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Do-it-yourself wiring diagram for a car battery. Charger for car battery. Using a laptop charger for the battery

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.

Probably every motorist is familiar with the problem of a dead or completely failed battery. Of course, resuscitating a car is not so difficult, but what if there is absolutely no time and you need to go urgently? After all, not everyone has a charger. From this material you will learn how to make a charger for a car battery with your own hands, what types there are.

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Pulse chargers for batteries

Not so long ago, transformer-type chargers were found everywhere, but today finding such a charger will be quite problematic. Over time, transformers faded into the background, losing ground. Unlike a transformer, a pulse charger allows you to provide full power, but this advantage is not the main one.

Working with a transformer required some skill, but with pulse memory devices they are quite easy to operate. In addition, unlike transformers, their cost is more affordable. Also, the transformer is characterized by large dimensions, and the dimensions of the pulse devices are more compact.

The battery of a pulse device, unlike a transformer, is charged in two stages. The first is constant voltage, the second is constant current. Usually, modern memory devices are based on similar, but quite complex circuits. So, if this device fails, the motorist will most likely have to buy a new one.

As for lead-acid batteries, these batteries are, in principle, temperature sensitive. If it’s hot outside, then the charge level should be at least half, and if the temperature is sub-zero, then the battery should be charged at least 75%. Otherwise, the charger will simply stop functioning and will need to be recharged. 12-volt pulse chargers are excellent for such purposes, since they do not have a negative impact on the battery itself (video author: Artem Petukhov).

Automatic chargers for car batteries

If you are a novice motorist, then it would be better for you to use an automatic battery charger. These chargers are equipped with rich functionality and protective options, which allows you to warn the driver if the connection is incorrect. In addition, the automatic charger will prevent voltage from being applied if it is not connected correctly. Sometimes charging can independently calculate the charge level and battery capacity.

Automatic memory circuits are equipped with additional devices - timers, which allow you to perform several different tasks. We are talking about fully charging the battery, rapid charging, as well as full. When the task is completed, the charger will notify the motorist about this and will automatically turn off.

As you know, if the precautions for using batteries are not followed, sulfitation, that is, salts, can occur on the battery plates. Thanks to the charge-discharge cycle, you can not only remove salts, but also increase the service life of the battery as a whole. In general, the cost of modern 12-volt chargers is not particularly high, so every motorist can purchase such a device. But there are times when the device is needed right now, but there is no way to charge the battery. You can try to make a simple homemade 12 volt charger with and without an ammeter, we will talk about this later.

How to make a device yourself

How to make a simple homemade one? Several methods are given below (video author - Crazy Hands).

Charger for battery from PC power supply

A good 12 volt one can be built using a working power supply from a computer and an ammeter. This rectifier with ammeter is suitable for almost all batteries.

Almost every power supply is equipped with a PWM - a working controller on a chip. To properly charge the battery, you need about 10 current (from a full battery charge). So if you have a power supply greater than 150W, you can use it.

1. The wires should be removed from the -5 volt, -12 volt, +5V and +12V connectors.
2. After this, resistor R1 is unsoldered; instead, a 27 kOhm resistor should be installed. Also, output 16 must be disconnected from the main drive.
3. Next, on the back side of the power supply you need to mount a current regulator of type R10, and also run two wires - the network wire and for connecting to the terminals. Before making a rectifier, it is advisable to prepare a block of resistors. To make it, you just need to connect two resistors in parallel to measure current, the power of which will be 5 W.
4. To set the rectifier to 12 volts, you also need to install another resistor on the board - a trimmer. To avoid possible connections between the electrical circuit and the housing, remove a small portion of the trace.
5. Next, in the diagram it is necessary to tin and solder the wiring on pins 14, 15, 16 and 1. Special clamps must be mounted on the pins so that the terminal can be hooked. In order not to confuse plus and minus, the wires should be marked; for this you can use insulating tubes.

If you will only use a 12-volt do-it-yourself charger to charge the battery, then you will not need an ammeter and voltmeter. Using an ammeter will allow you to know the exact state of charge of the battery. If the dial scale on the ammeter does not fit, then you can draw your own on the computer. The printed scale is installed in the ammeter.

The simplest memory using an adapter

You can also make a device where the main function of the current source will be performed by a 12 volt adapter. This device is quite simple; its manufacture does not require a special circuit. One important point should be taken into account - the voltage indicator in the source must correspond to the battery voltage. If these indicators differ, then you will not be able to charge the battery.

1. Take the adapter; the end of its wire should be cut and exposed to 5 cm.
2. Then the wires with different charges should be moved away from each other by about 35-40 cm.
3. Now clamps should be installed at the ends of the wires, as in the previous case, they should be marked in advance, otherwise you may get confused later. These clamps are connected to the battery one by one, only after that it will be possible to turn on the adapter.

In general, the method is simple, but the difficulty of the method is to choose the right source. If during charging you notice that the battery gets very hot, you need to interrupt this process for a few minutes.

Charger from a household light bulb and diode

This method is one of the simplest. To build such a device, prepare in advance:

• a regular lamp, high power is welcome, as it affects the charging speed (up to 200 W);
• a diode through which current flows in one direction, for example, such diodes are installed in laptop chargers;
• plug and cable.

The connection procedure is quite simple. A more detailed diagram is presented in the video at the end of the article.

Conclusion

Please note that in order to make a high-quality memory, it is not enough just to read this article. You must have certain knowledge and skills and familiarize yourself with the videos presented here in detail. An incorrectly assembled device can damage the battery. On sale in the automotive market you can find inexpensive and high-quality chargers that will last for many years.

Video “How to build a charger from a diode and a light bulb?”

Find out how to do this type of exercise correctly from the video below (video author: Dmitry Vorobyev).

Analysis of more than 11 circuits for making a charger with your own hands at home, new circuits for 2017 and 2018, how to assemble a circuit diagram in an hour.

TEST:

To understand whether you have the necessary information about batteries and chargers for them, you should take a short test:

1. What are the main reasons why a car battery discharges on the road?

A) The motorist got out of the vehicle and forgot to turn off the headlights.

B) The battery has become too hot due to exposure to sunlight.

1. Can the battery fail if the car is not used for a long time (sitting in a garage without starting)?

A) If left idle for a long time, the battery will fail.

B) No, the battery will not deteriorate, it will only need to be charged and it will function again.

1. What current source is used to recharge the battery?

A) There is only one option - a network with a voltage of 220 volts.

B) 180 Volt network.

1. Is it necessary to remove the battery when connecting a homemade device?

A) It is advisable to remove the battery from its installed location, otherwise there is a risk of damaging the electronics due to high voltage.

B) It is not necessary to remove the battery from its installed location.

1. If you confuse “minus” and “plus” when connecting a charger, will the battery fail?

A) Yes, if connected incorrectly, the equipment will burn out.

B) The charger simply will not turn on; you will need to move the necessary contacts to the correct places.

Answers:

1. A) Headlights not turned off when stopping and sub-zero temperatures are the most common causes of battery discharge on the road.
2. A) The battery fails if it is not recharged for a long time when the car is idle.
3. A) For recharging, a mains voltage of 220 V is used.
4. A) It is not advisable to charge the battery with a homemade device if it is not removed from the car.
5. A) The terminals should not be mixed up, otherwise the homemade device will burn out.

Battery on vehicles require periodic charging. The reasons for the discharge can be different - from headlights that the owner forgot to turn off, to negative temperatures outside in winter. For recharge battery You will need a good charger. This device is available in large varieties in auto parts stores. But if there is no opportunity or desire to purchase, then memory You can do it yourself at home. There are also a large number of schemes - it is advisable to study them all in order to choose the most suitable option.

Definition: A car charger is designed to transmit electric current with a given voltage directly to Battery

Answers to 5 Frequently Asked Questions

1. Will I need to take any additional measures before charging the battery in my car?– Yes, you will need to clean the terminals, since acid deposits appear on them during operation. Contacts It needs to be cleaned very well so that current flows to the battery without difficulty. Sometimes motorists use grease to treat terminals; this should also be removed.
2. How to wipe charger terminals?— You can buy a specialized product in a store or prepare it yourself. Water and soda are used as a self-made solution. The components are mixed and stirred. This is an excellent option for treating all surfaces. When the acid comes into contact with soda, a reaction will occur and the motorist will definitely notice it. This area will need to be thoroughly wiped to get rid of all acids. If the terminals were previously treated with grease, it can be removed with any clean rag.
3. If there are covers on the battery, do they need to be opened before charging?— If there are covers on the body, they must be removed.
4. Why is it necessary to unscrew the battery caps?— This is necessary so that the gases formed during the charging process can freely exit the case.
5. Is there a need to pay attention to the electrolyte level in the battery?- This is done without fail. If the level is lower than required, then you need to add distilled water inside the battery. Determining the level is not difficult - the plates must be completely covered with liquid.

It’s also important to know: 3 nuances about operation

The homemade product differs somewhat in its method of operation from the factory version. This is explained by the fact that the purchased unit has built-in functions, helping in work. They are difficult to install on a device assembled at home, and therefore you will have to adhere to several rules when operation.

1. A self-assembled charger will not turn off when the battery is fully charged. That is why it is necessary to periodically monitor the equipment and connect it to multimeter– for charge control.
2. You need to be very careful not to confuse “plus” and “minus”, otherwise Charger will burn.
3. The equipment must be turned off when connecting to charger.

By following these simple rules, you will be able to recharge correctly battery and avoid unpleasant consequences.

Top 3 charger manufacturers

If you don’t have the desire or ability to assemble it yourself memory, then pay attention to the following manufacturers:

1. Stack.
2. Sonar.
3. Hyundai.

How to avoid 2 mistakes when charging a battery

It is necessary to follow the basic rules in order to properly nourish battery by car.

1. Direct to mains battery connection is prohibited. Chargers are intended for this purpose.
2. Even device made with high quality and from good materials, you will still need to periodically monitor the process charging, so that troubles don't happen.

Following simple rules will ensure reliable operation of self-made equipment. It is much easier to monitor the unit than to spend money on components for repairs.

The simplest battery charger

Scheme of a 100% working 12 volt charger

Look at the picture for the diagram memory at 12 V. The equipment is intended for charging car batteries with a voltage of 14.5 Volts. The maximum current received during charging is 6 A. But the device is also suitable for other batteries - lithium-ion, since the voltage and output current can be adjusted. All the main components for assembling the device can be found on the Aliexpress website.

Required components:

1. dc-dc buck converter.
2. Ammeter.
3. Diode bridge KVRS 5010.
4. Hubs 2200 uF at 50 volts.
5. transformer TS 180-2.
6. Circuit breakers.
7. Plug for connecting to the network.
8. "Crocodiles" for connecting terminals.
9. Radiator for diode bridge.

Transformer any one can be used at your own discretion. The main thing is that its power is not lower than 150 W (with a charging current of 6 A). It is necessary to install thick and short wires on the equipment. The diode bridge is fixed on a large radiator.

Look at the picture of the charger circuit Dawn 2. It is compiled according to the original Memory If you master this scheme, you will be able to independently create a high-quality copy that is no different from the original sample. Structurally, the device is a separate unit, closed with a housing to protect the electronics from moisture and exposure to bad weather conditions. It is necessary to connect a transformer and thyristors on the radiators to the base of the case. You will need a board that will stabilize the current charge and control the thyristors and terminals.

1 smart memory circuit

Look at the picture for a circuit diagram of a smart charger. The device is necessary for connection to lead-acid batteries with a capacity of 45 amperes per hour or more. This type of device is connected not only to batteries that are used daily, but also to those on duty or in reserve. This is a fairly budget version of the equipment. It does not provide indicator, and you can buy the cheapest microcontroller.

If you have the necessary experience, then you can assemble the transformer yourself. There is also no need to install audible warning signals - if battery connects incorrectly, the discharge lamp will light up to indicate an error. The equipment must be equipped with a switching power supply of 12 volts - 10 amperes.

1 industrial memory circuit

Look at the industrial diagram charger from Bars 8A equipment. Transformers are used with one 16-volt power winding, several vd-7 and vd-8 diodes are added. This is necessary in order to provide a bridge rectifier circuit from one winding.

1 inverter device diagram

Look at the picture for a diagram of an inverter charger. This device discharges the battery to 10.5 Volts before charging. The current is used with a value of C/20: “C” indicates the capacity of the installed battery. After that process the voltage rises to 14.5 Volts using a discharge-charge cycle. The ratio of charge and discharge is ten to one.

1 electrical circuit charger electronics

1 powerful memory circuit

Look at the picture at the diagram of a powerful charger for a car battery. The device is used for acidic battery, having high capacity. The device easily charges a car battery with a capacity of 120 A. The output voltage of the device is self-regulated. It ranges from 0 to 24 volts. Scheme It is notable for the fact that it has few components installed, but it does not require additional settings during operation.

Many could already see the Soviet Charger. It looks like a small metal box and may seem quite unreliable. But this is not true at all. The main difference between the Soviet model and modern models is reliability. The equipment has structural capacity. In the event that to the old device connect the electronic controller, then charger it will be possible to revive. But if you no longer have one at hand, but there is a desire to assemble it, you need to study the diagram.

To the features their equipment includes a powerful transformer and rectifier, with the help of which it is possible to quickly charge even a very discharged battery. Many modern devices will not be able to reproduce this effect.

Electron 3M

In an hour: 2 do-it-yourself charging concepts

Simple circuits

1 the simplest scheme for an automatic charger for a car battery

I made this charger to charge car batteries, the output voltage is 14.5 volts, the maximum charge current is 6 A. But it can also charge other batteries, for example lithium-ion ones, since the output voltage and output current can be adjusted within a wide range. The main components of the charger were purchased on the AliExpress website.

These are the components:

You will also need an electrolytic capacitor 2200 uF at 50 V, a transformer for the TS-180-2 charger (see how to solder the TS-180-2 transformer), wires, a power plug, fuses, a radiator for the diode bridge, crocodiles. You can use another transformer with a power of at least 150 W (for a charging current of 6 A), the secondary winding must be designed for a current of 10 A and produce a voltage of 15 - 20 volts. The diode bridge can be assembled from individual diodes designed for a current of at least 10A, for example D242A.

The wires in the charger should be thick and short. The diode bridge must be mounted on a large radiator. It is necessary to increase the radiators of the DC-DC converter, or use a fan for cooling.

Charger assembly

Connect a cord with a power plug and a fuse to the primary winding of the TS-180-2 transformer, install the diode bridge on the radiator, connect the diode bridge and the secondary winding of the transformer. Solder the capacitor to the positive and negative terminals of the diode bridge.

Connect the transformer to a 220 volt network and measure the voltages with a multimeter. I got the following results:

1. The alternating voltage at the terminals of the secondary winding is 14.3 volts (mains voltage 228 volts).
2. The constant voltage after the diode bridge and capacitor is 18.4 volts (no load).

Using the diagram as a guide, connect a step-down converter and a voltammeter to the DC-DC diode bridge.

Setting the output voltage and charging current

There are two trimming resistors installed on the DC-DC converter board, one allows you to set the maximum output voltage, the other allows you to set the maximum charging current.

Plug in the charger (nothing is connected to the output wires), the indicator will show the voltage at the device output and the current is zero. Use the voltage potentiometer to set the output to 5 volts. Close the output wires together, use the current potentiometer to set the short circuit current to 6 A. Then eliminate the short circuit by disconnecting the output wires and use the voltage potentiometer to set the output to 14.5 volts.

This charger is not afraid of a short circuit at the output, but if the polarity is reversed, it may fail. To protect against polarity reversal, a powerful Schottky diode can be installed in the gap in the positive wire going to the battery. Such diodes have a low voltage drop when connected directly. With such protection, if the polarity is reversed when connecting the battery, no current will flow. True, this diode will need to be installed on a radiator, since a large current will flow through it during charging.

Suitable diode assemblies are used in computer power supplies. This assembly contains two Schottky diodes with a common cathode; they will need to be parallelized. For our charger, diodes with a current of at least 15 A are suitable.

It must be taken into account that in such assemblies the cathode is connected to the housing, so these diodes must be installed on the radiator through an insulating gasket.

It is necessary to adjust the upper voltage limit again, taking into account the voltage drop across the protection diodes. To do this, use the voltage potentiometer on the DC-DC converter board to set 14.5 volts measured with a multimeter directly at the output terminals of the charger.

How to charge the battery

Wipe the battery with a cloth soaked in soda solution, then dry. Remove the plugs and check the electrolyte level; if necessary, add distilled water. The plugs must be turned out during charging. No debris or dirt should get inside the battery. The room in which the battery is charged must be well ventilated.

Connect the battery to the charger and plug in the device. During charging, the voltage will gradually increase to 14.5 volts, the current will decrease over time. The battery can be conditionally considered charged when the charging current drops to 0.6 - 0.7 A.

November 26, 2016

Car enthusiasts who do not change their cars every 2 years will sooner or later encounter a discharged battery. This happens both due to its wear and the fault of other elements of the on-board electrical network. To continue to use the battery, you need to constantly recharge it. There are two options here: buy a factory-made device for this purpose or assemble a charger for the car with your own hands.

Briefly about factory charger models

The retail chain sells 3 types of devices designed to restore car power supplies:

• pulse;
• automatic;
• transformer charging and starting devices.

The first type of charger is capable of fully charging batteries using pulses in two modes - first at a constant voltage, and then at a constant current. These are the simplest and most affordable products suitable for recharging all types of car batteries. Automatic models are more complex, but do not require supervision during operation. Despite the higher price, such chargers are the best choice for a novice driver, since thanks to the protection systems they will never overheat or damage the battery.

Recently, mobile devices have appeared on sale, equipped with their own battery, which transfers charge to the car battery if necessary. But they will also have to be periodically charged from a 220 V power supply.

Powerful transformer devices, capable of not only recharging the power source, but also rotating the machine’s starter, are more related to professional installations. Such a charger, although it has wide capabilities, costs a lot of money, so it is of little interest to ordinary users.

But what to do when the battery is already dead, there is no charger at home yet, and you need to go to work tomorrow? A one-time option is to turn to neighbors or friends for help, but it is better to make a primitive memory device with your own hands.

What should the device consist of?

The main elements of any charger are:

1. 220 V mains voltage converter - coil or transformer. Its task is to provide a voltage acceptable for recharging the battery, which is 12-15 V.
2. Rectifier. It converts alternating current from household electricity into direct current, which is necessary to restore battery charge.
3. Switch and fuse.
4. Wires with terminals.

Factory devices are additionally equipped with instruments for measuring voltage and current, protective elements and timers. A homemade charger can also be upgraded to the factory level, provided that you have knowledge of electrical engineering. If you only know the basics, then at home you can assemble the following primitive structures:

• charging from a laptop adapter;
• charger made from parts from old household appliances.

Recharging using a laptop adapter

Devices for powering laptops already have a built-in converter and rectifier. In addition, there are elements of stabilization and smoothing of the output voltage. To use them as a charging device, you should check the value of this voltage. It must be at least 12 V, otherwise the car battery will not charge.

To check, you need to insert the adapter plug into the socket and connect the positive terminal of the voltmeter to the contact located inside the round plug. The negative contact is located outside. If the voltmeter shows 12 V or more, then connect the adapter to the battery as follows:

1. Take 2 copper wires, strip their ends and attach them to the plug contacts.
2. Connect the negative terminal of the battery to the wire from the external contact of the adapter.
3. Connect the wire from the internal contact to the “positive” terminal.
4. Place a low-power 12 V car light bulb in the gap of the positive wire; it will serve as a ballast resistor.
5. Open the battery cover or unscrew the plugs and plug in the adapter.

Such charging for a car battery is not capable of restoring a completely dead power source. But if the charge has been partially lost, then in a few hours the battery can be recharged to start the engine.

As a charger, it is allowed to use other types of adapters that provide an output voltage of 12-15 V.

Negative point: if the “banks” are short-circuited inside the battery, then the low-power adapter can quickly fail, and you will be left without a car and a laptop. Therefore, you should carefully monitor the process for the first half hour and if it overheats, immediately turn off charging.

Assembling a memory from old radio components

The option with adapters is not suitable for constant use, since there is a risk of damaging the device, despite the fact that the charging speed is quite low. A more powerful and reliable charger can be made from parts of old televisions and tube radios, although you will have to work hard to make it. To assemble the circuit you will need:

• power transformer that reduces the voltage to 12-15 V;
• diodes of the D214...D243 series – 4 pcs.;
• electrolytic capacitor with a nominal value of 1000 μF, rated at 25 V;
• old toggle switch (220 V, 6 A) and 1 A fuse socket;
• wires with alligator clips;
• suitable metal housing.

The first step is to check the voltage at the output of the transformer by connecting the primary (power) winding to the mains and taking readings from the ends of other windings (there are several of them). Having selected contacts with the appropriate voltage, bite off or insulate the rest.

An option with a voltage of 24...30 V is suitable if 12 V is not available. It can be reduced by half by changing the scheme.

Assemble a homemade battery charger in this order:

1. Install the transformer in a metal case, place 4 diodes there, screwed with nuts to a sheet of getinax or textolite.
2. Connect the power cable to the power winding of the transformer through a switch and fuse.
3. Solder the diode bridge according to the diagram and connect it with wires to the secondary winding of the transformer.
4. Place a capacitor at the output of the diode bridge, observing the polarity.
5. Connect the charging wires with alligator clips.

To monitor voltage and current, it is advisable to install an indicating ammeter and voltmeter in the memory. The first is connected to the circuit in series, the second in parallel. Subsequently, you can improve the device by adding a manual voltage regulator, a pilot lamp and a safety relay.

If the transformer produces up to 30 V, then instead of the diode bridge, install 1 diode connected in series. It will “rectify” the alternating current and reduce it by half - to 15 V.

The speed of charging the battery with a homemade device depends on the power of the transformer, but it will be much higher than when recharging with an adapter. The disadvantage of a self-made device is the lack of automation, which is why the process will have to be controlled so that the electrolyte does not boil away and the battery does not overheat.