How to finding a leak current in the car

How to finding a leak current in the car-Methods of self-identification of leakage current in the battery, sometimes after a long parking lot when the only audible clicks relay or starter still turns on, but turns slightly. All these symptoms indicate that the battery while parked discharged in whole or in part.

Self-discharge can not explain it – good battery discharged for a long time, a few months – and so there was a leak current, or there is a fault in the system of charging, and the driver parked the car, did not know that the battery is not sufficiently charged.

Common causes finding a leak current

Diagnosing the cause of premature discharge, it is necessary (and it is a general rule for the diagnosis of any malfunction in the car) to cut off the reasons showing not a malfunction. Or rather, a lack of attention to the car. For example, the battery may be old and to develop the resource, the terminals are covered with scale, or the wires may be in poor condition, etc. Often the cause of the discharge are or parking lights. If, however, reason to think that the reason for the discharge was one of the above or similar factors, no one can state any wiring and start looking for the leak.

Permissible limits battery current consumption

In the car there are a number of “authorized” regular consumers of electricity. It can be hours, the memory of the electronic engine control unit, alarm system, etc. All they are constantly fed, as computer memory, for example, wash not recommended, otherwise the unit will re-train, re-memorizing the current settings, and alarm system generally works just in those moments when the engine is off and the vehicle is stationary.

From this it follows that the current consumption in the parking lot – normal and should have some constant value, which can be calculated by folding the consumption of all consumers. For example, the signaling may consume approximately 20 mA, the memory hours – 1 mA cassette – 3 mA, and so forth. The total intake should range between 50 – 80 mA. This low consumption (for example, even one included lamp consumes near 500 mA), and much to defuse the modern battery such leaks can not, even in winter.

If the results of the measurements it appears that the average value of the constant consumption significantly exceeded, then the on-board network is leaking and needs to be addressed.

Independently determine whether the leakage current

The main reasons for the intensive two discharge – the presence of an “unauthorized” user current or short circuit in the circuit board. Detect leakage current absorbed by constantly running a consumer, you can, using a household appliance called “meter”.

For troubleshooting multimeter should be converted into an ammeter mode, do not forget that the current system voltage constant, and put the measuring range of up to 10 amps.

Before the measurements, the ammeter must be properly connected to the on board network, and electrical systems, on the contrary, should be, if possible, are disabled.

Cause unauthorized current consumption often becomes any instrument of the number of additional equipment

Most often, an ammeter connected to the open circuit. In order to form a gap, it is necessary to remove from the positive terminal of the battery wire, and then re-complete the circuit by connecting one lead of the ammeter to the terminal itself, and the other – to remove wires. In any case, do not connect the multimeter working as an ammeter to the positive and negative terminals of the battery, as a result of this action will turn the very short-circuit, and the device will burn the fuse.

If you did everything correctly, the display will show the meter number that corresponds to the strength of the current consumed constantly connected appliances. If the current higher than normal, it means that there is a leak.

Search leakage

Cause unauthorized current consumption often becomes any instrument of the number of additional equipment (normal or abnormal), which in modern cars every year it becomes more and more.

Starting to look for leaks, first of all, you should pay attention to the devices installed in cars abnormally, for example, on an alarm or the cooling fan. Native wiring car is well protected, and the emergence of a short-circuit it is possible only after significant metal damage (destruction of the protective casing in a car accident, for example). But abnormal wiring devices have to be laid into the first place that a superficial examination seems appropriate, in fact, those not being. It is in this posting more often and there is a short circuit – the most common cause of leakage current.

For example, the wires can be routed too close to the engine block and begin to melt under the influence of heat coming from it, or simply rubbing against the edge of the metal bracket. And then, and another leads to disruption of the insulation and the appearance of a short circuit.

So, the search algorithm leakage, on the advice of master electricians have to be. By measuring the strength of the current-meter and making sure that there is a leak, you need to move on to the visual inspection, since abnormally installed devices and their parts subject to mechanical stress. For example, in the case of alarm it may be a “limit switches” – special long button opens and closes the circuit when opening and closing doors.

Making sure that the visible signs of deformation, erosion and corrosion on wires not, you should resort to more sophisticated methods of diagnosis, allowing narrow down the search. For example, electricians often take out the fuses one by one from each chain, carefully making sure that the spark contacts when open or not. If a spark occurs, as in the circuit voltage should not be (instruments that it nourishes, must be turned off at the moment), it is possible leakage there.

To identify suspicious of the wiring is to be found in her circuit, wire, one after another on the subject of integrity. This is done by the same multimeter but ohmmeter mode, since in this case it is necessary to observe the resistance of wires of interest to us. Indications resistance, as well as the current strength at normal discharge accumulators must be greater than zero, and the specific value depends on the cross section of the electric wire.

So, find the leak current self is quite possible, if you learn how to use a multimeter and learn the method of exclusion, paying attention along the way for various oddities – melted or frayed wires, rust near the wiring and so on.