Is your battery draining quickly? It's time to sound the alarm!

What causes a car battery to drain?

It is difficult to find the reasons for battery discharge without special devices. The culprit for the loss of voltage may be either the power supply equipment or the battery itself. A couple of factors affect the normal performance of the battery:

• battery wear;
• generator failure;
• climatic conditions;
• short circuit in the electrical equipment circuit.

The conditions and significance of the vehicle’s operation are important. When starting the engine, the starter consumes a large amount of energy. It takes some time to restore the charge.

With frequent trips over short distances, the generator may simply not have enough time to charge the battery.

Subjective reasons

Very often, the source of problems associated with battery discharge is the human factor. In cases of inattention, inexperience, or other character traits, the driver may forget to turn off the interior lighting, side lights or headlights, radio or other electrical appliances.

Often, such motorists discharge even completely new batteries overnight, and the next morning they make a warranty claim. No arguments work on them. You can convince them of your own mistake only by clearly demonstrating the device that was left on.

If you ignore the battery, do not monitor its condition, and use it intensively, the likelihood of self-discharge increases. Incorrect driving, the distinctive features of which are frequent engine starts and short distances, can also drain the battery. It is quite simple to prevent such situations by paying a little more attention to the battery and the car.

problems and battery wear

Diagnostics of the battery condition must be done with the engine turned off and without load (with the terminals disconnected). The density of the electrolyte is determined with a hydrometer; the usual indicators are 1.26 - 1.28 g/cc. Smaller numbers indicate an incomplete charge.

When checking with a hydrometer, you should pay attention

on the electrolyte level in each jar. Refill containers with distilled water, following safety precautions.

To check the battery with a tester, the toggle switch of the device is set to the 20 V constant voltage control mode. The multimeter probes are connected to the positive and negative terminals of the battery. The charge level of the power supply is shown in the table:

Voltage, V	12,8 -12,9	12,6 — 12,7	12,2 -12,3	11,9 — 12,0
% charge	100	75	50	25

Tester readings of 11.8 V and below indicate that the battery is completely discharged. Its voltage is not enough to start the engine.

Regardless of the numbers on the display, the battery must be left in a state of calm, and after some time the measurement must be taken again. If the next time the indicators turn out to be significantly lower than the previous ones, the problem is in the battery. The power supply will require servicing or replacement.

If these multimeter readings do not change within several days, then the discharge occurs for the second reason.

Battery Operation

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1.1. Operating Basics

Caring owners monitor the charge of batteries during operation using accessible methods. Periodically, preferably at least once every 2-3 months, even with trouble-free operation, it is necessary to check the voltage at the terminals of the starter battery when the engine is idle and when the engine is running, as well as the presence of leaks in the vehicle's electrical system (chapters 4.3-4.5).

All starter batteries lose some water from the electrolyte during operation. As a result, the reserve level of electrolyte above the plates decreases and the concentration of acid in the electrolyte increases (the density of the electrolyte increases), which negatively affects the battery life. The rate of water loss critically depends on both the materials used to produce the battery and the condition of the vehicle's electrical equipment. Depending on the combination of all these factors, it can differ by 10 or even 20 times. Therefore, reducing the electrolyte level in a battery to a critical level is possible in 1-3 months (with a faulty voltage regulator) and in 2-4 years. When using classic lead serviced batteries, you have to put up with checking the electrolyte level at least 1-2 times a month and topping up with distilled water, as well as a relatively high self-discharge rate - up to 14% per month, which progresses during operation and after 1.5-2 years of work increases by 3-4 times. Therefore, if such batteries are not used for a long time, they must be recharged every 1-2 months.

To prevent the battery from draining when the car is parked for a long time

, it is recommended to disconnect it from the network, since, as a result of current leakage in the electrical system, the battery may be so discharged that it will not be able to start the engine. If, even when disconnected from the on-board power supply, the battery discharges quickly, this indicates increased self-discharge for the old battery or an internal defect (short circuit) for the new battery. The reasons for increased self-discharge can be either a manufacturing defect, violations of operating conditions or natural wear of the battery (see section 3.2). We must try to prevent recurrence of deep discharges of the battery, amounting to more than 40-50% of its capacity - after which the battery will not be able to quickly fully charge from the generator.

The following reasons for deep discharges of batteries are possible: - “leakage” of current in the electrical network (for example, due to poor-quality wiring or faulty switches);
— malfunction of the generator or voltage regulator, low tension of the engine generator drive belt; - long-term use of network consumers when the engine is not running, for example, an alarm system when a car is parked for a long time. 1.2.
Causes of deterioration and failure of the battery Deterioration of performance or failure of the battery occurs if: - there is a manufacturing defect (warranty case); — battery operating conditions are violated (accelerated wear); — the battery has completely exhausted its natural resource.

Manufacturing defects

The quality of the battery is ensured during its development and manufacturing. At the final stage of production, all batteries, depending on the state of delivery (filled and charged or dry charged), are subjected to appropriate control checks. Defects that could not be identified at the final stage of battery production are discovered at the initial stage of their operation - in the first 3-8 months.

A decrease in performance in engine starting mode or complete battery failure with sufficient electrolyte density and open circuit voltage (OCV) are usually associated with the presence of manufacturing defects (they are listed in Chapter 2.5). Batteries with manufacturing defects that are discovered during the warranty period must be replaced with new ones in accordance with the established procedure.

Accelerated wear

Accelerated wear of the battery always occurs due to violation of its operating conditions specified in the warranty card. The most harmful for the battery is operation under conditions of overcharging or undercharging, as well as frequent deep discharges.
Recharging
occurs when using batteries in cars whose charging voltage level exceeds 14.5 V. The fact is that as the degree of charge increases above 75-80%, along with the main process of charging the battery electrodes, a secondary process begins: the decomposition of water into hydrogen and oxygen. Moreover, its speed increases rapidly with an increase in the charging voltage at the battery terminals above 14.5 V. Overcharging is a consequence of a violation of the operating mode of the voltage regulator due to the failure of its individual elements. In some cases, as practice has shown, the charging voltage with a faulty regulator reaches 17-18 V. This leads to accelerated loss of water and corrosion of the positive current leads (grids) of the battery plates.

Under the influence of overcharging, the electrolyte level quickly decreases. Therefore, it must be brought to normal in a timely manner by adding only distilled water to the batteries. Adding electrolyte to batteries is strictly prohibited.

Then it is necessary to immediately find the cause of the increase in voltage and eliminate the malfunction in the vehicle's electrical system.

During prolonged recharging or when the charging voltage is significantly exceeded (above 15.5 V), the loss of water can be so great that the upper edges of the plates and separators are exposed. This often leads to a battery explosion (see chapter 3.7).

Operating the battery in a vehicle with a charging voltage level less than 13.8 V leads to progressive undercharging

. In this case, the performance of the battery gradually deteriorates, since the degree of its charge decreases in proportion to the operating time until it reaches a value corresponding to the charging voltage level. For example, with a charging voltage of 13.6 V and an average intensity of use, the degree of charge of the battery at a positive temperature will be about 65%, and at a negative temperature less than 50%. Let us remind you that the degree of charge of the battery in winter is 70-75% if the voltage at the battery terminals is 13.9-14.3 V with the engine running and the high beams on.

Often the cause of a decrease in the charging voltage level and, consequently, the degree of charge of the battery, is a weakening of the generator drive belt tension. Therefore, it is recommended to periodically check the belt tension and, if necessary, make adjustments in accordance with the vehicle operating instructions.

Long-term operation of batteries at a charge level of 50-60% leads to a rapid loss of performance due to accelerated melting of the active mass of the battery electrodes. In addition, at low temperatures, the electrolyte in heavily discharged batteries can freeze, which will lead to the destruction of the battery case and its complete failure.

Accelerated wear can be so severe that the battery fails even during the warranty period due to unfavorable operating conditions (malfunctions of vehicle electrical equipment, violation of battery operating instructions).

Failure of starter batteries during the warranty period due to accelerated wear does not qualify as a warranty failure.

Therefore, such batteries cannot be replaced with new ones under the warranty obligations of the battery manufacturers.

Deterioration of battery properties due to aging

Due to natural wear and tear during operation, the main parameters of the battery change. Under the influence of corrosion, the cross-section of the main structural elements of the positive electrode array decreases. This leads to an increase in the internal resistance of the battery, that is, to a slight decrease in the discharge voltage even when it is fully charged. The capacity of the battery gradually decreases during operation.

This occurs because with alternating charges and discharges that take place during the operation of the battery in a car, the positive active mass gradually floats due to destruction, and its amount participating in the chemical reaction decreases.
The process of sliding of the positive active mass is accelerated by the frequent repetition of deep discharges, the cause of which is either a current leak in the electrical network or undercharging due to a malfunction of the generator or voltage regulator. The capacity decreases especially quickly during deep discharges in batteries with arrays of positive electrodes made of lead-calcium alloys.
The capacity of the negative electrodes also decreases if the battery has been operated for a long time at an increased charging voltage and the electrolyte density has risen above 1.31 g/cm3. In addition, as mentioned earlier, long-term operation of the battery at a low state of charge (40-60%) leads to accelerated melting of the active mass on both electrodes.

As the battery wears out, its self-discharge rate and water consumption during operation increase.

After a year of using the battery, these values ​​increase by 1.5-2 times, and after two years - by 2-4 times. The rate of increase in self-discharge and water consumption is maximum for batteries of traditional design, and minimum for batteries with current leads made of a lead-calcium alloy. From all of the above, a very important conclusion arises: as the battery ages, it requires more careful attention. So, for example, during normal operation with an average annual mileage of 15-20 thousand km, it is enough to check the condition of the battery once a year, preferably in the fall before the start of winter operation. After two years of operation (30-40 thousand kilometers), it is advisable to check the condition of the battery at least once every 3-4 months. If the battery has worked for more than three years (45-60 thousand km), it is advisable to monitor its condition in winter monthly even in the absence of failures. A criterion for the suitability of a battery that has operated under operating conditions for a long time can be a test discharge, which can be performed in specialized service centers. A fully charged battery is discharged at a positive temperature with a current equal to half the cold cranking current according to EN or SAE.

If at the 30th second of discharge the voltage at the terminals is more than 9.6 V, the battery is suitable for further use. If it is less than or equal to 9.6 V, then the battery has exhausted its resource and must be replaced.

False battery faults

In addition to the battery, which is certainly part of the electric starting system, the car is also equipped with other electrical equipment, malfunctions of which are often mistaken for a battery malfunction. For successful engine starting, the condition of the connecting contacts of the wires and battery pole inputs is important. A dense film of oxides that forms on them and on the inner surface of the wire tips can become an obstacle to powering the starter. At the same time, the data displayed on the instrument panel, coming from a standard car voltmeter, shows that the battery voltage has dropped to zero. In other words, there is a simulation of an open circuit inside the battery, or an open circuit in the external circuit, or a complete failure of the battery. As a result, an inexperienced car enthusiast places the blame for an unsuccessful start not on oxidized contacts, but on a faulty battery, which in this situation may be absolutely serviceable and well charged. Therefore, it is necessary to promptly clean the pole terminals of the battery from oxides.

In a car's starting system, the starter is the main component that consumes electricity from the battery.
Many motorists unfairly refer its malfunctions to the battery. For example, at the moment of start-up, worn bushings in which the armature supports are placed create play during its rotation, due to which the armature can cling to the stator and stop. When repeated attempts are made to start the engine, the armature may not stop. An electrician will easily figure out that the cause of the failure was a malfunction of the starter and will clear the “charges” from the battery. Another element that can “cast a shadow” on the battery is the “mass” wire. As a rule, it consists of two parts: one of them runs from the battery to the car body, the other from the body to the engine. The latter is often out of sight of the motorist (under the engine), which makes it difficult to assess the condition of its connections, which are often covered with oxides and dirt. This can lead to a sharp drop in battery voltage and lead to battery failure. Naturally, this is not the battery’s fault. In the cases considered, it is necessary to check the condition of the battery (electrolyte density, voltage at the pole terminals), or move it to another car and try to start its engine. A successful start will confirm the health status of the “suspected” battery. In actual operation, the charge of the battery depends entirely on the operating mode of the vehicle, the generator, electricity consumers, their technical indicators, the condition of the electrical wiring and the tension of the generator drive belt. In the event of abnormal operation or malfunction of the specified electrical equipment and other structural elements of the vehicle, a completely serviceable battery may be completely discharged. Its successful charging under stationary conditions followed by testing will confirm that the cause of the discharge is faulty electrical equipment, which should be checked. The situations considered can arise either individually or all together (on cars older than 5-6 years) and create difficulties when starting the car engine both in summer and winter. A preventative maintenance regime for electrical equipment products sharply reduces the frequency of unexpected failures and increases the service life of each product, including the battery. 1.3.
How can you increase battery life? The service life of a starter battery, as a chemical current source, is determined mainly by the mode of its use, during which wear processes of the electrodes (plates) located in it occur. Understanding these processes allows us to ensure a high failure-free operation of the battery in the car.

A specific design of a battery has a certain design and technological (taking into account alloying additives to lead) resource, using which we obtain its real service life. What is the best way to properly manage the stored life of the electrodes so that the battery lasts as long as possible?

It is known that the lattice of positive plates is subject to oxidation by atomic oxygen (electrocorrosion) during the decomposition of water in the final (after 85% charge) stage of charge. The most intensive process of destruction of the grids of the positive plates of the battery occurs from the charging current at 100% charge (overcharge mode). This process predominates in the operation of the battery during summer operation, as well as with increased settings of the voltage regulator. Intensive destruction of the active mass of the plates occurs in conditions when the starter battery operates for a long time at a low degree of charge (40-60%). In this case, the active substance from the plates floats into sludge, reducing the battery capacity, its discharge power and the period of reliable operation. Normal operation of the battery is disrupted when the electrolyte level drops below the minimum mark (exposure of the upper edges of the plates).

It is unacceptable to top up with electrolyte or water of untested quality, store the battery in a discharged state, allow ice to form in winter, or subject it to deep periodic discharges. Thus, the greatest reliability and durability of the battery can be achieved by regularly monitoring its condition in accordance with the operating instructions.

The simplest and most reliable methods for checking the condition of the battery are measuring the density of the electrolyte and measuring the voltage at the pole terminals. If the pole terminals are practically accessible for cleaning them from oxides and connecting the device for all batteries, then not all types have the ability to measure the density of the electrolyte in the battery banks.

Below are several basic rules and requirements, compliance with which increases the battery life: - the density of the electrolyte in the battery cells (at a normal level above the plates) must be at least 1.24 g/cm3 (+25°C), and the open circuit voltage ( NRC) - not lower than 12.5 V; — the pole terminals must be periodically cleaned of oxides; — The battery on the car must be securely fastened to the installation site; — starting a carburetor engine should be carried out with a duration of attempts of 5-10 seconds; repeated startup attempts should be carried out at intervals of 30-60 seconds; — a battery discharged due to an unsuccessful engine start must be charged as soon as possible; — in winter, it is useful to heat the battery with heat so that it can be charged more efficiently from the generator. To do this, it is advisable to close part of the radiator (from the battery side) from the oncoming cold air flow.

The condition of the battery largely depends on the proper operation of the electrical equipment.

First of all, this includes the generator, voltage regulator and starter. If the wiring is faulty, the condition of the battery at any time may be such that it cannot start the engine. Worn contacts in the ignition switch, starter relay, and the condition of the generator rectifier unit can be detected by diagnostics. Their timely replacement allows you to protect the battery from possible deep discharges due to “leakage” currents, which negatively affect the subsequent service life of the battery. Batteries with calcium electrodes are particularly susceptible to deep, periodic discharges. This feature, unknown to a wide range of car owners, sometimes leads to bewilderment as to why the service life of the battery (the most modern) is very short.

From the above it follows that the service life of the starter battery (as a margin of safety and reliability), embedded in its parts and connections during manufacture, cannot be changed upward during operation. Controlling the conditions that have the worst impact on reducing battery life makes it possible to ensure a sufficient duration of trouble-free operation under specific operating conditions. It is important to remember that battery performance does not remain constant, and the rate at which it decreases can be controlled by the car owner.

1.4. Features of winter battery operation

The starter batteries are designed for general climatic conditions, allowing them to be used year-round in a wide range of ambient temperature changes. The temperature in the engine compartment of a car is largely supplemented by heat from the engine.

Limit values ​​of ambient air temperature (from -40°С to 60°С for batteries sealed with mastic, and from -40°С to 70°С for batteries with a common cover) are determined for the operation of batteries according to the conditions for preserving them as products (strength of materials ). However, prolonged exposure to extreme temperatures reduces the performance and service life of the starter battery. The performance of the battery decreases most sharply in the engine starting mode in winter (cold) time.

Winter operation of the battery is accompanied by the following factors:

1. The temperature of the battery electrolyte decreases (its viscosity increases, the rate of its diffusion into the pores of the active material of the plates decreases, and electrical conductivity decreases) and for this reason the efficiency of the charging process from the generator decreases at the same charging voltage values ​​on the car. 2. Starting a cold engine requires more power and energy from the battery due to increased discharge current values ​​and longer starter operation. This leads to a deeper discharge of the battery and a decrease in its charge. 3. The number of electricity consumers switched on is increasing, both for comfort in the cabin and for safe movement, powered by the generator and, at idle speed, by the battery. 4. Reducing daylight hours necessitates longer operation of lighting devices, which reduces the ability of the generator to effectively recharge the battery. 5. Deterioration of road conditions leads to a decrease in vehicle dynamics, which reduces the energy output of the generator. This, in turn, reduces the ability to fully charge the battery.

The influence of the listed factors on the reduction of battery charge objectively increases to a much greater extent if the car’s generator, due to wear and tear of parts, does not provide the nominal output (load current). The car owner, as a rule, after many years of operation, does not check the generator for output and, as a result, in winter, finds himself faced with a half-discharged battery, unable to start a cold engine.

Changes in temperature and high humidity in the ambient air under the hood in winter lead to deterioration in the performance of electrical equipment and the occurrence of “leaks” through wet wires, which contribute to a deeper discharge of the battery. At the same time, its performance in startup mode is reduced.

To eliminate the negative effects of winter conditions on the state of charge of the battery, it is useful to carry out the following measures:

— control the tension of the generator drive belt, at which, according to the instructions for the car, full energy output is ensured to power the switched-on consumers and recharge the battery;
— do not allow switched-on consumers to operate for a long time on the vehicle when the engine is not running; - periodically monitor the absence of current “leakage” from the battery to various electrical equipment products. If the storage (parking) conditions of the car allow you to disconnect the battery, then it is advisable to do this during prolonged inactivity (remove one tip); — it is useful to additionally connect the “ground” wire from the battery to the engine in order to reduce voltage losses at the starter when starting the engine, since voltage transitions from the terminal to the body, from the body to the engine and the starter during the starting current lead to its decrease,
i.e. to loss of power consumed from the battery; - periodically monitor the electrolyte density (if there are plugs on the battery cover), and if this is not possible, measure the voltage at the battery pole terminals 8-10 hours after stopping the engine. If the open circuit voltage (OCV) is less than 12.6 V, then it is advisable to recharge the battery.

Carrying out the above measures in winter conditions will eliminate failures in the operation of starter batteries and preserve their service life for a long period of operation.
1.5.
How to determine when it's time to change the battery? Each battery has its own design resource. Its use is individual for each car. The failure-free operation of the battery depends on the technical parameters of the electrical equipment, the mode and operating conditions of the machine. Battery failure may occur due to low charge, at which its performance is insufficient to start the engine. It should be noted that it is in this mode of operation that most drivers assess its suitability. But if a failure occurs, the battery should be sentenced to replacement only after a thorough check of its indicators - measuring the density of the electrolyte, its presence above the plates, measuring the voltage at the pole terminals of the battery without load and with load (on a load probe plug, or on a stand). If the electrolyte density in all battery cells is normal or close to normal (1.25-1.28 g/cm3), and the NRC is not lower than 12.5 V, then it is necessary to check for an open circuit inside the battery. If there is no break, then the failure to start the engine occurred for other reasons (for example, due to the starter or wiring). If the electrolyte density is low in all cells, the battery should be charged until the density stabilizes. The charging time will depend on the current value, and the electrolyte density of a charged battery at a normal electrolyte level should be 1.27 + 0.01 g/cm3, and the NRC should be at least 12.7 V. Checking a charged battery can be done in the engine start mode (at the technical center they check it on a stand). If the battery is functional (the starter turns confidently), it is too early to change it. When measuring the density of the electrolyte shows that in one of the cells it is very low, and when recharging in this cell there is no “boiling” of the electrolyte, and its density does not increase, the battery should be replaced. With a short service life, this is possible due to a factory defect, and after more than 2-3 years of operation - due to natural wear and tear. At the same time, all six batteries in the battery reach a state of low performance (except for deep discharge) when operating for a long time in excess charge (overcharge) mode. This occurs when the voltage regulator malfunctions, as well as when the vehicle is used at a high intensity (taxi mode). In this state, worn electrodes have increased resistance in the starting mode (in the presence of normal electrolyte density), the battery voltage drops sharply within one or two attempts to start the engine, after which failure occurs. The electrolyte in the battery cells acquires a dark (sometimes reddish) color associated with the destruction of the active substance of the plates. This battery needs to be replaced. It is more difficult to diagnose batteries that do not have filler plugs. In the event of a failure, measuring the voltage at the battery pole terminals (NRC) does not give an answer about the reasons for its decrease: a deep discharge or a defect. Therefore, the battery must first be charged. If charging is possible in the operating instructions mode, and the voltage at the end of the charge has reached 16.0 V, the battery is checked in the vehicle in engine start mode. It is also possible to check at a technical center or warranty workshop on a stand, or with special devices (for example, BAT 121 from Bosch). Based on the test results, a decision is made on the suitability of the battery for further use.

1.6. The appearance of ice in the battery cells

Lead batteries have two strictly fixed states: discharged and charged. When transitioning from one state to another, the voltage and density of the electrolyte change linearly within certain limits (Fig. 4 and Table 1)

. The voltage at the battery pole terminals (NRC) in a charged state is 12.7-12.9 V, and in a discharged state - 12 V and below. In the event of malfunctions in the vehicle's electrical equipment, an unauthorized discharge may result in the voltage at the pole terminals being below 6 V.

Fig.4. Enlarge >>

When active materials are discharged with the participation of sulfuric acid, lead sulfate is formed on the electrodes, the concentration of the electrolyte decreases, as a result of which its density decreases.
The deeper the battery discharges, the lower the density of the electrolyte. The electrodes contain such an amount of active material that is necessary to ensure the specified electrical characteristics of the battery. Accordingly, the volume of the electrolyte contains the amount of sulfuric acid necessary for full use of the active substance of the plates in the reaction. So at the end of a complete discharge of the battery, there is very little sulfuric acid in the electrolyte. At the end of a deep discharge, the density of the electrolyte reaches a value close to the density of water. It is known that an electrolyte with a density of 1.28 g/cm3 freezes at a temperature of -65°C, with a density of 1.20 g/cm3 at -28°C, and with a density of 1.10 g/cm3 at -7°C (Fig. 4)

. Battery manufacturers consider it unacceptable to use batteries with a charge level below 75% (electrolyte density 1.24 g/cm3, NRC - 12.6 V) in winter. This is dictated by the need to maintain the functionality of the battery, eliminate the possibility of ice appearing inside it, and reduce the harmful effect of deep discharge during winter operation on the battery life associated with the destruction of the active mass of the plates. It turns out that if the battery freezes (ice in all cells), it means that it was discharged during operation below the permissible value (there is no control of electrolyte density, electrical equipment is faulty, the power of the generator has decreased - there are many reasons). There are times when only one cell out of six freezes. This is possible when the battery has a defect (short circuit) in one cell, due to which the density of the electrolyte in it decreases and it solidifies at low ambient temperatures. At the same time, in other battery cells the electrolyte may not freeze, since its density remains normal. This case of ice formation is caused by a manufacturing defect and is a warranty issue and not an operating issue. Such a battery should not be used - it must be opened to determine the defect and replaced. In winter, you should add distilled water to the battery to restore the electrolyte level above the plate blocks only before leaving the car, or when stationary recharging the battery. This eliminates the possibility of ice forming in the battery cells due to freezing of the added water before it has time to mix with the cold electrolyte.

Table 1

Dependence of the open circuit voltage (OCV) of the battery at different electrolyte temperatures

Degree of charge, %	Equilibrium open circuit voltage (OCV), V, at different temperatures
	+20…+25 degrees C	+5…-5 deg.C	-10…+10 degrees C
100	12,70-12,90	12,80-13,00	12,90-13,10
75	12,55-12,65	12,55-12,75	12,65-12,85
DANGEROUS AREA
50	12,20-12,30	12,30-12,40	12,40-12,50
25	11,95-12,10	12,10-12,20	12,20-12,30
0	11,60-11,80	11,70-11,90	11,80-12,00

1.7. About the causes of battery explosion

Lead-acid starter batteries, used on various types of automobile and tractor equipment, have one little-known unpleasant feature that must be taken into account during operation. The fact is that during the charging process at its final stage, the electrolytic decomposition of the water contained in the electrolyte begins in the battery. This releases gases: hydrogen and oxygen. Part of the oxygen released oxidizes the lattice of the positive plates, which leads to accelerated corrosion. Hydrogen and most of the released oxygen come out of the electrolyte to the surface, creating the appearance of boiling, and accumulate under the caps in each battery cell. If the holes in the plugs are not clogged with dirt and there are no other obstacles, through them this mixture of gases comes out and easily dissipates into the environment. The ratio of oxygen and hydrogen is such that it is a mixture that, in the presence of a spark or open flame, burns explosively. The force of the explosion and its consequences depend entirely on the amount (volume) of gas accumulated at that moment. For example, with an increased value of the charging voltage from the generator (the operation of the voltage regulator is disrupted), the intensity of gas formation inside the battery increases and, consequently, its release. When the electrolyte level is low (no regular topping up), the gas volume under the battery cell caps increases.

The accumulation of gas near the battery can be facilitated by the insulation used by some drivers, who forget about the need to freely remove the gas mixture.

In this state (operating mode), the appearance of a spark from faulty electrical wiring or an open flame (cigarette) is dangerous for the battery - it explodes and is destroyed. If battery parts break, they can cause damage to surrounding objects and people. A spark can also occur from the wires at the points of their connection with the pole terminals of the battery. If the battery pole terminals and the inner surface of the tips are not cleaned of oxides for a long time, normal electrical contact is disrupted and sparks may form.

A spark can also form between parts inside the battery when the electrolyte level is below the upper edges of the plates. Thus, violation of safety precautions and battery maintenance regime, long-term operation of the battery in cars with deviations in the technical parameters of electrical equipment products, cause the accumulation of released “explosive” gas and provoke an explosion, leading to the destruction of the housing of lead-acid starter batteries. Such an explosion can cause harm to humans.

Based on materials from the magazine “Secrets of Selection and Application.
Car batteries." Authors: N. Kurzukov, V. Yagnyatinsky

Generator failure

This unit charges the battery during engine operation. Monitoring the operation of the generator is provided by a light bulb or ammeter on the control panel. But they are not always able to provide all the data on the state of charge of the battery.

It is possible to check the serviceability of the generator with a tester. The device toggle switch is set to the “20 V” DC position. The engine starts, after which the probes of the device are connected to the terminals. The multimeter readings should be at least 14 -14.2 V.

To fully test the generator, you need to load it to the maximum, turning on all the wonderful electrical equipment (high beams, dimensions, stove). A working generator along with this

must produce 13.8 - 13.9 V.

The reason for a low charge is usually low tension on the alternator belt or wear on the brushes. Poor contact or terminal oxide will also affect the charging status.

Fundamentally important! While testing the generator, the terminals must be connected to the battery. The readings without load will be zero.

Video - how to check the operation of a car generator:

It is possible to check charging without a tester. After starting the engine, you need to disconnect one of the terminals from the battery. If the car does not stall, it means the generator is working. Upon completion, you need to turn on all electrical equipment, and the engine must continue to idle.

A noticeable decrease in speed indicates that the device is not operating at a high level.

Car problems

Alarm goes off

Why does a car battery discharge? 6 photos
In standby mode, security systems consume a minimum of electricity and are not able to discharge a working battery. In those cases when the alarm is activated for no apparent reason, the battery life can be significantly reduced.

The most common reasons for frequent alarm activation:

• Incorrect shock sensor sensitivity setting. If the design of the sensor does not allow it to be “coarsened,” then contact a specialist - either he will modify the device circuit or select a less sensitive analogue.
• Incorrect installation and adjustment of the free play of the door, hood and trunk lid limit switches, as well as changes in the gaps between body elements. The reason may be oxidation of the contacts of the switches, as well as the ingress of water into them.
• Damage to the electronic unit of the security system. However, sometimes failures are caused by water getting into the body of the unit and it is enough to simply rinse its circuit with alcohol.

Included electrical appliances

Almost all regular current consumers are completely de-energized when the ignition is turned off. But devices installed independently, bypassing the ignition switch, may well deplete the battery during prolonged inactivity. Sometimes unqualified auto electricians, not wanting to understand the wiring diagram, also connect regular consumers in this way - for example, a heater fan.

The generator does not charge well

To check the generator, measure the voltage at the battery terminals with the engine running. A working generator, even with the headlights and other consumers on, must produce at least 14 V. A slight decrease in voltage is allowed only in idle mode. If the voltage drops below 12 V when the headlights are turned on, the generator must be repaired.

But incomplete restoration of battery life is sometimes explained by short trips interspersed with long periods of downtime. In such cases, the battery simply does not have time to restore the charge used to start the engine. This is especially true in cold weather. Sometimes the owner, having arrived at work in the morning, leaves the car for the whole day, and in the evening he can no longer start it.

The battery may partially drain even while driving in city traffic. Long periods of idle time in traffic jams, when the engine is idling and all conceivable consumers are turned on, do not help replenish the battery charge.

The wiring is worn out

Deterioration of contacts in the connecting blocks of wiring harnesses due to their oxidation leads to an increase in the resistance of electrical circuits, and hence, energy consumption.

In addition, damaged insulation and dirt provoke current leakage, which was mentioned above. In order to identify the “culprit” of a leak, you need to measure its value using the elimination method. The circuit that, when disconnected, stops the loss of current, is subject to thorough inspection and repair (or replacement of the wiring harness).

Effect of climatic other factors and conditions

From time to time, external bodies become the cause of the discharge. An unclean battery surface may cause self-discharge. Once in the active mass of the electrolyte, foreign elements lead to chemical reactions that cause the battery to discharge.

In hot weather, chemical reactions occur faster.

Fundamentally important! At high air temperatures, the battery loses more than one percent of its capacity in one day.

Another one

The reason why the battery may discharge is high humidity. Water is a good conductor of current, therefore, if liquid gets on elements of electrical equipment, a short circuit may occur in the electrical equipment, which will lead to leakage of current. In addition, wet leaves that have accumulated under the hood near the contacts of windshield wipers, etc., can also create a “shorty” problem.

alkali and acid interaction slows down at low temperatures, and in cold weather the battery drains much faster. In cold regions, it is recommended to increase the battery density to 1.28 - 1.30 g/cc. by adding electrolyte. Indeed, such actions significantly reduce the operational life.

On a note

Daily discharges to zero kill the battery. It is better to prevent illness than to put up with the fact that the battery quickly loses its charge when driving a car. If a moment of intense discharge occurs, it is useful to identify it and refrain from cranking the starter again.

What to do to prevent the battery from draining quickly

• Charging with a low current (about 1-2 A) prevents the initial sulfation of the plates. Connect the charger once a month at night and a regular battery will last 5-6 years without problems, and an AGM or EFB battery will last even longer.
• Learn how to properly store your battery in the garage and at home. When parked in the cold for more than a day, remove the power source and bring it into a warm room (no more than +25°C).
• Regularly clean the terminals on the car and the down conductors on the power source with a special brush for battery terminals (pictured) or a simple sandpaper. Oxides cause undercharging.

• With the arrival of cold weather, recharge the product more often to 100% with normal current (10% of capacity).
• Keep the outer surface of the battery clean. You can wipe with a 10% solution of ammonia and soda ash, then wipe dry.
• If the battery is serviceable, clean the holes in the lids of the cans with a thin wire. Check the electrolyte level before charging. Standard: +10…15 mm from the safety shield. Compare the density of the electrolytic fluid with the voltage.
• Periodically test the on-board network for current leaks.

"Shorty" in the electrical circuit

This problem is the most difficult to find and fix. “Shorties” appear and appear sometimes. This makes troubleshooting and detection more difficult. With frequent use of the car, the battery does not have time to be completely discharged, and the owner of the vehicle is unaware of the presence of malfunctions for a long period.

Electrical equipment of vehicles

consists of a single-wire positive circuit. The body, engine and all iron parts are a minus. When the conductors of good and negative charge come into contact, a short circuit occurs, as a result of which the battery “runs out”.

Shorties can appear both in the wiring and in electrical appliances of the car.

The fault can be found in the following way. After turning off the ignition, remove the positive terminal and touch it to the positive terminal of the battery. If sparking appears between the elements, it means there is a short circuit in the circuit.

The next move is to search for current leakage.

How to find out the circuit in which the short circuit occurs

Any car has a current leak (alarm system, injection system controller memory, radio, clock, etc.). The acceptable value at which the battery will not discharge is 0.02 - 0.06 A. Before measuring current leakage, you must turn off all electrical appliances. It is fundamentally important not to forget to slam all the doors and lock the limit switches under the hood. Leakage measurements are performed with the ignition off in the following sequence:

1. The tester's toggle switch is set to 10 Ampere measurement mode.
2. The negative wire is removed from the battery.
3. One probe of the device is connected to the removed wire.
4. The second tester probe is connected to the battery negative.

The polarity on the digital multimeter display does not matter.

Video - how to measure battery current leakage:

If the leakage current exceeds the permissible limit, go to look for the circuit in which the discharge occurs. For this

All fuses are removed one by one and the device indicators are checked. If, after removing the next fuse, the numbers have dropped significantly, the problem must be looked for in that circuit.

Having figured out which specific devices a particular conductor protects, you need to disconnect them from consumption one by one. The fuse should be installed in place. A decrease in the current leakage indicator on the display will indicate the problematic element.

Advice! To ensure a guaranteed result, you need to check all fuses, since faults can occur in several circuits at one time.

To finally get rid of current leaks during parking, you need to install a ground switch in the negative wire circuit from the battery terminal to the body.

Driver errors

When preparing your car for the night, you need to make sure that all devices are turned off. Any energy consumer can completely discharge the battery overnight. We invite you to watch a detailed video study of why your car battery dies overnight.

Battery failure is one of the most common nightmares of car enthusiasts. The situation when a car was put in the garage in working condition in the evening, and in the morning all attempts to start it were in vain, is not uncommon. The battery shows absolutely no signs of life. Such a “surprise” can come from a completely new battery in a car. Let's try to figure out what could be the reasons for this malfunction and why the battery drains overnight.

How to perform a battery health test

Reasons for a lean mixture on the injector - we understand the problem

Battery replacement can be scheduled or unscheduled, depending on the situation. Throughout the entire period of operation of the vehicle, its owner has to repeatedly carry out a similar procedure to combat rapid discharge.

Advice! Before you begin replacing your car battery, review all of the vehicle manufacturer's recommendations to ensure you make the right choice.

Main technical parameters of modern car batteries:

To assess the suitability of a battery for further use, it is important to carry out the following steps:

1. Perform a high-quality external inspection of the battery, check for serious damage or cracks on the case itself, and assess the condition of all terminals.
2. Check compliance with the standards for the level and permissible density of the electrolyte.
3. Measure the voltage with a load plug and determine the capacitance. Based on the results obtained, evaluate the possibility of further operation of the battery.

Service life of car batteries

There are three types of car starting lead-acid batteries used in passenger vehicles:

• low maintenance;
• serviced models;
• unattended.

The most convenient to use are car batteries that have a sealed housing and do not require additional maintenance.

Manufacturers guarantee uninterrupted operation of maintenance-free batteries for 2.5-3 years; they are not afraid of discharge.

Advice! Choose a standard lead-acid battery for your car; it will withstand about 1000 discharge and charge cycles.

During operation, it is necessary to ensure that the nominal capacity of the battery does not decrease less than 20%, and do not allow complete discharge. Experienced car owners know that they should not allow a situation where the battery remains uncharged for a long time.

If you want to extend the life of your battery, follow the manufacturer's recommendations for battery use.

With rational use of a car battery, you can increase its service life by 25-30 percent and significantly reduce the risk of rapid discharge.

Among the types of batteries, gel models with a gel-like electrolyte consistency are gaining popularity. Such batteries can withstand multiple full discharges, and their service life is 10 years. Among the disadvantages, we note the high cost of the battery, as well as increased sensitivity to current stability during fast charging.

What can you do if your battery is low?

According to the observations of many drivers, the battery can run out at the most inopportune moment. It may also discharge when parked. Therefore, it would be nice to know some ways to start a battery.

Using a ROM (start-charger), you can start any car, even one equipped with an automatic transmission. Therefore, the method is called universal.

The procedure is quite simple:

• connect the device to the electrical network;
• move the button to the “start” position;
• connect the positive clamp to the positive terminal, and the negative terminal to the engine block;
• turn on the ignition and the car will start.

Once you are sure that the engine is running smoothly, the ROM can be turned off and disconnected.

The essence of the method is to “recharge” a dead battery with a charge from the battery of another car. If you do everything correctly and follow safety precautions, you can avoid unpleasant consequences and start the engine.

Lighting from another car is often the only way to deal with a problem on the highway. The main thing is that the parameters of the “donor” battery are approximately the same as those of your power source. Read more about lighting in this article.

Suitable for vehicles with manual transmission. The car accelerates to a speed of about 15 km/h, in third gear. Then the driver of the towed vehicle slowly releases the clutch, as a result of which the internal combustion engine should start. Subsequently, the battery will be recharged from the generator.

So, now you know why your car battery drains quickly and how to find the cause of this problem, so you won’t have to guess what to do in such a situation, but immediately start troubleshooting the problem according to our recommendations. However, it is better if you notice the signs of a depleting battery in time and take appropriate measures in time.

Many drivers have encountered the problem of batteries not working. In this article, we will consistently try to understand the causes and solutions to problems, one of which is the battery is not charging. Diagnostics will allow you to identify faults with reliable accuracy, and the car owner will be able to outline solutions. Step-by-step actions if .

The problem of battery discharge in the winter season is quite common. Therefore, knowing how to start a car if the battery is dead will be useful to every car enthusiast. Indeed, often the cause of a dead battery is its wear or the appearance of a current leak after unqualified installation of additional electrical equipment. Is the problem really in the battery? Winter mode of vehicle operation - .

After purchasing a new battery for a car, the owner has many questions regarding charging time and operating conditions. In some cases, car enthusiasts do not know how to prepare an electric current source for operation and whether there is any need for such an event at all. In the article we will talk about whether it is necessary to charge a new car battery, how long it takes.

Battery - device, principle of operation, classification

The basis of the battery, which is designed to provide voltage to the vehicle's on-board network, is usually banks. A standard battery uses six of them. In this case, each of these cans produces a voltage of about 2V. It consists of two special plates that are coated with a special chemically active substance. One plate carries a negative charge, and the other carries a positive charge. The jar is filled with a special electrolyte, which is made on the basis of hydrochloric acid.

Battery diagram

Complex chemical processes occur in a battery, the result of which is the conversion of electrical energy into chemical energy during charging or chemical energy into electrical energy during discharge. It is discharged when various devices - so-called consumers - are connected to it. There are quite a lot of them in a modern car (starter, generator, external and internal lighting, audio system, climate system and much more). When the battery is discharged, the plates located on top of it are coated with lead sulfate. In this case, what is called electrolyte depletion and a decrease in its density occurs. To charge the battery, a generator installed in the car is used, which generates electrical energy when the engine is running. In offline mode, the voltage is restored by a special device. During the charging process, a chemical reaction occurs as a result of which the lead sulfate and water contained in the battery are converted into the following elements - lead, its dioxide and sulfuric acid. In this case, the reverse process occurs - the density of the electrolyte contained in the battery increases. Today there is a large selection of batteries. Conventionally, they can be divided into several categories:

1. By capacity.
2. According to the starting current power.

Its capacity is determined by calculating the amount of energy released by a fully charged battery after a twenty-hour discharge. It is measured in special units - ampere hours (Ah). Rechargeable batteries can be with normal starting current or increased. The second option is usually used to start diesel engines or engines that are used at low temperatures.

How to check if a dead car battery is working with a multimeter

The main function of any high-quality car battery is to supply electricity to the starter, which is the main element of the engine starting system. The battery is the primary source of electrical current in a vehicle; its discharge causes the vehicle to stop. With the help of the battery, all on-board network devices operate when the engine is turned off.

If the battery quickly discharges (loss of nominal capacity), problems may occur with cold starting of the car engine, as well as with the uninterrupted supply of electricity to all units. Let's try to find out if there are ways to check the performance of the battery and diagnose electrical equipment.

Diagnosis of possible faults

A complete rapid discharge of a car battery is possible during abnormal operation of the generator. The main faults in the circuit are associated with a break in the generator belt, breakdown of the voltage regulator relay, malfunction of the semiconductor rectifier, short circuit of the stator winding turns, wear of the commutator, mechanical damage to generator parts, and damage to electrical wiring.

The main signs of such problems in the charging circuit, leading to battery discharge, are:

• battery warning light is constantly on;
• loud noise when the car generator is running;
• lack or complete lack of charge on the battery.