Long-term use of the car leads to the fact that the generator stops charging the battery. As a result, the car will no longer start. To revive the car you need a charger. In addition, lead-acid batteries are highly sensitive to temperatures. Therefore, problems may arise with their operation if the temperature outside is sub-zero.
A car charger is not particularly technically complex. To collect it you don’t need to have any highly specialized knowledge, just perseverance and ingenuity. Of course, you will need certain parts, but they can easily be purchased on the radio market for almost nothing.
Types of chargers for cars
Science does not stand still. Technologies are developing at an incredible speed; it is not surprising that transformer chargers are gradually disappearing from the market, and they are being replaced by pulsed and automatic chargers.
The pulse charger for the car has compact dimensions. His easy to use, and unlike transformer type devices of this class provide a full battery charge. The charging process takes place in two stages: first at constant voltage, then at current. The design consists of similar circuits.
The automatic car charger is extremely easy to use. In fact, this is a multifunctional diagnostic center, which is extremely difficult to assemble on your own.
The most advanced devices of this class will notify you with a signal if the poles are connected incorrectly. Moreover, the power supply will not even start. You cannot ignore the diagnostic functions of the device. It is able to measure battery capacity and even charge level.
Electrical circuits have a timer. Therefore, an automatic car charger allows for various types of charging:
- full,
- fast,
- restorative.
Once the automatic car charger has finished charging, a beep will sound and the current will automatically stop flowing.
Three ways to make a car charger with your own hands
How to make a charger from a computer block
Old computers are not uncommon. Some people leave them out of a sense of nostalgia, while others hope to use serviceable components somewhere. If you don’t have an old desktop computer at home, it’s okay. Second-hand The power supply can be purchased for 200-300 rubles.
Power supplies from desktop computers are ideal for creating any chargers. The controller used here is the TL494 chip or a similar KA7500 chip.
The power supply for the charger must be 150 W or higher. All wires from sources -5, -12, +5, +12 V are soldered off. The same is done with resistor R1. It needs to be replaced with a trim resistor. In this case, the value of the latter should be 27 Ohms.
The operating diagram of a car charger from a power supply is extremely simple. The voltage from the bus marked at +12 V is transmitted to the upper pin. In this case, pins 14 and 15 are simply cut off due to their uselessness.
Important! The only pin that needs to be left is the sixteenth one. It is adjacent to the main wire. But at the same time it needs to be turned off.
A potentiometer-regulator R10 should be installed on the rear wall of the power supply. You also need to run two cords: one for connecting the terminals, the other for the network. Additionally, you need to prepare a block of resistors. It will allow for adjustments.
To make the block described above, you will need two current measuring resistors. It is best to use 5W8R2J. A power of 5 W is quite enough. The block resistance will be 0.1 Ohm, and the total power will be 10 W.
To configure, you will need a trim resistor. It is attached to the same board. Part of the print track is first removed. This will eliminate the possibility of communication between the case and the main circuit, and will also significantly increase the safety of the car charger.
Before as solder pins 1, 14-16, they must first be tinned. Multi-core thin wires are soldered. Full charge is determined by the open circuit voltage. The standard range is 13.8-14.2 V.
The full charge is set by a variable resistor. It is important that potentiometer R10 is in the middle position. To connect the output to the terminals, special clamps are installed at the ends. It is best to use the crocodile type.
The insulating tubes of the clamps must be made in different colors. Traditionally, red is a plus, blue is a minus. But you can choose any colors you like. This is not important.
Important! If you mix up the wires, it will damage the device.
To save time and money when assembling a charger for a car, you can eliminate the volt and ammeter from the design. The initial current can be set using potentiometer R10. Recommended value is 5.5 and 6.5 A.
Charger from adapter
The best option for creating a car charger is a 12-volt adapter. But when choosing a voltage, you must first consider the battery parameters.
The adapter wire must be cut at the end and exposed. About 5-7 centimeters will be enough for comfortable work. Wires with opposite charges must be laid at a distance of 40 centimeters from each other. A “crocodile” is put on the end of each one.
The clamps are connected to the battery in sequential order. Plus to plus, minus to minus. After that, all you need to do is turn on the adapter. This is one of the simplest schemes for creating a charger for a car with your own hands.
Important! During the charging process, you need to ensure that the battery does not overheat. If this happens, the process must be interrupted immediately to avoid damage to the battery.
Everything ingenious is simple or a car charger made from a light bulb and a diode
Everything you need to create this charger can be found at home. The main element of the design will be an ordinary light bulb. Moreover, its power should not be higher than 200 W.
Important! The more power, the faster the battery will charge.
When charging, some care must be taken. You should not charge a low-capacity battery with a 200-watt light bulb. Most likely this will lead to it simply boiling. There is a simple calculation formula that will help you choose the optimal light bulb power for your battery.
You will also need a semiconductor diode that will conduct electricity in only one direction. It can be made from a regular laptop charger. The final element of the design will be a wire with terminals and a plug.
It is very important to follow safety rules when creating a charger for a car. First, always unplug the circuit before touching any of the elements with your hand. Secondly, all contacts must be carefully isolated. There should be no exposed wires.
When assembling the circuit, all elements are connected in series: lamp, diode, battery. It is important to know the polarity of the diode in order to connect everything correctly. For greater safety, use rubber gloves.
When assembling the circuit, pay special attention to the diode. There is usually an arrow on it that points to the plus. Since it only allows electricity to pass in one direction, this is extremely important. You can use a tester to check the polarity of the terminals.
If everything is configured and connected correctly, the light will light at half a channel. If there is no light, it means you did something wrong or the battery is completely discharged.
The charging process itself takes about 6-8 hours. After this time period, the car charger must be disconnected from the network to avoid overheating of the battery.
If you urgently need to recharge the battery, the process can be accelerated. The main thing is that the diode is powerful enough. You will also need a heater. All elements are connected into one circuit. The efficiency of this charging method is only 1%, but the speed is many times higher.
Results
The simplest car charger can be assembled with your own hands in a few hours. At the same time, a set of necessary materials can be found in every home. More complex devices require more time to create, but they have increased reliability and a good level of security.
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:- 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.
- 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.
- 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.
- 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.
- 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:
- A) Headlights not turned off when stopping and sub-zero temperatures are the most common causes of battery discharge on the road.
- A) The battery fails if it is not recharged for a long time when the car is idle.
- A) For recharging, a mains voltage of 220 V is used.
- A) It is not advisable to charge the battery with a homemade device if it is not removed from the car.
- 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
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- You need to be very careful not to confuse “plus” and “minus”, otherwise Charger will burn.
- 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:
- Stack.
- Sonar.
- 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.
- Direct to mains battery connection is prohibited. Chargers are intended for this purpose.
- Even device it is 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:
- dc-dc buck converter.
- Ammeter.
- Diode bridge KVRS 5010.
- Hubs 2200 uF at 50 volts.
- transformer TS 180-2.
- Circuit breakers.
- Plug for connecting to the network.
- "Crocodiles" for connecting terminals.
- 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 DIY charging concepts
Simple circuits
1 the simplest scheme for an automatic charger for a car battery
Who has not encountered in their practice the need to charge a battery and, disappointed in the lack of a charger with the necessary parameters, was forced to purchase a new charger in a store, or reassemble the necessary circuit?
So I have repeatedly had to solve the problem of charging various batteries when there was no suitable charger at hand. I had to quickly assemble something simple, in relation to a specific battery.
The situation was tolerable until the need for mass preparation and, accordingly, charging the batteries arose. It was necessary to produce several universal chargers - inexpensive, operating in a wide range of input and output voltages and charging currents.
The charger circuits proposed below were developed for charging lithium-ion batteries, but it is possible to charge other types of batteries and composite batteries (using the same type of cells, hereinafter referred to as AB).
All presented schemes have the following main parameters:
input voltage 15-24 V;
charge current (adjustable) up to 4 A;
output voltage (adjustable) 0.7 - 18 V (at Uin=19V).
All circuits were designed to work with power supplies from laptops or to work with other power supplies with DC output voltages from 15 to 24 Volts and were built on widespread components that are present on the boards of old computer power supplies, power supplies of other devices, laptops, etc.
Memory circuit No. 1 (TL494)
The memory in Scheme 1 is a powerful pulse generator operating in the range from tens to a couple of thousand hertz (the frequency varied during research), with an adjustable pulse width.
The battery is charged by current pulses limited by feedback formed by the current sensor R10, connected between the common wire of the circuit and the source of the switch on the field-effect transistor VT2 (IRF3205), filter R9C2, pin 1, which is the “direct” input of one of the error amplifiers of the TL494 chip.
The inverse input (pin 2) of the same error amplifier is supplied with a comparison voltage, regulated by a variable resistor PR1, from a reference voltage source built into the chip (ION - pin 14), which changes the potential difference between the inputs of the error amplifier.
As soon as the voltage value on R10 exceeds the voltage value (set by the variable resistor PR1) at pin 2 of the TL494 microcircuit, the charging current pulse will be interrupted and resumed again only at the next cycle of the pulse sequence generated by the microcircuit generator.
By thus adjusting the width of the pulses on the gate of transistor VT2, we control the battery charging current.
Transistor VT1, connected in parallel with the gate of a powerful switch, provides the necessary discharge rate of the gate capacitance of the latter, preventing “smooth” locking of VT2. In this case, the amplitude of the output voltage in the absence of a battery (or other load) is almost equal to the input supply voltage.
With an active load, the output voltage will be determined by the current through the load (its resistance), which allows this circuit to be used as a current driver.
When charging the battery, the voltage at the switch output (and, therefore, at the battery itself) will tend to increase over time to a value determined by the input voltage (theoretically) and this, of course, cannot be allowed, knowing that the voltage value of the lithium battery being charged should be limited to 4.1V (4.2V). Therefore, the memory uses a threshold device circuit, which is a Schmitt trigger (hereinafter - TS) on an op-amp KR140UD608 (IC1) or on any other op-amp.
When the required voltage value on the battery is reached, at which the potentials at the direct and inverse inputs (pins 3, 2 - respectively) of IC1 are equal, a high logical level (almost equal to the input voltage) will appear at the output of the op-amp, causing the LED indicating the end of charging HL2 and the LED to light up optocoupler VH1 which will open its own transistor, blocking the supply of pulses to output U1. The key on VT2 will close and the battery will stop charging.
Once the battery is charged, it will begin to discharge through the reverse diode built into VT2, which will be directly connected in relation to the battery and the discharge current will be approximately 15-25 mA, taking into account the discharge also through the elements of the TS circuit. If this circumstance seems critical to someone, a powerful diode (preferably with a low forward voltage drop) should be placed in the gap between the drain and the negative terminal of the battery.
The TS hysteresis in this version of the charger is chosen such that the charge will begin again when the voltage on the battery drops to 3.9 V.
This charger can also be used to charge series-connected lithium (and other) batteries. It is enough to calibrate the required response threshold using variable resistor PR3.
So, for example, a charger assembled according to scheme 1 operates with a three-section serial battery from a laptop, consisting of dual elements, which was mounted to replace the nickel-cadmium battery of a screwdriver.
The power supply from the laptop (19V/4.7A) is connected to the charger, assembled in the standard case of the screwdriver charger instead of the original circuit. The charging current of the “new” battery is 2 A. At the same time, transistor VT2, working without a radiator, heats up to a maximum temperature of 40-42 C.
The charger is switched off, naturally, when the battery voltage reaches 12.3V.
The TS hysteresis when the response threshold changes remains the same as a PERCENTAGE. That is, if at a shutdown voltage of 4.1 V, the charger was turned on again when the voltage dropped to 3.9 V, then in this case the charger was turned on again when the voltage on the battery decreased to 11.7 V. But if necessary, the hysteresis depth can change.
Charger Threshold and Hysteresis Calibration
Calibration occurs using an external voltage regulator (laboratory power supply).The upper threshold for triggering the TS is set.
1. Disconnect the upper pin PR3 from the charger circuit.
2. We connect the “minus” of the laboratory power supply (hereinafter referred to as the LBP everywhere) to the negative terminal for the battery (the battery itself should not be in the circuit during setup), the “plus” of the LBP to the positive terminal for the battery.
3. Turn on the charger and LBP and set the required voltage (12.3 V, for example).
4. If the end of charge indication is on, rotate the PR3 slider down (according to the diagram) until the indication goes out (HL2).
5. Slowly rotate the PR3 engine upward (according to the diagram) until the indication lights up.
6. Slowly reduce the voltage level at the output of the LBP and monitor the value at which the indication goes out again.
7. Check the level of operation of the upper threshold again. Fine. You can adjust the hysteresis if you are not satisfied with the voltage level that turns on the charger.
8. If the hysteresis is too deep (the charger is switched on at a too low voltage level - below, for example, the battery discharge level), turn the PR4 slider to the left (according to the diagram) or vice versa - if the hysteresis depth is insufficient, - to the right (according to the diagram). When changing depth of hysteresis, the threshold level may shift by a couple of tenths of a volt.
9. Make a test run, raising and lowering the voltage level at the LBP output.
Setting the current mode is even easier.
1. We turn off the threshold device using any available (but safe) methods: for example, by “connecting” the PR3 engine to the common wire of the device or by “shorting” the LED of the optocoupler.
2. Instead of the battery, we connect a load in the form of a 12-volt light bulb to the output of the charger (for example, I used a pair of 12V 20-watt lamps to set up).
3. We connect the ammeter to the break of any of the power wires at the input of the charger.
4. Set the PR1 engine to minimum (to the maximum left according to the diagram).
5. Turn on the memory. Smoothly rotate the PR1 adjustment knob in the direction of increasing current until the required value is obtained.
You can try to change the load resistance towards lower values of its resistance by connecting in parallel, say, another similar lamp or even “short-circuiting” the output of the charger. The current should not change significantly.
During testing of the device, it turned out that frequencies in the range of 100-700 Hz were optimal for this circuit, provided that IRF3205, IRF3710 were used (minimum heating). Since the TL494 is underutilized in this circuit, the free error amplifier on the IC can be used to drive a temperature sensor, for example.
It should also be borne in mind that if the layout is incorrect, even a correctly assembled pulse device will not work correctly. Therefore, one should not neglect the experience of assembling power pulse devices, described repeatedly in the literature, namely: all “power” connections of the same name should be located at the shortest distance relative to each other (ideally at one point). So, for example, connection points such as the collector VT1, the terminals of resistors R6, R10 (connection points with the common wire of the circuit), terminal 7 of U1 - should be combined almost at one point or through a straight short and wide conductor (bus). The same applies to drain VT2, the output of which should be “hung” directly onto the “-” terminal of the battery. The terminals of IC1 must also be in close “electrical” proximity to the battery terminals.
Memory circuit No. 2 (TL494)
Scheme 2 is not very different from Scheme 1, but if the previous version of the charger was designed to work with an AB screwdriver, then the charger in Scheme 2 was conceived as a universal, small-sized (without unnecessary configuration elements), designed to work with composite, sequentially connected elements up to 3, and with singles.
As you can see, to quickly change the current mode and work with different numbers of elements connected in series, fixed settings have been introduced with trimming resistors PR1-PR3 (current setting), PR5-PR7 (setting the end of charging threshold for a different number of elements) and switches SA1 (current selection charging) and SA2 (selecting the number of battery cells to be charged).
The switches have two directions, where their second sections switch the mode selection indication LEDs.
Another difference from the previous device is the use of a second error amplifier TL494 as a threshold element (connected according to the TS circuit) that determines the end of battery charging.
Well, and, of course, a p-conductivity transistor was used as a key, which simplified the full use of the TL494 without the use of additional components.
The method for setting the end of charging thresholds and current modes is the same, as for setting up the previous version of the memory. Of course, for a different number of elements, the response threshold will change multiples.
When testing this circuit, we noticed stronger heating of the switch on the VT2 transistor (when prototyping I use transistors without a heatsink). For this reason, you should use another transistor (which I simply didn’t have) of appropriate conductivity, but with better current parameters and lower open-channel resistance, or double the number of transistors indicated in the circuit, connecting them in parallel with separate gate resistors.
The use of these transistors (in a “single” version) is not critical in most cases, but in this case, the placement of the device components is planned in a small-sized case using small radiators or no radiators at all.
Memory circuit No. 3 (TL494)
In the charger in diagram 3, automatic disconnection of the battery from the charger with switching to the load has been added. This is convenient for checking and studying unknown batteries. The TS hysteresis for working with a battery discharge should be increased to the lower threshold (for switching on the charger), equal to the full battery discharge (2.8-3.0 V).
Charger circuit No. 3a (TL494)
Scheme 3a is a variant of scheme 3.
Memory circuit No. 4 (TL494)
The charger in diagram 4 is no more complicated than the previous devices, but the difference from the previous schemes is that the battery here is charged with direct current, and the charger itself is a stabilized current and voltage regulator and can be used as a laboratory power supply module, classically built according to “datasheet” to the canons.
Such a module is always useful for bench tests of both batteries and other devices. It makes sense to use built-in devices (voltmeter, ammeter). Formulas for calculating storage and interference chokes are described in the literature. I’ll just say that I used ready-made various chokes (with a range of specified inductances) during testing, experimenting with a PWM frequency from 20 to 90 kHz. I didn’t notice any particular difference in the operation of the regulator (in the range of output voltages 2-18 V and currents 0-4 A): minor changes in the heating of the key (without a radiator) suited me quite well. The efficiency, however, is higher when using smaller inductances.
The regulator worked best with two series-connected 22 µH chokes in square armored cores from converters integrated into laptop motherboards.
Memory circuit No. 5 (MC34063)
In diagram 5, a version of the PWM controller with current and voltage regulation is made on the MC34063 PWM/PWM chip with an “add-on” on the CA3130 op amp (other op amps can be used), with the help of which the current is regulated and stabilized.
This modification somewhat expanded the capabilities of the MC34063, in contrast to the classic inclusion of the microcircuit, allowing the function of smooth current control to be implemented.
Memory circuit No. 6 (UC3843)
In diagram 6, a version of the PHI controller is made on the UC3843 (U1) chip, CA3130 op-amp (IC1), and LTV817 optocoupler. The current regulation in this version of the charger is carried out using a variable resistor PR1 at the input of the current amplifier of the U1 microcircuit, the output voltage is regulated using PR2 at the inverting input IC1.
There is a “reverse” reference voltage at the “direct” input of the op-amp. That is, regulation is carried out relative to the “+” power supply.
In schemes 5 and 6, the same sets of components (including chokes) were used in the experiments. According to the test results, all of the listed circuits are not much inferior to each other in the declared range of parameters (frequency/current/voltage). Therefore, a circuit with fewer components is preferable for repetition.
Memory circuit No. 7 (TL494)
The memory in diagram 7 was conceived as a bench device with maximum functionality, therefore there were no restrictions on the volume of the circuit and the number of adjustments. This version of the charger is also made on the basis of a PHI current and voltage regulator, like the option in diagram 4.
Additional modes have been introduced into the scheme.
1. “Calibration - charge” - for pre-setting the end voltage thresholds and repeating charging from an additional analog regulator.
2. “Reset” - to reset the charger to charge mode.
3. “Current - buffer” - to switch the regulator to current or buffer (limiting the output voltage of the regulator in the joint supply of the device with battery voltage and the regulator) charge mode.
A relay is used to switch the battery from the “charge” mode to the “load” mode.
Working with the memory is similar to working with previous devices. Calibration is carried out by switching the toggle switch to the “calibration” mode. In this case, the contact of the toggle switch S1 connects the threshold device and a voltmeter to the output of the integral regulator IC2. Having set the required voltage for the upcoming charging of a specific battery at the output of IC2, using PR3 (smoothly rotating) the HL2 LED lights up and, accordingly, relay K1 operates. By reducing the voltage at the output of IC2, HL2 is suppressed. In both cases, control is carried out by a built-in voltmeter. After setting the PU response parameters, the toggle switch is switched to charge mode.
Scheme No. 8
The use of a calibration voltage source can be avoided by using the memory itself for calibration. In this case, you should decouple the TS output from the SHI controller, preventing it from turning off when the battery charge is complete, determined by the TS parameters. The battery will one way or another be disconnected from the charger by the contacts of relay K1. The changes for this case are shown in Figure 8.
In calibration mode, toggle switch S1 disconnects the relay from the positive power supply to prevent inappropriate operations. In this case, the indication of the operation of the TC works.
Toggle switch S2 performs (if necessary) forced activation of relay K1 (only when calibration mode is disabled). Contact K1.2 is necessary to change the polarity of the ammeter when switching the battery to the load.
Thus, a unipolar ammeter will also monitor the load current. If you have a bipolar device, this contact can be eliminated.
Charger design
In designs it is desirable to use as variable and tuning resistors multi-turn potentiometers to avoid suffering when setting the necessary parameters.
Design options are shown in the photo. The circuits were soldered impromptu onto perforated breadboards. All the filling is mounted in cases from laptop power supplies.
They were used in designs (they were also used as ammeters after minor modifications).
The cases are equipped with sockets for external connection of batteries, loads, and a jack for connecting an external power supply (from a laptop).
Over 18 years of work at North-West Telecom, he has made many different stands for testing various equipment being repaired.
He designed several digital pulse duration meters, different in functionality and elemental base.
More than 30 improvement proposals for the modernization of units of various specialized equipment, incl. - power supply. For a long time now I have been increasingly involved in power automation and electronics.
Why am I here? Yes, because everyone here is the same as me. There is a lot of interest here for me, since I am not strong in audio technology, but I would like to have more experience in this area.
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Today we will look at 3 simple charger circuits that can be used to charge a wide variety of batteries.
The first 2 circuits operate in linear mode, and linear mode primarily means high heat. But the charger is a stationary thing, and not portable, so that efficiency is a decisive factor, so the only disadvantage of the presented circuits is that they need a large cooling radiator, but otherwise everything is fine. Such schemes have always been used and will be used, as they have undeniable advantages: simplicity, low cost, do not “crap” the network (as in the case of pulsed circuits) and high repeatability.
Let's look at the first diagram:
This circuit consists of just a pair of resistors (with the help of which the end of charge voltage or the output voltage of the circuit as a whole is set) and a current sensor that sets the maximum output current of the circuit.
If you need a universal charger, the circuit will look like this:
By rotating the trimming resistor, you can set any output voltage from 3 to 30 V. In theory, up to 37V is possible, but in this case, 40V must be supplied to the input, which the author (AKA KASYAN) does not recommend doing. The maximum output current depends on the resistance of the current sensor and cannot be higher than 1.5A. The output current of the circuit can be calculated using the following formula:
Where 1.25 is the voltage of the reference source of the lm317 microcircuit, Rs is the resistance of the current sensor. To obtain a maximum current of 1.5A, the resistance of this resistor should be 0.8 Ohm, but in the circuit it is 0.2 Ohm.
The fact is that even without a resistor, the maximum current at the output of the microcircuit will be limited to the specified value; the resistor here is mostly for insurance, and its resistance is reduced to minimize losses. The greater the resistance, the more the voltage across it will drop, and this will lead to strong heating of the resistor.
The microcircuit must be installed on a massive radiator; an unstabilized voltage of up to 30-35V is supplied to the input, this is slightly less than the maximum permissible input voltage for the lm317 microcircuit. It must be remembered that the lm317 chip can dissipate a maximum of 15-20W of power, be sure to take this into account. You also need to take into account that the maximum output voltage of the circuit will be 2-3 volts less than the input.
Charging occurs at a stable voltage, and the current cannot exceed the set threshold. This circuit can even be used to charge lithium-ion batteries. If there is a short circuit at the output, nothing bad will happen, the current will simply be limited, and if the cooling of the microcircuit is good and the difference between the input and output voltages is small, the circuit can operate in this mode for an infinitely long time.
Everything is assembled on a small printed circuit board.
You can find it, as well as the printed circuit boards for the two subsequent circuits, along with the general archive of the project.
Second scheme is a powerful stabilized power supply with a maximum output current of up to 10A, it was built on the basis of the first option.
It differs from the first circuit in that an additional direct conduction power transistor is added here.
The maximum output current of the circuit depends on the resistance of the current sensors and the collector current of the transistor used. In this case, the current is limited to 7A.
The output voltage of the circuit is adjustable in the range from 3 to 30V, which will allow you to charge almost any battery. The output voltage is regulated using the same trimming resistor.
This option is great for charging car batteries; the maximum charge current with the components indicated in the diagram is 10A.
Now let's look at the principle of operation of the circuit. At low current values, the power transistor is closed. As the output current increases, the voltage drop across the specified resistor becomes sufficient and the transistor begins to open, and all the current will flow through the open junction of the transistor.
Naturally, due to the linear operating mode, the circuit will heat up, the power transistor and current sensors will heat up especially harshly. The transistor with the lm317 chip is screwed onto a common massive aluminum radiator. There is no need to insulate the heat sink substrates, since they are common.
It is very desirable and even mandatory to use an additional fan if the circuit will be operated at high currents.
To charge batteries, you need to set the end-of-charge voltage by rotating the trimming resistor and that’s it. The maximum charging current is limited to 10 amperes; as the batteries charge, the current will drop. The circuit is not afraid of short circuits; in case of a short circuit, the current will be limited. As in the case of the first scheme, if there is good cooling, the device will be able to tolerate this operating mode for a long time.
Well, now some tests:
As you can see, the stabilization is working, so everything is fine. And finally third scheme:
It is a system that automatically turns off the battery when fully charged, that is, it is not really a charger. The initial circuit underwent some modifications, and the board was refined during testing.
Let's look at the diagram.
As you can see, it is painfully simple, it contains only 1 transistor, an electromagnetic relay and small things. The author also has a diode bridge at the input and primitive protection against polarity reversal on the board; these components are not shown on the diagram.
The input of the circuit is supplied with constant voltage from the charger or any other power source.
It is important to note here that the charging current should not exceed the permissible current through the relay contacts and the fuse tripping current.
When power is supplied to the input of the circuit, the battery is charged. The circuit contains a voltage divider that monitors the voltage directly on the battery.
As it charges, the voltage on the battery will increase. As soon as it becomes equal to the operating voltage of the circuit, which can be set by rotating the trimming resistor, the zener diode will operate, sending a signal to the base of the low-power transistor and it will operate.
Since an electromagnetic relay coil is connected to the collector circuit of the transistor, the latter will also work and the indicated contacts will open, and further power supply to the battery will stop, at the same time the second LED will work, notifying that charging is complete.
There are a huge number of circuits and designs that will allow us to charge a car battery; in this article we will consider only a few of them, but the most interesting and the simplest possible
As a basis for this car charger, let's take one of the simplest circuits that I could dig up on the Internet; first of all, I liked the fact that the transformer can be borrowed from an old TV
As I said above, I took the most expensive part of the charger from the power supply of the Record TV; it turned out to be the TS-160 power transformer, which was especially pleasing; it had a sign displaying all possible voltages and currents. I chose a combination with the maximum current, that is, from the secondary winding I took 6.55 V at 7.5 A
But as you know, charging a car battery requires 12 volts, so we simply connect two windings with the same parameters in series (9 and 9" and 10 and 10"). And at the output we get 6.55 + 6.55 = 13.1 V AC voltage. To straighten it, you will need to assemble a diode bridge, but given the high current strength, the diodes should not be weak. (You can see their parameters in). I took the domestic D242A diodes recommended by the circuit
From the electrical engineering course we know that a discharged battery has a low voltage, which increases as it charges. Based on the current strength at the beginning of the charging process, it will be very high. And a large current will flow through the diodes, which will cause the diodes to heat up. Therefore, in order not to burn them, you need to use a radiator. The easiest way to use a radiator is to use the case of a non-working power supply from a computer. Well, to understand at what stage the battery is charging, we use an ammeter that we connect in series. When the charging current drops to 1A, we consider the battery to be fully charged. Do not remove the fuse from the circuit, otherwise when the secondary winding closes (which can sometimes happen when one of the diodes short-circuits), your power transformer will shut down
The simple homemade charger discussed below has large limits for regulating the charging current up to 10 A, and does an excellent job of charging various starter batteries of batteries designed for a voltage of 12 V, i.e. it is suitable for most modern cars.
The charger circuit is made on a triac regulator, with an additional diode bridge and resistors R3 and R5.
Device operation When power is applied at a positive half-cycle, capacitor C2 is charged through the circuit R3 - VD1 - R1 and R2 - SA1. With a negative half-cycle, capacitor C2 is charged through diode VD2; only the charging polarity changes. When the threshold charge level is reached, a neon lamp flashes on the capacitor, and the capacitor is discharged through it and the control electrode of the VS1 smistor. In this case, the latter will open for the remaining time until the end of the half-period. The described process is cyclical and is repeated every half-cycle of the network.
Resistor R6 is used to generate discharge current pulses, which increases battery life. The transformer must provide a voltage on the secondary winding of 20 V at a current of 10 A. The triac and diodes must be placed on the radiator. It is advisable to place resistor R1 regulating the charging current on the front panel.
When setting up the circuit, first set the required charging current limit with resistor R2. A 10A ammeter is inserted into the open circuit, then the handle of the variable resistor R1 is set to the extreme position, and the resistor R2 to the opposite position, and the device is connected to the network. By moving knob R2, set the required value of the maximum charging current. Finally, the scale of resistor R1 is calibrated in amperes. It must be remembered that when charging a battery, the current through it decreases by an average of 20% by the end of the process. Therefore, before starting the operation, you should set the initial current slightly higher than the rated value. The end of the charging process is determined using a voltmeter - the voltage of the disconnected battery should be 13.8 - 14.2 V.
Automatic car charger- The circuit turns on the battery for charging when its voltage drops to a certain level and turns it off when it reaches the maximum. The maximum voltage for acid car batteries is 14.2...14.5 V, and the minimum permissible during discharge is 10.8 V
Automatic voltage polarity switch for charger- designed for charging twelve-volt car batteries. Its main feature is that it allows connecting a battery with any polarity.
Automatic charger- The circuit consists of a current stabilizer on transistor VT1, a control device on comparator D1, thyristor VS1 for fixing the state and key transistor VT2, which controls the operation of relay K1
Restoring and charging a car battery- Restoration method with “asymmetrical” current. In this case, the ratio of charging and discharging current is selected to be 10:1 (optimal mode). This mode allows you not only to restore sulfated batteries, but also to carry out preventive treatment of serviceable ones.
Method for restoring acid batteries using alternating current- The technology for restoring lead batteries with alternating current allows you to quickly reduce the internal resistance to the factory value, with slight heating of the electrolyte. The positive half-cycle of the current is used completely when charging batteries with slight operating sulfation, when the power of the charging current pulse is sufficient to restore the plates.
If you have a gel battery in your car, the question will arise as to how to charge it. Therefore, I propose this simple circuit on the L200C chip, which is a conventional voltage stabilizer with a programmable output current limiter. R2-R6 - Current setting resistors. It is advisable to place the microcircuit on a radiator. Resistor R7 adjusts the output voltage from 14 to 15 volts.
If you use diodes in a metal case, then they do not need to be installed on the radiator. We select a transformer with an output voltage on the secondary winding of 15 volts.
A fairly simple circuit designed for a charging current of up to ten amperes, copes well with batteries from a Kamaz vehicle.
Lead-acid batteries are very critical to operating conditions. One of these conditions is the charging and discharging of the battery. Excessive charge leads to boiling of the electrolyte and destructive processes in the positive plates. These processes intensify if the charging current is high
Several simple circuits for charging car batteries are considered.
The circuit of an automatic charger for car batteries described in this article allows you to charge the battery in a car in automatic mode, i.e. the circuit will automatically turn off the battery at the end of the charging process.
Sometimes there is a need to charge the battery far from a quiet and cozy garage, but there is no charging. It doesn’t matter, let’s try to mold it from what was. For example, for the simplest charging we need an incandescent light bulb and a diode.
You can take any incandescent lamp, but with a voltage of 220 volts, but the diode must be powerful and designed for a current of up to 10 Amps, so it is best to install it on a radiator.
To increase the charge current, the lamp can be replaced with a more powerful load, for example an electric heater.
Below is a diagram of a slightly more complex charger circuit, the load of which is a boiler, electric stove, or the like.
The diode bridge can be borrowed from an old computer power supply. But do not use Schottky diodes, although they are quite powerful, their reverse voltage is about 50-60 Volts, so they will burn out immediately.
