I made this charger for charging car batteries, the output voltage is 14.5 volts, maximum current charge 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 fixed to large radiator. It is necessary to increase the radiators of the DC-DC converter, or use a fan for cooling.
Charger assembly
Connect the cord with a power plug and fuse to the primary winding of the TS-180-2 transformer, install diode bridge to 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 can be set to 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 at direct connection. 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 it will flow through it during charging. high current.
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.
Very often, especially in the cold season, motorists are faced with the need to charge car battery. It is possible, and advisable, to purchase a factory charger, preferably a charging and starting one for use in the garage.
But, if you have electrical engineering skills and certain knowledge in the field of radio engineering, then you can make a simple charger for a car battery with your own hands. In addition, it is better to prepare in advance for the possible event that the battery suddenly discharges far from home or a place where it is parked and serviced.
General information about the battery charging process
Charging a car battery is necessary when the voltage drop across the terminals is less than 11.2 Volts. Despite the fact that the battery can start the car engine even with such a charge, during long-term parking at low voltages, plate sulfation processes begin, which lead to loss of battery capacity.
Therefore, when wintering a car in a parking lot or garage, it is necessary to constantly recharge the battery and monitor the voltage at its terminals. A better option is to remove the battery and place it in warm place, but still do not forget about maintaining its charge.
The battery is charged using constant or pulsed current. In the case of charging from a constant voltage source, a charge current equal to one tenth of the battery capacity is usually selected.
For example, if the capacity battery is 60 ampere-hours, the charging current should be selected at 6 amperes. However, research shows that the lower the charge current, the less intense the sulfation processes.
Moreover, there are methods for desulfating battery plates. They are as follows. First, the battery is discharged to a voltage of 3 - 5 Volts with high currents of short duration. For example, such as when turning on the starter. Then there is a slow full charge with a current of about 1 Ampere. Such procedures are repeated 7-10 times. There is a desulfation effect from these actions.
Desulfating pulse chargers are practically based on this principle. The battery in such devices is charged with pulsed current. During the charging period (several milliseconds), a short discharge pulse of reverse polarity and a longer charging pulse of direct polarity are applied to the battery terminals.
It is very important during the charging process to prevent the effect of overcharging the battery, that is, the moment when it is charged to the maximum voltage (12.8 - 13.2 Volts, depending on the type of battery).
This can cause an increase in the density and concentration of the electrolyte, irreversible destruction of the plates. This is why factory chargers are equipped with electronic system control and shutdown.
Schemes of homemade simple chargers for a car battery
Protozoa
Let's consider the case of how to charge a battery using improvised means. For example, a situation when you left your car near your house in the evening, forgetting to turn off some electrical equipment. By morning the battery was discharged and would not start the car.
In this case, if your car starts well (with half a turn), it is enough to “tighten” the battery a little. How to do it? First, you need a constant voltage source ranging from 12 to 25 volts. Secondly, restrictive resistance.
What can you recommend?
Nowadays, almost every home has a laptop. The power supply of a laptop or netbook, as a rule, has an output voltage of 19 Volts and a current of at least 2 amperes. The external pin of the power connector is minus, the internal pin is positive.
As a limiting resistance, and it is mandatory!!!, you can use the car's interior light bulb. You can, of course, have more power from turn signals or even worse stops or dimensions, but there is a possibility of overloading the power supply. The simplest circuit is assembled: minus the power supply - light bulb - minus the battery - plus the battery - plus the power supply. In a couple of hours the battery will be charged enough to start the engine.
If you don’t have a laptop, you can pre-purchase a powerful rectifier diode on the radio market with a reverse voltage of more than 1000 Volts and a current of 3 Amperes. It is small in size and can be put in the glove compartment for an emergency.
What to do in an emergency?
Can be used as a limiting load ordinary lamps incandescent at 220 Volt. For example, a 100 Watt lamp (power = voltage X current). Thus, when using a 100-watt lamp, the charge current will be about 0.5 Ampere. Not much, but overnight it will give 5 Amp-hours of capacity to the battery. Usually it is enough to crank the car starter a couple of times in the morning.
If you connect three 100-watt lamps in parallel, the charging current will triple. You can charge your car battery almost halfway overnight. Sometimes they turn on an electric stove instead of lamps. But here the diode may already fail, and at the same time the battery.
In general, this kind of experiments with direct charging of the battery from an alternating voltage network of 220 Volts extremely dangerous. They should only be used in extreme cases when there is no other option.
From computer power supplies
Before you start making your own charger for a car battery, you should evaluate your knowledge and experience in the field of electrical and radio engineering. Accordingly, select the complexity level of the device.
First of all, you should decide on the element base. Very often, computer users are left with old system units. There are power supplies there. Along with the +5V supply voltage, they contain a +12 Volt bus. As a rule, it is designed for current up to 2 Amperes. This is quite enough for a weak charger.
Video - step-by-step instruction on the manufacture and diagram of a simple charger for a car battery from computer unit power supply:
But 12 volts is not enough. It is necessary to “overclock” it to 15. How? Usually using the “poke” method. Take a resistance of about 1 kiloOhm and connect it in parallel with other resistances near the microcircuit with 8 legs in the secondary circuit of the power supply.
Thus, the transmission coefficient of the circuit is changed feedback, respectively, and the output voltage.
It’s difficult to explain in words, but usually users succeed. By selecting the resistance value, you can achieve an output voltage of about 13.5 Volts. This is enough to charge a car battery.
If you don’t have a power supply at hand, you can look for a transformer with a secondary winding of 12 - 18 Volts. They were used in old tube televisions and other household appliances.
Now such transformers can be found in waste sources uninterruptible power supply, you can buy it for pennies on secondary market. Next, we begin manufacturing the transformer charger.
Transformer chargers
Transformer chargers are the most common and safe devices widely used in automotive practice.
Video - a simple charger for a car battery using a transformer:
The simplest circuit of a transformer charger for a car battery contains:
- network transformer;
- rectifier bridge;
- restrictive load.
A large current flows through the limiting load and it gets very hot, so to limit the charging current, capacitors are often used in the primary circuit of the transformer.
In principle, in such a circuit you can do without a transformer if you choose the capacitor wisely. But without galvanic isolation from the network alternating current such a circuit will be dangerous from the point of view of electric shock.
More practical are charger circuits for car batteries with regulation and limitation of the charge current. One of these schemes is shown in the figure:
You can use the rectifier bridge of a faulty car generator as powerful rectifier diodes by slightly reconnecting the circuit.
More complex pulse chargers with desulfation function are usually made using microcircuits, even microprocessors. They are difficult to manufacture and require special installation and configuration skills. In this case, it is easier to purchase a factory device.
Safety requirements
Conditions that must be met when using a homemade car battery charger:
- The charger and battery must be located on a fireproof surface during charging;
- when using simple chargers, it is necessary to use personal protective equipment (insulating gloves, rubber mat);
- when using newly manufactured devices, constant monitoring of the charging process is necessary;
- the main controlled parameters of the charging process are current, voltage at the battery terminals, temperature of the charger body and battery, control of the boiling point;
- When charging at night, it is necessary to have residual current devices (RCDs) in the network connection.
Video - diagram of a charger for a car battery from a UPS:
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Comments on the article:
Lyokha
The information presented here is certainly interesting and informative. As a former radio engineer of the Soviet school, I read it with great interest. But in reality, now even “desperate” radio amateurs are unlikely to bother searching for circuit diagrams for a homemade charger and later assembling it with a soldering iron and radio components. Only radio fanatics will do this. It’s much easier to buy a factory-made device, especially since the prices, I think, are affordable. IN as a last resort, you can turn to other car enthusiasts with a request to “light up”, fortunately, now there are plenty of cars everywhere. What is written here is useful not so much for its practical value (although that too), but for instilling interest in radio engineering in general. After all, most modern children not only cannot distinguish a resistor from a transistor, but they won’t be able to pronounce it the first time. And this is very sad...
Michael
When the battery was old and half-dead, I often used a laptop power supply to recharge. I used an unnecessary old one as a current limiter. back light with four 21 Watt bulbs connected in parallel. I control the voltage at the terminals, at the beginning of charging it is usually about 13 V, the battery greedily eats up the charge, then the charging voltage increases, and when it reaches 15 V, I stop charging. It takes half an hour to an hour to reliably start the engine.
Ignat
I have a Soviet charger in my garage, it’s called “Volna”, made in ’79. Inside is a hefty and heavy transformer and several diodes, resistors and transistors. Almost 40 years in service, and this despite the fact that my father and brother use it constantly, not only for charging, but also as a 12 V power supply. But now it’s really easier to buy a cheap one Chinese device for five hundred square meters, rather than bother with a soldering iron. And on Aliexpress you can even buy it for one and a half hundred, although it will take a long time to send it. Although I liked the option from the computer power supply, I have a dozen old ones lying around in the garage, but they work quite well.
San Sanych
Hmmm. Of course, the Pepsicol generation is growing... :-\ The correct charger should produce 14.2 volts. No more and no less. With a greater potential difference, the electrolyte will boil, and the battery will swell so that it will then be problematic to remove it or, conversely, not to install it back in the car. With a smaller potential difference, the battery will not charge. The most normal circuit presented in the material is with a step-down transformer (first). In this case, the transformer must produce exactly 10 volts at a current of at least 2 amperes. There are plenty of these on sale. It is better to install domestic diodes - D246A (must be installed on a radiator with mica insulators). At worst - KD213A (these can be glued with superglue to aluminum radiator). Any electrolytic capacitor with a capacity of at least 1000 uF for an operating voltage of at least 25 volts. A very large capacitor is also not needed, since due to the ripples of the under-rectified voltage we obtain the optimal charge for the battery. In total we get 10 * root of 2 = 14.2 volts. I myself have had such a charger since the days of the 412th Muscovite. Not killable at all. 🙂
Kirill
In principle, if you have the necessary transformer, it is not so difficult to assemble a transformer charger circuit yourself. Even for me, not a very big specialist in the field of radio electronics. Many people say, why bother if it’s easier to buy. I agree, but it’s not about the final result, but about the process itself, because it’s much more pleasant to use a manufactured thing with my own hands than purchased. And most importantly, if this homemade product breaks down, then the one who assembled it knows his battery charger thoroughly and is able to fix it quickly. And if a purchased product burns out, then you still need to dig around and it’s not at all a fact that a breakdown will be found. I vote for self-built devices!
Oleg
In general, I think that the ideal option is an industrial charger, so I have one and carry it in the trunk all the time. But in life situations are different. Once I was visiting my daughter in Montenegro, and there they generally don’t carry anything with them and rarely do anyone even have one. So she forgot to close the door at night. The battery is drained. No diode at hand, no computer. I found a Boschevsky screwdriver with 18 volts and 1 ampere current. So I used his charger. True, I charged it all night and periodically checked for overheating. But she couldn’t stand it, in the morning they started her with half a kick. So there are many options, you have to look. Well, regarding homemade chargers, as a radio engineer I can only recommend transformer ones, i.e. isolated via the network, they are safe compared to capacitors, diodes with a light bulb.
Sergey
Charging the battery with non-standard devices can lead to either complete irreversible wear or a decrease in guaranteed operation. The whole problem is connecting homemade products, so that the rated voltage does not exceed the permissible one. It is necessary to take into account temperature differences and this is very important point, especially in winter time. When we decrease by a degree, we increase it and vice versa. There is an approximate table depending on the type of battery - it is not difficult to remember. Another important point is that all measurements of voltage and, of course, density are made only when the engine is cold, with the engine not running.
Vitalik
In general, I use the charger extremely rarely, maybe once every two or three years, and only when I go away for a long time, for example in the summer for a couple of months to the south to visit relatives. And so basically the car is in operation almost every day, the battery is charged and there is no need for such devices. Therefore, I think that buying for money something that you practically never use is not very smart. The best option- assemble such a simple craft, say, from a computer power supply, and let it lie around, waiting in the wings. After all, the main thing here is not to fully charge the battery, but to cheer it up a little to start the engine, and then the generator will do its job.
Nikolai
Just yesterday we recharged the battery using a screwdriver charger. The car was parked outside, the frost was -28, the battery was spun a couple of times and stopped. We took out a screwdriver, a couple of wires, connected it, and after half an hour the car started up safely.
Dmitriy
A ready-made store charger is of course an ideal option, but who wants to use their own hands, and considering that you don’t have to use it often, you don’t have to spend money on the purchase and do the charging yourself.
A homemade charger should be autonomous, not require supervision or current control, since we charge most often at night. In addition, it must provide a voltage of 14.4 V and ensure that the battery is turned off when the current and voltage exceed the norm. It should also provide protection against polarity reversal.
The main mistakes that “Kulibins” make is connecting directly to a household electrical network, this is not even a mistake, but a violation of safety regulations, the next limiting the charging current is by capacitors, and it’s also more expensive: one bank of capacitors 32 uF at 350-400 V (less than that is not possible) will cost like a cool branded charger.
The easiest way is to use a computer switching power supply (UPS), it is now more affordable than a hardware transformer, and you don’t need to do separate protection, everything is ready.
If you don't have a computer power supply, you need to look for a transformer. A power supply with filament windings from old tube TVs - TS-130, TS-180, TS-220, TS-270 - is suitable. They have plenty of power behind their eyes. You can find an old TN filament transformer at the car market.
But all this is only for those who are friends with electricians. If not, don’t bother - you won’t do the exercises that meet all the requirements, so buy ready-made ones and don’t waste time.
Laura
I got a charger from my grandfather. Since Soviet times. Homemade. I don’t understand this at all, but when my friends see it, they click their tongues in admiration and respect, saying, this is a thing “for centuries.” They say it was assembled using some lamps and still works. True, I practically don’t use it, but that’s not the point. All Soviet technology They criticize it, but it turns out to be many times more reliable than the modern one, even homemade.
Vladislav
In general, a useful thing in the household, especially if there is a function for adjusting the output voltage
Alexei
I’ve never had the opportunity to use or assemble homemade chargers, but I can quite imagine the principle of assembly and operation. I think that homemade products are no worse than factory ones, it’s just that no one wants to tinker, especially since store-bought ones are quite affordable.
Victor
In general, the schemes are simple, there are few parts and they are accessible. Adjustment can also be done if you have some experience. So it's quite possible to collect. Of course, it is very pleasant to use a device assembled with your own hands)).
Ivan
The charger is, of course, a useful thing, but now there are more interesting specimens on the market - their name is start-chargers
Sergey
There are a lot of charger circuits and as a radio engineer I have tried many of them. Until last year, I had a scheme that worked for me since Soviet times and it worked perfectly. But one day (through my fault) the battery completely died in the garage and I needed a cyclic mode to restore it. Then I didn’t bother (due to lack of time) with creating new scheme, but just went and bought it. And now I carry a charger in the trunk just in case.
Hello uv. reader of the blog “My Radio Amateur Laboratory”.
In today's article we will talk about a long-used, but very useful diagram thyristor phase-pulse power regulator, which we will use as a charger for lead-acid batteries.
Let's start with the fact that the charger on the KU202 has whole line advantages:
— Ability to withstand charging current up to 10 amperes
— The charge current is pulsed, which, according to many radio amateurs, helps extend the life of the battery
— The circuit is assembled from non-scarce, inexpensive parts, which makes it very accessible in price category
- And the last plus is the ease of repetition, which will make it possible to repeat it, both for a beginner in radio engineering, and simply for a car owner who has no knowledge of radio engineering at all, who needs high-quality and simple charging.
Over time, I tried a modified scheme with automatic shutdown battery, I recommend reading
At one time, I assembled this circuit on my knee in 40 minutes, along with wiring the board and preparing the circuit components. Well, enough stories, let's look at the diagram.
Scheme of a thyristor charger on KU202
List of components used in the circuit
C1 = 0.47-1 µF 63V
R1 = 6.8k - 0.25W
R2 = 300 - 0.25 W
R3 = 3.3k - 0.25W
R4 = 110 - 0.25 W
R5 = 15k - 0.25W
R6 = 50 - 0.25W
R7 = 150 - 2W
FU1 = 10A
VD1 = current 10A, it is advisable to take a bridge with a reserve. Well, at 15-25A and the reverse voltage is not lower than 50V
VD2 = any pulse diode, reverse voltage not lower than 50V
VS1 = KU202, T-160, T-250
VT1 = KT361A, KT3107, KT502
VT2 = KT315A, KT3102, KT503
As mentioned earlier, the circuit is a thyristor phase-pulse power regulator with an electronic charging current regulator.
The thyristor electrode is controlled by a circuit using transistors VT1 and VT2. The control current passes through VD2, which is necessary to protect the circuit from reverse surges in the thyristor current.
Resistor R5 determines the battery charging current, which should be 1/10 of the battery capacity. For example, a battery with a capacity of 55A must be charged with a current of 5.5A. Therefore, it is advisable to place an ammeter at the output in front of the charger terminals to monitor the charging current.
Regarding the power supply, for this circuit we select a transformer with an alternating voltage of 18-22V, preferably in terms of power without reserve, because we use a thyristor in the control. If the voltage is higher, raise R7 to 200 Ohm.
We also do not forget that the diode bridge and the control thyristor must be installed on the radiators through heat-conducting paste. Also, if you use simple diodes such as D242-D245, KD203, remember that they must be isolated from the radiator housing.
We put a fuse at the output for the currents you need; if you do not plan to charge the battery with a current higher than 6A, then a 6.3A fuse will be enough for you.
Also, to protect your battery and charger, I recommend installing mine or, which, in addition to protection against polarity reversal, will protect the charger from connecting dead batteries with a voltage of less than 10.5V.
Well, in principle, we looked at the charger circuit for the KU202.
Printed circuit board of the thyristor charger on KU202
Assembled from Sergei
Good luck with your repetition and I look forward to your questions in the comments.
For safe, high-quality and reliable charging of any types of batteries, I recommend
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Don’t want to delve into the routine of radio electronics? I recommend paying attention to the proposals of our Chinese friends. For quite reasonable price You can buy some pretty good quality chargers
A simple charger with an LED charging indicator, green battery is charging, red battery is charged.
There is short circuit protection and reverse polarity protection. Perfect for charging Moto batteries with a capacity of up to 20A/h; a 9A/h battery will charge in 7 hours, 20A/h in 16 hours. The price for this charger is only 403 rubles, free delivery
This type of charger is capable of automatically charging almost any type of 12V car and motorcycle batteries up to 80A/H. It has unique way charging in three stages: 1. Charging DC, 2. Charging constant voltage, 3. Drop recharging up to 100%.
There are two indicators on the front panel, the first indicates the voltage and charging percentage, the second indicates the charging current.
Quite a high-quality device for home needs, the price is just RUR 781.96, free delivery. At the time of writing these lines number of orders 1392, grade 4.8 out of 5. When ordering, do not forget to indicate Eurofork
Charger for a wide variety of battery types 12-24V with current up to 10A and peak current 12A. Able to charge Helium batteries and SA\SA. The charging technology is the same as the previous one in three stages. The charger is capable of charging both automatic mode, and manually. The panel has an LCD indicator indicating voltage, charging current and charging percentage.
