Charger connection diagram. We make our own car battery chargers. Types of chargers

In order for a car to start, it needs energy. This energy is taken from the battery. As a rule, its recharging occurs from the generator while the engine is running. When the car is not used for a long time or the battery is defective, it discharges to such a state that that the car can no longer start. In this case, external charging is required. You can buy such a device or assemble it yourself, but this will require a charger circuit.

The principle of operation of a car battery

The car battery supplies power to various devices in the car when the engine is off and is designed to start it. By type of execution, a lead-acid battery is used. Structurally, it is assembled from six batteries with a nominal voltage value of 2.2 volts, connected in series. Each element is a set of lattice plates made of lead. The plates are coated with an active material and immersed in an electrolyte.

The electrolyte solution contains distilled water and sulfuric acid. The frost resistance of the battery depends on the density of the electrolyte. Recently, technologies have appeared that make it possible to adsorb the electrolyte in a glass fiber or thicken it using silica gel to a gel-like state.

Each plate has a negative and a positive pole, and they are isolated from each other using a plastic separator. The body of the product is made of propylene, which is not destroyed by acid and serves as a dielectric. The positive pole of the electrode is coated with lead dioxide, and the negative with spongy lead. Recently, batteries with electrodes made of lead-calcium alloy have been produced. These batteries are completely sealed and require no maintenance.

When a load is connected to the battery, the active material on the plates reacts chemically with the electrolyte solution, and an electric current is generated. The electrolyte depletes over time due to the deposition of lead sulfate on the plates. The battery (battery) begins to lose charge. During charging, a chemical reaction occurs in the reverse order, lead sulfate and water are converted, the density of the electrolyte increases and the charge value is restored.

Batteries are characterized by a self-discharge value. It occurs in the battery when it is inactive. The main reason is the contamination of the surface of the battery and the poor quality of the distiller. The rate of self-discharge is accelerated by the destruction of lead plates.

Types of chargers

A large number of car charger circuits have been developed using different element bases and a principled approach. According to the principle of operation, charge devices are divided into two groups:

1. Starting and charging, designed to start the engine when the battery is not working. By briefly applying a large current to the battery terminals, the starter is turned on and the engine starts, and later the battery is charged from the car's generator. They are produced only for a certain current value or with the possibility of setting its value.
2. Pre-start chargers, terminals from the device are connected to the battery terminals and current is supplied for a long time. Its value does not exceed ten amperes, during this time the battery energy is restored. In turn, they are divided into: gradual (charging time from 14 to 24 hours), accelerated (up to three hours) and conditioning (about an hour).

According to their circuitry, pulse and transformer devices are distinguished. The first type is used in the work of a high-frequency signal converter, characterized by small size and weight. The second type is used as a basis for a transformer with a rectifier unit, easy to manufacture, but have a lot of weight and low coefficient of performance (COP).

A do-it-yourself charger for car batteries was made or purchased at a retail outlet, the requirements for it are the same, namely:

• output voltage stability;
• high value of efficiency;
• short circuit protection;
• charge control indicator.

One of the main characteristics of the charge device is the amount of current that charges the battery. It will be possible to properly charge the battery and extend its performance only when selecting its desired value. In this case, the charging speed is also important. The higher the current, the higher the speed, but a high speed value leads to rapid degradation of the battery. It is believed that the correct current value will be a value equal to ten percent of the battery capacity. Capacity is defined as the amount of current given off by the battery per unit of time, it is measured in ampere-hours.

Homemade charger

Every motorist should have a charging device, so if there is no opportunity or desire to purchase a ready-made device, there is nothing left but to charge the battery yourself. It is easy to make with your own hands both the simplest and the multifunctional device. This will require a diagram. and a set of radio elements. It is also possible to convert an uninterruptible power supply (UPS) or a computer unit (AT) into a device for recharging the battery.

Transformer charger

Such a device is the easiest to assemble and does not contain scarce parts. The scheme consists of three nodes:

• transformer;
• rectifier block;
• regulator.

Voltage from the industrial network is supplied to the primary winding of the transformer. The transformer itself can be used of any kind. It consists of two parts: core and windings. The core is assembled from steel or ferrite, the windings are made from conductive material.

The principle of operation of the transformer is based on the appearance of an alternating magnetic field when current passes through the primary winding and transfers it to the secondary. To obtain the required voltage level at the output, the number of turns in the secondary winding is made less than in the primary. The voltage level on the secondary winding of the transformer is chosen to be 19 volts, and its power should provide a threefold reserve for the charge current.

From the transformer, the reduced voltage passes through the rectifier bridge and enters the rheostat connected in series to the battery. The rheostat is designed to regulate the magnitude of voltage and current by changing the resistance. The resistance of the rheostat does not exceed 10 ohms. The current value is controlled by an ammeter connected in series in front of the battery. Such a scheme will not be able to charge batteries with a capacity of more than 50 Ah, since the rheostat starts to overheat.

You can simplify the circuit by removing the rheostat, and install a set of capacitors at the input in front of the transformer, which are used as reactances to reduce the mains voltage. The smaller the nominal value of the capacitance, the less voltage is supplied to the primary winding in the network.

The peculiarity of such a scheme is the need to ensure the signal level on the secondary winding of the transformer is one and a half times greater than the operating voltage of the load. Such a circuit can be used without a transformer, but it is very dangerous. Without galvanic isolation, you can get an electric shock.

Pulse charger

The advantage of pulsed devices is high efficiency and compact size. The device is based on a chip with pulse width modulation (PWM). You can assemble a powerful pulse charger with your own hands according to the following scheme.

The IR2153 driver is used as a PWM controller. After the rectifier diodes, a polar capacitor C1 is placed in parallel with the battery with a capacitance in the range of 47–470 microfarads and a voltage of at least 350 volts. The capacitor removes mains voltage spikes and line noise. The diode bridge is used with a rated current of more than four amperes and with a reverse voltage of at least 400 volts. The driver controls powerful N-channel IRFI840GLC field-effect transistors mounted on heatsinks. The current of such a charge will be up to 50 amperes, and the output power will be up to 600 watts.

You can make a pulse charger for a car with your own hands using a converted AT format computer power supply. They use the common TL494 chip as a PWM controller. The alteration itself consists in increasing the output signal to 14 volts. To do this, you need to correctly install the tuning resistor.

The resistor that connects the first leg of the TL494 to the stabilized + 5 V bus is removed, and a variable resistor with a nominal value of 68 kOhm is soldered in place of the second one connected to the 12 volt bus. This resistor sets the desired output voltage level. The power supply is switched on through a mechanical switch, according to the diagram indicated on the power supply housing.

Device on the LM317 chip

A fairly simple but stable charging circuit is easily implemented on the LM317 integrated circuit. The microcircuit provides a signal level setting of 13.6 volts at a maximum current strength of 3 amperes. The LM317 stabilizer is equipped with built-in short circuit protection.

Voltage is supplied to the device circuit through the terminals from an independent power supply unit with a constant voltage of 13–20 volts. The current, passing through the indicator LED HL1 and the transistor VT1, is supplied to the LM317 stabilizer. From its output directly to the battery through X3, X4. The divider, assembled on R3 and R4, sets the required voltage value for opening VT1. The variable resistor R4 sets the charging current limit, and R5 the output signal level. The output voltage is set from 13.6 to 14 volts.

The scheme can be simplified as much as possible, but its reliability will decrease.

In it, the resistor R2 selects the current. A powerful nichrome wire element is used as a resistor. When the battery is discharged, the charge current is maximum, the VD2 LED lights up brightly, as the charge progresses, the current begins to decline and the LED dims.

Charger from an uninterruptible power supply

It is possible to construct a charger from a conventional uninterruptible power supply even with a malfunction of the electronics assembly. To do this, all electronics are removed from the unit, except for the transformer. A rectifier circuit, current stabilization and voltage limiting are added to the high-voltage winding of the 220 V transformer.

The rectifier is assembled on any powerful diodes, for example, domestic D-242 and a network capacitor 2200 uF at 35-50 volts. The output will be a signal with a voltage of 18-19 volts. As a voltage stabilizer, an LT1083 or LM317 chip is used with a mandatory installation on a radiator.

By connecting the battery, a voltage of 14.2 volts is set. It is convenient to control the signal level using a voltmeter and an ammeter. The voltmeter is connected in parallel with the battery terminals, and the ammeter in series. As the battery charges, its resistance will increase and the current will decrease. It is even easier to make a regulator with a triac connected to the primary winding of a transformer like a dimmer.

When making the device yourself, you should remember about electrical safety when working with a 220 V AC network. As a rule, a correctly made charging device from serviceable parts starts working immediately, you just need to set the charge current.

Sometimes it happens that the battery in the car sits down and it is no longer possible to start it, because the starter does not have enough voltage and, accordingly, current to turn the engine shaft. In this case, you can “light it up” from another car owner so that the engine starts and the battery starts charging from the generator, but this requires special wires and a person who wants to help you. You can also charge the battery yourself using a specialized charger, but they are quite expensive and you don’t have to use them very often. Therefore, in this article we will take a closer look at a homemade device, as well as instructions on how to make a charger for a car battery with your own hands.

Homemade device

Normal voltage on a battery disconnected from the vehicle is between 12.5V and 15V. Therefore, the charger must provide the same voltage. The charge current should be approximately 0.1 of the capacity, it may be less, but this will increase the charging time. For a standard battery with a capacity of 70-80 Ah, the current should be 5-10 amps, depending on the specific battery. Our homemade battery charger must meet these parameters. To assemble a charger for a car battery, we need the following items:

Transformer. We can use any of the old electrical appliances or those bought on the market with an overall power of about 150 watts, more, but not less, otherwise it will get very hot and may fail. Well, if the voltage of its output windings is 12.5-15 V, and the current is about 5-10 amperes. You can see these parameters in the documentation for your part. If there is no required secondary winding, then it will be necessary to rewind the transformer to a different output voltage. For this:

Thus, we have found or assembled the perfect transformer to make a DIY battery charger.

We will also need:

Having prepared all the materials, you can proceed to the very process of assembling a car memory.

Assembly technology

To make a charger for a car battery with your own hands, you must follow the step-by-step instructions:

1. We create a homemade charging scheme for the battery. In our case, it will look like this:
   
2. We use the transformer TS-180-2. It has several primary and secondary windings. To work with it, you need to connect two primary and two secondary windings in series to get the desired voltage and current at the output.
   
   
3. With the help of a copper wire, we connect pins 9 and 9 'to each other.
   
4. On a fiberglass plate we assemble a diode bridge from diodes and radiators (as shown in the photo).
   
5. Conclusions 10 and 10 'we connect to the diode bridge.
6. Install a jumper between pins 1 and 1'.
   
7. Using a soldering iron, we attach a power cord with a plug to terminals 2 and 2 '.
8. We connect a 0.5 A fuse to the primary circuit, a 10-amp fuse, respectively, to the secondary circuit.
9. In the gap between the diode bridge and the battery, we connect an ammeter and a piece of nichrome wire. We fix one end of which, and the second should provide a movable contact, thus the resistance will change and the current supplied to the battery will be limited.
10. We isolate all connections with heat shrink or electrical tape and place the device in the case. This is necessary to avoid electric shock.
11. We install a moving contact at the end of the wire so that its length and, accordingly, the resistance are maximum. And connect the battery. By decreasing and increasing the length of the wire, you need to set the desired current value for your battery (0.1 of its capacity).
12. In the process of charging, the current supplied to the battery will decrease by itself and when it reaches 1 ampere, we can say that the battery is charged. It is also desirable to directly control the voltage on the battery, however, for this it must be disconnected from the charger, since when charging it will be slightly higher than the actual values.

The first start of the assembled circuit of any power source or memory is always carried out through an incandescent lamp, if it lights up at full heat - either there is an error somewhere, or the primary winding is closed! An incandescent lamp is installed in the break of the phase or neutral wire that feeds the primary winding.

This scheme for a home-made battery charger has one big drawback - it does not know how to independently disconnect the battery from charging after reaching the desired voltage. Therefore, you will have to constantly monitor the readings of the voltmeter and ammeter. There is a design that does not have this drawback, but its assembly will require additional parts and more effort.

A good example of a finished product

Operating rules

The disadvantage of a homemade charger for a 12V battery is that after the battery is fully charged, the device does not automatically turn off. That is why you will have to periodically glance at the scoreboard in order to turn it off in time. Another important nuance is that it is strictly forbidden to check the memory “for a spark”.

Homemade battery chargers usually have a very simple design, and in addition to that, increased reliability just because of the simplicity of the circuit. Another plus from making charging with your own hands is the relative cheapness of components and, as a result, the low cost of the device.

Why prefabricated construction is better than purchased

The main task of such equipment is to maintain the charge of the car battery at the required level if necessary. If the battery discharge occurred near the house, where there is the right device, then there will be no problems. Otherwise, when there is no suitable equipment to power the battery, and there are not enough funds either, you can assemble the device yourself.

The need to use auxiliary means to recharge the car battery is primarily due to low temperatures in the cold season, when a half-discharged battery is the main, and sometimes not solvable problem, unless the battery is recharged in time. Then homemade chargers for powering car batteries will be a salvation for users who do not plan to invest in such equipment, at least at the moment.

Operating principle

Up to a certain level, the battery of a car can be powered from the vehicle itself, or more precisely, from an electric generator. After this node, a relay is usually installed, which is responsible for setting the voltage to no more than 14.1V. In order for the battery to be charged to the limit, a higher value of this parameter is required - 14.4V. Accordingly, batteries are used to implement such a task.

The main components of this device are a transformer and a rectifier. As a result, a direct current with a voltage of a certain value (14.4V) is supplied to the output. But why is there a run-up with the voltage of the battery itself - 12V? This is done in order to ensure the ability to charge a battery that is discharged to a level where the value of this battery parameter was equal to 12V. If charging is characterized by the same value parameter, then as a result, powering the battery will become a difficult task.

Watch the video, the simplest battery charger:

But there is a nuance here: a slight excess of the battery voltage level is not critical, while a significantly overestimated value of this parameter will have a very bad effect on the battery performance in the future. The principle of operation, which distinguishes any, even the simplest charger for powering a car battery, is to increase the resistance level, which will lead to a decrease in the charging current.

Accordingly, the higher the voltage value (tends to 12V), the lower the current. For normal battery operation, it is desirable to set a certain amount of charge current (about 10% of the capacity). In a hurry, it is tempting to change the value of this parameter to a higher one, however, this is fraught with negative consequences for the battery itself.

What is required to make a battery?

The main elements of a simple design: a diode and a heater. If you connect them correctly (in series) to the battery, you can achieve what you want - the battery will be charged in 10 hours. But for those who like to save electricity, such a solution may not be suitable, because in this case the consumption will be about 10 kW. The operation of the resulting device is characterized by low efficiency.

Basic elements of a simple design

But to create a suitable modification, it will be necessary to slightly modify individual elements, in particular, a transformer, the power of which should be at the level of 200-300 watts. If you have old technology, this part from a conventional tube TV will do. To organize the ventilation system, a cooler is useful, it is best if it is from a computer.

When a simple do-it-yourself battery charger is created, a transistor and a resistor also act as the main elements. To get the structure working, you will need a compact on the outside, but quite a roomy metal case, a good option is a box from the stabilizer.

In theory, even a novice radio amateur who has not previously encountered complex circuits can assemble this kind of equipment.

Diagram of a simple battery charger

The main difficulty lies in the need to modify the transformer. At this power level, the windings are characterized by low voltage indicators (6-7V), the current will be 10A. Usually, a voltage of 12V or 24V is required, depending on the battery type. To obtain such values ​​​​at the output of the device, it is necessary to ensure the parallel connection of the windings.

Staged assembly

A homemade charger for powering a car battery begins with the preparation of the core. The winding of the wire on the windings is carried out with maximum compaction, it is important that the turns fit snugly against each other, and there are no gaps left. We must not forget about the insulation, which is placed at intervals of 100 turns. The cross section of the wire of the primary winding is 0.5 mm, the secondary one is from 1.5 to 3.0 mm. Considering that at a frequency of 50 Hz, 4-5 turns can provide a voltage of 1V, respectively, to obtain 18V, about 90 turns are required.

Next, a diode of suitable power is selected to withstand the loads applied to it in the future. The best option is the generator diode of the car. To eliminate the risk of overheating, it is necessary to ensure effective air circulation inside the case of such a device. If the box is not perforated, care should be taken before assembly. The cooler must be connected to the output of the charger. Its main task is to cool the diode and the transformer winding, which is taken into account when choosing a site for installation.

Watch the video, detailed instructions for manufacturing:

The circuit of a simple charger for powering a car battery also contains a variable resistor. For the normal functioning of charging, it is necessary to obtain a resistance of 150 ohms and a power of 5 watts. More than others, the KU202N resistor model meets these requirements. You can choose a different option, but its parameters must be similar in value to those specified. The purpose of the resistor is to regulate the voltage at the output of the device. The KT819 transistor model is also the best option from a number of analogues.

Evaluation of efficiency, cost

As you can see, if you need to assemble a homemade car battery charger, its circuit is more than simple to implement. The only difficulty is the layout of all the elements and their installation in the case with subsequent connection. But such work can hardly be called laborious, and the cost of all parts used is extremely small.

Some of the details, and perhaps all of them, will most likely be found at home by a radio amateur, for example, a cooler from an old computer, a transformer from a tube TV, an old case from a stabilizer. As for the degree of efficiency, such self-assembled devices do not have a very high efficiency, however, as a result, they still cope with their task.

Watch the video, useful tips from a specialist:

Thus, large investments in the creation of home-made charging are not required. On the contrary, all the elements cost very little, which sets off this solution favorably in comparison with a device that can be purchased off the shelf. The scheme discussed above is not highly efficient, but its main plus is a charged car battery, albeit after 10 hours. You can improve this option or consider many others that are proposed for implementation.

There are cases, especially in winter, when car owners need to recharge the car battery from an external power source. Of course, people who do not have good skills in working with electrical engineering, it is advisable to buy a factory battery charger, it is even better to purchase a starter-charger to start the engine with a discharged battery without wasting time for external recharging.

But if you have a little knowledge in the field of electronics, you can assemble a simple charger do it yourself.

general characteristics

To properly maintain the battery and extend its service life, recharging is required when the voltage at the terminals drops below 11.2 V. At this voltage, the engine is likely to start, but if it is parked for a long time in winter, this will lead to sulfation of the plates and, as a result, to a decrease in capacity batteries. When parking for a long time in winter, it is necessary to regularly monitor the voltage at the battery terminals. It should be 12 V. It is best to remove the battery and bring it to a warm place, remembering to monitor charge level.

The battery is charged with direct or pulsed current. When using a constant voltage power supply, the current for proper charging should be one tenth of the battery capacity. If the battery capacity is 50 Ah, then a current of 5 amperes is required for charging.

To extend the life of the battery, methods of desulfation of battery plates are used. The battery is discharged to less than five volts by repeatedly drawing a large current of short duration. An example of such consumption is starting a starter. After that, a slow full charge is made with a small current within one ampere. Repeat the process 8-9 times. The desulfation method is long in time, but according to all studies it gives a good result.

It must be remembered that when charging it is important not to overcharge the battery. The charge is made up to a voltage of 12.7-13.3 volts and depends on the battery model. Maximum charge indicated in the documentation for the battery, which can always be found on the Internet.

Overcharging causes boiling, increases the density of the electrolyte and, as a consequence, the destruction of the plates. Factory charging devices have charge control and subsequent shutdown systems. Build your own systems, without having sufficient knowledge in electronics, it is quite difficult.

Do-it-yourself assembly schemes

It is worth talking about simple charging devices that can be assembled with minimal knowledge in electronics, and the charge capacity can be tracked by connecting a voltmeter or an ordinary tester.

Charging scheme for emergency cases

There are times when a car that has stood overnight near the house cannot be started in the morning due to a dead battery. There can be many reasons for this unfortunate circumstance.

If the battery was in good condition and slightly discharged, the following will help solve the problem:

Great as a power source laptop charger. It has an output voltage of 19 volts and a current of two amperes, which is quite enough to complete the task. On the output connector, as a rule, the internal input is positive, the external circuit of the plug is negative.

As a limiting resistance, which is mandatory, you can use a salon light bulb. Can be used more powerful lamps, for example, on the dimensions, but this will create an extra load on the power supply, which is very undesirable.

An elementary circuit is being assembled: the minus of the power supply is connected to the light bulb, the light bulb to the minus of the battery. Plus goes directly from the battery to the power supply. Within two hours, the battery will receive a charge to start the engine..

From the power supply from a desktop computer

Such a device is more difficult to manufacture, but it can be assembled with minimal knowledge of electronics. The basis will be an unnecessary block from the system unit of the computer. The output voltages of such blocks are +5 and +12 volts with an output current of about two amperes. These parameters allow you to assemble a weak charger, which, when properly assembled, will serve the owner for a long time and reliably. Fully charging the battery will take a long time and will depend on the capacity of the battery, but there will be no plate desulfation effect. So, step by step assembly of the device:

1. Disassemble the power supply and unsolder all wires except green. Remember or mark the input points of black (GND) and yellow +12 V.
2. Solder the green wire to the place where the black one was (this is necessary to start the unit without a PC motherboard). In place of the black wire, solder a tap, which will be negative for charging the battery. In place of the yellow wire, solder the positive battery charging lead.
3. You need to find a TL 494 chip or its equivalent. The list of analogues is easy to find on the Internet, one of them will definitely be found in the circuit. With all the variety of blocks, they are not produced without these microcircuits.
4. From the first leg of this microcircuit - it is the lower left one, find the resistor that goes to the +12 volt output (yellow wire). This can be done visually along the tracks in the diagram, you can use a tester by connecting the power and measuring the voltage at the input of the resistors going to the first leg. Do not forget that a voltage of 220 volts goes to the primary winding of the transformer, so safety measures must be observed when starting the unit without a case.
5. Solder the found resistor, measure its resistance with a tester. Choose a variable resistor that is close in value. Set it to the value of the required resistance and solder it in place of the removed circuit element with flexible wires.
6. Starting the power supply by adjusting the variable resistor, get a voltage of 14 V, ideally 14.3 V. The main thing is not to overdo it, remembering that 15 V is usually the limit for working out protection and, as a result, shutdown.
7. Solder a variable resistor without knocking down its setting, and measure the resulting resistance. Select the required or as close as possible resistance value or dial from several resistors and solder it into the circuit.
8. Check the unit, the output should be the desired voltage. If desired, a voltmeter can be connected to the outputs on the plus and minus circuit by placing it on the case for clarity. Subsequent assembly occurs in the reverse order. The device is ready for use.

The unit will perfectly replace the inexpensive factory charger and is quite reliable. But it is MANDATORY to remember that the device has overload protection, but this will not save you from a polarity error. Simply put, if you confuse plus and minus when connecting to a battery, the charger will fail instantly..

Charger circuit from an old transformer

If there is no old computer power supply at hand, and radio engineering experience allows you to independently mount simple circuits, then you can use the following rather interesting battery charging circuit with control and regulation of the supplied voltage.

To assemble the device, you can use transformers from old uninterruptible power supplies or Soviet-made TVs. Any powerful step-down transformer with a total set of voltages on the secondary windings of about 25 volts is suitable.

The diode rectifier is assembled on two KD 213A diodes (VD 1, VD 2), which must be installed on the radiator and can be replaced by any imported analogues. There are many analogues, and they are easily selected from reference books on the Internet. Surely the necessary diodes can be found at home in old unnecessary equipment.

The same method can be applied to replace the control transistor KT 827A (VT 1) and the zener diode D 814 A (VD 3). The transistor is mounted on a radiator.

Adjustment of the supplied voltage is carried out by a variable resistor R2. The scheme is simple and obviously working. It can be collected by a person with minimal knowledge of electronics.

Pulse charging for batteries

The circuit is difficult to assemble, but this is the only drawback. Finding a simple circuit for a pulsed charging unit is unlikely to succeed. This is offset by the pluses: such blocks almost do not heat up, while they have serious power and high efficiency, they are distinguished by their compact size. The proposed circuit, mounted on a board, fits into a container with a size of 160 * 50 * 40 mm. To assemble the device, it is necessary to understand the principle of operation of the PWM (Pulse Width Modulation) generator. In the proposed version, it is implemented using a common and inexpensive controller IR 2153.

With the applied capacitors, the power of the device is 190 watts. This is enough to charge any light car battery with a capacity of up to 100 Ah. By installing capacitors of 470 microfarads, the power will double. It will be possible to charge a battery with a capacity of up to two hundred ampere / hours.

When using devices without automatic battery charge control, you can use the simplest network, daily Chinese-made relay. This eliminates the need to monitor the time the unit is disconnected from the network.

The cost of such a device is about 200 rubles. Knowing the approximate charging time of your battery, you can set the desired shutdown time. This ensures that the power supply is interrupted in a timely manner. You can get distracted by business and forget about the battery, which can lead to boiling, destruction of the plates and battery failure. A new battery will cost much more.

Precautionary measures

When using self-assembled devices, the following safety precautions should be observed:

1. All appliances, including batteries, must be placed on a fireproof surface.
2. During the initial use of the manufactured device, it is necessary to ensure full control of all charging parameters. It is imperative to control the heating temperature of all charging elements and batteries, do not allow the electrolyte to boil. The voltage and current parameters are controlled by the tester. Primary control will help determine the time to fully charge the battery, which will come in handy in the future.

Assembling a battery charger is easy even for a beginner. The main thing is to do everything carefully and observe safety measures, because you will have to deal with an open voltage of 220 volts.

It is difficult to overestimate a high-quality car battery. However, over time, it becomes less capacious and is able to discharge faster. This process is influenced by other factors related to operating conditions. In order not to get into a difficult situation, it is worth having a simple do-it-yourself charger at home or in the garage.

In most cases, the concept of a homemade charger will be relatively simple. It will be possible to assemble such a device from improvised inexpensive components. At the same time, the electric unit will help to quickly start the passenger car. It is preferable to get start-charging equipment, but it requires a little more power from the elements used.

It is necessary to use electric recharge for the battery in situations where the measurement at the terminals of the electrical appliance shows a level below 11.2 V for most passenger cars. Although the engine is able to start at this voltage level, unwanted chemical processes begin inside. Sulfation and destruction of the plates occurs. The capacity is markedly reduced.

It is important to know that during a long winter or parking a car for several weeks, the charge level drops, so it is recommended to control this value with a multimeter, and, if necessary, use a self-made charger for car batteries or bought in a car shop.

Two types of devices are most often used to recharge the battery:

• issuing on the "crocodiles" voltage of a constant type;
• systems with a pulse type of work.

When charging from a DC device, the value of the charge current is selected arithmetically corresponding to 1/10 of the capacitance value set by the manufacturer. When a 60Ah battery is available, the output amperage should be at the level of 6A. It is worth considering studies according to which a moderate decrease in the number of amperes per output helps to reduce sulfation processes.

If the plates are partially covered with an undesirable sulfate coating, then experienced motorists will use desulfation operations. The applied methodology is as follows:

• we discharge the battery until 3-5 V appears on the multimeter after measurement, using high currents for the operation and a short duration of their exposure, for example, scrolling with a starter;
• at the next stage, we slowly fully charge the block from a one-ampere source;
• the previous operations are repeated for 7-10 cycles.

A similar principle of operation is involved in factory pulse-type desulfating chargers. For one cycle, a short pulse of reverse polarity is supplied to the battery terminals for several milliseconds, changing to direct polarity.

It is necessary to monitor the status of the device and prevent overcharging of the battery. When the values ​​\u200b\u200bof 12.8-13.2 V are reached on the contacts, it is worth disconnecting the system from the recharge. Otherwise, the phenomenon of boiling will occur, an increase in the concentration and density of the electrolyte poured inside and the subsequent destruction of the plates. To prevent negative phenomena, the factory circuit diagram of the charger is endowed with electronic control and automatic shutdown boards.

What is the scheme of a car charger

In garage conditions, you can use several types of car chargers. They can be both the most primitive, consisting of several elements, and rather bulky multifunctional stationary devices. Usually car owners follow the path of simplification.

The simplest schemes

If there is no factory charger available, and it is necessary to reanimate the battery without delay, then the simplest option will do. It involves a limiting resistance in the form of a load and a power source capable of generating 12-25 V.

It will be possible to assemble a homemade charger even “on your knees” if there is a laptop charger in the house. Usually they give out about 19 V and 2 A. When assembling, it is worth considering the polarity:

• external contact - minus;
• internal contact is a plus.

Important! A limiting resistance must be installed, which is often used as a light bulb from the passenger compartment.

It is not worth unscrewing the lamp from the turn signal or even the “stops”, as they will become an overload for the circuit. The circuit consists of such interconnected elements: the negative terminal of the laptop unit - the lamp - the negative terminal of the battery being charged - the positive terminal of the battery being charged - the plus of the laptop unit. One and a half to two hours is enough to bring the battery back to life so much that it will be possible to start the engine from it.

In the absence of laptops or netbooks, we recommend that you go to the radio market in advance for a powerful diode designed for a reverse voltage of more than 1000 V and a current of more than 3 A. The small dimensions of the part allow you to carry it with you in the glove compartment or trunk so as not to get into an undesirable position.

You can use such a diode in a homemade circuit. First we recline and take out the battery. At the next stage, we mount a chain of elements: the first contact of a household socket in the apartment - the negative contact on the diode - the positive contact of the diode - the limiting load - the negative terminal of the battery - the plus of the battery - the second contact of the household socket.

The limiting load in such an assembly is usually a powerful incandescent lamp. It is preferable to choose them from 100 watts. The resulting current can be determined from the school formula:

U*I=W, Where

• U – voltage, V;
• I - current strength, A;
• W - power, kW.

Based on calculations with a load of 100 watts and 220 volts, power output is limited to about half an ampere. During the night, the battery will receive about 5 A, which will ensure the engine starts. It will be possible to triple the power and at the same time speed up charging by adding a couple more of these lamps to the circuit. You should not overdo it and run powerful consumers such as an electric stove to such a system, as you can disable the diode and battery.

It is important to know that the assembled direct-charge circuit of a do-it-yourself car charger is recommended for use as a last resort, if there is no other way out.

Alteration of a computer power supply

Before you start experimenting with electrical appliances, you need to objectively assess your own strengths in implementing the intended implementation. After that, you can start assembling.

First of all, the selection of the material base is carried out. Often, old computer systems are used for such a thing. Take out the power supply. Traditionally, they are equipped with leads of different voltages. In addition to five-volt contacts, there are 12 V taps. The latter are also endowed with a current of 2 A. These parameters are almost enough to assemble the circuit with your own hands.

We recommend raising the voltage to 15 V. This is often done empirically. To adjust, you need a kilo-ohm resistance. Such a resistor is thrown in parallel with other existing resistors in the block near the eight-legged microcircuit in the secondary circuit of the PSU.

In a similar way, the value of the transfer coefficient of the feedback circuit is changed, which affects the output voltage. The method usually provides a rise to 13.5 V, which is enough for simple tasks with a car battery.

Crocodile tucks are thrown over the output contacts. Additional limiting protections do not need to be installed, since there is limiting electronics inside.

transformer circuit

Due to its availability, reliability and simplicity, it has long been in demand among experienced drivers. It uses transformers with a secondary winding that delivers 12-18 V. Such elements are found in old TVs, tape recorders and other household appliances. Of the more modern devices, you can advise used uninterruptible power supplies. They are available on the secondary market for a small fee.

In the most minimalistic version of the scheme, there is such a set:

• diode rectifier bridge;
• transformer selected according to the parameters;
• protective load calculated according to the network.

Since a large current flows through the limiting load, it overheats from this. To balance the amperage without exceeding the charging current, a capacitor is added to the circuit. Its place is the primary circuit of the transformer.

In extreme situations, with a well-calculated capacitor volume, you can take a chance and remove the transformer. However, such a circuit will become unsafe in terms of electric shock.

Circuits in which there is an adjustment of parameters and limitation of the charge current can be called optimal. We present one of the examples on the page.

It will be possible to get a diode bridge with minimal effort from a failed car generator. It is enough to unsolder it and reconnect it if necessary.

Basics of safety when assembling and operating circuits

When working on completing a charger for a car battery, certain factors should be taken into account:

• everything must be mounted and installed on a fireproof site;
• when working with direct-flow primitive chargers, you need to arm yourself with means of protection against electric shock: rubber gloves and a rug;
• in the process of charging the battery for the first time with home-made devices, it is necessary to control the current state of the operating system;
• control points are the current strength with the voltage at the charging output, the permissible degree of heating of the battery and the charger, preventing the electrolyte from boiling;
• if you leave the equipment overnight, it is important to equip the circuit with a residual current device.

Important! A powder fire extinguisher should always be nearby to protect against the possible spread of fire.