Constant undercharging of the battery or its absolute discharge at the most inopportune moment - headache many car owners. One source of these problems could be the alternator. But how to check it? Maybe it's not about him at all? Let's figure it out together how much the generator should produce for the normal functioning of all car systems and maintaining the battery in a charged state.
Battery in the car - important element system responsible for providing onboard network machines with electricity. The generator is used to charge the battery while it is active. Unstable work a device that generates electricity causes a voltage drop in the network and the lack of recovery of the power source capacity.
The normal performance of the generator is understood as the timely and full replenishment of the charge level. battery which decreases under load. Checking the amount of battery charge from the generator is simple and can be done by the car owner on their own.
Diagnostics automotive device, which generates energy, includes visual inspection the unit, its elements and related parts, as well as the measurement of voltage and current. At least twice a year, the tension of the drive belt should be checked, excessive loosening of which leads to a decrease in the performance of the generator, and sometimes can lead to a breakdown of the device. Once a year, you can check the elements of equipment - fasteners, diode bridge, voltage regulator and others. The guarantee of the absence of problems will be and timely service battery - cleaning the terminals, adding distilled water.
Diagnostics of indicators such as voltage, current, resistance is also required twice a year. For its implementation, you will need special devices - a voltmeter, multimeter or load fork.
How much charge should go to the battery from the generator
It is traditionally believed that 13.5-14.5V should be supplied by the generator to the battery and this is completely enough to make up for the cost of the battery.
It should be borne in mind that the use of a battery in a car more power than the manufacturer recommends, it also requires the installation of a more efficient generating device.
It is necessary to take into account the load that the generator must withstand - it is calculated according to the maximum performance of all electrical appliances and auto systems.
Don't forget that charging current from a device that generates energy, will allow you to start the car in the cold season. In order to avoid problems with the car factory, we recommend purchasing generating equipment, the charge current of which will be approximately 10% of the power source capacity. That is, for a battery of 100 A / h, a generator is needed that can produce 10A. Note that for many cars, 100 amp equipment will be pushed to its limit because the power consumption of the car system is around 80 amps. Therefore, the choice of a source that generates energy must take into account both the battery capacity and the consumption in the network.
How to check alternator voltage on battery
The potential difference can be diagnosed in two ways - directly on the generating equipment and through the battery. The generator is directly connected to the power source with a thick wire, therefore, to check the level of potential difference, you can measure the voltage at the power source. This will require special devices- voltmeter, multimeter or load plug.
The wires of the first measuring instruments are connected to the battery in any sequence. The plug must be connected to the battery terminals with strict polarity. It is generally accepted that normal voltage the network must be at least 12 volts. On Idling without including all electrical appliances car, this indicator should be at the level of 13.5-14V. A drop in voltage values to 13.3-13.8 volts is considered acceptable.
At the same time, conventional test equipment can check the resistance of the generator elements - rotor, stator and diode bridge. Diagnostics of rotary equipment is carried out by its winding. It is necessary to connect the probes of the device with slip rings. If the multimeter gives readings from 2.3 to 5.1 ohms, then this element is working. The current consumption of the winding should be within 3-4.5 amperes.
Its normal resistance is 0.2 Ohm. The diode bridge is checked by the presence or absence of resistance, the indicators do not matter. The only thing worth considering is that there should not be a zero dimension. Measurements are carried out in pairs - positive exit and all plates on this side or minus and all elements.
We remind you that for normal charging car battery the voltage output by the generator should be between 13.5 and 14 volts.
How many amps does a car alternator put out per battery
The current strength required by the electrical system of each car is individual and depends on the number of electricity consumers and their values. And also the charge current must be sufficient to charge the power supply.
It is worth noting that ampere readings appear only when there is a load in the car's electrical system and, accordingly, the battery is discharged. After starting the engine of the car, the charge current is about 6-10 amperes and drops over time, because the battery is charging, which takes on the main energy consumption. If you turn on additional equipment - headlights, radio or heated mirrors, you can see an increase in the charging current.
When buying a generator, pay attention to its specifications, which the manufacturer indicates on the case - it is there that you will find information about the maximum current that will be supplied to the battery.
In the table below, you can see the approximate values \u200b\u200bof the current strength that the generator shows at different loads.
Table 1. How many amps does the generator produce under load.
Signs of a malfunctioning generator
IN modern machines electrical system failures are among the most common. A large number of electronics obliges you to carefully monitor the operation and condition of the generator and battery, because their failure can immobilize the car. The most common signs of a generator failure are:
- light indication of the battery on the instrument panel;
- unstable operation of the battery (its boiling over or undercharging);
- different intensity of headlights;
- extraneous sounds from the generator.
If you notice incorrect operation of the car, then perhaps the battery charging current from the generator is insufficient.
All malfunctions of electrical equipment, to which the vehicle’s energy-generating device belongs, are mechanical (deformation or breakage of fasteners, housing, malfunction of bearings, clamping springs, drive belt, etc.) or electrical (winding breaks, malfunctions of the diode bridge, burnout or wear of brushes , short circuits between turns, breakdowns, etc.).
Don't write off a broken generator: find out if there are repair kits and spare parts. Replace them if possible. If you cannot do it yourself repair work, then give the generator to the workshop. Many craftsmen will be able to restore the unit at no extra cost and in the shortest possible time.
However, individual breakdowns require the purchase of a new device that generates electricity. For example, a failing bearing that is soldered into the generator housing cannot be repaired or replaced in most cases.
Remember that failure of this assembly can be caused not only by wear and corrosion, but also bad quality elements, accessories; excessive load; external influence of salts, liquids, temperatures.
Other causes of low voltage
Not always a small potential difference in the system is associated with a breakdown of the generator or bad battery. If the diagnostics of these elements did not reveal any problems, then you should pay attention to the following:
- the condition of the battery terminals - junction density and oxidation;
- wiring problems - oxidation, violation of its integrity;
- output contacts to electrical appliances;
- correctly selected energy consumers.
Each contact must be tightly adjoining and integral, that is, the absence of formations (for example, sulfation) that will interfere with the passage of current is necessary. Incorrect connection of the contacts leads to an accelerated discharge of the battery even when the car is not running.
To improve the connection of the elements of the electrical system of the car, it is necessary to clean all the contacts and restore the integrity of the wires by replacing them or connecting and winding them with insulating tape.
In conclusion, I would like to repeat that the stable operation of the car requires constant control all elements, and Special attention must involve a generator. The battery is charged from it and provides electricity to the whole automotive system. Pay attention to all the elements: generator brushes, slip rings, voltage regulator, winding equipment.
The most accurate measurements should be made with the battery fully charged and various modes. Remember that the manufacturer ties the characteristics of the generator to the number of engine revolutions - they help to generate a certain current.
Detailed video on how to check the generator:
Do you have experience diagnosing a generator and solving problems in electrical system car? Please share your experience and opinion with our readers in the comments. If you have questions about the topics covered, we will be happy to answer them.
In recent decades, many devices have appeared that use to provide battery life accumulators or batteries direct current. These are power tools, telephones, computers, various household appliances. Each of them, as a rule, comes with a charger to keep the battery in working condition. Alas, situations often arise in which the battery does not charge at all or the discharge occurs very quickly. One of the reasons for the occurrence of such phenomena may be a malfunction charger(ZU).
Principle of operation
The operation of the charger is based on lowering the voltage and converting alternating current into permanent. For this, a step-down transformer is present in the circuit and diode bridge. The charging voltage should be 5-10% higher than the nominal value of this parameter for the battery, and the charging current should be about 10% of its capacity. Sometimes the phone is charged from the car's DC battery. In this case, rectification (conversion from AC to DC) is not needed.
Examination
To check the performance of the charger transformer, it is enough to connect a lamp in parallel with the terminals, the value of which corresponds to the charger. You can check the presence of voltage at the terminals of the charger with a tester (digital multimeter).
A complete picture of the status can only be obtained by checking the charger with a multimeter. For different devices, recharging occurs in different ways, and obviously, the methods of verification are different.
Mobile phones and computers
Memory check mobile phone or a tablet computer comes down to measuring the voltage at the terminals. It must correspond to that specified in the instruction manual or the sticker (marking) on the case.
The multimeter switches to DC voltage measurement mode if it does not support the auto-tuning function. Sometimes the contacts of the memory connector are so small that it is not possible to reach them with the probes of the multimeter. In this case, you can carefully use ordinary steel sewing needles. If in this case it is impossible to make a measurement, it is necessary to disassemble the charger case and find the leads to which the ends of the power cord are soldered.
Power tools and household appliances
Charging the batteries of power tools is carried out using more advanced devices. Such memory has, as a rule, three outputs: two power and one control. The manager serves to transfer information about the state of the battery to the memory. When the nominal charge is reached or the battery overheats, the charger current is limited.
To check, the voltage at the terminals of the power contacts is measured. This would be the end of the test, but there are cases when, with a good memory, the batteries do not charge, or it turns off very quickly without charging the battery.
In this case, it is necessary to measure the charging voltage with the battery connected. Since the chargers are made with contacts protected from access by foreign objects, you will have to disassemble the case and solder the wires to the wires. Sometimes this is easy to do, and sometimes you have to make an effort, making furrows in the body with a sharp knife.
After that, you can check the charge with a multimeter, using wires to connect. If the measured value fluctuates from nominal to zero, most likely, the power contacts have weakened. If a premature shutdown occurs, attention must be paid to the control contact.
If, after contact is restored, the battery is not fully charged, the reason is not in the charger, but in the thermistor installed in the battery itself.
Cars and motorcycles
Particularly noteworthy is the way to check chargers for car batteries. They are used for intermittent charging when the car or motorcycle is used infrequently and the alternator is not charging.
Such memory devices can be quite powerful, and can also be used as starting devices that issue high current. Their design may include cooling fans, measuring instruments - a voltmeter and an ammeter, or control lamp as a charging tester.
Checking the memory consists in checking the parameters of the output current, checking the correctness of the instrument readings. In this case, you must clearly understand how to check the charger with a multimeter.
The output voltage is measured first. For a charged battery with a voltage of 12 V, it should be in the range of 13.2 - 14.4 V.
The voltage is measured with a multimeter, in DCV mode, connected in parallel with the outputs of the charger. If, with a completely discharged battery, the charger does not provide a charging voltage of more than 13.2 V, then it cannot be used, recharging will not occur. At the same time, the voltmeter on the case is checked, if it is provided for by the design.
The next step is to measure the charging current. If the charger is automatic, it should correspond to 1/10 of the battery capacity. If manual control is provided, the current is set using the regulator. It is measured with a multimeter in ammeter mode, connected in series to the circuit.
For starting devices the test is carried out at the maximum starting current. A serviceable charger should provide a charge of at least 13.2 V after disconnection.
In some cases, motorists begin to wonder how to check a car battery charger. After all, it is not so rare to charge the battery, especially in winter. The speed and reliability of this work primarily depends on the efficiency of the charger. Checking its performance will take you not so much time. It should also be noted that different types devices show different efficiency. The reason for this is the different settings of the chargers. For correct check you just need to know how the device works.
How to test a car battery charger? To do this, you just need to understand how it works. Indeed, without this, it is not only impossible to check the device, but also to use it correctly, in the case of manual control.
If we consider the charger device, then it consists of a transformer and a rectifier. A voltage of 14.4 V is formed at the output. This indicator will surprise many motorists. After all, its battery voltage is 12 V, why use a higher voltage for charging. The fact is that a discharged battery does not pass a voltage of 12 V or lower through itself. Only the higher voltage level should be used for charging. In such a case, it will pass through the electrolyte and charge it.
Through many years of experiments, it was found that the most the best option is a voltage of 14.4 volts. It allows you to charge the battery with maximum efficiency, and does not damage it. more current quite dangerous, and can lead to a rapid failure of the battery.
When the battery is connected to a power source, the process of restoring its capacity begins. In the process, the internal resistance changes. Therefore, as the charge level increases, the charging current decreases. In theory, when fully charged, the current should drop by 0, and the battery voltage should rise to 13 V. Considering some features of the batteries, they should be charged with a current not exceeding 10% of the total capacity.
It is calculated like this: if the battery has a capacity of 70 Ah, then maximum current charge is 7 A. At the same time, the charging time will be 10 hours.
During operation, the current will constantly decrease. On automatic devices, this happens without human intervention. On models with manual control, you will have to make adjustments yourself.
Some drivers, in order to speed up the charging process, increase the charging current.
This is not recommended. At great strength current, the risk of damage to the battery plates is much higher. But, in rare cases, you can slightly exceed the current level. This reduces the charging time by a third. But, at the same time, you should be as careful as possible. At the first sign of electrolyte boiling, the current level should be immediately reduced. The boost charging method cannot be used on automatic chargers.
Examination
It is worth paying attention to the technical characteristics of chargers, so you can understand the principle of its verification. Some motorists rely on the readings of the devices that are installed on the chargers. Only this does not give any guarantees, they may well be “knocked down” and give erroneous readings. Therefore, it is advisable to periodically test the charger for performance.
The first test will be a voltage measurement. To do this, connect the charger to the battery. At the same time, the voltage on the crocodiles is checked. It should be 14.4 V, and in no case should it fluctuate. Any deviations are considered a malfunction. If the voltage is lower, but not much. For example - 14 V, then it is quite possible to use this device further. Just be aware of this feature, and do not try to charge fully discharged batteries.
At voltages below 13 V, it is not advisable to use the charger. Also, when the voltage rises above the normal value, it is not recommended to use a charger. This can lead to breakage
The next step is to check the current strength. To do this, you need an ammeter or a multimeter that allows you to measure the current strength. They include it in one of the arms of the charger, in other words, the current is supplied to one of the terminals through an ammeter.
There are several ways to measure the supplied current, and control the operation of the charger. Most often, they check the coincidence of the readings of the built-in devices and the real current strength. To do this, simply plug the charger into the network, with an ammeter attached to it. And compare instrument readings. You can also control the progress of the charge, as in simple devices manually operated as well as automatic.
Checking the correct operation of automatic chargers is as follows. Take a fully discharged battery. The charger is connected to it, through a multimeter. The strength of the current supplied to the battery is checked. It should be equal to 10% of the battery capacity. In case of any deviations, the device is considered faulty.
Repair
If you have identified deviations from the norm, then you should deal with the troubleshooting. To do this, you need to disassemble the device, and check its components separately. Do not forget to disconnect the device from the network before starting work.
First of all, check the diode bridge. To do this, voltage is applied to the memory. Current must be present both at the switch terminals and after the bridge. If this does not happen or the readings differ from the norm, you need to check all the diodes of the bridge separately. Serviceable ones should show little resistance on the one hand, on the other hand, the resistance should tend to infinity. Replace any faulty diodes.
Automatic chargers have additional fee that controls the operation of the device. It's fairly easy to check. Just measure the voltage at the output. If it is absent, or significantly below the norm, then check the components individually or replace the entire board. The cause of unstable voltage is the breakdown of the capacitor.
Transformer fails most of the time.. It is checked by ringing the primary winding. A working transformer should have a resistance of 20-30 ohms. In the event of a breakdown, this indicator usually tends to infinity. If it malfunctions, it is not advisable to restore the charger. The cost of a new transformer is usually equal to buying another charger. If you have extensive experience in electrical engineering, you can try to restore the winding. To do this, you will have to remove the old winding and wind a new one. But, keep in mind that rewinding does not always help.
Conclusion. As a rule, the average motorist during the winter is faced with the need to charge the car battery several times during the winter. To do this, you just need to have a good charger. But, the question often arises, how to check the charger for a car battery. After all, this electrical device does not always work perfectly. Therefore, it is advisable to periodically check the correctness of its operation.
The battery is the most important thing in any car. It is this element that gives the starting current to the starter. It is thanks to the battery that the engine starts quickly and hassle-free. But this is not always the case. In order not to experience difficulties with starting, you need to periodically check its charge level. This can be done in several ways.
How to check the car battery charge at home? You will find the answer to this question later in our article.
Methods
There are several ways to check the battery charge of a car:
- by indicator;
- using a load fork;
- multimeter;
- by measuring the density of the electrolyte.
Each of them has its own characteristics. Let's look at these methods in more detail.
Built-in indicator
Majority imported batteries have a built-in indicator by which you can check the charge. For the first time such batteries appeared in Japan. Then European manufacturers began to practice this trick.
What is its essence? On the battery cover there is a transparent window (a kind of peephole). If you look at it, you can see that it is painted in green color. But this is not always the case. The green tint in the window will only appear if the battery is fully charged. If the window is transparent or white, then the battery has lost some of its charge. The most terrible case is a black window. In this case, the battery has sat down "to zero", and it needs to be charged urgently.
Note that this is one of the most simple ways how to check the charge of a car battery without a voltmeter and other devices. After all, all you need is to open the hood and look into that very window. But it is worth noting that not all batteries have such a peephole (especially when it comes to domestic ones). Therefore, to determine the charge level, you need to know other methods.
load fork
This is perhaps the most professional way to check battery health. Typically, this method is used in service stations. What is its essence? The device is connected to the battery terminals and gives a short circuit current.
That is, the load plug imitates the operation of the starter and shows how many volts the battery sags when the driver tries to start the engine. To date, this is the most accurate scheme for checking the condition of the battery. To read the readings correctly, remember that after a load, the voltage on the battery must be at least 10 volts. If the battery sags to 9 and below, then it is already weak. Such a battery will quickly discharge in winter.
Using a multimeter
This is an indispensable device that every motorist should have. Allows not only to check the battery voltage level, but also the resistance of the sensors, the load of the on-board network in real time and many others important parameters. You can buy this device for 300-700 rubles, which is 2-3 times cheaper than a load plug. It is very easy to use this device.
How to check the battery charge of a car with a multimeter? First you need to collect it. We perform the following actions:
- We connect two wires with positive and negative polarity to the corresponding connectors.
- There will be probes at the ends of the wires. We apply them to
- We first set the device to the voltage measurement mode and set the rotary switch to 20 volts.
- We connect the terminals of the multimeter to the battery and look at the result. In this case, the ignition of the car must be turned off.
Reading data from a multimeter
What is the normal value for a battery? Experts note that a fully charged battery should produce a voltage of at least 12.5 volts. If the multimeter shows exactly 12V, then the battery is half discharged. The fact that the battery needs to be charged urgently is indicated by an indicator of 11.5 volts and below.
Electrolyte
There is another way to check the battery charge of a car with your own hands. It is especially relevant in anticipation of winter. As you know, with a drop in temperature, the density of the electrolyte decreases. Accordingly, the charge and performance of the battery drops. How to check the car battery charge? For this we need a hydrometer. Below is a detailed instruction:
- So, open the hood and, using a negative screwdriver, unscrew the “banks” of the battery one by one. There are only 6 of them.
- We immerse our hydrometer inside and wait until it is filled with electrolyte.
- Next, we take out the device and look at the readings.
- After a short time, the float will float up to right level. There will be several divisions on the scale. An indicator of 1.23-1.27 grams per cubic centimeter is considered normal. If the density of the electrolyte is 1.2 grams, then the battery is discharged by about a quarter. ABOUT deep discharge indicates an indicator of 1.1 and below grams per cubic centimeter.
It is also worth checking the electrolyte level itself in each of the "cans". If it is insufficient, it should be renewed. This can be done with distilled water (the coolant is also diluted with it).
Don't ignore insufficient level electrolyte in the battery. This can cause frequent loss of charge and shedding lead plates. As a result, the battery will become unusable, and with any attempts to recharge the liquid will boil.
How to check the car battery charge with a charger?
Each charger has a scale that determines the battery voltage. In the absence of a multimeter, load plug and hydrometer, you can use it. How to check the car battery charge in this way?
Everything is very simple - we connect the leads of the charger to the battery terminals and press the test button. You should not connect the device to the outlet - in this case, it will charge, and the readings will be at least 13 volts.
Can you charge at home?
In the absence of a garage, the possibility of recharging the battery in the apartment is allowed. But it is better to do it on the balcony. During this process, the electrolyte releases sulfur dioxide and oxygen chloride that are harmful to humans. Inhalation may cause dizziness and nausea. Therefore, we charge in the most remote and well-ventilated area. Also keep an eye on the state of the electrolyte.
The battery must not be allowed to boil. This reduces its resource. On average, a 60-amp passenger car battery is charged in 7-8 hours. In this case, the minimum current strength must be set on the memory. Stress loads are harmful to batteries. If the battery takes a long time to charge, or one of the cans boiled after half an hour, then it has become unusable.
Finally
So, we figured out how to check the car battery charge. One of the easiest ways is with a multimeter. As for the hydrometer, this is already preventive measure. Yes, such a device can measure the "residual life" of the battery. But, for the most part, it is a diagnostic tool (equivalently, like a load fork). Therefore, each device is good in its own way.
Sometimes it is extremely difficult to determine exactly where the malfunction occurred - in the charger or the battery itself, despite the fact that we can talk not only about a car, but also about a cell phone, a flashlight and many other first and second necessities. Meanwhile, it is not so difficult to cope with diagnostics on your own, because you can check the current of the charger with a multimeter and, if desired, even the most inexperienced person in this area can complete the task. And the fastest and easiest way to check the charger with a multimeter is to put the multimeter into active mode (current measurement mode) and connect it to the break of any of the output bare wires. In fact, we are talking about a series connection with a maximum constant current on a multimeter varying in the range from 10 to 20 Amperes (you can limit yourself to 10 A).
If at the same time it turns out that the measurement result is below zero, then it is necessary to swap the clamps. There is quite interesting way how to test your phone charger with a multimeter. To do this, you need to turn on the charging itself in the network, after which a needle from a disposable syringe is carefully inserted into the hole of its connector with a sharp ring, which will serve as a kind of current conductor. The next step is to alternately bring the probe of one pin measuring device to the installed needle, and the second to the wire of the charger connected to the mains, as a result of which the necessary data should be displayed on the electronic display of the multimeter. If zeros continue to burn on the display, provided that certain indicators are displayed when diagnosing other serviceable means with the same multimeter, then we can safely say that this charger is out of order.
In this case, it is imperative to take into account the power of the charger, setting the current strength of the multimeter to the appropriate value for this indicator in advance. For example, in order to check the health of charging from a phone, tablet or any other device whose power is 5 Volts, you need to set the current strength on the meter to 20 Amps. In addition, the DC current measurement function (DCV) must be activated, otherwise the multimeter will not respond to the equipment under test in any way. It often happens that when the charger is connected to the battery, it starts to charge, but for some reason it is consumed too quickly, or even stops at a certain point. In this case, the contacts could have moved away, oxidized or clogged in the charging, and in order to check this, you need an ammeter and a special adapter to connect it to the connector.
If desired, such an adapter can be made by hand, using a fragment of a failed motherboard from an old PC. In this case, it will not be possible to do without a soldering iron, with which it will be possible to solder the cleaned wires to a homemade adapter. In total, four ends of the wire should be soldered, the middle two of which will be necessary to determine the type of connection of the tested charger, since the current for the used connector from a PC with a fragment of the motherboard should not exceed 500 milliamps. To connect the ammeter, it is necessary to solder the two ends of the connecting wire to the break of one of the internal wires connected to the adapter. It is also necessary to take care of the insulation so that the wires soldered to the connector do not get confused with each other. For this one extreme connecting wire is sealed with electrical tape along with the four main wires, and the second is left free.
The next step involves connecting the probes of the pins measuring device with stripped ends of two additional wires soldered along the edges of the connector. After that, the current strength is set on the multimeter (10 Amperes is enough) and the charger connected to the network is connected. If the current strength is too low or if it changes, then it can be argued that the charger has been damaged or failed due to too long use.
