Many modern chargers for car batteries, incl. generator voltage regulators installed on cars operate according to the following algorithm:

First, the battery is charged with maximum current, the voltage on the battery grows to a value of 14.4 V (2.4 V per bank), then the battery is charged constant voltage 14.4 V (at the same time, the charge current gradually decreases and is close to 0 at 100% charge)

This mode is optimal for acid and gel batteries. Its advantages are:

• fast battery charge up to 70 - 80% of battery capacity
• overcharging of the battery is excluded (the battery can be connected to the charger indefinitely)

ACER ADP 90 SB BB laptop battery charger

This power supply is almost ideal for use as a charger.

Its output parameters are:
• Output voltage: 19V;
• Maximum output current: 4.74A.

This power supply supports output voltage 19 V, and in case of overload, the voltage at its output is reduced so much that the output current does not exceed 4.74 A.

All that is required in this device- change the stabilization voltage. In order for the output voltage of the PSU to become equal to 14.4 V, it is necessary to reduce the resistance R133. You can replace R133 with a value of 25.5 kΩ with an 18.42 kΩ resistor or solder a 68 kΩ resistor in parallel with the existing R133 25.5 kΩ. In the second case, the output voltage will be about 14.5 V

Remove capacitor C136. Otherwise, when the output current exceeds 4.74 A, the power supply restarts many times, the circuit operates in protection mode, but it should be in current limiting mode.

The power supply can be used in two modes:
• Power supply 19 V 4.74 A;
• Charger for batteries 14.4 V 4.74 A.

To do this, it is enough to provide a mode switch with which you can select the value of R133.

By replacing the D131 diode assembly with green and red LEDs, you can control (current stabilization / voltage stabilization) the charger's operating mode.

Resistor R105 acts as a shunt across which the voltage drop is measured. At the first start, you should pay attention to the heating of this element.

PS: I was not able to check this circuit in practice due to the lack of this power supply. Therefore, I draw your attention to the possible heating of the resistor R105.

Voltage regulator test circuit:
MOTOROLA 9RC2054
MOBILETRON VR-VW010
TRANSPO M511
HUCO 13 0696
GER04

The VALEO SG15L027 155A generator is installed on RENAULT SCENIC 2 cars with a 1.9 dci 120 hp engine. F9Q.

A water-cooled generator is used to heat the windshield with heating elements.

How to charge a car battery with a laptop power supply.
Power supply parameters Uout 18.5 V Iout 3.5 A
I found a low beam lamp 12 V 55 W to limit the charge current.
Connected in series:
+ PSU output
+ lamps
- lamps

Many modern car battery chargers work according to the following algorithm:

• Battery charge direct current, the voltage on the battery grows, up to a value of 14.4 V (2.4 V per bank)
• Charging the battery with a constant voltage of 14.4 V (in this case, the charge current gradually decreases and is close to 0 at 100% charge)

For recharging battery the best option- a ready-made charger (charger). But you can do it yourself. There are many different ways homemade memory assembly: from the most simple circuits using a transformer, to pulse circuits with the possibility of adjustment. The average in terms of complexity of execution is the memory of computer block nutrition. The article describes how to make a charger from a computer power supply with your own hands for car battery.

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Manufacturing instructions

Converting a computer PSU into a charger is not difficult, but you need to know the basic requirements for a charger designed to charge car batteries. For a car battery, the charger must have the following characteristics: the maximum voltage supplied to the battery must be 14.4 V, the maximum current depends on the charger itself. It is these conditions that are created in electrical system car when recharging the battery from the generator (video by Rinat Pak).

Tools and materials

Considering the requirements described above, to make a memory device with your own hands, you first need to find a suitable power supply. Suitable used ATX in working order, the power of which is from 200 to 250 watts.

As a basis, we take a computer that has the following characteristics:

• output voltage 12V;
• rated voltage 110/220 V;
• power 230 W;
• the value of the maximum current is not more than 8 A.

Of the tools and materials you will need:

• soldering iron and solder;
• screwdriver;
• 2.7 kΩ resistor;
• 200 Ohm and 2 W resistor;
• 68 ohm and 0.5 W resistor;
• resistor 0.47 ohm and 1 W;
• resistor 1 kOhm and 0.5 W;
• two capacitors for 25 V;
• 12 V automotive relay;
• three diodes 1N4007 for 1 A;
• silicone sealant;
• green LED;
• voltammeter;
• "crocodiles";
• flexible copper wires 1 meter long.

Having prepared all the necessary tools and spare parts, you can begin to manufacture a battery charger from a computer power supply.

Action algorithm

Charging the battery must be carried out under voltage in the range of 13.9-14.4 V. All computers work with a voltage of 12V. Therefore, the main task of the alteration is to raise the voltage coming from the PSU to 14.4 V.
The main alteration will be carried out with the PWM mode of operation. For this, the TL494 chip is used. You can use a PSU with absolute analogues of this circuit. This scheme used to generate pulses, and also as a power transistor driver, which performs the function of protecting against high currents. To regulate the voltage at the output of the computer power supply, the TL431 chip is used, which is installed on an additional board.

There is also a tuning resistor, which makes it possible to adjust the output voltage in a narrow range.

Work on the alteration of the power supply consists of the following steps:

1. For alterations in the block, you first need to remove all unnecessary parts from it and solder the wires. In this case, the 220/110 V switch and the wires going to it are superfluous. The wires should be unsoldered from the PSU. The unit requires a voltage of 220 V to operate. By removing the switch, we will eliminate the possibility of the unit burning if the switch is accidentally switched to the 110 V position.
2. Next, solder, bite off unnecessary wires, or use any other method to remove them. First, we look for the blue 12V wire coming from the capacitor, we solder it. There can be two wires, both must be soldered. We only need a bundle of yellow wires with a 12 V output, leaving 4 pieces. We also need a mass - these are black wires, we also leave 4 of them. In addition, you need to leave one green wire. The remaining wires are completely removed or soldered.
3. On the board, along the yellow wire, we find two capacitors in a circuit with a voltage of 12V, they usually have a voltage of 16V, they must be replaced with 25V capacitors. Over time, capacitors become unusable, so even if the old parts are still in working condition, it is better to replace them.
4. At the next stage, we need to ensure the operation of the unit every time it is connected to the network. The fact is that the power supply unit in the computer works only if the corresponding wires in the output bundle are closed. In addition, overvoltage protection must be excluded. This protection is set to disconnect the power supply from electrical network, if the output voltage supplied to it exceeds the specified limit. It is necessary to exclude protection, since a voltage of 12 V is acceptable for a computer, and we need to get 14.4 V at the output. For built-in protection, this will be considered an overvoltage and it will turn off the unit.
5. The shutdown overvoltage action signal as well as the enable and disable signals pass through the same optocoupler. There are only three optocouplers on the board. With their help, communication is carried out between the low-voltage (output) and high-voltage (input) parts of the PSU. In order for the protection not to work in case of overvoltage, it is necessary to close the contacts of the corresponding optocoupler with a solder jumper. Thanks to this, the unit will always be in the on state if it is connected to the mains and will not depend on what voltage the output will be.
6. Then, in order to obtain a stable output voltage at idle, it is necessary to increase the load on the PSU output through the channel where the voltage was 12 V, and it will become 14.4 V, and through the 5 V channel, but we do not use it. A 200 ohm, 2 W resistor will be used as a load for the first 12 V channel, and a 68 ohm, 0.5 W resistor will be used to load the 5 V channel. Once these resistors are in place, the no-load output voltage at idle can be adjusted to 14.4V.
7. Next, you need to limit the current at the output. For each power supply it is individual. In our case, its value should not exceed 8 A. To achieve this, it is necessary to increase the resistor value in the primary winding circuit of the power transformer, which is used as a sensor used to determine the overload. To increase the rating, the installed resistor must be replaced with a more powerful one with a resistance of 0.47 ohms and a power of 1 watt. After this replacement, the resistor will function as an overload sensor, so the output current will not exceed 10 A even if the output wires are shorted, simulating a short circuit.
8. At the last stage, you need to add a protection circuit for the power supply from connecting the charger to the battery with the wrong polarity. This is the circuit that will really be created with your own hands and is not in the computer's power supply. To assemble the circuit, you will need a 12 V automotive relay with 4 terminals and 2 diodes rated for a current of 1 A, for example, 1N4007 diodes. In addition, you need to connect the green LED. Thanks to the diode, it will be possible to determine the state of charge. If it glows, it means that the battery is connected correctly and is being charged. In addition to these details, you also need to take a resistor with a resistance of 1 kOhm and a power of 0.5 W. The figure shows the protection circuit.
9. The principle of operation of the scheme is as follows. The battery with the correct polarity is connected to the output of the charger, that is, the power supply. The relay is activated by the remaining energy in the battery. After the relay is activated, the battery starts charging from the assembled charger through the closed contact of the PSU relay. Charging will be confirmed by a glowing LED.
10. To prevent overvoltage that occurs during the disconnection of the coil due to the electromotive force of self-induction, a 1N4007 diode is connected in parallel with the relay circuit. It is better to glue the relay to the heatsink of the power supply with silicone sealant. Silicone retains its elasticity after drying and is resistant to thermal stresses such as contraction and expansion, heating and cooling. When the sealant dries, the remaining elements are attached to the relay contacts. Instead of sealant, bolts can be used as fasteners.
11. It is better to select wires for the charger in different colors, for example, red and black. They should have a cross section of 2.5 square meters. mm, be flexible, copper. The length must be at least a meter. At the ends of the wires, they must be equipped with alligator clips, special clips, with which the charger is connected to the battery terminals. For fixing wires in the housing assembled device, you need to drill the appropriate holes in the radiator. Through them you need to pass two nylon ties, which will hold the wires.

Ready charger

To control the charging current, an ammeter can also be mounted in the charger case. It must be connected in parallel to the power supply circuit. As a result, we have a memory that we can use to charge the car battery and not only.

Conclusion

The advantage of this charger is that the battery will not be recharged when using the device and will not deteriorate, no matter how long it is connected to the charger.

The disadvantage of this charger is the absence of any indicators by which one could judge the degree of charge of the battery.

It is difficult to tell if the battery is charged or not. You can calculate the approximate charging time by using the readings on the ammeter and applying the formula: current strength in Amperes multiplied by time in hours. It was experimentally obtained that it takes 24 hours, that is, a day, to fully charge a conventional battery with a capacity of 55 A / h.

This charger retains the function of overload and short circuit. But if it is not protected from reverse polarity, you can not connect the charger to the battery with the wrong polarity, the device will fail.

Ways to charge your car battery when you don't have a charger

Any car owner is familiar with the situation with a discharged battery. I have to go, but the car won't start. Everyone knows that you need to charge the battery and the problem will be solved. But what if there is no such possibility? That is, the charger (memory) is missing. This can happen for various reasons. The memory could break, it was left in the garage far from you, or it simply does not exist. What to do in this case? How to charge a car battery without a charger? In this article, we will analyze several examples of charging a battery without a charger.

Here it should be argued as follows. What do we need to charge? A car battery with a nominal voltage of 12 volts and an average capacity of 50-70 Ah. This means that you need a power supply with an output voltage of more than 14 volts, which produces a current of at least 1 ampere. Although 1 ampere is not enough to charge an average car battery. It is better if the power supply provides 3-4 amperes.

You will also need some ballast. It can be a light bulb or a resistor that will be included in the circuit when the battery is charging. Do not neglect the ballast load, because without it, the power supply or car battery may fail.

And, of course, you will need a means to control the electrical parameters when charging. This is an ammeter and voltmeter. It is easier and more convenient to use a multimeter, which has voltmeter and ammeter modes, as well as much more.

In addition to the above, you will need copper wires, a soldering iron with solder (if you make a homemade charger for permanent use), and insulating tape.

Now let's look at several options for how to charge a car battery without a charger.

Ways to charge a car battery without a charger

Before we begin, I would like to say a few words about security. If you do not have experience with electricity, then it is better not to do the steps described below at all (the exception is the option with portable batteries). Better get a battery charger from a car shop and charge in a civilized way. If your experience in handling a car is not enough for this, then it is better to contact the station after-sales service to accumulators.

When performing work, observe all precautions required when working with electricity. In the case of charging the battery with a homemade charger, there is one significant problem. There is no control of the end of charging. In most factory chargers, the process stops automatically, and in the case of a homemade charger, you will have to monitor this yourself.

When the battery is recharged, the process of active evolution of hydrogen and oxygen on the electrodes begins. Together they form an explosive mixture that can explode very violently when struck by a spark. Therefore, you need to charge the battery in a well-ventilated area, there should not be open flames or sparks nearby.

Charging the battery with a portable charger

Now there are enough such portable batteries on sale. Most of them can be classified as launchers. That is, with their help, you can start the car engine, as well as simply recharge the battery. More often they are used as starting devices somewhere in field conditions.

Portable memory devices are based on lithium batteries. In some advanced models, they even install small containers. Often, such devices have "crocodiles" for connecting to the terminals and another adapter for the cigarette lighter. It is better to take just such models so that recharging the car battery through the cigarette lighter is available. The battery of such devices can be charged from the mains through an adapter or from the car's on-board network when the engine is running.

By functionality, such chargers can be divided into three groups:

• household;
• Professional;
• Combined.

The design of portable start-up chargers usually contains a diode bridge, a transformer (rectifier) ​​and an ammeter. In more expensive devices There are various types of protection, as well as the ability to adjust the current and voltage. Professional models have more power than others (40-50 watts). In addition, they have the ability to charge several batteries for the car at once.

enjoy portable charger even an inexperienced car owner can. Simply connect the terminals of the device to the terminals of the car battery in the correct polarity and wait a while. Let's say right away that it will not work to fully charge the battery from a portable charger. Most likely, you won’t be able to charge even 50% (it depends on the capacity). But you can give the battery the charge necessary to start the engine. After that, the battery will be recharged from the generator.

Using laptop charger

Now about how to charge a car battery without a charger by charging from a laptop. This will require charging from a laptop, a light bulb or resistor, copper wires. The image below shows a schematic of a homemade charger using a laptop charger.

To assemble the circuit, you need to bring two wires from the laptop charging, plus and minus. Plus is inside, minus is outside. After that, connect the negative wire to the negative terminal of the battery. And after that, in the gap, connect a car light bulb or a tuning resistor. The option with a resistor is preferable, since the resistance value can be changed. Connect the second terminal of the resistor to the positive terminal of the car battery. Below is how the whole circuit looks like in reality.

The circuit indicates a resistance of 10 ohms, just for example, based on a current of 2 amperes. If you want to charge the battery faster, decrease the resistance. This is a convenient tuning resistor.

In this way, you can fully charge the car battery. You just need to control the end of the process. To do this, you can measure the voltage at the terminals. If it is above 14 volts and does not change, and the electrolyte is actively “boiling”, then the process can be stopped. This, of course, is all approximate, but in such conditions it will do.

Many people, when purchasing new computer equipment, throw their old one into the trash. system unit. It's pretty short-sighted, because it may still contain workable components that can be used for other purposes. In particular, we are talking about the computer's power supply, from which you can.

It is worth noting that the cost of making your own hands is minimal, which allows you to significantly save your money.

The computer power supply is a voltage converter, respectively +5, +12, -12, -5 V. By certain manipulations, you can make a completely working charger for your car from such a PSU. In general, there are two types of chargers:

Chargers with many options (starting the engine, exercising, recharging, etc.).

Battery charger - such chargers are needed for cars that have small mileage between runs.

We are interested in the second type of chargers, because most Vehicle are operated by short runs, i.е. the car was started, drove a certain distance, and then drowned out. Such operation leads to the fact that the car battery runs out of charge rather quickly, which is especially typical for winter time. Therefore, such stationary units are in demand, with the help of which you can very quickly charge the battery, returning it to working condition. The charging itself is carried out using a current of about 5 Amperes, and the voltage at the terminals ranges from 14 to 14.3 V. The charging power, which is calculated by multiplying the voltage and current values, can be provided from the computer power supply, because its average power is about 300 -350 W.

Converting a computer power supply into a charger