The battery charging lamp is on, but there is charge - what is the reason?

The panels of devices of classic cars of domestic production are not very informative. They have nothing superfluous, except the performance of the main engine systems, but they are enough to ensure that the driver was informed in time about possible malfunctions of the machine. However, it happens that some device is out of order, and then it is impossible to determine the breakdown at its initial stage.

In this article we will talk about the case when the battery charging lamp is constantly on, using the example of popular classic cars VAZ 2106 and 2107. We will consider the main causes of this phenomenon, and also try to diagnose and eliminate possible malfunctions.

Why do I need a battery charging light

In order for the driver to monitor the status of charging the battery, a voltmeter with a scale is placed on the instrument panel, as well as a small red window under which the warning light is installed. When we insert the ignition key and rotate it in the lock for one turn, this lamp turns on and lights up in red. The arrow of the voltmeter is in the zero position. This means that the generator is at rest and does not allow charging on the battery. When the engine starts, the lamp should go out, and the needle of the device will swerve to the right, indicating the amount of voltage applied to the battery. This happens when the power supply system of the machine is fully operational. But if the VAZ 2107 or 2106 battery charging light is on and after the engine starts, it's likely that something has crashed. And our task with you is to find its cause and eliminate it.

What can indicate a constantly burning battery charging lamp

If the battery charging light is on in the VAZ 2107 or VAZ 2106 , there can only be one reason: the battery does not receive voltage from the generator, or it does, but its value is insufficient. Faults that lead to this, there may be several:

• Violation of the normal contact on the battery terminals;
• Tension loosening or damage to the alternator belt;
• Absence of contact of its "minus" conclusion with "mass";
• A break in the excitation circuit of the rotor or the wear of the generator brushes ;
• Diode bridge failure.
• Malfunction of the corresponding fuse;
• Breakage of the relay-regulator.

Before starting diagnostics

An important point in deciding the question of why the VAZ 2107 or 2106 battery charging light is on, is the very fact of the battery voltage coming from the generator. In other words, if it does not arrive at the battery at all, there is nothing to be surprised at. The lamp must burn in a similar situation. But if the battery charging light is on, but there is a charge, it will be a little more difficult to solve this problem.

Our first priority is to determine if the battery voltage is being applied. This is not difficult at all, especially since only one instrument is needed - a voltmeter or a multimeter included in its mode. We start the car engine, raise the hood and make voltage measurements on the battery terminals with the generator running. If all the elements of the system are working, the voltmeter should give out 13.6-14.2 V, and no less. This is the operating figure for the normal charging of the battery. If the voltage is below these values, then there is some kind of malfunction.

Breaking the contact on the battery terminals

At this stage of the diagnostics, you need to check the condition of the terminals of the wires and the battery terminals. Often they are oxidized, so that the contact between them weakens. In the case when the battery light is on, but there is a charge, it is this fault that is most often the cause. The generator operates in normal mode, the voltage is applied to the terminals, but is lost due to a weak contact. So it turns out that the charging is on, but the battery charging light is on. And it burns in most cases a dim light. Eliminates such a malfunction by cleaning the terminals and the battery terminals, as well as treating them with a water repellent liquid.

Tension loosening or generator belt damage

During the diagnosis it is necessary to check the condition of the generator belt. Sometimes it happens that, due to its long work or under the influence of other factors, it deforms, as a result of which the generator drive gives omissions. Pay attention to the belt tension. Its weakening leads to the same effect.

If the belt is not deformed and has no visible damage, you can simply tighten it. Otherwise, it must be replaced. Normal is the belt tension, at which it can be turned around the horizontal axis by 85-90 degrees.

The absence of a contact between the output of the generator and the "mass"

This fault, like the first in our list, occurs due to oxidation of the terminals and terminals. In addition, contact breakage is possible due to the weakening of their attachment. The solution to this problem is to clean the terminals and terminals, and also to process them with liquid of the VD-40 type.

Malfunction of the generator

In the case when the battery charging light is on, but there is a charge (VAZ 2106, 2107), the generator must be checked. The most common of its problems in the context of our malfunction are the break in the excitation circuit of the rotor or the wear (damage) of the brushes.

First of all, the generator must be dismantled and dismantled. To check the winding of the rotor, we use the same multimeter, included in the ohmmeter mode. We connect its probes to the winding leads and measure its resistance. In a working rotor, it should not be less than 4.5 ohms. If the resistance does not reach this value, it is likely that the interturn closure occurred somewhere. In the event that it is not detected at all, a winding breakage is possible.

We pass to brushes. We take them out of the seats and inspect them for wear. If the length of the brushes does not exceed 7 millimeters or if there are signs of damage, we change them. Pay attention also to the state of the brush collector. If there are defects in its copper plates, we change the rotor.

Diode bridge

The diode bridge serves to convert the alternating voltage to a constant voltage. In the event of a breakdown of at least one of the diodes, the device ceases to cope with its tasks, because of which the voltage on the vehicle's side circuit starts to flow, which does not correspond to its parameters. That is why the rectifying bridge must be checked in the event that the battery charging lamp is on, but there is charging (VAZ 2107, 2106).

Determine the serviceability of diodes can also be done with a multimeter in the appropriate mode. We turn on the tester and connect the red test lead to the positive terminal of the bridge, and the black one to one of the contacts marked "AU". The threshold (transmission) voltage for silicon diodes is from 400 to 1000 mV. If the device shows you a value that does not fit into the specified frame, the bridge must be replaced. It is impossible to repair it.

Fuse fault

The electric charging circuit of the battery, like any other, is protected by a fuse. It is located in the assembly block under the hood of the car. In the "six" and "seven" this fuse is usually designated as F10, but, in any case, before checking it is better to look through the user's instruction. Most often, when it malfunctions, there is no voltage to the battery at all, but it also happens that it causes the battery charging lamp to light, but there is charge.

The fuse is checked by the tester after it is removed from the seat. If the device shows that the part has become unusable, just replace it.

Malfunction of the relay-regulator

Another reason that the battery charging lamp is on, but charging is, there may be a failure of the relay-controller. It, in fact, is responsible for the timely on-off of this lamp. In cars VAZ 2106, 2107 the relay is installed in the engine compartment on the upper part of the mudguard of the wheel on the right side. The principle of his work is the following. When the ignition is switched on (with the engine switched off), the current coming from the battery flows through its closed contacts and feeds the test lamp.

When we start the motor, the generator is turned on, feeding the relay with the rectified voltage. Under the action of it, the device's anchor is attracted to the core, breaking the contacts. At the same time, the lamp should go out.

It is not difficult to check the relay yourself. For this it is sufficient to detach both wires from it and close them together. We start the engine and look at the warning light. If it is not lit, we will replace the relay.

Some useful tips

To avoid problems related to a malfunction of the battery charging electric circuit, use the following tips.

1. Often pay attention to the dashboard of the car. So you will know not only about the charging state of the battery, but also about the operation of other systems and mechanisms.
2. Systematically check the generator belt. From its condition and tension depends the correct operation of the entire on-board network with the engine running. Finding the slightest defect of the belt, do not pull with its replacement.
3. Do not be lazy at least once a month to check the voltage supplied by the generator to the battery terminals. When identifying inconsistencies with the recommended indicators, perform a full diagnosis of the on-board network.
4. Periodically conduct a visual inspection of the battery terminals and the generator terminals. After detecting their oxidation, peel them with a fine sandpaper and treat them with a liquid of the VD-40 type.
5. Do not allow water to enter the generator, battery and relay-regulator. It can cause a short circuit in the electrical circuit. It is better to instruct the engine specialist to wash the engine .
6. During the repair of the battery charging circuit, avoid using spare parts that cast doubt on the quality.