Why does your car battery drain quickly?

Why does the car battery drain quickly when it is parked?

If the battery, fully charged the day before, suddenly refused to turn the starter, then keep in mind that a voracious consumer has entered the on-board network. Without the slightest idea about electricity, it is better to entrust its search to the service station masters. To avoid getting scammed, please note: a friendly technician will definitely ask a few questions about electrical equipment. For example, were the lights turned off at night, or was the radio changed? Well, those who are familiar with a multimeter can do it on their own, and the editors of Autostadt.su will tell you what and how.

Your car's battery suddenly runs out: are you sure you're not distracted?

A simple reason for losing all charge literally overnight could be elementary absent-mindedness. For example, when parking the car, the owner forgot to turn off the lights or the music. Therefore, rule No. 1 is to remember/check whether all electrical appliances connected bypassing the ignition switch were de-energized.

We recommend checking it out, especially if there are children in the family who are partial to the car. Sitting in the driver's seat as a child, there is a desire to twist everything that turns, including the buttons that turn on the consumers.

Well, and a cigarette lighter. It works in almost all cars, even when the keys are far from the ignition switch. This means that the navigator, recorder and other non-standard gadgets steal current from the battery when it is idle. Therefore, make it a habit to unplug all cords from the socket when parking your car for a long time.

Why did the new battery discharge to zero overnight after being installed in the car?

If you managed to blame everything on the old power source, then know that this is a grave mistake. Before replacing the battery with a new one, the owner is obliged to check the generator, leakage current, and diagnose the long-lived voltage. What should be the voltage on a car battery without load is the subject of the previous article.

Car radio. Trivial neglect of installation rules leads to high current consumption when switched off.
Signaling. Cheap equipment often malfunctions, and makeshift power supply negates the advantages of even reliable anti-theft models.

Are you confident in the impeccable competence of the installer of the new head unit? If not, then check the connection diagram of the car radio to the on-board electrical network. A classic mistake is to twist the control yellow and power red positive wires. In this situation, the battery is forced to power the radio processor even after it is turned off.

Is the wiring ok? Then study the typical reasons why a tape recorder exhibits increased appetite:

The output stage of the internal amplifier is active after switching off. As a result, the head unit “eats” about 1 A, and the manufacturer calmly attributes this fact to the design features. You can overcome this immodest need by integrating a disconnect button into the power supply wiring.
The external amplifier power control circuit is faulty. If there is one, then inspect the REM output. Using it, the car radio turns the amplifier on and off.
Radio malfunction. A short circuit and other troubles that may occur inside the head unit cannot be ruled out.

There are countless cars in which an abnormal alarm suddenly began to take on a life of its own. This is due to the “quality” of the equipment and its “good” connection to the on-board network. It’s best to find out what exactly is wrong with a private auto electrician. It could be a sensor or an incorrectly connected circuit.

Other reasons

The main note for gadget lovers: do not forget to turn off what you have connected.

This especially applies to the Bluetooth diagnostic scanner, which is connected to the OBD II port. Well, if you decide to open the factory wiring for the sake of installing, say, a radar detector, then remember - it is not recommended to power the equipment directly from “+”. Start at the ignition switch, build the fuse into the positive branch and there will be much fewer problems. It also happens that no one climbed anywhere, but the quiescent current increased sharply. This can be caused by a malfunction of any standard electrical equipment on board:

Short circuit in the window lift motor.
Bluetooth block.
Pilot systems for monitoring on-board electrical equipment with a single bus (if such a unit is on strike, then the symptoms are immediately visible - for example, some electrical device (headlights, etc.) turns on spontaneously).

How to find out the exact reason why your car battery drains quickly

It is necessary to move from assumptions to repair and adjustment work in tandem with a multimeter. This miracle device will indicate whether the current leakage exceeds the permissible figures. If yes, then with its help you can find out the exact reason why the battery discharges quickly when the car is stationary.

So, grab the multimeter, move the handle to the 200 mA position, remove the negative terminal, and place the probes in the gap between the wire and the battery negative. We fix the value.

Attention! The ignition must be turned off.

So, on a car without external signaling and music, the leakage current should be literally 70-80 mA.

Rejected? Then it’s not surprising that your car’s battery drains quickly. Rather, dive into the mounting block and pull the fuses one by one, while measuring the amperage. When the numbers drop noticeably, consider that the gluttonous chain has been found. If this is not observed, then the power circuits remain - the generator, starter and ignition system. First, inspect their contacts and wires. Oxidized terminals and poor insulation contribute to leakage.

Please note that we indicated the normal quiescent current for cars, as they say, from the assembly line. It’s hard to say how much the stuffed version should have. If only because some non-standard security systems in the “auto locked” state consume about 50 mA, while others consume 100 mA. If you want to see the quiescent current on a locked car, hold the hood switch and set the alarm to security mode.

Do not forget that driving short distances in traffic jams leads to chronic undercharging of the battery, especially in cold weather. From which one day the battery will be forced to give up the starter, requiring resuscitation from the mains charger. And not just any way! Each battery has its own charging technology: we have already explained what proper charging of an AGM battery and provided instructions for charging an EFB battery .

Doesn’t hold a charge: why does a car battery drain quickly when idle?

A defective radio, video recorder and alarm system powered in a makeshift way, a Bluetooth adapter forgotten in the diagnostic socket - all this can drain the battery to zero literally overnight. The situation will force you to throw the charger crocodiles on the “+” and “–” or use one of the models for rating portable starting chargers . But just waking up to take care of the battery is not enough. An integrated approach is needed.

Aging, undercharging and frost: why a car’s original battery discharges quickly after 3-5 years of use

Intensive discharge is usually attributed to the old battery, they say, it has served its intended period... The power source really does not last forever. Even in a state of rest and periodic recharging, it will serve faithfully for no more than 10 years. Approaching “death” is interpreted simply - the product has lost capacity.

What contributes to aging

You can explain from a scientific point of view why the battery quickly discharges and why it generally deteriorates using detailed theses:

Irreversible sulfation of plates. Lead sulfate, gradually sticking to the electrodes, reduces their active area, lowering the actual potential in A*h. This phenomenon is activated when stored in a discharged state or when the level of electrolyte in the jars is insufficient. Increasing the density of the electrolytic liquid, increasing its temperature and self-discharge contribute to this process.
Accelerated self-discharge. Globally, this is caused by dirt and dust accumulated on the box (the down conductors become shorted). Locally, this occurs in banks due to shedding of the active mass from the plates and destruction of the partitions between the electrodes. In new batteries, the process develops due to the presence of metal impurities in the separators, because metals are constantly split off and contribute to the flow of discharge currents.
Short circuit of positive and negative plates. This happens due to the coating falling off from them.
Destruction of positive electrodes in banks. This is the result of sloughing of the active mass and corrosion of the down conductors.
Cracks in the mastic and its peeling off from the plates during aging.

Constant undercharging

When the engine hums, the generator powers the vehicle's on-board equipment and battery. Priority is given to radios, headlights, heating and preheating, the remainder goes to the battery. Only experienced drivers add a voltmeter to the dashboard. And believe me, he is capable of terrifying. So, it is within his competence to explain why the car battery discharges quickly even after replacement:

At idle, figures of the order of 14.0-14.5 Volts are typical for an unloaded network. The beauty is that the generator is working properly and the battery is being restored successfully.
At XX with the lights and music on, the norm is 13.7-13.8 V. There are no comments on the “gene”, only the battery does not get enough current.

Long-term degradation is that chronic undercharging provokes sulfation. Over time, the battery begins to charge quickly and discharge just as quickly. The immediate effect is different. The battery simply does not restore capacity, but only wastes it. In city conditions this most often happens. To charge you need revolutions, but where can you get them in a traffic jam?

For your information . The energy expended by the starter to rotate the flywheel for 5 seconds is recovered from the generator in 20-30 minutes of continuous driving. The tachometer needle should not fall below 1,500 rpm.

You can directly encounter undercharging immediately after installing a new battery. A more capacious analogue attracts with an impressive A*h number on the label. In fact, the generator power is not enough to restore the charge to 100% within the usual time frame.

Frosty days

In cold weather, the battery loses capacity, causing discharge to occur faster. At temperatures below -15°C, a loss of 1 Ah per degree is completely normal. If you do not drive, the current source will run out and the electrolyte will freeze. Crystallization of the electrolytic liquid is dangerous because the body of the product may crack and the plates may become warped. The exception is AGM, in which the electrolyte is absorbed.

Current leaks: why even a new battery drains quickly when idle

The car radio, ECU and other equipment do not turn off completely. It goes into deep sleep mode and “eats” electricity even when the engine is turned off. In addition to them, there are active consumers in the form of an alarm system and an on-board control unit. The energy they consume when the ignition is off is called current leakage.

The total flow current at rest is no more than 50 mA. If everything is in good condition, the car’s battery will not run out in a week, or even a month of parking. You can check for leaks on any machine using a multimeter:

Disconnect the terminal from the battery.
Switch the tester to 10A measurement mode and connect the wires to the corresponding terminals on the device.
Touch the battery terminal with one probe, and the removed terminal with the other.

Attention! Work is carried out with the engine stopped and the on-board equipment turned off. 50 mA = 0.05 A.

If the value exceeds the specified value, we search for a “gluttonous” circuit. To do this, remove the fuses one by one and connect an ammeter instead. A serious consumer will be alerted to a jump in the device readings. The wiring of the multimedia system and alarm are at risk.

If you suspect a “head”, check out the characteristics of the device. It happens that the quiescent current of the amplifier is 1A. This appetite is due to the activity of the output stage even in the OFF position. The phenomenon is rare, but it does occur.

On a note . Remove the front panel of the radio and evaluate the quiescent current of the circuit. It will definitely be smaller, since in this position the player is completely de-energized.

Do not neglect the rules for installing a multimedia center. A typical mistake is to twist the yellow (control) and red (power) pluses. The low-current yellowish wire should connect to ACC+ on the ignition switch. Then the processor and memory of the device will be active only after turning the key.

What else should you do if the car battery loses an impressive current to power the rest of the audio system and therefore quickly discharges overnight? There are highly specialized problems here:

The REM output on the additional amplifier, through which the car radio controls its power supply, has failed.
One of the components inside the Hi-Fi device has shorted.
The fact of increased appetite has been noticed. You can install a button in the power circuit.

Signaling

When dealing with a “non-standard” signaling system, assessing it for the presence of “glitches” is goal No. 1. One of the symptoms is spontaneous unlocking/locking of doors. It is possible that the operation is correct, but one of the functions is not connected correctly. For example, auto start may not fully work due to the deactivated handbrake sensor, but the headlights or DRLs will turn on.

Possible problems with nutrition. To identify them, you can check the current leakage on a locked car:

Raise the hood.
Remove one of the terminals.
Connect the tester in ammeter mode (10A).
Pinch the hood position sensor.
Security the car using the key fob.
Take readings.

Third party equipment

Tips for properly powering the same DVR are written based on experience. Do not connect any unobtrusive device directly to “+”. Connect to the ignition switch and install a fuse in the circuit.

If the car is used, you need to check the main points, where the constant plus is usually taken from:

Interior lighting.
Cigarette lighter.
Positive battery terminal.

Another option is the ELM 327 adapter forgotten in the diagnostic socket. It consumes about 0.45 A, since it does not allow the ECU to go into sleep mode after turning off the ignition.

Glitches in standard systems

Each car has its own package of “surprises”. For example, the window lift motor may short out. From special cases - a Bluetooth unit or the head unit of a complete vehicle control system (sores of the Mitsubishi Outlander). Headlights turning on spontaneously is a very common complaint. Usually the dealer's flashing service helps out.

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.

How to find out if the battery is almost discharged

By load. methods for checking the battery upon purchase and ordinary observation are relevant

The starter barely turned the engine shaft.
When you turn on the heated seats/windows or headlights, the radio turns off.

What to do if your car battery drains quickly

Every motorist may encounter a situation where the battery in a car quickly discharges. However, the cause of this process is not necessarily a malfunction of the battery itself.

It is quite possible that the electrical equipment of the car or even the driver himself, who chooses an irrational driving mode or battery maintenance, is to blame for the battery discharge.

A car battery is an electrical device with a nominal voltage of 12 V, which performs 3 main functions:

engine starting;
ensuring the operation of electrical appliances when the engine is not running;
assistance in the operation of the generator - the main source of electric current of the car.

Why does my car battery drain quickly?

To understand the reasons, it is necessary to identify a list of equipment involved in current consumption, the source of which is the battery.

This includes:

engine starting system;
electrical appliances that work even when the engine is turned off - headlights, radio, alarm.

Sources of problems may be:

The battery itself has failed or is not working correctly due to wear or other reasons.
The service life of car batteries is from 3 to 5 years, after which it completely exhausts its resource.
Premature causes of battery failure include violation of the integrity of the case, sulfation, shedding of the active mass, low electrolyte level or its density that does not meet the standards.
Problem with the generator.
A car generator is the main source of current for car systems, including the battery.
When the car is moving, the battery is gradually charged; if the generator is not working properly, the battery may receive insufficient charge or not be charged at all.
Leaks in the on-board network.
Loss of current in vehicle wiring can cause a short circuit or increased current consumption.
Improper driver behavior.
The main source of trouble for the battery is, oddly enough, the car owner himself, who is associated with a whole range of reasons why the car’s battery quickly runs out.

These include, for example:

forgetfulness - leaving the headlights, radio, light bulb in the cabin or trunk on overnight, you shouldn’t be surprised to find a dead battery in the morning;
incorrect travel mode - frequent engine starts and short trips lead to increased energy consumption and insufficient recharging by the generator;
installation of additional current consumers - additional headlights, non-original speaker systems, TV, homemade alarms and other energy-consuming devices;
Insufficient charging or, conversely, overcharging the battery leads to battery malfunction or accelerated wear.

The car battery drains quickly: what to do?

To determine the reasons for battery discharge, you will need a voltmeter and knowledge of what current should be in various parts of the vehicle's electrical system.

The first step is to check the health of the battery itself and its components.

The test is carried out using a load fork, consisting of a voltmeter and a load resistance that simulates the process of starting the engine.

First, the battery is checked only with a voltmeter, the voltage should be 12.7 V, using a load - 10.2 V. Lower numbers indicate a faulty battery. It is also necessary to check the electrolyte level and its density.

Ideally, the electrolyte level should be from 1 to 1.5 cm above the surface of the electrodes. The density of the electrolyte is measured with a hydrometer and should be approximately 1.23 g/cm 3 .

Increased density and low electrolyte level indicate evaporation, in which case you can simply add distilled water to the required level.

Insufficient density indicates possible problems inside the battery or its wear and tear.

Next, you need to check the generator, which is the source of energy for the battery.

A generator malfunction is indicated by a voltage of less than 14 V at its contacts. You can check the voltage level using the same voltmeter.

If the voltage level exceeds 14 V, then such a generator is too powerful for the installed battery, which leads to heating and evaporation of the electrolyte.

One of the causes of discharge may be a loose alternator belt. To check its tension level, you need to listen to the sound when igniting: a piercing whistle that appears indicates a loose belt.

By tightening the generator mounting nut using a wrench, you can get rid of this problem. If the belt is in order, then it is better to entrust the repair of the part to professionals from a car service center.

Checking the on-board network for leaks or the presence of problem consumers is quite difficult, but you can try to do it yourself.

To measure, you will need a multimeter. To do this, you need to turn off all energy-consuming equipment, remove the negative terminal from the battery and turn on the 10 A measurement mode on the multimeter.

One rod is connected to the negative terminal, the second is attached to the negative current terminal. The recorded value should not exceed 0.02 A.

In the case of large readings, it can be argued that there is a leak in the network or a problematic consumer, which can be identified by turning off energy-consuming devices one by one.

If the reason is in the wiring, then it is better to leave the troubleshooting and repair to a professional auto electrician.

Good to know

When a car's battery discharges quickly, correcting the driver's behavior, aimed at increasing his literacy in servicing the car and its parts, which include the battery, can also help.

1. In cases where you have to park your car for a long time, you can disconnect the battery.
  It is especially useful to do this in winter, when the device discharges much faster. This will help prevent the electrolyte from completely discharging and freezing, which in turn leads to battery wear.
2. All electrical devices connected to the network must be checked.
  Makeshift alarms, an abundance of acoustic devices and even incorrect settings can lead to energy consumption. For example, the Bluetooth button on the radio that is always on is a powerful energy consumer.
3. The generator charges the battery only at engine speeds exceeding 1500 rpm.
  Therefore, in traffic jams it is better to turn off power consumers.
4. When charging the battery at home, you should avoid the “fast charging” mode.
  The optimal mode is to set the current value equal to 10% of the battery capacity, which is indicated on the device label. The full cycle will take 14-16 hours.

Why does my car battery drain quickly?

The battery discharges quickly, which significantly complicates the process of operating the vehicle. After all, whether the driver can move unhindered depends on the performance of the power source. The battery is also used to power certain units and devices installed in the car.

Why does my battery drain quickly?

Experts identify 5 reasons why your car battery drains quickly. In order to correctly navigate and correct the situation, they must be studied in advance.

The battery life is completely exhausted

This is considered the most common reason why the battery in a car quickly runs out. This situation arises after 3-5 years, when the power source and its elements are worn out. After prolonged use, the battery loses not only its charge, but also its capacity.

The problems with lead acid batteries are related to the sulfation process. Its essence lies in the gradual accumulation of salts on the plates. This provokes a decrease in the working area at the terminals and deterioration of contact with the electrolytic composition.

In order to get rid of this problem, perform the following steps:

To prevent rapid battery discharge, a reduction in the number of short runs is required. After all, constantly starting the engine consumes a lot of energy. When moving a short distance, the expended energy is not fully restored.
The car battery is periodically charged using a charging unit. After all, the source deteriorates if it remains in a discharged state for a long time.
Deep discharge of the battery is prohibited. After all, this provokes a rapid loss of capacity and a reduction in working life.
Periodic check of electrolytic composition. Not only the composition level is monitored, but also the condition. Lead plates must be in an electrolytic composition.
Carrying out maintenance and prevention.

Such measures are effective for sources that have been in operation for 1-2 years. For a period of 3-4 years, a new battery is required.

Problems with the generator

It is not uncommon for a car battery to die because the generator is not functioning well. If the battery does not receive the required charge from the generator, it will be completely discharged within a short time after stopping.

What to do in this case? To test the functionality of the generator, use a multimeter. Next, the standard and additional equipment is launched. And only after that the voltage is established using a multimeter. Its value should be 13-14 V. If lower values are displayed on the multimeter monitor, then the required charge is not supplied to the source.

Reasons why the generator does not transfer charge to the battery:

The alternator belt has become deformed or broken.
Insufficient belt tension.
Violation of the integrity of electrical wiring and conductive contacts.
Poor functioning of the voltage regulator.
The diode bridge has failed.

To determine the exact cause of the deterioration in the performance of the generator and its elimination, specialists from a car service center are involved. Long-term use of a faulty generator leads to the fact that even a new battery is replaced.

Unacceptable temperature conditions

The question of why a vehicle battery is discharged often arises in winter. This is because the electrolytic composition becomes thicker at low temperatures. As a result, contact deteriorates.

In order to prevent such an outcome, the charge level of the car battery is monitored more carefully. To do this, evaluate the density of the electrolytic composition. There are tables online that give approximate values.

When operating vehicles in winter, follow the following rules:

You should not leave an uncharged battery.
The density of the electrolytic composition increases by 0.01-0.03 g/cm3.
The power supply is quickly supplied with a special case.
You should not leave the battery in the cold. Responsible drivers move the power source to a warm room.

Leakage current

Often the question of why the battery drains quickly also arises due to current losses. Current leaks occur due to:

Presence of oxides on conductive terminals.
Damage to the insulating layer, deterioration of electrical wiring.
Incorrect connection of electrical equipment.

Determination of leakage current is carried out in several stages:

Removing the ignition key.
Opening windows and closing doors. This is because the central locking is blocked while checking the power source.
Disabling equipment and devices that are connected to the electrical system.
Removing the negative conductive terminal.
Measuring leakage current using a multimeter.

The norm is 15-70 mA. If other parameters are displayed on the monitor, then you should involve a specialist.

What mistakes do drivers make?

Batteries run out due to the irresponsible attitude of drivers. Leaving the headlights and heating on all night leads to discharge.

You will have to correct the situation in domestic vehicles yourself. For new foreign cars, manufacturing companies have prepared devices that turn off headlights and heaters.

Reasons for battery discharge.

How to prevent battery drain?

To maintain a new or used battery in working condition, preventive measures are carried out.

1-2 times a year, the battery is recharged from a charger that is connected to the network. Experts recommend conducting training cycles.
After recharging the power source, check the density of the electrolytic composition and its level. Such actions are not performed if a maintenance-free device is installed in the vehicle.
Maintaining electrical wiring and devices in working order. Even minimal violations provoke current leakage and battery discharge.
Cleaning the battery case.
Cleaning terminals and other elements.

Causes of car battery boiling

Boiling of the power source provokes problems with electrical wiring and equipment, and starting the motor. If the battery gets very hot, then:

Lead plates and leads are gradually destroyed.
The likelihood of the lead plates shorting out and the source exploding increases.
Moving with a boiling power source provokes damage to wires and the vehicle body.
If the battery boils, the charging current also increases. This negatively affects the condition of the generator.

Why does my car battery boil?

1. Charging the battery at increased voltage and current

The result is overcharging of the power supply due to problems with the relay, which is designed to regulate the voltage.

The use of a current source for charging that is not regulated also leads to overcharging. This provokes a gradual boiling of the electrolytic composition, destruction of the plates, which should not be allowed.

Therefore, for recharging, drivers use only industrial-type chargers.

Occurs due to the fact that the battery is subjected to shaking and vibration. Gradually, the interplate zones are destroyed. The result is a short circuit and battery explosion.

Identifying a shorted power supply without testing is problematic. Therefore, novice drivers often use them. When a pulse is applied, the battery continues to heat up and the electrolyte boils.

To prevent this, inspections are recommended.

Plaque gradually forms on the lead plates that are part of the battery. It provokes a decrease in capacity, rapid discharge.

When charging the battery using a mains charger, the current increases. Therefore, the source can overheat and boil.

A dead battery cannot be recharged from a generator. After all, it can boil away.

4. Increasing load current

Simultaneous connection of several systems that consume energy leads to overload of the electrical network. If the used charge is not replenished, the battery heats up and the electrolyte boils.

Installing a battery in a vehicle that does not meet the standards leads to a reduction in technological and ventilation openings. The result is a boiled-out battery.

Boiling is also provoked by polarity reversal. After all, if the terminals are incorrectly positioned, large currents are supplied.

When the battery boils, perform the following actions:

Stop the engine and turn off the ignition.
Provide natural ventilation and open the hood.
Wait until the battery cools down.
Pour distilled water into the “jars” to increase the electrolyte level.
Check the voltage using a multimeter.

To prevent the boiling process, remove foreign objects from the power source. 1-2 times a month, check the condition of the electrolytic composition, voltage level, and evaluate the conductive terminals and housing.

Why buy a new battery when you can keep the old one in working condition? To do this, it is enough to follow a number of rules that have been tested in practice. It is periodically necessary to carry out preventive measures and maintenance of the battery, electrical devices, and wiring.

Video on the topic of fast battery discharge

Why does your car battery drain quickly?

The main function of a car battery, as a primary source of current, is to supply electrical energy to the starter - a key element of the starting system of the power unit. In addition, the rechargeable battery (AB) powers the devices and devices of the on-board network when the engine is not running. Cold starting of the engine and uninterrupted supply of electricity to all units that consume electricity can be difficult if the battery quickly discharges, loses its rated capacity and starting current parameters. How to check the performance of the battery, diagnose electrical equipment and identify the causes of accelerated battery discharge?

Car battery life

Lead-acid starting batteries used in modern passenger cars come in three types: maintenance-free, low-maintenance, and maintenance-free. The most convenient to use and, therefore, popular are batteries that have a sealed housing and do not require any maintenance.

The service life of maintenance-free batteries is about 3 years. The main parameter characterizing the battery life is the number of discharge-charge cycles. For example, standard lead-acid batteries can withstand from several hundred to 1000 discharge-charge cycles. In this case, the nominal capacity of the battery should not decrease by more than 20%. It is important not to allow the battery to remain in a discharged or partially charged state for a long time.

It is worth remembering that the battery life depends on compliance with the rules, conditions and mode of its operation. For example, careful and rational use of the battery, provided that frequent deep discharges are avoided (more than 80% of the declared battery capacity), allows the battery to last much longer.

Recently, gel batteries, in which the electrolyte has the consistency of a gel, have become popular. Such batteries are characterized by increased durability (up to 10 years), they can withstand repeated deep discharges (up to 100% of the nominal capacity), but they are quite expensive and very sensitive to the stability of charging current parameters.

Checking the functional suitability of the battery

Planned or forced replacement of a car battery is a rather rare phenomenon, but inevitable. Over the entire period of operation of the vehicle, this procedure is performed repeatedly. Before installing a new battery in a car, you must read the car manufacturer's recommendations and strictly adhere to them. The main technical characteristics of car batteries are:

voltage (for all passenger cars it is 12.8 volts (V));
rated capacity (expressed in ampere hours (Ah));
starting current (measured in amperes (A));
housing dimensions and polarity (straight or reverse).

In order to check how suitable a battery is for use as an autonomous source of electric current, you must perform the following operations:

visual inspection: the housing is examined for cracks and damage, the condition of the terminals is determined;
checking the level and density of the electrolyte (for serviced or partially serviced batteries): a hydrometer is used for measurement;
voltage measurement using a load plug: used for all types of batteries and carried out in two stages - without load and under load;
measuring capacitance and checking the obtained values for compliance with the specified parameters: a special device is used for diagnostics.

Diagnosis of faults in the charging circuit

Abnormal operation or complete failure of a car generator is one of the reasons that the battery quickly discharges. The most common malfunctions in the battery charging circuit are:

alternator belt breaks – battery charging stops completely;
breakdown of the voltage regulator relay - the charging current parameters do not correspond to the norm;
failure of the semiconductor rectifier (diode bridge) - alternating current is not converted to direct current;
short circuit of the stator winding turns;
severe wear of slip rings (commutator);
mechanical damage to generator parts: pulley damage, wear of graphite brushes, destruction of bearings;
damage to electrical wiring, oxidation of contacts in the charging circuit.

Characteristic signs indicating the presence of malfunctions in the charging circuit are:

constant indication (illumination) of the battery charge warning lamp;
pronounced noise when the generator operates;
insufficient or excessive battery charge;
complete lack of battery charge.

Reasons for rapid battery discharge

Too rapid discharge of a car battery can be caused by a number of operational or technical reasons.

Battery defects

The main reason for the inability to further use the battery is its natural wear and tear. Factors that reduce the functional suitability of the battery include:

sulfation: the formation of lead sulfate on the surface of the plates interferes with the normal flow of current-generating processes;
electrochemical corrosion: destruction or oxidation of electrodes contributes to a decrease in the discharge capacity of the battery;
loss of homogeneity, shedding of the porous active mass of the electrodes;
complete or partial mechanical destruction of the housing.

A completely exhausted resource is a completely natural reason for the failure of a battery, but there are other factors that cause abnormal operation of the battery. The main problem is the excessively rapid discharge of the battery due to the large leakage current in the vehicle's on-board electrical network.

Leakage current

There are two types of leakage current: internal and external. Internal leakage currents in batteries have incomparably lower values than external ones. Therefore, when determining the causes of rapid battery discharge, the main emphasis is on searching for sections of the circuit or individual devices where there is a significant external current leakage.

In a healthy on-board electrical network of a vehicle, the permissible leakage current is in the range from 15 mA to 70 mA. It is important to remember that the value of this parameter directly depends on the number of devices and devices - energy consumers integrated into the on-board electrical network.

During normal operation of the power supply system, and especially the battery charging circuit, some reduction in capacity caused by leakage current is compensated by constant recharging of the battery from the generator. The problem of current loss is most clearly visible in the cold season, when the battery cannot maintain its nominal capacitance parameters for a long time.

The procedure for identifying places of current leakage in the electrical network of a car is carried out according to a strictly defined scheme. To measure leakage current, an ammeter or digital multimeter is used - a combined electrical measuring device. Before starting measurements, you must turn off the ignition and turn off all instruments and devices of the car that consume electricity. Then you need to remove the “negative” terminal from the battery and connect an ammeter or multimeter configured to measure current between it and the ground cable in series. It is worth noting that the leakage current can be measured both with the “positive” terminal removed (“plus break”), and with the “minus” disconnected (preferable).

If the measurements show an excess of the maximum permissible norm (more than 70-80 mA), then it is necessary to identify in which circuit of the on-board electrical network the current leak occurs. To answer this question, without disconnecting the measuring device, you need to pull the fuses out of the fuse box one by one. When, in the absence of any of the fuses, the current readings drop to normal, this means that a circuit has been detected in which there is a significant current leak. All elements of the damaged circuit are thoroughly checked and diagnosed: wiring, connectors, terminals, connected devices and devices. It is worth noting that if, after manipulating the fuse block, it was not possible to identify the cause of the current leak, then it is necessary to examine the generator, starter, additional equipment for faults, and also check the contacts and integrity of the insulation of all wiring of the vehicle's electrical network.

Additional electricity consumers

The practice of repairing and servicing the on-board electrical network of a car shows that a large current leakage most often occurs due to incorrect connection of additional electrical equipment. Most often these are powerful acoustic systems, multifunctional electronic car alarms, additional optics (fog lights, high beams, daytime running lights).

For example, a custom music system that includes an amplifier, a subwoofer, a set of speakers, and sometimes several monitors requires more electrical power than a standard car generator can provide. In addition, the rather complex connection scheme of the listed equipment into a single system and the need to lay additional cables can cause various types of connection errors. The way out of this situation is to replace the standard generator with a more powerful one or install an additional battery on the car.