This Charger I made it for charging 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. 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. 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. 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 power supplies. This assembly contains two Schottky diodes with a common cathode; they will need to be paralleled. 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, it’s interesting, really. Go!

METHOD ONE - LAMP AND DIODE

Photo 13 This is one of the most simple ways charging, 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 the output of the device is not completely D.C., 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, than more powerful lamp, the greater the current at the output; in theory, the lamp is here only for current extinguishing.

Diode, as already said, for rectification AC voltage, it must be powerful, and 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.

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 charging current, you can replace the incandescent lamp with another, more powerful load- 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 alternating current(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 6 A), but to obtain such a current we need a whole battery of capacitors, so we will limit ourselves to a current of 1.3-1.4 A, 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:

All motorists have found themselves in such an 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 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.

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 strength 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. I disassembled a non-working one as a radiator computer unit 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!

Pulses of constant 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

Take the time to modify your device with 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 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 it charges when 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 area.

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.

Desulfating scheme charger devices proposed by Samundzhi and L. Simeonov. The charger is made using a half-wave rectifier circuit based on diode VI with parametric voltage stabilization (V2) and a current amplifier (V3, V4). The H1 signal light lights up when the transformer is connected to the network. The average charging current of approximately 1.8 A is regulated by selecting resistor R3. The discharge current is set by resistor R1. The voltage on the secondary winding of the transformer is 21 V (amplitude value 28 V). The voltage on the battery at the rated charging current is 14 V. Therefore, the charging current of the battery occurs only when the amplitude of the output voltage of the current amplifier exceeds the battery voltage. During one period of alternating voltage, one pulse is formed charger then during time Ti. Radomkrofon circuits The battery discharge occurs during the time Tz = 2Ti. Therefore, the ammeter shows the average importance charger current, equal to approximately one third of the amplitude value of the total charger and discharge currents. You can use the TS-200 transformer from the TV in the charger. The secondary windings are removed from both coils of the transformer and a new winding consisting of 74 turns (37 turns on each coil) is wound with PEV-2 1.5 mm wire. Transistor V4 is mounted on a radiator with an effective surface area of ​​​​approximately 200 cm2. Details: Diodes VI type D242A. D243A, D245A. D305, V2 one or two zener diodes D814A connected in series, V5 type D226: transistors V3 type KT803A, V4 type KT803A or KT808A. When setting up...

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The simplest and cheapest switch is two diodes connected in an “OR” circuit. Load connected to each power source (battery and adapter) via separate diodes Schottky, is powered by the source whose voltage is greater.

The disadvantage of this approach is the power dissipation (PD = Ibatt × Vdiode) and voltage drop (Vdiode = 350 mV at 0.5 A for the PMEG2010AEH diode) when the battery is connected to the load. These losses are not particularly significant if high-voltage multi-cell batteries are used. But for single-element Li+, or two-element NiMH battery power losses and voltage drop across the diodes cannot be neglected.

An alternative to diodes can be charger chips that have a POK output (POK - “Power OK”), for example the MAX8814 chip, which switches loads with a voltage drop of only 45 mV at a current of 0.5 A (Fig. 1), which gives a gain compared to 305 mV diodes. Power losses in such circuits are 152.5 mW (175 mW - 22.5 mW) less than in circuits with diode “OR”. At lower currents, the circuit's performance becomes even better. So, with a load current of 100 mA, for example, the voltage drop across the diode is 270 mV, and on transistors of an alternative circuit it is only 10 mV.

This circuit switches the load without any involvement of the microcontroller or system program. When the load is powered by batteries and Vdc In is disabled, the POK output of U1 is high. In this case, the load is connected to the battery through Q4 and Q3. Node 1 receives battery voltage through R2, and transistors Q1 and Q2 are turned off. When Vdc In is connected to a constant voltage source, Q1 and Q2 remain off for a while thanks to capacitor C1, which increases the voltage at node 1 to Vbatt + Vdc.

High voltage appears at the gates of Q1 and Q2 immediately after Vdc is applied. To prevent the possibility of damage to the POK pin, transistor Q5 is added as a source follower. The gate of Q5 is supplied with battery voltage and the POK pin will not exceed this voltage. When the voltage at the POK pin drops, current begins to flow through Q5, the voltage at the gates of Q1 and Q2 goes low, and transistors Q1 and Q2 turn off. Vdc In is connected to the load, and U1 begins to charge the battery. C1 and R1 create a slight delay to allow Q3 to turn off completely and avoid uncontrolled current flowing to the battery.

If the external DC voltage source is removed from Vdc In, the POK pin will go into a high impedance state and battery current will flow through the internal diode of transistor Q3. The load voltage will be equal to Vbatt - Vdiode. Due to the battery voltage applied to the gate, Q5 will be open until POK reaches a level sufficient to connect the load through Q4 and Q3. Rice. Figure 2 illustrates the behavior of this circuit when the load is switched from a constant voltage source to the battery and then back to a constant voltage source.

By changing the circuit, you can use charge control chips that do not have a POK output, for example, the MAX1507 (Fig. 3). A signal similar to POK can be generated by a comparator (U3) comparing Vdc In with the battery voltage. The response of such a circuit is very similar to the response of the original circuit (Fig. 4).