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 increases to a value of 14.4 V (2.4 V per cell), then the battery is charged constant voltage 14.4 V (at the same time, the charging 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 eliminated (the battery can be connected to the charger indefinitely)

Charger for batteries from laptop ACER ADP 90 SB BB

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

Its output parameters:

Output voltage: 19 V;
Maximum output current: 4.74 A.

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.

Everything you need in this device- change the stabilization voltage. In order for the output voltage of the power supply 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 kOhm with a resistor of 18.42 kOhm or solder a resistor of 68 kOhm in parallel with the existing R133 25.5 kOhm. 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 is repeatedly restarted, 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 operating mode of the charger.

Resistor R105 acts as a shunt across which the voltage drop is measured. When starting up for the first time, you should pay attention to the heating of this element.

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

Diagram for checking voltage regulators:
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 using heating elements

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

Many modern chargers for car batteries operate according to the following algorithm:

Battery charge DC, the battery voltage increases to 14.4 V (2.4 V per cell)
Charging the battery with a constant voltage of 14.4 V (in this case, the charging current gradually decreases and is close to 0 at 100% charge)

For recharging battery best option- ready-made charger (charger). But you can do it yourself. There are many different ways assembling a homemade memory: from the most simple circuits using a transformer, up to pulse circuits with the possibility of adjustment. The average complexity of execution is the memory from computer unit 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 power supply into a charger is not difficult, but you need to know the basic requirements for chargers 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. These are the conditions that are created in electrical system car when recharging the battery from a generator (video author Rinat Pak).

Tools and materials

Taking into account the requirements described above, to make a charger with your own hands, you first need to find a suitable power supply. A used ATX in working condition with a power of 200 to 250 W is suitable.

We take as a basis a computer that has the following characteristics:

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

Tools and materials you will need:

soldering iron and solder;
screwdriver;
2.7 kOhm resistor;
200 Ohm and 2 W resistor;
68 Ohm resistor and 0.5 W;
resistor 0.47 Ohm and 1 W;
resistor 1 kOhm and 0.5 W;
two 25 V capacitors;
12V automotive relay;
three 1N4007 diodes 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 charger for the battery from the computer power supply.

Algorithm of actions

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

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

Work on remaking the power supply consists of the following stages:

To make modifications to the block, you first need to remove all unnecessary parts from it and unsolder the wires. What is superfluous in this case is the 220/110 V switch and the wires going to it. The wires should be unsoldered from the power supply. The unit requires a voltage of 220 V to operate. By removing the switch, we will eliminate the possibility of the unit burning out if the switch is accidentally switched to the 110 V position.
Next, we unsolder, bite off unnecessary wires, or use any other method to remove them. First, we find the blue 12V wire coming from the capacitor and solder it. There may be two wires, both need to be unsoldered. We only need a bunch of yellow wires with a 12 V output, leaving 4 pieces. We also need ground - 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.
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 order, it is better to replace them.
At the next stage, we need to ensure that the unit operates every time it is connected to the network. The fact is that the power supply in a computer only works if the corresponding wires in the output bundle are short-circuited. In addition, overvoltage protection must be excluded. This protection is installed in order to disconnect the power supply from electrical network, if the output voltage supplied to it exceeds a specified limit. It is necessary to exclude the protection, since the computer is allowed a voltage of 12 V, and we need to get 14.4 V at the output. For the built-in protection, this will be considered overvoltage and it will turn off the unit.
The overvoltage shutdown action signal, as well as the on and off 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 power supply. To prevent the protection from tripping during overvoltage, you need to close the contacts of the corresponding optocoupler with a solder jumper. Thanks to this, the unit will be on all the time if it is connected to the electrical network and will not depend on what voltage is at the output.
Then, to obtain a stable output voltage at idle, it is necessary to increase the load on the power supply output through the channel, where the voltage was 12 V, but will become 14.4 V, and through the 5 V channel, but we do not use it. As a load for the first 12 V channel, a resistor with a resistance of 200 Ohms and a power of 2 W will be used, and the 5 V channel will be supplemented for the load with a resistor with a resistance of 68 Ohms and a power of 0.5 W. Once these resistors are installed, the no-load no-load output voltage can be adjusted to 14.4V.
Next you need to limit the output current. It is individual for each power supply. In our case, its value should not exceed 8 A. To achieve this, you need to increase the value of the resistor in the primary circuit of the winding of the power transformer, which is used as a sensor used to determine overload. To increase the value, the installed resistor must be replaced with a more powerful one with a resistance of 0.47 Ohms and a power of 1 W. 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.
At the last stage, you need to add a circuit to protect 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 included in the computer power supply. To assemble the circuit, you will need a 12 V automotive relay with 4 terminals and 2 diodes rated for 1 A, for example, 1N4007 diodes. In addition, you need to connect a green LED. Thanks to the diode, it will be possible to determine the charging status. If it lights up, it means the battery is connected correctly and is charging. In addition to these parts, 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.
The operating principle of the circuit 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 due to the energy remaining in the battery. After the relay operates, the battery begins to charge from the assembled charger through the closed contact of the power supply relay. Charging confirmation will be indicated by a glowing LED.
To prevent overvoltage that occurs when the coil is turned off due to the electromotive force of self-induction, a 1N4007 diode is connected to the circuit in parallel with the relay. It is better to glue the relay to the power supply heatsink with silicone sealant. Silicone remains elastic after drying and is resistant to thermal stress, such as compression 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.
It is better to choose wires for the charger of 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. The ends of the wires must be equipped with crocodiles and special clamps with which the charger is connected to the battery terminals. To secure wires in the housing assembled device, you need to drill the appropriate holes in the radiator. You need to thread two nylon ties through them, which will hold the wires.

Ready charger

To control the charging current, you can also install an ammeter into the charger body. It must be connected in parallel to the power supply circuit. As a result, we have a charger that we can use to charge the car battery and more.

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 state of charge of the battery.

It is difficult to determine whether 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 in Amperes multiplied by time in hours. It was experimentally found that full charge A conventional battery with a capacity of 55 A/h needs 24 hours, that is, a day.

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

Ways to charge a car battery without a charger

Any car owner is familiar with the situation of a dead battery. I need to drive, but the car won’t start. Everyone knows that you need to charge the battery and the problem will be solved. But what to do if this is not possible? That is, there is no charger (charger). This can happen for various reasons. The charger could have broken down, been left in a garage far from you, or simply isn’t there. What to do in this case? How to charge a car battery without a charger? In this article we will look at several examples of charging a battery without a charger.

Here we should reason 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 the average car battery. It is better if the power supply provides 3-4 amperes.

Some ballast will also be required. This could be a light bulb or a resistor that will be included in the circuit when charging the battery. Do not neglect the ballast load, since without it the power supply or car battery may fail.

And, of course, you will need a means to monitor electrical parameters during charging. These are an ammeter and a 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 are making a homemade charger for permanent use), and insulating tape.

Now let's look at several options for charging 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 safety. If you do not have experience with electricity, then it is better not to engage in the actions described below at all (with the exception of the option with portable batteries). It is better to purchase a battery charger from a car store and charge it in a civilized way. If your experience in handling cars is not enough for this, then it is better to contact the station service to battery workers.

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

When the battery is recharged, the process of active release 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, with no open flames or sparks nearby.

Charge the battery using a portable charger

Nowadays there are enough such portable batteries on sale. Most of them can be classified as starting-charging. 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 the field.

Portable chargers are based on lithium batteries. Some advanced models even install small containers. Often such devices have “crocodiles” for connecting to the terminals and also an adapter for the cigarette lighter. It is better to take exactly such models so that recharging of the car battery through the cigarette lighter is available. The battery of such devices can be charged from the mains via an adapter or from the car’s on-board power supply when the engine is running.

Based on functionality, such chargers can be divided into three groups:

Household;
Professional;
Combined.

The design of portable starting and charging devices usually includes 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 current and voltage. Professional models have more power than others (40-50 watts). In addition, they have the ability to charge several car batteries at once.

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

Using a laptop charger

Now let’s talk about how to charge a car battery without a charger using a laptop charger. To do this, you will need a laptop charger, a light bulb or resistor, and copper wires. The image below schematically shows a homemade charger using laptop charging.

To assemble the circuit, you need to bring out two wires from the laptop charging, plus and minus. The plus is inside, the minus is outside. After this, connect the negative wire to the negative terminal of the battery. And then connect a car light bulb or trimming resistor into the gap. 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 in reality.

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

This way you can fully charge your 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 be suitable.

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 functional components, which can be used for other purposes. In particular, we're talking about about the computer power supply, from which you can.

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

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

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

Battery recharger - such chargers are needed for cars with low mileage between runs.

We are interested in the second type of chargers, because most vehicles are used for short runs, i.e. the car was started, driven a certain distance, and then turned off. Such operation leads to the car battery running out of charge quite quickly, which is especially typical in winter. 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 Amps, 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