The rate of current leakage in the car. How can I check the current leakage in a car with a multimeter? Finding and eliminating current leakage in the car

If the car stands for a long time in the parking lot and is not used, then after the driver turns the key in the ignition, nothing will happen. In the process, a relay can click, perhaps even a starter will come to life. But if it does, it's not enough to rotate the crankshaft. All this - symptoms of the discharge of the battery during the time the car was parked.

There is a current leakage rate in the car. But when the battery is discharged, these figures are much higher than these normal ones. Let's look at how you can detect leakage current and fix this fault.

Why is the battery down?

During a long parking time, the charge should not go away, but it is also necessary to take into account leakage currents. Particularly quickly the battery discharges in modern cars. Here the network includes a considerable number of different electronic devices and gadgets. Often in such cases, the current leakage rate in the car is much higher than the allowable. Among the typical reasons, it is possible to distinguish old and substandard wiring, as well as insulation of wires. Another common cause is incorrectly connected electronic equipment. It can be an audio system, multimedia, a navigator and so on. The causes of current leakage in the car may be dirty or oxidized contacts. All this essentially "sits" AKB.

Allowable current consumption of the battery

In modern machines there is a certain number of consumers of electrical energy on an ongoing basis. It can be hours, computer memory, immobilizers, alarms and other similar equipment. They are connected to the grid and consume electricity. And constantly.

For example, let's take volatile memory of the computer. If you erase it, the unit will begin the process of retraining and will again remember all the current settings. Security systems begin to work only when the car is parked. From this it can be concluded that a small consumption of electrical energy is a normal situation.

But there is a current leakage rate in the 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, signaling requires no more than 20 mA. To operate the clock, 1 mA is needed. The audio system consumes about 3 mA and so on. In total, the total figure will be in the range of 50 to 80 mA. This is quite a bit. Even one lamp in the headlight, which you forgot to turn off, consumes from 500 mA. And the current leakage rate in a car of 50 A can not cause a complete discharge of batteries even in winter.

Determine what is the amount of consumption, you can use a multimeter. And if in the process of measuring the level of consumption is higher than the allowable, then. There is a problem with the on-board network. It must be found and eliminated.

Determine where the current goes on its own

As you know, the main reasons, because of which the batteries are very low, only two. These are additional consumers or a short circuit in the network. So, let's see how to measure the leakage current in the car with a multimeter. With this operation, you can find and detect a thin place in the on-board network. To locate a leak, the meter must be turned on to measure the current. Do not forget that the car network has a constant current. As for the measuring range, it will be enough to have 10 amperes.

How to connect a multimeter

Before you begin to search for a leakage current in the car, you need to connect the device correctly to the on-board network. As for consumers of electricity from the battery, they should be turned off whenever possible. To conduct measurements, the ammeter is inserted into a circuit break. To get such a break, remove the wire from the positive terminal of the battery. Then connect one contact of the ammeter to the positive of the battery. And the second - to the wire just taken off. Never connect the instrumentation to the plus and minus on the battery. The result is a short circuit. Nothing happens with the machine, but a fuse will burn in the multimeter. If everything is connected correctly, then on the screen of the device there will be a number that corresponds to the current that is consumed by permanently switched on electrical appliances. If the permissible leakage current 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 for this problem is an electronic device from additional or non-standard equipment. In modern cars every year, such nodes are becoming more and more. Begin the search is necessary with those devices and devices that are installed independently, that is, non-standard. It can be different fans, alarms, yes anything. Factory wiring in vehicles is reliably protected. And short circuits in it occur only in the event of any significant damage. For example, as a result of an accident, a protective cover can be damaged. But the wires, laid by the owner of the car, often lie carelessly. They are placed in the first place, which, when examined briefly, seems to be the most suitable. It is in these wires that the cause of short circuits is hidden. A fault leads to a leakage of currents. The wires laid by the car owner can be in dangerous proximity to the engine block. The engine, as is known, is heated in the process of work. Thus, the insulation of wires can melt in a banal way.

дверей автомобиля). Also, the cords rub against the edges of the metal parts (especially at the points of contact of the car doors). They are rubbed - as a result, the integrity of the insulation is broken and a short circuit appears.

Specialists on autoelectrics recommend immediately after the measurements (if the current leakage rate in the car does not correspond to the reading of the multimeter), go to a visual inspection of everything that is installed non-standardly. Also, it is necessary to examine separate parts and elements of devices and devices that are subject to mechanical influences. If it is a question of signaling, then it can be a terminal. If there are no signs of disturbance, burning, corrosion, then it is worth moving on to more complex methods of troubleshooting. With this diagnostic, you can significantly narrow the range of possible malfunctions.

How to perform deep diagnostics

So, we already know how to measure the leakage current in the car with a multimeter. In this case, the device is connected in the same way as in the previous case. But each fuse is taken out in turn and the relay is disconnected. This is done to open the circuit in the vehicle's on-board network. When the leakage rate becomes close to normal, then a chain with a problem consumer is detected. Next, you should already replace or repair improperly working equipment.

Additional diagnostics

Sometimes there are difficult situations in which even after checking for leaks with the help of fuse extraction there is no positive result and the source of the problem is not found. In this case, nothing remains but to check the current leakage in the vehicle in the circuits. They are not protected by fuses. It's a generator and a starter. Very often the battery bursts due to the malfunction of the generator. The cell simply does not charge the battery. To check the generator, connect the multimeter to the battery terminals. The device is put into the voltage measurement mode. The voltage is then measured. If the battery is discharged completely, the device will show from 12.6 to 12.9 V. Then you need to start the engine, turn on the dipped beam, the stove, the rear window heating system and measure the voltage again - ideal values from 12.8 to 13.4 V. Maximum - 14.3 V. If the voltage is within this range when the motor is wound, the working element is working. If it is smaller, then the problem is in the generator, which does not charge the battery.

Elimination of leaks

Before you eliminate the leakage current in the car, you need to find the source. As it can be anything. And to fix the problem, you need to repair or replace an improperly functioning electronic device. Also, to eliminate, it is enough to remove the short circuit.

Conclusion

If there is a feeling that the battery discharges faster, then you should start looking for a short circuit or a "wedge on the mass." Now we know how to check the leakage current in the car and how to troubleshoot.