etc. The charger is easy to use, does not require adjustments while charging the battery, is not afraid of short circuits, and is simple and cheap to manufacture.
Recently, I came across a diagram of a powerful charger for car batteries with a current of up to 20A on the Internet. In fact, this is a powerful regulated power supply assembled with just two transistors. The main advantage of the circuit is the minimum number of components used, but the components themselves are quite expensive, we are talking about transistors.
Naturally, everyone in the car has cigarette lighter chargers for all kinds of devices: navigator, phone, etc. The cigarette lighter is naturally not without dimensions, and especially since there is only one (or rather, a cigarette lighter socket), and if there is also a person who smokes, then the cigarette lighter itself must be taken out somewhere and put somewhere, and if you really need to connect something to the charger, then using the cigarette lighter for its intended purpose is simply impossible , you can solve the connection of all kinds of tees with a socket like a cigarette lighter, but it’s like that
Recently I came up with the idea of assembling a car charger based on cheap Chinese power supplies with a price of $5-10. In electronics stores you can now find units that are designed to power LED strips. Since such tapes are powered by 12 Volts, therefore the output voltage of the power supply is also within 12 Volts
I present the design of a simple DC-DC converter that will allow you to charge a mobile phone, tablet computer or any other portable device from a 12-volt car on-board network. The heart of the circuit is a specialized 34063api chip designed specifically for such purposes.
After the article charger from an electronic transformer, many letters were sent to my email address asking me to explain and tell how to power up the circuit of an electronic transformer, and in order not to write to each user separately, I decided to print this article, where I will talk about the main components that need will be modified to increase the output power of the electronic transformer.
The article will tell you how to make a homemade one with your own hands. You can use absolutely any circuits, but the simplest manufacturing option is to remake a computer power supply. If you have such a block, it will be quite easy to find a use for it. To power motherboards, voltages of 5, 3.3, 12 Volts are used. As you understand, the voltage of interest to you is 12 Volts. The charger will allow you to charge batteries whose capacity ranges from 55 to 65 Ampere-hours. In other words, it is enough to recharge the batteries of most cars.
General view of the diagram
To make the alteration, you need to use the diagram presented in the article. made with your own hands from the power supply of a personal computer, allows you to control the charging current and voltage at the output. It is necessary to pay attention to the fact that there is protection against short circuit - a 10 Ampere fuse. But it is not necessary to install it, since most power supplies of personal computers have protection that turns off the device in the event of a short circuit. Therefore, charger circuits for batteries from computer power supplies are able to protect themselves from short circuits.
The PSI controller (designated DA1), as a rule, is used in the power supply of two types - KA7500 or TL494. Now a little theory. Can a computer's power supply properly charge the battery? The answer is yes, since lead batteries in most cars have a capacity of 55-65 Ampere-hour. And for normal charging it needs a current equal to 10% of the battery capacity - no more than 6.5 Amperes. If the power supply has a power of over 150 W, then its “+12 V” circuit is capable of delivering such current.
Initial stage of remodeling
To replicate a simple homemade battery charger, you need to slightly improve the power supply:
- Get rid of all unnecessary wires. Use a soldering iron to remove them so as not to interfere.
- Using the diagram given in the article, find a constant resistor R1, which must be unsoldered and in its place install a trimmer with a resistance of 27 kOhm. A constant voltage of “+12 V” must subsequently be applied to the upper contact of this resistor. Without this, the device will not be able to operate.
- The 16th pin of the microcircuit is disconnected from the minus.
- Next, you need to disconnect the 15th and 14th pins.
It turns out to be quite simple and homemade. You can use any circuits, but it’s easier to make it from a computer power supply - it’s lighter, easier to use, and more affordable. When compared with transformer devices, the mass of the devices differs significantly (as do the dimensions).
Charger adjustments
The back wall will now be the front; it is advisable to make it from a piece of material (textolite is ideal). On this wall it is necessary to install a charging current regulator, indicated in the diagram R10. It is best to use a current-sensing resistor as powerful as possible - take two with a power of 5 W and a resistance of 0.2 Ohm. But it all depends on the choice of battery charger circuit. Some designs do not require the use of high-power resistors.
When connecting them in parallel, the power is doubled, and the resistance becomes equal to 0.1 Ohm. On the front wall there are also indicators - a voltmeter and an ammeter, which allow you to monitor the relevant parameters of the charger. To fine-tune the charger, a trimming resistor is used, with which voltage is supplied to the 1st pin of the PHI controller.
Device requirements
Final assembly
Multi-core thin wires must be soldered to pins 1, 14, 15 and 16. Their insulation must be reliable so that heating does not occur under load, otherwise the homemade car charger will fail. After assembly, you need to set the voltage with a trimming resistor to about 14 Volts (+/-0.2 V). This is the voltage that is considered normal for charging batteries. Moreover, this value should be in idle mode (without a connected load).
You must install two alligator clips on the wires that connect to the battery. One is red, the other is black. These can be purchased at any hardware or auto parts store. This is how you get a simple homemade charger for a car battery. Connection diagrams: black is attached to the minus, and red to the plus. The charging process is completely automatic, no human intervention is required. But it is worth considering the main stages of this process.
Battery charging process
During the initial cycle, the voltmeter will show a voltage of approximately 12.4-12.5 V. If the battery has a capacity of 55 Ah, then you need to rotate the regulator until the ammeter shows a value of 5.5 Amperes. This means that the charging current is 5.5 A. As the battery charges, the current decreases and the voltage tends to a maximum. As a result, at the very end the current will be 0 and the voltage will be 14 V.
Regardless of the selection of circuits and designs of chargers used for manufacturing, the operating principle is largely similar. When the battery is fully charged, the device begins to compensate for the self-discharge current. Therefore, you do not risk the battery overcharging. Therefore, the charger can be connected to the battery for a day, a week, or even a month.
If you don’t have measuring instruments that you wouldn’t mind installing in the device, you can refuse them. But for this it is necessary to make a scale for the potentiometer - to indicate the position for the charging current values of 5.5 A and 6.5 A. Of course, the installed ammeter is much more convenient - you can visually observe the process of charging the battery. But a battery charger, made with your own hands without the use of equipment, can be easily used.
Every motorist sooner or later has problems with the battery. I did not escape this fate either. After 10 minutes of unsuccessful attempts to start my car, I decided that I needed to purchase or make my own charger. In the evening, after checking out the garage and finding a suitable transformer there, I decided to do the charging myself.
There, among the unnecessary junk, I also found a voltage stabilizer from an old TV, which, in my opinion, would work wonderfully as a housing.
Having scoured the vast expanses of the Internet and really assessed my strengths, I probably chose the simplest scheme.
After printing out the diagram, I went to a neighbor who is interested in radio electronics. Within 15 minutes, he collected the necessary parts for me, cut off a piece of foil PCB and gave me a marker for drawing circuit boards. After spending about an hour, I drew an acceptable board (the dimensions of the case allow for spacious installation). I won’t tell you how to etch the board, there is a lot of information about this. I took my creation to my neighbor, and he etched it for me. In principle, you could buy a circuit board and do everything on it, but as they say to a gift horse...
Having drilled all the necessary holes and displayed the pinout of the transistors on the monitor screen, I took up the soldering iron and after about an hour I had a finished board.
A diode bridge can be bought on the market, the main thing is that it is designed for a current of at least 10 amperes. I found D 242 diodes, their characteristics are quite suitable, and I soldered a diode bridge on a piece of PCB.
The thyristor must be installed on a radiator, since it gets noticeably hot during operation.
Separately, I must say about the ammeter. I had to buy it in a store, where the sales consultant also picked up the shunt. I decided to modify the circuit a little and add a switch so that I could measure the voltage on the battery. Here, too, a shunt was needed, but when measuring voltage, it is connected not in parallel, but in series. The calculation formula can be found on the Internet; I would add that the dissipation power of the shunt resistors is of great importance. According to my calculations, it should have been 2.25 watts, but my 4-watt shunt was heating up. The reason is unknown to me, I don’t have enough experience in such matters, but having decided that I mainly needed the readings of an ammeter, and not a voltmeter, I decided on it. Moreover, in voltmeter mode the shunt noticeably warmed up within 30-40 seconds. So, having collected everything I needed and checked everything on the stool, I took up the body. Having completely disassembled the stabilizer, I took out all its contents.
Having marked the front wall, I drilled holes for the variable resistor and switch, then with a small diameter drill around the circumference I drilled holes for the ammeter. Sharp edges were finished with a file.
After racking my brains a bit over the location of the transformer and radiator with thyristor, I settled on this option.
I bought a couple more crocodile clips and everything is ready to charge. The peculiarity of this circuit is that it only works under load, so after assembling the device and not finding voltage at the terminals with a voltmeter, do not rush to scold me. Just hang at least a car light bulb on the terminals, and you will be happy.
Take a transformer with a voltage on the secondary winding of 20-24 volts. Zener diode D 814. All other elements are indicated in the diagram.