If you don’t have a charger, but you need to charge the battery, there are simple ways. Chargers from improvised means and method - Diode and Lamp

I made this charger to charge car batteries, output voltage 14.5 volts, maximum charge current 6 A. But it can also charge other batteries, such as lithium-ion ones, since the output voltage and output current can be adjusted within a wide range. Main Components charger were purchased on the AliExpress website.

These are the components:

Still needed electrolytic capacitor 2200 uF at 50 V, transformer for the TS-180-2 charger (see how to solder the TS-180-2 transformer), wires, power plug, fuses, 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:

The alternating voltage at the terminals of the secondary winding is 14.3 volts (mains voltage 228 volts).
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. Connect the output wires to each other, set the current using the current potentiometer short circuit 6 A. Then eliminate the short circuit by disconnecting the output wires and using the voltage potentiometer, 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 units nutrition. 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.

Very often there is a problem with charging a car battery, and there is no charger at hand, what to do in this case? Today I decided to publish this article, where I intend to explain all the known methods of charging a car battery, isn’t it interesting? Let's go!

METHOD ONE - LAMP AND DIODE

Photo 13 This is one of the simplest charging methods, since the “charger” in theory consists of two components - an ordinary incandescent lamp and a rectifying diode. The main disadvantage of this charging is that the diode cuts off only the lower half-cycle, therefore, we do not have a completely constant current at the output of the device, but you can charge a car battery with this current!

The light bulb is the most ordinary one, you can take a 40/60/100 watt lamp, the more powerful the lamp, the greater the output current, in theory the lamp is here only for current extinguishing.

The diode, as already said, to rectify alternating voltage, it must be powerful, and it must be designed for reverse voltage at least 400 Volts! The diode current must be more than 10A! This is a mandatory condition, I highly recommend installing the diode on the heat sink; you may have to cool it additionally.

And in the figure there is an option with one diode, although in this case the current will be 2 times less, therefore the charging time will increase (with a 150 Watt bulb, it is enough to charge a dead battery for 5-10 hours to start the car even in cold weather)

To increase the charge current, you can replace the incandescent lamp with another, more powerful load - a heater, boiler, etc.

METHOD TWO - BOILER

This method works on the same principle as the first, except that the output of this charger is completely constant.

The main load is the boiler; if desired, it can be replaced with a lamp, as in the first option.

You can take a ready-made diode bridge, which can be found in computer power supplies. It is MANDATORY to use a diode bridge with a reverse voltage of at least 400 Volts with a current of AT LEAST 5 Amps, install the finished bridge on a heat sink, since it will overheat quite strongly.

The bridge can also be assembled from 4 powerful rectifier diodes, and the voltage and current of the diodes should be the same as when using the bridge. In general, try to use a powerful rectifier, as powerful as possible, excess power never hurts.

DO NOT USE powerful SCHOTTTKY diode assemblies from computer power supplies, they are very powerful, but the reverse voltage of these diodes is about 50-60 Volts, so they will burn out.

METHOD THREE - CONDENSER

I like this method the most; the use of a quenching capacitor makes the charging process safer, and the charge current is determined from the capacitor’s capacitance. The charge current can be easily determined by the formula

I = 2 * pi * f * C * U,

where U is the network voltage (Volts), C is the capacity of the quenching capacitor (μF), f is the frequency AC(Hz)

All car enthusiasts have experienced this unpleasant situation. There are two options: start the car with a charged battery from a neighbor’s car (if the neighbor doesn’t mind), in the jargon of car enthusiasts this sounds like “lighting a cigarette.” Well, the second way out is to charge the battery.

When I found myself in this situation for the first time, I realized that I urgently needed a charger. But I didn’t have an extra thousand rubles to buy a charger. I found it on the Internet simple diagram and decided to assemble a charger on our own.

I simplified the transformer circuit. Windings from the second column are indicated with a stroke.

F1 and F2 are fuses. F2 is needed to protect against short circuits at the output of the circuit, and F1 – against excess voltage in the network.

Description of the assembled device

Here's what I got. It looks so-so, but most importantly it works.

Transformer

Now let's talk about everything in order. A power transformer of the TS-160 or TS-180 brand can be obtained from old black-and-white Record TVs, but I didn’t find one and went to a radio store. Let's take a closer look.

Here are the petals where the leads of the transformer windings are soldered.

And here right on the transformer there is a sign indicating which petals have what voltage. This means that if we apply 220 Volts to petal No. 1 and 8, then on petals No. 3 and 6 we will get 33 Volts and a maximum load current of 0.33 Ampere, etc. But we are most interested in windings No. 13 and 14. On them we can get 6.55 Volts and a maximum current of 7.5 Amperes.

In order to charge the battery, we just need a large amount of current. But we don’t have enough voltage... The battery produces 12 Volts, but in order to charge it, the charging voltage must exceed the battery voltage. 6.55 Volts will not work here. The charger should give us 13-16 Volts. Therefore, we resort to a very cunning solution.

As you noticed, the transformer consists of two columns. Each column duplicates another column. The places where the winding leads come out are numbered. In order to increase the voltage, we simply need to connect two windings in series. To do this, we connect windings 13 and 13′ and remove the voltage from windings 14 and 14′. 6.55 + 6.55 = 13.1 Volts. This is the alternating voltage we will get.

Diode bridge

In order to rectify the alternating voltage, we use a diode bridge. We assemble a diode bridge using powerful diodes, because a decent amount of current will pass through them. To do this, we will need D242A diodes or some others designed for a current of 5 Amperes. A direct current of up to 10 Amps can flow through our power diodes, which is ideal for our homemade charger.

You can also separately buy a diode bridge as a ready-made module. The KVRS5010 diode bridge, which can be bought on Ali at this link or in the nearest radio store

A fully charged battery has low voltage. As it charges, the voltage across it becomes higher and higher. Consequently, the current in the circuit at the very beginning of charging will be very large, and then it will decrease. According to the Joule-Lenz Law, when the current is high, the diodes will heat up. Therefore, in order not to burn them, you need to take heat from them and dissipate it in the surrounding space. For this we need radiators. As a radiator, I disassembled a non-working computer power supply, cut a tin into strips and screwed a diode onto them.

Ammeter

Why is there an ammeter in the circuit? In order to control the charging process.

Don't forget to connect the ammeter in series with the load.

When the battery is completely discharged, it begins to consume (I think the word “eat” is inappropriate here) current. It consumes about 4-5 Amps. As it charges, it uses less and less current. Therefore, when the arrow of the device shows 1 Ampere, the battery can be considered charged. Everything is ingenious and simple :-).

Crocodiles

We remove two crocodiles for the battery terminals from our charger. When charging, do not confuse the polarity. It's better to mark them somehow or take different colors.

If everything is assembled correctly, then on the crocodiles we should see this kind of signal shape (in theory, the tops should be smoothed out, since it’s a sinusoid), but is that something you can present to our electricity provider))). Is this your first time seeing something like this? Let's run here!

Impulses DC voltage charge the battery better than pure direct current. How to obtain pure direct current from alternating current is described in the article How to obtain direct current from alternating voltage.

Conclusion

Don't be lazy to modify your device fuses. Fuse ratings on the diagram. Do not check the voltage on the charger crocodiles for a spark, otherwise you will lose the fuse.

Attention! The circuit of this memory is intended for fast charging your battery in critical cases when you urgently need to go somewhere in 2-3 hours. Do not use it for everyday use, as it charges at maximum current, which is not the best charging mode for your battery. When overcharging, the electrolyte will begin to “boil” and toxic fumes will begin to be released into the surrounding space.

Those who are interested in the theory of chargers (chargers), as well as the circuits of normal chargers, then be sure to download this book on this link. It can be called the bible on chargers.

Buy a car charger

Aliexpress has really good and smart chargers that are much lighter than ordinary transformer chargers. Their price averages from 1000 rubles.

Very often there is a problem with charging a car battery, and there is no charger at hand, what to do in this case. Today I decided to publish this article, where I intend to explain all the known methods of charging a car battery, it’s interesting, really. Let's go!

METHOD ONE - LAMP AND DIODE

The light bulb is the most ordinary one, you can take a 40/60/100 watt lamp, the more powerful the lamp, the greater the output current, in theory the lamp is here only for current extinguishing.

The diode, as I already said, to rectify alternating voltage, it must be powerful, and it must be designed for a reverse voltage of at least 400 Volts! The diode current must be more than 10A! This is a mandatory condition, I highly recommend installing the diode on the heat sink; you may have to cool it additionally.

To increase the charge current, you can replace the incandescent lamp with another, more powerful load - a heater, boiler, etc.

METHOD TWO - BOILER

This method works on the same principle as the first, except that the output of this charger is completely constant.

The main load is the boiler; if desired, it can be replaced with a lamp, as in the first option.

DO NOT USE powerful SCHOTTTKY diode assemblies from computer power supplies, they are very powerful, but the reverse voltage of these diodes is about 50-60 Volts, so they will burn out.

METHOD THREE - CONDENSER

I = 2 * pi * f * C * U,

where U is the network voltage (Volts), C is the capacitance of the quenching capacitor (uF), f is the alternating current frequency (Hz)

For charging car battery you need to have a fairly large current (a tenth of the battery capacity, for example - for a 60 A battery, the charging current should be 6A), but to obtain such a current we need a whole battery of capacitors, so we will limit ourselves to a current of 1.3-1.4A, for this , the capacitance of the capacitor should be around 20 µF.
A film capacitor is required, with a minimum operating voltage of at least 250 Volts, great option MBGO type capacitors of domestic production.

DIY 12V battery charger

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:

Diode bridge KBPC5010.

You will also need an electrolytic capacitor 2200 uF at 50 V, a transformer for the TS-180-2 charger (see this article for 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.

Circuit diagram of a charger for a car battery

Charger assembly

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

The alternating voltage at the terminals of the secondary winding is 14.3 volts (mains voltage 228 volts).
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.

Reverse polarity protection

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.

How to charge the battery

Car charger

Attention! The circuitry of this charger is designed to quickly charge your battery in critical cases when you urgently need to go somewhere in 2-3 hours. Do not use it for everyday use, as the charge is constant voltage, which is not the best charging mode for your battery. When overcharging, the electrolyte begins to “boil” and toxic fumes begin to be released into the surrounding space.

Once upon a time in the cold winter

I left the house, it was bitterly cold!

I get into the car and insert the key

The car is not moving

After all, Akum died!

A familiar situation, isn't it? 😉 I think all car enthusiasts have found themselves in such an unpleasant situation. There are two ways out: start the car from the charged battery of the neighbor’s car (if the neighbor doesn’t mind), in the jargon of car enthusiasts this sounds like “lighting a cigarette.” Well, the second way out is to charge the battery. Chargers are not very cheap. Their price starts from 1000 rubles. If your pocket is tight from money, then the problem is solved. When I found myself in this situation where the car wouldn't start, I realized that I urgently needed a charger. But I didn’t have an extra thousand rubles to buy a charger. I found a very simple circuit on the Internet and decided to assemble the charger on my own. I simplified the transformer circuit. Windings from the second column are indicated with a stroke.

F1 and F2 are fuses. F2 is needed to protect against a short circuit at the output of the circuit, and F1 - against excess voltage in the network.

And this is what I got.

Now let's talk about everything in order. A power transformer of the TS-160 brand and a TS-180 can be pulled out from old black-and-white Record TVs, but I didn’t find one and went to the radio store. Let's take a closer look.

Petals. where the terminals of the trance windings are soldered.

And right here on the trance there is a sign indicating which petals produce what voltage. This means that when we apply 220 Volts to petals No. 1 and 8, then on petals No. 3 and 6 we will get 33 Volts and the maximum current to the load is 0.33 Amperes, etc. But we are most interested in windings No. 13 and 14. On them we can get 6.55 Volts and a maximum current of 7.5 Amperes.

In order to charge the battery, we just need a large amount of current. But our tension is low. The battery produces 12 volts, but in order to charge it, the charging voltage must exceed the voltage of the battery. 6.55 Volts will not work here. The charger should give us 13-16 Volts. Therefore, we resort to a very clever solution. As you noticed, the trance consists of two columns. Each column duplicates another column. The places where the winding leads come out are numbered. In order to increase the voltage, we simply need to connect two voltage sources in series. To do this, we connect windings 13 and 13′ and remove the voltage from windings 14 and 14′. 6.55 + 6.55 = 13.1 Volts. This is the alternating voltage we will get. Now we need to straighten it, that is, turn it into direct current. We assemble a Diode Bridge using powerful diodes, because a decent amount of current will pass through them. For this we need D242A diodes. A direct current of up to 10 Amperes can flow through them, which is ideal for our homemade charger :-). You can also buy a diode bridge separately as a module. The KVRS5010 diode bridge, which can be bought on Ali using this link or in the nearest radio store, is just right.

I think everyone remembers how to check diodes for functionality; those who don’t remember, go here.

A little theory. A fully seated battery has a low voltage. As charging progresses, the voltage becomes higher and higher. Therefore, according to Ohm’s Law, the current strength in the circuit at the very beginning of charging will be very large, and then less and less. And since the diodes are included in the circuit, a large current will pass through them at the very beginning of charging. According to the Joule-Lenz Law, the diodes will heat up. Therefore, in order not to burn them, you need to take heat away from them and dissipate it in the surrounding space. For this we need radiators. As a radiator, I ripped out a non-working computer power supply and used its tin case.

Don't forget to connect the ammeter in series with the load. My ammeter has no shunt. Therefore, I divide all readings by 10.

Why do we need an ammeter? In order to find out whether our battery is charged or not. When the Akum is completely discharged, it begins to eat (I think the word “eat” is inappropriate here) current. It consumes about 4-5 Amps. As it charges, it uses less and less current. Therefore, when the needle of the device shows 1 Ampere (in my case on a scale of 10), then the battery can be considered charged. Everything is ingenious and simple :-).

We remove two hooks for the battery terminals from our charger; in our radio store they cost 6 rubles apiece, but I advise you to take a better quality one, since these break quickly. When charging, do not confuse the polarity. It’s better to mark the hooks somehow or take different colors.

If everything is assembled correctly, then on the hooks we should see this signal shape (in theory, the tops should be smoothed, like a sinusoid). but can you show something to our electricity provider))). Is this your first time seeing something like this? Let's run here!

Constant voltage pulses charge batteries better than pure direct current. And how to obtain a pure constant from an alternating voltage is described in the article How to obtain a constant from an alternating voltage.

Below in the photo the Akum is almost already charged. We measure its current consumption. 1.43 Amps.

Let's leave a little more for charging

Take the time to modify your device with fuses. Fuse ratings on the diagram. Since this kind of trans is considered power, when the secondary winding, which we brought to charge the battery, is closed, the current will be crazy and a so-called Short Circuit will occur. Your insulation and even wires will immediately begin to melt, which can lead to dire consequences. Do not check the voltage at the charger hooks for a spark. If possible, do not leave this device unattended. Well, yes, cheap and cheerful ;-). If you really want to, you can modify this charger. Install short circuit protection, self-shutdown when the battery is fully charged, etc. At cost, such a charger cost 300 rubles and 5 hours of free time for assembly. But now, even in the most severe frost, you can safely start the car with a fully charged battery.

Those who are interested in the theory of chargers (chargers), as well as the circuits of normal chargers, then be sure to download this book on this link. It can be called the bible on chargers.

How to make a diode bridge

How to make a diode bridge to convert AC voltage to DC, single-phase and three-phase diode bridge. Below is a classic diagram of a single-phase diode bridge.

As you can see in the figure, four diodes are connected, an alternating voltage is supplied to the input, and the output is plus and minus. The diode itself is a semiconductor element that can only pass through itself a voltage with a certain value. In one direction, the diode can only pass through negative voltage, but not plus, and vice versa in the opposite direction. Below is the diode and its designation in the diagrams. Only minus can pass through the anode, and only plus through the cathode.

Alternating voltage is a voltage where plus and minus change with a certain frequency. For example, the frequency of our 220-volt network is 50 hertz, that is, the polarity of the voltage changes from minus to plus and back 50 times per second. To rectify the voltage, direct the plus to one wire and the plus to the other, two diodes are needed. One is connected as an anode, the second as a cathode, so when a minus appears on the wire, it goes along the first diode, and the second minus does not pass, and when a plus appears on the wire, then, on the contrary, the first plus diode does not pass, but the second does. Below is a diagram of the operating principle.

For rectification, or rather the distribution of plus and minus in alternating voltage, only two diodes are needed per wire. If there are two wires, then there are respectively two diodes per wire, for a total of four and the connection diagram looks like a diamond. If there are three wires, then six diodes, two per wire, and you get a three-phase diode bridge. Below is a connection diagram for a three-phase diode bridge.

The diode bridge, as can be seen from the pictures, is very simple; it is the simplest device for converting alternating voltage from transformers or generators to direct voltage. Alternating voltage has a frequency of voltage change from plus to minus and back, so these ripples are transmitted after the diode bridge. To smooth out the pulsations, if necessary, install a capacitor. The capacitor is placed in parallel, that is, one end is to the plus at the output, and the other end is to the plus. The capacitor here serves as a miniature battery. It charges and, during the pause between pulses, powers the load while discharging, so the pulsations become unnoticeable, and if you connect, for example, an LED, it will not flicker and other electronics will work correctly. Below is a circuit with a capacitor.

I also want to note that the voltage passed through the diode decreases slightly; for a Schottky diode it is about 0.3-0.4 volts. In this way, you can use diodes to lower the voltage, say 10 diodes connected in series will lower the voltage by 3-4 volts. Diodes heat up precisely because of the voltage drop, say a current of 2 amperes flows through the diode, a drop of 0.4 volts, 0.4 * 2 = 0.8 watts, so 0.8 watts of energy is spent on heat. And if 20 amperes goes through a powerful diode, then the heating losses will already be 8 watts.

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Lada Priora Hatchback Rocket › Logbook › DIY charger

I bought a tester today and sat down to solder a charger from the remains of a subwoofer that had been torn apart earlier. A little theory for those who decide to repeat it. Charger. The power supply essentially consists of two modules. The first is a transformer, its task is to lower the voltage to the required 12 volts in our case. The second is a diode bridge; it is needed to convert alternating voltage to direct voltage. You can, of course, complicate everything and add all sorts of filters for light bulbs and devices. But we won’t do this because we’re too lazy.

We take a transformer. The first thing we need to find is the primary winding. We will supply it with 220 V from the outlet. We put the tester in resistance measurement mode. And it rings all the wires. We find the pair that gives the greatest resistance. This is the primary winding. Next, we call the remaining pairs and remember/write down what was called with what.

After we have found all the pairs, we apply 220 V to the primary winding. We switch the tester to AC voltage measurement mode and measure how many volts are on the secondary windings. In my case, it was 12 V at full speed. I took one with the thickest wires, cut the rest and insulated them

With that finished, let's move on to the diode bridge.

Removed 4 diodes from the subwoofer board

twisted it together into a diode bridge and soldered the connections

Diagram of a diode bridge and graph of changes in the structure of a sinusoid

this is what happened to me

All that remains is to connect everything and check for functionality

What happened to me

We plug it into the network and measure the voltage. Left relative last photo there will be a minus on the diode bridge. On the right is a plus. We solder wires there that we will later connect to the plus and minus of our battery.

It is advisable to run one of the wires to the battery through a light bulb to protect the battery from an overdose of electricity

This is what happened in the end

And the last test with the connected LED strip

We are considering a car battery charger made on the basis of a power converter halogen lamps 12V type TASCHIBRA. Converters of this type are often found on sale among electrical products. TASCHIBR is quite different good reliability and maintaining operability at negative ambient temperatures.

This device is made on the basis of a self-oscillating converter with a conversion frequency of approximately 7 to 70 kHz, which depends on the resistance of the converter connected to the output active load. As the load power increases, the conversion frequency increases. Interesting feature TASCHIBR is a disruption of generation when the load increases beyond the permissible limit, which can be a kind of protection against short circuit. Let me make a reservation right away that I was not going to consider options for the so-called “rework” or “refinement” of these converters, which is described in some publications. I propose to use TASCHIBR "as is" with the exception, perhaps, of increasing the number of turns of the secondary winding, which is necessary in order to ensure the charging current of the desired value

As is known, to ensure the required charging current, a voltage of at least 15-16 V must be generated on the secondary winding.

The picture shows that the existing white secondary winding wire was used as additional turns. For a 50 W converter it was enough to add 2 turns to the secondary winding. In this case, it is necessary to ensure that the direction of winding is carried out in the direction (i.e., consistent) of the existing winding, in other words, that the magnetic flux of the newly appearing turns coincides in direction with the magnetic flux of the “native” secondary winding of TASHIBR, designed to power 12V halogen lamps and located on top of the primary at 220V.

The bridge rectifier is made from Schottky diodes such as 1N5822. It is possible to use domestic high-speed diodes, for example KD213.

The optimal charging process is based on limiting both the charge current and the voltage level at the battery terminals. Let's set a current of approximately 1.5 A and a voltage of no more than 14.5V. The control circuit shown in Fig. 1 has the characteristics under consideration. The key element of the circuit is a triac V type BT134-600, switched on by an optosimistor MOS3083. The current limitation is formed by the voltage drop across resistor R2 with a resistance of 1 Ohm and a dissipation power of 2 W. When the voltage drop across it exceeds 1-1.5 V, transistor VT2 opens and bypasses the LED of the optosimistor VD5, interrupting the power supply to the TASCHIBR. If it is necessary to increase the charging current level, for example to 3 - 4 A, it is necessary to reduce the resistance of resistor R2 accordingly, paying attention to the choice of the required dissipation power for this resistor. As the battery charges, the voltage at its terminals approaches 14.5V. Current begins to flow through the zener diode VD3, which causes transistor VT3 to open. The VD4 LED, at the same time, begins to flicker, signaling the end of the charging process, and a current begins to flow through the VD2 diode, opening the VT2 transistor, which leads to the locking of the triac V. To indicate the fact of the triac opening, a transistor switch VT1 with a VD1 LED in the circuit of its collector is used . This transistor must be germanium, due to the small voltage drop across the optosimistor LED (about 1V).

Among the disadvantages of this type of charger, it should be noted that its performance depends on the voltage level on the battery, since, obviously, the circuit initially receives power from battery, which to ensure the operation of the circuit should not fall below 6V. However, due to the rarity of such cases, this can be tolerated. If forced charging is necessary, you can install an additional SW button, as shown in the diagram, by pressing which you can bring the battery voltage to the required level.

The charger was made in a single copy. No printed circuit board was developed. The device is mounted in a machine housing of a suitable size.

List of radioelements

Designation	Type	Denomination	Quantity	Note	My notepad
VT1	Bipolar transistor	MP37B	1		To notepad
VT2	Bipolar transistor	BC547C	1		To notepad
VT3	Bipolar transistor	BC557B	1		To notepad
V	Triac	BT134-600	1		To notepad
VD1	LED	ARL-3214UGC	1		To notepad
VD2	Rectifier diode	1N4148	1		To notepad
VD3	Zener diode	D814D	1		To notepad
VD4	LED	ARL-3214URC	1		To notepad
VD5	Optosimistor	MOC3083	1		To notepad
D1	Schottky diode	1N5822	4	Diode bridge	To notepad
C1	Electrolytic capacitor	470 µF	1		To notepad
C2	Capacitor	1 µF	1		To notepad
F1	Fuse	1A	1		To notepad
R1, R3	Resistor	820 Ohm	2		To notepad
R2	Resistor	1 ohm	1	2W	To notepad
R4, R5	Resistor	6.8 kOhm	2