Do-it-yourself inverter starting device for a car. Starter charger for car

You need such a device. Especially if your car constantly has problems at the start and with the battery, who knows where it will happen next time? And if you purchase a charger for personal use, you will not only protect yourself from the possibility of getting stuck in some unpleasant place, but you will also be able to help a person who finds himself in a similar situation, especially in cold weather, when many engines fail start up. In addition, almost any charger can charge a phone or tablet - they have long included such a feature as additional ports, especially for such purposes.

There are several types of starter chargers, and before you start choosing them, you should familiarize yourself with the benefits of each of them.

Pulse. The operation of a pulse device is based on pulse voltage conversion. Under the influence of the frequency of the electric current, the voltage first increases, and then decreases and transforms. These devices, as a rule, have little power and are only suitable for recharging a dead battery. And if the charge is very low and it’s frosty outside, charging with it will take a very long time. Among the advantages of such a charger are an affordable price, light weight and small dimensions. As for the disadvantages, these are, first of all, low power and difficulty in repair. In addition, they are very sensitive to unstable voltage.

Transformer. The operation of such a device is based on a transformer, which converts current and voltage. They are able to increase the charge of any battery, no matter how discharged it is. In addition, such units are absolutely independent of the stability of the network and fluctuations in it do not affect their operation in any way. They work in any condition and in the vast majority of cases will start the engine, even if the battery charge is almost zero. Among the main advantages: power and reliability, absolute unpretentiousness. However, there are also disadvantages. These are the high price of the products, large weight and dimensions.

Boosters, or battery-type jump starters, are portable batteries. They work on the principle of a portable charging unit - first the battery is charged, and the car with a low battery charge is started from the battery. As a rule, they come in two types - household and professional. The difference is in the volume of built-in batteries and dimensions. Household starting devices of this type usually have a small capacity, which is quite enough to power one car. A professional battery device is a full-fledged autonomous charger for a car, and not just one, but several. And thanks to the extremely large capacity, they can be used to start engines with different on-board networks, both 12V and 24V. Their advantage is that they are autonomous and mobile, but due to their weight and dimensions, they can only be conveniently moved on a flat surface on the wheels of the housing.

Capacitor starter. Starting the engine and discharging the battery is carried out according to a rather complex circuit, the main part of which is powerful capacitors. First they charge, and then release their charge to start the engine. Due to the fact that they charge themselves very quickly and also quickly start the engine. They are not very popular due to their high cost. In addition, their use leads to rapid wear of the car battery.

Starting the internal combustion engine of even a passenger car in winter, and even after a long period of parking, is often a big problem. This issue is even more relevant for powerful trucks and tractor-trailer equipment, of which there are many already in private use - after all, they are operated mainly in conditions of garage-free storage.

And the reason for difficult starting is not always that the battery is “not in its first youth.” Its capacity depends not only on the service life, but also on the viscosity of the electrolyte, which, as is known, thickens with decreasing temperature. And this leads to a slowdown in the chemical reaction with its participation and a decrease in the battery current in starter mode (by about 1% for each degree of temperature decrease). Thus, even a new battery significantly loses its starting capabilities in winter.

Do-it-yourself starting device for a car

To insure against unnecessary hassle associated with starting a car engine in the cold season, I made a starting device with my own hands.
The calculation of its parameters was carried out according to the method specified in the list of references.

The operating current of the battery in starter mode is: I = 3 x C (A), where C is the nominal battery capacity in Ah.
As you know, the operating voltage on each battery (“can”) must be at least 1.75 V, that is, for a battery consisting of six “cans,” the minimum operating voltage of the Up battery will be 10.5 V.
Power supplied to the starter: P st = Uр x I р (W)

For example, if a passenger car has a 6 ST-60 battery (C = 60A (4), Rst will be 1890 W.
According to this calculation, according to the scheme given in, a launcher of the appropriate power was manufactured.
However, its operation showed that it was possible to call the device a starting device only with a certain degree of convention. The device was capable of operating only in the “cigarette lighter” mode, that is, in conjunction with the car’s battery.

At low outside temperatures, starting the engine with its help had to be done in two stages:
- recharging the battery for 10 - 20 seconds;
- joint (batteries and devices) engine promotion.

An acceptable starter speed was maintained for 3 - 5 seconds, and then decreased sharply, and if the engine did not start during this time, it was necessary to repeat it all over again, sometimes several times. This process is not only tedious, but also undesirable for two reasons:
- firstly, it leads to overheating of the starter and increased wear;
- secondly, it reduces the battery life.

It became clear that these negative phenomena can be avoided only when the power of the launcher is sufficient to start a cold car engine without the help of a battery.

Therefore, it was decided to manufacture another device that satisfies this requirement. But now the calculation was made taking into account losses in the rectifier unit, supply wires and even on the contact surfaces of the connections during their possible oxidation. One more circumstance was also taken into account. The operating current in the primary winding of the transformer when starting the engine can reach values of 18 - 20 A, causing a voltage drop in the supply wires of the lighting network by 15 - 20 V. Thus, not 220, but only 200 V will be applied to the primary winding of the transformer.

Diagrams and drawings for starting the engine

According to the new calculation according to the method specified in, taking into account all power losses (about 1.5 kW), the new starting device required a step-down transformer with a power of 4 kW, that is, almost four times more than the power of the starter. (Corresponding calculations were made for the manufacture of similar devices intended for starting the engines of various cars, both carburetor and diesel, and even with a 24 V on-board network. Their results are summarized in the table.)

At these powers, a crankshaft rotation speed is ensured (40 - 50 rpm for carburetor engines and 80 - 120 rpm for diesel engines), which guarantees reliable engine starting.

The step-down transformer was made on a toroidal core taken from the stator of a burnt-out 5 kW asynchronous electric motor. Cross-sectional area of the magnetic circuit S, T = a x b = 20 x 135 = 2700 (mm2) (see Fig. 2)!

A few words about preparing the toroidal core. The stator of the electric motor is freed from winding residues and its teeth are cut out using a sharp chisel and hammer. This is not difficult to do, since the iron is soft, but you need to use safety glasses and gloves.

The material and design of the handle and base of the trigger are not critical, as long as they perform their functions. My handle is made of a steel strip with a cross section of 20x3 mm, with a wooden handle. The strip is wrapped in fiberglass impregnated with epoxy resin. A terminal is mounted on the handle, to which the input of the primary winding and the positive wire of the starting device are then connected.

The frame base is made of a steel rod with a diameter of 7 mm in the form of a truncated pyramid, the ribs of which they are. The device is then attracted to the base by two U-shaped brackets, which are also wrapped in fiberglass impregnated with epoxy resin.

A power switch is attached to one side of the base, and a copper plate of the rectifier unit (two diodes) is attached to the other. A minus terminal is mounted on the plate. At the same time, the plate also serves as a radiator.

The switch is type AE-1031, with built-in thermal protection, rated for a current of 25 A. Diodes are type D161 - D250.

The estimated current density in the windings is 3 - 5 A/mm2. The number of turns per 1 V of operating voltage was calculated using the formula: T = 30/Sct. The number of turns of the primary winding of the transformer was: W1 = 220 x T = 220 x 30/27 = 244; secondary winding: W2 = W3 = 16 x T = 16x30/27 = 18.
The primary winding is made of PETV wire with a diameter of 2.12 mm, the secondary winding is made of an aluminum busbar with a cross-sectional area of 36 mm2.

First, the primary winding was wound with a uniform distribution of turns around the entire perimeter. After that, it is turned on through the power cord and the no-load current is measured, which should not exceed 3.5A. It must be remembered that even a slight decrease in the number of turns will lead to a significant increase in the no-load current and, accordingly, to a drop in the power of the transformer and starting device. Increasing the number of turns is also undesirable - it reduces the efficiency of the transformer.

The turns of the secondary winding are also evenly distributed around the entire perimeter of the core. When laying, use a wooden hammer. The leads are then connected to the diodes, and the diodes are connected to the negative terminal on the panel. The middle common terminal of the secondary winding is connected to the “positive” terminal located on the handle.

Now about the wires connecting the starter to the starter. Any carelessness in their manufacture can nullify all efforts. Let's show this with a specific example. Let the resistance Rnp of the entire connecting path from the rectifier to the starter be equal to 0.01 Ohm. Then, at a current I = 250 A, the voltage drop on the wires will be: U pr = I r x Rpr = 250 A x 0.01 Ohm = 2.5 V; in this case, the power losses on the wires will be very significant: P pr = Upr x Iр = 625 W.

As a result, a voltage of not 14, but 11.5 V will be supplied to the starter in operating mode, which, of course, is undesirable. Therefore, the length of the connecting wires should be as short as possible (1_p 100 mm2). The wires must be stranded copper, in rubber insulation. For convenience, the connection to the starter is made quick-release, using pliers or powerful clamps, for example, those used as electrode holders for household welding machines. In order not to confuse the polarity, the handle of the clamps of the positive wire is wrapped with red electrical tape, and the handle of the negative wire is wrapped with black tape.
The short-term operating mode of the starting device (5 - 10 seconds) allows its use in single-phase networks. For more powerful starters (over 2.5 kW), the PU transformer must be three-phase.

A simplified calculation of a three-phase transformer for its manufacture can be made according to the recommendations set out in, or you can use ready-made industrial step-down transformers such as TSPK - 20 A, TMOB - 63, etc., connected to a three-phase network with a voltage of 380 V and producing a secondary voltage of 36 V.

The use of toroidal transformers for single-phase starting devices is not necessary and is dictated only by their best weight and dimensions (weight about 13 kg). At the same time, the technology for manufacturing a starting device based on them is the most labor-intensive.

The calculation of the starting device transformer has some features. For example, the calculation of the number of turns per 1 V of operating voltage, made according to the formula: T = 30/Sct (where Sct is the cross-sectional area of the magnetic circuit), is explained by the desire to “squeeze” the maximum possible out of the magnetic circuit to the detriment of efficiency. This is justified by its short-term (5 - 10 seconds) operating mode. If dimensions do not play a decisive role, you can use a more gentle mode by calculating using the formula: T = 35/Sct. The magnetic core is then taken with a cross-section that is 25 - 30% larger.
The power that can be “removed” from the manufactured PU is approximately equal to the power of the three-phase asynchronous electric motor from which the transformer core is made.

When using a powerful starting device in a stationary version, according to safety requirements, it must be grounded. The handles of the connecting pliers must be rubber insulated. To avoid confusion, it is advisable to mark the “plus” part, for example, with red electrical tape.

When starting, the battery does not need to be disconnected from the starter. In this case, the clamps are connected to the corresponding terminals of the battery. To avoid overcharging the battery, the starting device is immediately turned off after starting the engine.

Nobody argues that the battery for any car is an extremely important element. But not every car owner knows that any battery, regardless of its cost, newness or brand, requires periodic maintenance. In addition to the battery itself, the generator, which constantly charges the battery during vehicle operation, also requires constant attention. As a result, quite often you can encounter the fact that the battery is not charged enough to start the engine without problems.

This problem is especially acute in winter, when not every car owner is able to start a car without outside help. This may be due to problems such as:

undercharging of the battery as a result of malfunctions of the car generator or other device;
lack of electrolyte, the volume of which must be periodically replenished;
incorrect electrolyte density;
destructive processes in the battery that interfere with the normal charging process.

All of the above is not a “sentence” for the battery, and can easily be eliminated with regular maintenance.

Starter charger - is it necessary to have it in the garage?

As a rule, most motorists periodically face the problem of difficult starting or its complete impossibility. With the onset of cold weather, the situation worsens sharply. There are not many ways to solve the problem that has already arisen, and you can start the engine when your own battery is dead as follows:

from the “pusher”;
by towing;
light the battery from another car;
quickly charge the battery with high current - a special device is used.

All these methods are far from ideal, and are impossible in some cases. For example, it is impossible to tow a car with an automatic transmission, but it is undesirable to tow a car with an injector. In order not to look for a donor for lighting a cigarette, which car owners are extremely reluctant to do, it is useful to have a battery charger in the garage, which allows you to quickly and safely start the engine in any frost and in any condition of the original battery.

The car battery jump starter has a compact size and high efficiency, so in case of any problems with the battery, it becomes the best option for starting the engine. All you need is an electrical outlet to operate it. It’s easy to use a portable charger for a car battery - just connect the positive wire to the corresponding terminal of the battery, and the negative wire to ground, closer to the starter. After turning on the ROM, you can easily start the engine, even if the battery is very “weak”.

ROM - buy or make it yourself

With all the advantages of factory-made devices, they still have some disadvantages. These include, first of all, the high cost of powerful devices, and those that are cheaper often have too little power and are not suitable for winter use. As a way out of this difficulty, you can consider the option of making your own starting and charging device for the battery, which does not require special knowledge in the field of radio electronics.

Of course, there is an obvious plus - this is the combination of a starting and charging device in a single housing. But if you have a separate “charger” for the battery, it is quite advisable to make a charging and starting device for the battery with your own hands. To make a simple, but quite powerful starting device, you will need one transformer and a pair of diodes. Estimated power of the created device must be at least 1.4 kW- this is enough to start the engine with almost zero battery charge. The ROM circuit is extremely simple, but from year to year, devices assembled in this way seriously help out many car enthusiasts.

Before assembling this starting device, you should prepare a sufficiently long power cable.

Advice! For it, it is optimal to use 2x2.5 copper wire - a smaller cross-section is undesirable.

To ensure ease of use, you can install switch S1, but it must withstand a load of at least 10A.

Output parameters are important indicators for reliable operation

The above diagram of a charging and starting device for a car battery is quite simple, but to create an effective device it is necessary to carefully calculate the output parameters - this will ensure easy starting and will not damage the battery itself. When trying to start, the engine “eats” quite a lot of energy - at least 100 A, with a voltage of up to 14 V. Accordingly, the power of the transformer must be at least 1400 W. A charging and starting device for a car battery of this power will easily start the engine without a battery at all.

Of course, a portable battery charger and jump starter, even of such power, does not replace a battery, which is still needed when starting. The starter can consume up to 200 A when starting, and part of this power will be provided by the battery, even if not fully charged. After successful spinning of the crankshaft, the energy consumption of the starter drops by almost half, and the starting device can cope with this task on its own. By the way, starting chargers purchased in a store provide no more than half of this power, and with a severely discharged battery they simply will not cope with the task of starting the engine.

The cross-section of the core used in this design is 36 cm2. The wire used for the primary winding must have a cross-section of at least 2 mm 2. It would be great if a transformer with such characteristics was factory-made. The original secondary winding must be removed and replaced with a self-wound one. In this case, a banal selection method is used. After, for example, 10 turns are wound, the transformer is connected to the network and the resulting voltage is measured.

It must be divided by the number of turns already made independently, i.e. 10 - the voltage on each turn is obtained. Then you need to divide 12 by the resulting voltage, the result is the required number of turns of each arm. Copper wire in high-quality insulation is suitable for secondary winding. with a cross section of at least 10 mm 2. After completing the work on creating the secondary winding, diodes are connected, which can be taken, for example, from an old welding machine. If all the work is done correctly, the control current measurement in the homemade ROM will not exceed 13.8 V.

How to prevent critical battery discharge

Despite the fact that the circuits of the charging and starting device for batteries are not difficult for self-assembly, it is better to try to avoid the use of starting charging devices. To do this, any battery, from the moment it is put into operation, requires constant maintenance. It is worth noting that all the procedures performed are not complicated and can be performed independently:

At least 6 times a year you should measure the voltage on the battery with a multimeter;
Monitor the electrolyte level 3-4 times a year;
fully charge the battery on a special charger;
monitoring the density of the electrolyte is the most important indicator that largely determines the performance of the battery.

All these activities should be regular, which will always allow you to be confident in your own battery. To carry out the tests, you will need a minimum amount of “equipment”:

To adjust the level in a timely manner, you will also need distilled water, which is added to the jars when there is a lack of solution, and a concentrated electrolyte, used when the density drops below the calculated value for a particular region.

The simplest calculations show that in order for the starting device to work effectively when connected in parallel with the battery, it must provide a current of at least 100 A at a voltage of 10...14 V. In this case, the rated power of the T1 network transformer used (Fig. 1) must be at least 800 W. As is known, the rated operating power of a transformer depends on the cross-sectional area of the magnetic core (iron) at the location of the windings.

The starting device circuit itself is quite simple, but requires the correct manufacture of a network transformer. It is convenient to use toroidal iron from any LATRA - this results in minimal dimensions and weight of the device. The perimeter of the iron cross-section can be from 230 to 280 mm (it differs for different types of autotransformers).

Before winding the windings, it is necessary to round off the sharp edges on the edges of the magnetic circuit with a file, after which we wrap it with varnished cloth or fiberglass.

The primary winding of the transformer contains approximately 260...290 turns of PEV-2 wire with a diameter of 1.5...2.0 mm (the wire can be of any type with varnish insulation). The winding is distributed evenly in three layers, with interlayer insulation. After completing the primary winding, the transformer must be connected to the network and the no-load current must be measured. It should be 200...380 mA. In this case, there will be optimal conditions for transforming power into the secondary circuit. If the current is less, part of the turns must be rewinded; if more, it must be rewinded until the specified value is obtained. It should be taken into account that the relationship between the inductive reactance (and therefore the current in the primary winding) and the number of turns is quadratic - even a slight change in the number of turns will lead to a significant change in the primary winding current.

There should be no heating when the transformer is operating in idle mode. Heating of the winding indicates the presence of interturn short circuits or pressing and short-circuiting of part of the winding through the magnetic core. In this case, the winding will have to be done again.

The secondary winding is wound with insulated stranded copper wire with a cross-section of at least 6 square meters. mm (for example, PVKV type with rubber insulation) and contains two windings of 15 ... 18 turns. The secondary windings are wound simultaneously (with two wires), which makes it easy to obtain their symmetry - the same voltage in both windings, which should be in the range of 12...13.8 V at a rated mains voltage of 220 V. It is better to measure the voltage in the secondary winding temporarily connected to terminals X2, XZ load resistor with a resistance of 5...10 Ohms.

The connection of rectifier diodes shown in the diagram allows the use of metal elements of the starter housing not only for fastening the diodes, but also as a heat sink without dielectric spacers (the “plus” of the diode is connected to the fastening nut).

To connect the starting device parallel to the battery, the connecting wires must be insulated and multi-core (preferably copper), with a cross-section of at least 10 square meters. mm (not to be confused with diameter). At the ends of the wire, after tinning, connecting lugs are soldered.