How to find current leakage in a car with a multimeter

Current leakage rate in a car. How to check current leakage in a car with a multimeter? Finding and eliminating current leaks in a car

Cars February 24, 2017

If the car is parked for a very long time and is not used, then after the driver turns the key in the ignition, nothing will happen. In the process, the relay may click, perhaps even the starter will come to life. But even if it rotates the crankshaft, it is not enough. All of these are symptoms of the battery being discharged while the car was parked.

There is a standard for current leakage in a car. But when the battery is discharged, these indicators are significantly higher than these normal values. Let's look at how you can detect current leakage and fix this fault.

Why does the battery run out?

During long-term parking, the charge should not go away, but leakage currents must also be taken into account. The battery discharges especially quickly in modern cars. Here, a considerable number of different electronic devices and gadgets are included in the network. Often in such cases, the rate of current leakage in the car is much higher than permissible.

Typical causes include old and poor-quality wiring, as well as wire insulation. Another common cause is improperly connected electronic equipment. This could be an audio system, multimedia, navigator, and so on. The causes of current leakage in a car may be dirty or oxidized contacts.

All this significantly “deads” the battery.

Acceptable battery current consumption standards

Modern machines have a certain number of consumers of electrical energy on an ongoing basis. This could be a clock, ECU memory, immobilizers, alarms and other similar equipment. They are connected to the network and consume electricity. And all the time.

For example, let's take the volatile memory of an ECU. If you erase it, the unit will begin the relearning process and will again remember all current settings. Security systems only start working when the car is parked. From this we can conclude that low electrical energy consumption is a normal situation.

But there is a norm for current leakage in a car. This norm is a certain constant value - it can be calculated. It is necessary to sum up the consumption of each consumer in the on-board network. For example, alarms require no more than 20 mA. The clock requires 1 mA to operate.

The audio system consumes about 3 mA and so on. In total, the total figure will be in the range from 50 to 80 mA. It's quite a bit. Even one lamp in the headlight, which they forgot to turn off, consumes 500 mA.

And the current leakage rate in a car of 50 A cannot cause a complete discharge of the battery even in winter.

You can determine how much consumption there is using a multimeter. And if during the measurement process the consumption level is higher than permissible, that means. There is a problem in the on-board network. It needs to be found and eliminated.

Video on the topic

We determine where the current disappears independently

As you know, there are only two main reasons why batteries are severely discharged. These are additional consumers or a short circuit in the network. So, let's see how to measure current leakage in a car with a multimeter.

Using this operation, you can find and detect a thin spot in the on-board network. To search for leaks, the measuring device should be turned on in current measurement mode. Do not forget that there is direct current in the automotive network.

As for the measurement range, 10 Amps will be sufficient.

How to connect a multimeter

Before you start searching for a current leak in your car, you need to correctly connect the device to the on-board network. As for consumers of electricity from the battery, it is better to turn them off if possible. To carry out measurements, an ammeter is connected to the open circuit.

To get such a gap, remove the wire from the positive terminal of the battery. Then connect one contact of the ammeter to the battery positive. And the second - to the wire you just removed. Never connect measuring instruments to the plus and minus on the battery. The result will be a short circuit.

Nothing will happen to the machine, but the fuse in the multimeter will blow. If everything is connected correctly, then a number will appear on the device screen that corresponds to the current consumed by constantly switched on electrical appliances.

If the permissible current leakage in the car is lower than the measurement result, you need to look for the cause further.

How to find a leak

As we know, one of the main reasons why this problem occurs is some kind of electronic device from additional or non-standard equipment. There are more and more such components in modern cars every year. It is necessary to start your search with those instruments and devices that are installed independently, that is, non-standard.

This could be various fans, alarms, or anything. Factory wiring in cars is reliably protected. And short circuits in it occur only in case of any significant damage. For example, as a result of an accident, the protective casing may be damaged. But the wires laid by the car owner themselves are often laid out carelessly.

They are placed in the first place available, which upon a quick inspection seems to be the most suitable. It is in these wires that the cause of short circuits is hidden. A short circuit leads to current leakage. The wires laid by the car owner may be dangerously close to the engine block. The engine, as you know, heats up during operation.

So, the insulation of the wires can simply melt.

The cords also rub against the edges of metal parts (especially where the car doors touch). They fray - as a result, the integrity of the insulation is compromised and a short circuit appears.

Auto electricians recommend that immediately after measurements (if the current leakage rate in the car does not correspond to the multimeter readings) proceed to a visual inspection of everything that is installed abnormally.

It is also necessary to examine individual parts and elements of instruments and devices that are subject to mechanical stress. If we are talking about signaling, then these could be limit switches.

If there are no signs of damage, burning, or corrosion, then you should move on to more complex troubleshooting methods. Using this diagnostic, you can significantly narrow the range of possible faults.

How to perform in-depth diagnostics

So, we already know how to measure current leakage in a car with a multimeter. In this case, the device is connected in the same way as in the previous case. But here each fuse is removed in turn and the relay is turned off.

This is done to open the circuit in the on-board network of the machine. When the leakage rate becomes close to normal, it means that a circuit with a problematic consumer has been detected.

Next, you should replace or repair the malfunctioning equipment.

Additional diagnostics

Sometimes there are difficult situations in which even after checking the leak by removing the fuses, there is no positive result and the source of the problem has not been found. In this case, there is nothing left but to check the current leakage in the car circuits. They are not protected by fuses in any way. This is the generator and starter.

Very often the battery bursts due to improper operation of the generator. The element simply does not charge the battery. To check the generator, a multimeter is connected to the battery terminals. The device is switched to voltage measurement mode. Next, the voltage is measured. If the battery is completely discharged, the device will show from 12.6 to 12.9 V.

Then you need to start the engine, turn on the low beam, heater, rear window heating system and measure the voltage again - ideal values ​​are from 12.8 to 13.4 V. Maximum - 14.3 V. If the voltage is in this range when the engine is running, then the working element is OK.

If it is less, then the problem is with the generator, which is not charging the battery.

Repairing leaks

Before eliminating a current leak in a car, you need to find the source. It can be anything. And to fix the problem, you need to repair or replace the malfunctioning electronic device. Also, to eliminate it, it is enough to remove the short circuit.

Conclusion

If you feel that the battery is discharging faster, then you should start looking for a short circuit or a “wedge to ground”. Now we know how to check for current leakage in a car and how to fix the problem.

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Source: http://monateka.com/article/405/

How to check current leakage on a car with a multimeter

Experienced car enthusiasts, and not only them, know the feeling of frustration that covers a car owner when there are problems with the car’s electrical wiring. It seems like a dark horse, you don’t know where or what to look for. Meanwhile, the car does not start because the battery is almost out of charge. Next, we will tell you how to check for current leakage on your car.

Content

The trouble itself usually arises due to common conditions:

• increased humidity and dirt where the wiring harnesses pass;
• wire insulation that has become leaky due to age;
• constant connection of many extra consumers;
• incorrect connection of additional equipment;
• poor quality electrical wiring repairs.

Therefore, you need to try to avoid all this. Otherwise, it’s not far from a fire in the car! However, if a leak does appear in the car, how can you check it? Of course, it’s better to immediately get a simple tester. Moreover, it is inexpensive. The cheapest multimeter will cost only a couple of hundred rubles, although it will not last long.

If you don’t have a tester at hand, and the check needs to be done urgently on the spot, then you can try to do this.

1. Inspect the battery terminals - is the cable fastening to one of them loose?
2. Next, inspect all the electrical appliances in the cabin - are they working properly? First of all, suspicion should be caused by devices installed in the car outside the scope of routine. As a rule, their electrical wiring is poorly protected.
3. Then you need to briefly turn on and off all the lights. Is the electrical wiring working properly everywhere? If something does not light up, there may be a short in the circuit of that light fixture or electrical appliance.
4. Inspect the entire line of the suspicious electrical consumer - from the battery to the consumer itself.

Also read about the signs of a malfunctioning diode bridge of the generator and replacing airbags yourself.

The most common characteristic, especially for older cars, is the destruction of the wiring insulation and, accordingly, its short circuit to the car body.

There is also a way to diagnose the disease with a simple light bulb. We'll tell you how to determine current leakage on a car with a twelve-volt light bulb.

1. Disconnect the wire from the positive terminal of the battery.
2. We connect one wire from the light bulb to the positive terminal of the battery, the second wire to the cable we just disconnected.
3. Turn off all devices, close all doors.
4. If everything is fine, the light should not light up.
5. If the light bulb is on, current is flowing somewhere.
6. Let's start looking for this place.

We have now outlined a kind of makeshift method that explains how you can check the battery current if you don’t have a universal meter at hand. But, of course, it is better to still have a testing device. As a last resort, you can ask someone for it.

How to do a competent check with a tester

Now let’s look at exactly how to determine a leak with a multimeter. We will need:

• universal current parameter meter;
• wrenches;
• pliers.

Let’s just warn you right away: this method, which explains how you can check the battery leakage current with a multimeter, requires the presence of an assistant. Although, if you wish, you can do it alone.

1. First of all, you need to turn off all on-board instruments, all lights, the radio, and remove the key from the ignition.
2. Next, unscrew the key and disconnect the negative terminal of the battery.
3. Now we take an electrical tester, set it to the “10 A” mode, apply one terminal of this device to the negative terminal of the battery, and the second terminal to the wire removed from the battery.
4. Here lies the answer to the question: how to check this same leakage current? The normal value reaches 70 mA. If the readings are higher, you need to look for the source of the loss.
5. Let's assume the readings are higher. Then we ask an assistant to open the fuse box and begin to carefully pull them out one by one from the sockets. The partner must use pliers with insulated handles or standard tweezers!
6. The circuit whose fuse is removed is restored to its normal amperage value is subject to further testing.
7. We return the fuse of the problematic chain to its place, then disconnect its links one by one. As soon as the value is restored again, it will become clear where the faulty link is. That is, there is either a defective device or a wiring fault.
8. After successful completion of the procedure, we fix the problem and connect the battery terminal back.

This entire sequence of how to determine a leak on a car can also be studied via video.

By the way, when doing this work with electrical wiring, do not forget about basic safety rules:

• first, put on rubber gloves;
• secondly, lower the windows in the car - suddenly the central locking will work.

Well, in general: we are careful in everything.

A specific example from VAZ

However, let’s assume that the multimeter did not show the normal amperage parameter when “ringing” all the circuits. How then can you check the leakage current in a car?

Let's look at a similar case using the example of a VAZ car. Let's see how to check current leakage on a VAZ 2110 car. For this we will again need:

• multimeter;
• keys;
• pliers.

The actions are as follows.

1. Let's say we removed all the fuses one by one, while simultaneously checking the readings, but the multimeter kept showing an increased ampere consumption.
2. We further determine the current leakage in the car circuit. Let's look at the generator.
3. To check the generator, start the engine, turn on all electrical appliances, lights, fog lights, then check the voltage at the motor terminals with a meter in voltage mode. It should be at least 12 volts.
4. If the generator is working properly, check the starter. Having disconnected its wires, we look to see if the loss of electric current in the gap between the battery terminal and the electrical wiring has disappeared.
5. Finally, we test the alarm. We constantly measure with an ammeter, and when the security mode sets in, we look at changes in the readings.

These are the basic principles that explain how to determine a leak in your own car with a tester.

What not to do

In conclusion, we will indicate incorrect methods for diagnosing the electrical equipment of a car, which lead to dire consequences. For clarity, the information is divided into sections in the following table.

Way	What is	Why is it dangerous?
Connecting an ammeter to the battery terminals	The tester in ammeter mode is connected with the red terminal to the battery positive, and the black terminal to the negative.	A short circuit occurs inside the multimeter and its fuse burns out.
Installing a non-standard fuse	In the circuit in which the fuse has blown, another fuse with an increased maximum permissible amperage is inserted - for further diagnostics of the circuit.	It is fraught with burnout of all the wiring of several links, and a fire is possible.

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In addition, we have described all possible algorithms that help check the leakage current on a car battery with an electric multimeter. The information provided will certainly come in handy for motorists who are faced with such a problem.

Now read about engine boring and cylinder block boring with your own hands.

Source: http://DaciaClubmd.ru/repair/elektrika/kak-proverit-utechku-toka-v-avto

Current leakage in a car: how to check and what is the norm

Current leakage is a process that can happen in almost every car, regardless of mileage, year of manufacture and manufacturer, and there are many reasons for this. As a result, the battery is discharged, which is why it is impossible to start the engine after a long period of parking.

There may be several reasons for an unauthorized leak, but often the driver himself is to blame for their occurrence, having equipped the car with various modern devices: an audio system, a navigator, a radar detector, an alarm system and others.

Their incorrect installation and connection to the wiring also very often creates a problem in the form of current leakage.

At the same time, all devices can function without complaints, but they are recharged from the battery when the engine is running and when the engine is switched off.

Often, current leaks occur due to faulty equipment; this is usually due to incorrect operation:

1) Starter.

2) Generator.

3) Standard alarm.

Also among the most common causes of current leakage are:

• Wear and tear of electrical equipment wiring. During prolonged use, the cause may be exposure to various unfavorable road and climatic conditions, which ultimately leads to chafing, as well as cracking of wire insulation, oxidation of contact blocks (terminals) and sockets for connecting electrical appliances.
• Installation of additional equipment. The car wiring provided by the automaker is well protected and a sudden short circuit is likely only in the event of serious mechanical damage. As for additional equipment, as a rule, they try to place it in a place that is most accessible during a quick inspection, but in reality it turns out to be problematic and can cause a current leak and, as a result, a short circuit.
• A common cause of current leakage. Wires may be located close to the engine block and, when exposed to high temperatures, melt or be damaged by sharp edges of metal fasteners, which can also damage the insulation and cause a short circuit.

Permissible leakage current

Any modern car has a set minimum permissible current leakage and in standby mode it is not so significant: the audio system memory consumes only - 3 mA, the alarm system (if it is normal) - 20-25 mA, the dashboard - 5 mA, exactly the central locking unit and the injection system controller consume the same amount. There are devices, for example, ECU memory, that operate in normal mode and should not be erased, and the alarm system consumes current only when the engine is not running. A small permissible current leakage is in the range of 30-40 mA - this is the norm.

Important! The maximum permissible current leakage rate is 50-80 mA (it directly depends on the power and the amount of additional equipment installed on the machine).

Diagnosis and elimination of causes of current leakage 

In order to measure battery current leakage, you need to prepare:

• Multimeter.
• Open-end wrench 10.
• Gloves.

How to check current leakage on a car with a multimeter

Before starting measurement work, you must turn off the ignition and remove the key from the lock. The windows in the car need to be opened and the doors closed. When measuring the current, the battery will turn on and off, so the central locking can work and open windows will serve as access to the interior.

• Carefully check that all current consumers are turned off (lights under the hood, in the glove compartment, trunk, etc.).
• Open the hood and disconnect the negative terminal from the battery.
• The multimeter should be switched to current measurement mode by connecting it to the gap between the negative terminal of the battery and the negative terminal.
• Turn on the device, take the results of current leakage.

Important! All described work should be carried out with the engine turned off.

Elimination of current leakage

The question of how to find a current leak in a car is clear and accessible to many car owners, but fixing the leak, as a rule, is trusted only to specialists. Although, if you know some of the features of this process, you can eliminate the cause of current leakage yourself.

First, you should search for the circuit through which current leakage most likely occurs. To do this, you need to sequentially remove the fuses from the mounting block, observing the indicators of the device. If you find a current leak, the value will decrease significantly.

The service manual for your vehicle contains an electrical diagram that will help you determine which equipment is connected to a given fuse and check it. If suddenly the equipment turns out to be faulty, you just need to take it for repairs or buy a new one.

Mounting block

If all fuses are checked, but the tester still detects a current leak, the cause is in an area not protected by fuses: the generator, starter or ignition system.

To do this, you need to disconnect the wires from these systems and carry out a thorough check.

Also, do not forget that the car can be equipped with self-installed devices that are connected to the ignition switch circuit without using fuses.

Next, you need to check all the wiring: if a suspicious part of it is discovered, you need to “ring” the wires for integrity and look for a short circuit. These actions must be performed using the same multimeter, only set to a different mode - an ohmmeter. This mode will allow you to observe the wire resistance.

Check the generator. To do this, you need to set the multimeter to voltmeter mode, connecting it in parallel with the devices. Voltage measurements should only be made when the engine is running and the sidelights and headlights are on. Normally, the voltage is 13.5–14 V.

Generator check

Another reason for current leakage can be an alarm system. To diagnose it, it is recommended to set the security mode and check it after about five minutes.

This time is quite enough for the alarm to go into standby mode and the leak to stop. If this happens, it means the alarm is working; if not, the reason is its malfunction.

In this case, you should contact a specialist; it will be very difficult to understand the alarm system yourself.

Why is high current leakage dangerous? 

The consequence of high current leakage is battery discharge. Modern batteries are not at all difficult to charge, however, in this case this is just a temporary solution to the problem.

Acid batteries consist of plates filled with electrolyte, which consists of a mixture of distilled water.

During an electrical discharge, acid settles on the plates (in the form of salts), reducing the working surface of the battery.

Over time, salts crystallize and they cease to dissolve in the electrolyte, which leads to a decrease in the battery capacity and renders it unusable.

Having discovered high rates of current leakage, you cannot delay eliminating this problem, since battery failure will cost much more than repair work.

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Source: http://jrepair.ru/interesnoe-na-jrepair-ru/agregats/utechka-toka-v-avtomobile-kak-proverit-i-kakaya-norma

Finding a current leak in a car with the battery disconnected

19.02.2018

This malfunction should not be confused with a short circuit in the electrical wiring. Car owners often say that “somewhere a wire has frayed, touched ground, and supposedly there is a loss of current from the battery through it.”

Current leakage, in contrast to short circuit, is when some consumer, without showing himself in any way, systematically consumes energy from the car battery, until it is completely discharged to zero.

Troubleshooting a real problem

The situation that will be described in this article actually happened to one of the so-called “masters of garage cooperatives.”
We brought the classic and asked to fix the problem associated with the rapid “death” of the battery. Well, then in order.

Let's figure out how to detect a current leak in our car. To do this, we need a multimeter that measures current up to 10A.

We set the measuring device to the DC current measurement mode. Insert the wire plugs into the corresponding sockets on the device.

Finding current leakage in the circuit

Next, disconnect the positive terminal from the battery and connect the positive clamp of the multimeter to the “+” terminal, and connect the “-” clamp to the terminal. On the device at this moment we will see data that says that 5A machines (for example) are currently consuming devices.

Next, let's create conditions as similar as possible to how you would leave a car in a parking lot. In the cabin, turn off the radio, external lighting devices and take the key from the ignition, and of course close all the doors.

Let’s assume that after performing all of the above manipulations, the multimeter shows that energy consumption is 2.5 A. This means that, as a result, after 10 hours the battery will lose 25 A/h of charge. For a typical 55Ah car battery, half of the capacity will be used up and eventually run down to zero.

Now we have found out that there is a leak and we need to find out what kind of unauthorized consumer it is that is consuming the energy of our battery. To do this, you need to decide in the direction of your search.

And here we have only one way: open the cover of the fuse box and begin to remove them from their sockets one by one, observing the ammeter readings. When one of the fuses was removed, the energy consumption stopped.

This means that a leak occurs along the line that protects the last removed fuse.

The remaining leakage values ​​of 0.03A are acceptable and can be ignored. To be sure that you have correctly identified the current leakage line, insert this fuse into its place and make sure that the current leakage has resumed.

Cause of current leakage in a car

Based on the markings on the inner cover of the fuse box, we determine that this is fuse R12 for the rear heated glass. But you need to check what other consumers are on the line that this fuse protects.

To do this, take a book on the car, in the “electrical equipment” section we look for a list of fuses and look: 12 – rear window heating element, relay (contacts) for turning on the rear window heating, cigarette lighter, plug socket for a portable lamp.

Let's check visually: there is nothing connected to the plug socket, and there is also nothing in the cigarette lighter. This means that the rear window heater remains.

We turn off the glass heater element itself and good luck - judging by the ammeter readings, the current leakage has stopped.
From the specific example it is clear that the line is connected via a relay.

The relay designation can be found on the inner surface of the fuse box cover. We remove the relay from the socket to check it.

We take a regular dial with sound indication and check. As a result, it turns out that the contacts are closed (and this should not be the case). What could have happened to cause the contacts in the relay to be closed? (Being ahead of the curve, let’s say that the car is not new and was purchased on the secondary market.)

We disassemble the relay and are surprised to find that the insides are wrapped with electrical tape:

Having examined the instrument panel in the cabin, we find two buttons: a button for turning on the heated rear window, which is in the off position, and next to it is a button for turning on the rear fog lights. They have the same pads, so we can assume that the previous car owner confused these pads with each other.

After which the rear window heating stopped working and he did not understand the problem, pulled out the relay and wrapped the insides with electrical tape, i.e. closed the contacts. The heating started working, but the owner of the car did not take into account that it would work constantly. But apparently after some time he was faced with the problem of constant battery discharge and did not come up with anything smarter than how to remove the voltage supply wire from the heater.

He removed and in this state sold the car to a new unfortunate owner, who, according to him, had already come to the parking lot four times and “lighted” the car from someone else’s car. This is once again confirmation that interfering with a car’s power supply system always entails negative consequences.

Replacing the relay corrected the problem.

Trust repairs to specialists

In conclusion, it should be noted that 95% of similar faults associated with current leakage occur due to the “smart” intervention of the car owners themselves.

Incorrectly connected radios, amplifiers, heaters, subwoofers, self-installed power windows most often lead to current leakage. At first they don’t notice it, then a moment comes when the battery no longer cranks the starter.

If you do not have the appropriate knowledge in the field of electronics and do not want to pay for your “creativity” later, it is better to trust the specialists, otherwise such malfunctions will haunt you constantly.

Well, how to find a current leak is described above, and this seemingly simple technique is available in garage conditions to every car owner.
The situations may be different, but the goal is the same - to find the “invisible” current consumer. We fix the problem and the issue, as they say, is closed!

Finding a current leak in a car with the battery disconnected Link to main publication

Source: https://akkumir.ru/otvet/poiskutechkitoka

What is the leakage current of a car battery and how to measure it?

Many car owners have encountered a situation where they were unable to start their car in the morning. And everything was fine in the evening. And the battery itself is new and in good condition. The reason here may be battery leakage current.

This phenomenon exists on any car, but must fit within a certain norm. If the leakage current limit is exceeded, the battery will discharge while parked. As a result, you will have problems starting the engine.

It's time to figure out what causes battery leakage current and how to bring it back to normal.

 

Causes of battery leakage current

The purpose of the battery is to start the engine and help the generator provide power to the consumers of the on-board network if the latter cannot cope with the load.

During the trip, the battery is recharged from the generator and compensates for the discharge. In theory, a car battery should not lose charge while parked, but there is a leakage current.

Moreover, in modern cars, where there are a lot of electronics, the leakage current increases and often exceeds the norm.

The main reasons for the increase in leakage current are the following:

• worn out or poor quality wiring, insulation;
• incorrect connection of electronics (sound system, TV, etc.);
• dirty, oxidized contacts.

Therefore, it is important to detect the cause of the leakage current and eliminate it. How to find the culprit of this phenomenon?

Additionally, we recommend reading the material about the reasons why the battery in a car is discharged.
Return to content
 

Diagnostics and standard battery leakage current

What you need when measuring battery leakage current:

• multimeter;
• open-end wrench 10;
• gloves.

How to take measurements?

• First, turn off the ignition and remove the key from the lock. Close the car doors and open the windows. During the measurement, the battery will be turned off and on. Therefore, the central locking may work. So, just in case, leave access to the salon;
• check that all current consumers are turned off (pay attention to the light bulbs under the hood, in the trunk, glove compartment, etc.);
• open the hood and disconnect the negative terminal from the battery;
• after this, switch the multimeter to current measurement mode and connect it to the gap between the negative terminal and the negative terminal of the battery;
• turn on the multimeter and take readings of the leakage current.

If in your case the leakage current of the car battery is much higher, then you need to look for the reason for this. How to do it?

Connect the multimeter as mentioned above, and begin to remove the fuses and relays one by one. This is done to alternately open the circuits in the on-board network. When the leakage current readings return to normal, it means you have found a circuit with a problem consumer. Next, you need to deal with this device in more detail (repair, replacement).

Below you can watch a video about measuring the leakage current of a car battery:

Additionally, you can read about how to check your car battery for performance.
Return to content
 

additional verification

A situation may arise where you have checked the leakage current by removing the fuses, but the source of the problem could not be determined. Then you need to check places that are not protected by fuses.

This is, for example, a starter and a generator. After all, often the cause of battery discharge is incorrect operation of the generator, which simply does not charge it. You can read about the car battery charge rate in the article at the link provided.

How to check the functionality of the generator?

• turn off the ignition, remove the key from the lock, turn off all current consumers in the car;
• connect the multimeter probes to the battery (black to minus, red to plus);
• switch the multimeter to voltage measurement mode;
• turn on and measure the voltage (on a fully charged battery the value is 12.6─12.9 volts);
• then we start the engine, turn on the low beam headlights, the heater, and the heated rear window;
• again measure the voltage on the battery (ideally, the voltage should be 12.8-13.4 volts. The maximum value is 14.3 volts).

If the voltage on the battery when the engine is running is in the specified range, then the generator is in good condition and will charge the battery.

If the voltage is significantly less, then the problem with a dead battery may be the generator, which simply does not charge it. This could be worn brushes or a faulty diode bridge.

In this case, it is already necessary to resolve the issue of replacing or repairing the generator.

The video shows how to check the operation of a car generator.

You can also read about how to open a car if the battery is dead.
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What should you keep in mind?

If the leakage current value significantly exceeds the norm, then at a minimum you should consult an automobile electrician. If you have a tester and the skills to handle it, then you can find the problematic device or faulty wiring yourself.

We also recommend reading about how to check battery capacity.
In any case, leakage current exceeding the norm cannot be ignored. After all, this can end not just with a dead battery, but also with a fire in worn-out wiring.

Be careful and good luck on the roads! If you have additions or feedback to the article, write them in the comments below.

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Source: http://akbinfo.ru/ustrojstvo/tok-utechki-akkumuljatora-avtomobilja-norma-i-izmerenie.html

How to check current leakage in a car

Among car owners, there is often a situation where it is impossible to start the car in the morning, although everything was fine in the evening. This can often happen after a long period of inactivity. Sometimes owners themselves forget to turn something off, thereby draining the battery.

But most often the causes of malfunction are dirty circuits, damaged or poor-quality insulation, or improperly installed equipment. Such leaks in the electrical system will drain the battery and, in extreme cases, cause a short circuit and can cause a fire.

If during the day a fire can be detected and extinguished, then at night the car can burn out completely and cause great damage to surrounding property.

Current leakage is a common problem faced by car enthusiasts.

Causes of current leakage

Modern batteries, with their small dimensions and low weight, are reliable to use, they are characterized by low self-discharge and resistance, they have a significant capacity, and a long service life is the norm for them. However, one must take into account the fact that most modern cars have a large number of various electronics: radio, amplifier, subwoofer, alarm, various lighting, DVR and much more.

There can be several reasons for unauthorized current leakage:

1. Wear and tear of electrical equipment wiring.

During long-term operation of a vehicle, the main cause of current leakage is exposure to unfavorable conditions, both climatic and road, which leads to cracking and chafing of wire insulation, oxidation of device connection sockets and terminal block contacts.

1. Installation of additional equipment.

The factory wiring of a car is usually quite protected, and a short circuit in it is possible only after significant mechanical damage.

But the wiring of additional equipment has to be laid in a place that, upon a quick inspection, seems quite suitable, but in fact is problematic.

It is in such wiring that a short circuit most often appears - the most common cause of current leaks.

Current leakage may be caused by incorrectly installed additional equipment.

1. Common cause of leakage.

Wires may be routed close to the engine block and melt due to heat or simply become damaged by the edges of metal fasteners. This may destroy the wire insulation and cause a short circuit.

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Leakage current detection

You can use a multimeter to detect current leakage. We will need it in ammeter, voltmeter and ohmmeter mode. First, you need to switch the device to ammeter mode, current mode to constant, and set the measurement range to 10–20 A.

Next, you need to use a key to remove the negative terminal of the battery and close the circuit by pressing one ammeter probe to the terminal, and the second to the disconnected wire.

Remember: you cannot connect a device switched on in ammeter mode to both terminals of the battery - there will be a short circuit and the fuse in your device will blow.

Before this, it would be nice to be on the safe side: turn off the ignition, close the doors and open the windows - the central locking may work when the battery is disconnected or connected. Another safety standard is to make sure that the alarm and audio system settings can also be restored.

Leakage Current Ratings

Any car has a minimal leak, but in standby mode it is not so significant: the alarm system normally consumes 20–25 mA, the audio system memory - 3 mA, the injection system controller - 5 mA, the dashboard and central locking unit consume the same amount.

These devices are constantly working: the ECU memory, for example, should not be erased, otherwise it will be retrained, and the alarm system consumes current precisely when the engine is not running. There may well be a small (30–40 mA) leak - this is normal.

However, the maximum permissible current leakage in a car is 50–80 mA (depending on the number and power of additional equipment installed on the car).

Elimination of current leakage

First you need to search for the circuit through which the leak occurs. To do this, remove the fuses from the mounting block one by one and observe the device.

As soon as you find the problem area, the amount of current leakage will decrease significantly. Next, using the electrical diagram of the car, you need to determine what equipment is connected to this fuse and check its functionality.

When faulty equipment is discovered, you need to take it in for repair or buy new one.

If the fuses are checked, and a current leak is still detected by the tester, then the cause of the leak is in an area not protected by fuses: the starter, generator or ignition system.

It is necessary to check by disconnecting the wires from the specified systems.

It is also necessary to take into account that the car may contain self-installed devices, which are often connected to the ignition switch circuit without using standard fuses!

You need to check the wiring: having found a suspicious part of the wiring, you need to look for a short circuit, “ringing” the wires to ensure their integrity. This is done with the same multimeter, but set to ohmmeter mode, since we need to observe the resistance of the wire being studied. The resistance reading will not be much more than zero, and how much will depend on the cross-section of the wire.

Check the generator: to do this, you need to set the multimeter to voltmeter mode and connect it in parallel with the devices. Voltage measurements must be made with the lights on, the sidelights on, and the engine running at high speed. Normally, the voltage should be 13.5–14 V.

With all current consumers involved and a sufficient generator speed, the voltage will normally be at least 12 volts. If contact is broken during testing, the measurements must be taken again: a significant and sudden jump may occur.

Another reason is the alarm system. To diagnose the alarm, you need to set it to security mode and check it after 5 minutes.

During this time, the alarm should go into standby mode and the leak will stop. If this happens, then the alarm is in order; if not, then the alarm is faulty.

In this case, it is better to contact specialists; doing something yourself will be very difficult.

It happens that current leakage occurs when two batteries are used in a car: one of them can absorb the second. To check, you need to disconnect one of the batteries and if the leak stops, then the problem is in the second battery.

Once again I would like to remind you that even if the leakage current slightly exceeds the permissible parameters, this is not normal. In this case, the battery will lose much more of its charge than it can get from the generator, especially during short trips within the city.

The situation also becomes more critical in winter! If you are not very confident in your abilities, periodically contact specialists with a request to carry out preventive diagnostics of the electrical equipment system.

The small amount you spend will more than pay for possible expenses in the event of dangerous situations arising due to problems in the vehicle’s electrical network.

Source: http://CarExtra.ru/sovety/proverit-utechku-toka.html