I leave the house in the morning, press the central locking button and... nothing. The car does not respond. No problem, we open it with the key. We turn the ignition key, but the lights don’t even light up, there’s a slight squeak from under the panel. Everything is clear - the battery is dead. Even if everything was fine yesterday, due to a number of reasons, the battery can be discharged in just one night. Most often, this violation is detected only in the morning, and leads to being late for work.

The consequences of such a situation can be extremely disastrous: the plates can crumble irreversibly. If this happens in the cold, the electrolyte may freeze and expand, damaging the battery case.

Reasons for rapid battery discharge

A dead battery in the morning is a consequence of an emergency situation. If the car battery is discharged to zero, it means that a fairly high power consumer was turned on.

How to find the reason

The algorithm of actions when searching for a problem depends on the urgency and the need for further movement.

Attention! In order to save time and money, use the rule from simple to complex, from cheap to expensive when making diagnostics. For example, there is no need to replace an expensive generator if the cause of the discharge is damaged wiring.

First, you need to visually inspect the ignition switch, battery and alternator, as well as all visible wiring. What to pay attention to:

If nothing critical is found, you can “light it” from another car or install a known-charged battery. When connecting wires, pay attention to the spark. A jumping spark indicates current consumption, which should not exist when the ignition is turned off. Often this is precisely the reason why the car battery quickly discharges.

Checking the operation of the generator

A separate point needs to be placed on the operation of the generator.

If there is no spark, start the car and check the operation of the generator. Apply the gas, if the belt makes a whistle, you need to tighten it. If everything is in order with the belt, we turn on all electrical consumers - headlights, lights, fan, and so on.

Lastly, turn on the wiper blades and monitor their speed. With increased energy consumption, a non-working generator is not able to provide energy to the wipers - they will move noticeably slower than usual. The voltage at the battery terminals will also be low - less than 12.8 volts. If this is the case, the cause of the dead battery should be associated with a malfunction of the generator.

A faulty generator cannot provide the car with electricity, this is one of the reasons why even a new battery in a car quickly discharges.

Looking for a current leak

Current leakage in a car is determined using an ammeter. It is found in most modern multimeters. We will need a measurement range from 0 to 20 Amps.

1. We put a known-good charged battery in the car, connect the negative terminal, and connect the ammeter to the gap between the positive wire and the battery terminal.
2. If the readings are higher than 0.2 - 0.4 amperes (there are always constant consumers - computer, clock, alarm, radio), then there is a current leak.
3. We are looking for an unauthorized consumer by turning off the fuses. If the numbers on the ammeter drop when the fuse is removed, then there is a breakdown in this circuit.
4. Disturbances in the wiring occur due to soured starter solenoids, a shorted temperature sensor on the radiator, or a short circuit in the generator windings.
5. Damage to the generator field wire inside the braid can cause the generator to be excited and draw a lot of current.

If no current leakage is observed, it is worth analyzing the operation of the alarm. It is constantly connected to the battery and is the most likely current consumer.

Can the alarm drain the battery?

Standard alarm consumes 0.08 ampere/hour. Complex alarms with remote notification waste 30% more. This is not much; a 60 Amp/hour battery will discharge after about a month of inactivity.

The alarm works like this: when armed, it goes into “sleep” mode. Current consumption is minimal. When a contact in the sensor circuit is closed, the unit is triggered, sending a signal to the headlights and siren, as well as an alert to the key fob. Modern alarms are able to respond to loud sounds, vibrations and even excessive proximity to the car. Such systems consume more current because they use the radar principle or photocells.

Reasons why alarms consume more current.

• Presence of a radio warning module. It requires more energy to operate than the alarm itself.
• Marriage signaling schemes.
• Incorrectly installed or too sensitive sensors The alarm goes off; if the siren is broken, this leads to an increased discharge.
• Immobilizer activation. In this case, the battery will work, but the ignition will not turn on.
• Faulty autostart tried to start the engine. The starter quickly drains the battery.
• The autonomous type alarm system has its own battery. If it wears out, the relay tries to charge it and “pulls” energy from the main one. Therefore, it is better to install a dependent alarm or check the battery of the main one.

Attention! Install and repair alarms in a specialized workshop from an experienced auto electrician. Incorrect connections or exposed wires may cause fire or serious damage.

It is quite difficult to check the serviceability of the alarm, since the discharge can be short in time and impossible to track. The test is simple:

1. The alarm is turned off and the car is operated without it. If the battery does not discharge, it is worth diagnosing or installing a new unit.
2. The hood rises, the sensor end is clamped. We measure the alarm current consumption. We provoke accidents - we knock on the fenders, we shake the car. The alarm consumes more current during activation, but after a set time it should turn off and not consume excess energy. If the alarm does not turn off, it can easily “drink” an entire battery overnight.

Useful video

This video clearly shows how to determine why the battery discharges overnight:

Conclusion

To avoid unpleasant moments in the morning, you should take care of your car. This applies not only to the appearance or cleanliness of the interior; first of all, you need to undergo periodic maintenance, carefully monitor extraneous noise, and look under the hood. The battery and generator brushes are consumables that need to be changed in accordance with technical regulations. Outside interference in the car's wiring, installation of low-quality alarm systems with “crooked” hands are generally dangerous and can cause a fire.

Operate your car correctly, study the life of a motorist, and you won’t have such problems in the morning.

Every car has such an important element as a battery. Thanks to the battery, the car can start. It provides the car with current for various devices - headlights, electricity supply to the starter, heated rear window, and other functions. There are times when the car battery discharges very quickly (overnight, 24 hours, 2 days) - what to do in such situations? What are the reasons for this device behavior?

The battery can be checked both at home and at a car service center. The only difference is the price and the equipment used. A “load fork” is used to check battery wear.

It allows you to check the battery without load, and under load - the readings of the built-in voltmeter are an indicator of wear (normal):

1. Checking the value, without load on the battery - for a new, fully charged battery, the value will be at least 12.7 Volts. If the battery shows a higher voltage value, and testing under load does not pass at all, then this means one thing - it’s time to buy a new one!
2. Load tests: The battery is loaded using the device - you need to wait a few seconds and take readings. For a fully working battery, the minimum voltage is 10.2 V. If the values ​​are different, it means that there are problems with the battery.

Factors affecting the natural wear and tear of the battery. Criteria that contribute to this:

Find out the charging time of your battery

• Closing plates of different polarity– also called closure. It is determined by the following signs: “boiling” of the electrolyte, and a “drop” in voltage, a decrease in the capacity of the battery. The way to fix the problem is to simply replace the faulty part (maintained batteries). With low-maintenance and maintenance-free batteries, the situation is more complicated - you need special equipment and knowledge, supported by practice: the malfunction is corrected by passing a larger current through the battery. For people who do not have special knowledge, it is recommended to replace the battery.

To slow down natural wear, it is enough to monitor the above indicators - this will increase the service life of the battery.

Generator

Another answer to the question “why does a car battery discharge” is a malfunction of the generator - it may not provide the charge necessary to restore the battery capacity. If the generator malfunctions, you must contact an auto electrician.

If the battery is charging, but the charge is not enough to replenish the capacity, the malfunction may be due to insufficient belt tension (a sign of a malfunction is a strong whistle when starting the engine). This can be solved by increasing the belt tension.

Auto electrics

One of the answers to the question: “why does the battery drain quickly in a car” is a problem with the car’s wiring. Causes: worn wiring, possible malfunction of current consumers. To diagnose the problem, you need to contact a car service center for the help of a specialist.

If the problem is not diagnosed in time, there is a high probability that the battery will run out very quickly (overnight, 24 hours, 2 days maximum)

Driver

Car driver

When the driver lacks experience, he can become the culprit for the rapid discharge of the battery. What to do to avoid becoming the culprit of the problem:

• It is worth checking the electrical components of the car (headlights, radio, etc.) when parking;
• It is necessary to monitor the battery and follow the operating instructions;
• Short trips – during short trips the battery does not have time to charge and will run out with frequent use.

What to do if your car battery is dead? You can light a cigarette from a charged battery, or put a dead battery on charge. The listed methods will take up time, which is sometimes sorely lacking. To avoid such a problem, monitor the condition of the battery, and problems with the battery will never arise!

If your car is fast, you should identify the reason why this is happening as quickly as possible. After all, a person is so attached to a vehicle that he cannot remain without it for a long time. Therefore, as soon as questions arise about technical malfunctions of the car, it is better to immediately eliminate them and enjoy driving every day. In the age of the World Wide Web, car enthusiasts are offered a lot of different useful information even about the smallest car breakdowns.

What is a car battery

The battery is one of the important parts of the car, which plays a significant role. Without it, your beloved “iron friend” simply will not be able to start, and you will waste your precious time restoring its operation. To do this, every self-respecting motorist should know: what such a part of his car consists of and why it is needed.

This is an electrical device, the so-called battery for cars, consisting of six two-volt cells that produce 12 volts at the output. All internal elements of the battery are made of lead plates, which are coated with a special active substance, and then lowered into the battery, due to which electric current is generated.

A car battery performs three important functions:

• launch ;
• enhances the operation of the generator if it is not able to cope with the load;
• ensures the operation of electronic devices when the engine is turned off.

Modern battery models are equipped with special indicators showing the charge level and electrolyte density. You can rely on these indicators, but, unfortunately, not 100%, since engineers have not yet come up with more accurate instruments. The car interior also has a battery charging light, which is located on the dashboard. When the driver turns on the ignition, a battery-shaped light comes on and then immediately goes off. If this indicator lights up when the engine is running, then you should check its operation and temporarily not operate the machine, but figure it out yourself or show it to a technical center specialist.

Why does my battery drain quickly?

The lifespan of car batteries ranges from 3 to 5 years, it all depends on the manufacturer, quality and operating conditions. But it happens that the service life of this part drops sharply, which creates a lot of unpleasant moments for drivers. If your battery is draining quickly, you need to start fixing the problem immediately.

Here are the steps you need to take to determine the reasons:

• Check car wiring. Often the problem is hidden in the car electrical network, which is “covered up” due to improper installation. To do this, you should carefully inspect all the wiring in the car and make sure that the wires are not oxidized, there are no fractures or abrasions, and also check the integrity of the connecting terminals.
• Check battery power. It happens that an already old and weak generator, with an increase in power, cannot be fully charged, and a powerful generator, on the contrary, is recharged with excess energy, which negatively affects its operation and functions.
• Battery condition is faulty. When inspecting a car battery, you should pay attention to the color of the electrolyte. If the electrolyte has acquired a dark color, then most likely this is the problem; in this case, the plates peel off, which requires immediate replacement of the battery.
• Should check generator operation. The generator is needed to constantly recharge the battery; if it charges poorly, then you should definitely check it. Most likely, recharging does not occur due to its malfunction or due to a poorly tensioned alternator belt.
• The car battery does not match your car model. There are cars in which manufacturers install low-quality batteries that produce too little power, and therefore they are often not enough for the full amount of work.
• Battery overcharging is a fairly common problem among car enthusiasts. Occurs due to overheating of the electrolyte inside the box. High temperature reduces the overall electrolyte level, so after such a process the battery becomes inoperative.

Reasons for new battery discharge

However, sometimes it happens that not only a battery that has served for several years, but also a new one can quickly discharge. Having bought a completely new battery, the driver may encounter an unpleasant problem in the form of its rapid discharge. In such cases, be sure to check the electronic wiring of the machine. To do this, you will need a special measuring device - a voltmeter. With this device you can measure and then compare the voltage in the battery and generator. And remember that these measurements should only be taken with the engine running.

• If the generator shows a voltage of 14 V, and the battery shows 13.5 V or even less, then this clearly indicates that the battery is undercharged. To eliminate this problem, clean the contacts of the generator and battery.
• The voltage at the generator contacts is less than 14 V. Such readings can only indicate a malfunction of the generator itself; in this case, you can independently only determine the length of the generator brushes, which must be at least 8 mm. To solve such a problem, it is better to contact the specialists of an auto center, unless, of course, you have excellent knowledge of automotive electrical engineering.
• If the output of the generator has a voltage of more than 14 V, this is too high an indicator, due to which the car battery is overcharged. With such excess voltage, the electrolyte becomes very hot, which leads to its evaporation and, accordingly, to a low electrolyte level.

What to do if your battery is dead

Not the most pleasant moment awaits the driver when, while trying to start his car, he realizes that he has. What to do in such a situation, where to run and who to call for help?

• The most proven method is to call a friend with a car for help or stop a car passing nearby to connect to its battery. But unfortunately, not all cars are able to accept this method of recharging; manufacturers often limit access to the battery.
• Charger. Automotive stores sell special devices for this, which in some cases will help solve your problem. To do this, the battery is connected to this device, and it, accordingly, is connected to the electrical network. Then the current is set equal to 10% of the battery volume, for example, if the battery is 60 A, then a current of 6 A is needed to charge. Before charging the battery, you must unscrew the plugs and follow the arrow that indicates the charge volume.
• Start the car from a pusher or ask another car to tow your car.
• Buying a new battery is the easiest, but, unfortunately, quite expensive way.

At the end of this article, I would like to give a few recommendations that will certainly help you increase the life of your battery and prevent such problems when, for example, the battery discharges quickly.

• Don't forget to turn off the lights, and also check that the alarm and other electronic devices are connected correctly. This is one of the reasons when, in the morning, leaving the house, the driver realizes that his battery is dead due to his forgetfulness and inattention.
• For those who often get stuck in traffic jams, you should know that the generator recharges the battery at rpms above 1500. Therefore It is advisable to turn off connected electronic devices 30 minutes before stopping completely.
• If you want to leave your car unattended for a long time, you can disconnect the battery for a short time. This method is often used in winter, when the air temperature drops to very low levels.

At the end of our article, I would like to wish car enthusiasts always good batteries and a pleasant ride. If you have questions or additions, please leave a comment on this article.

The battery is a very important component of the machine. When the engine is turned off, it supplies current consumers in the on-board network and supplies current to the starter when the engine starts. When the engine is running, the battery helps the generator provide power to the car's network if it fails. Therefore, a car cannot do without a battery. When the battery is discharged, the car turns into a pile of metal. Moreover, the car’s battery can be discharged overnight, and the car owner was completely unprepared for this. Sometimes owners cannot even just get inside the car due to a dead battery. And the day before there was nothing to predict such a situation. After this, they wonder why the car battery is draining. In this material we will try to analyze the reasons for the rapid discharge of a car battery.

No matter how good and high-quality the battery you choose, in some situations it can still fail. Therefore, you shouldn’t be surprised that your car’s battery dies overnight, even if it’s new. There are reasons for this situation. The main reasons are presented below:

• The battery has exhausted its service life;
• the battery is not charged from the generator during the trip;
• current leakage in the on-board network;
• left the devices in the car on (headlights, heating, radio);
• temperature conditions (severe frost).

Now, let's look at these reasons in more detail.

Why does my car battery drain quickly?

This is probably the most common reason for a car battery to drain quickly. This problem is typical for batteries that have been used for 4-5 years. In addition to the fact that such a battery discharges quickly, it also significantly loses capacity by this time.

It is no secret that the main “scourge” of acid batteries is sulfation. This phenomenon is the accumulation of lead sulfate on plates of different polarities. As a result, the area of ​​the active mass on the electrodes, which interacts with the electrolyte, decreases.

Thus, the battery gradually loses its capacity, which by the end of its service life drops to 30% of its nominal value. What can you do to reduce sulfation and prevent your battery from draining quickly? Below are some recommendations:

• Avoid frequent engine starts and short runs. The battery consumes a large amount of energy when starting the engine. If you then drive the car a short distance, the battery will not have time to replenish the loss of charge from the generator. It's not surprising if it then runs out of charge overnight;
• Charge the battery periodically using an AC charger. It is harmful for the battery to be in a discharged state. This aggravates and accelerates the sulfation process;
• Do not allow the battery to be deeply discharged. This significantly reduces its service life. This is especially harmful for calcium. As a result, the battery loses a lot of capacity and can easily be completely discharged overnight;
• Regularly check the electrolyte level in battery banks and do not allow operation with exposed plates;
• Carry out preventative maintenance periodically.

You can also play ahead of this situation before the cold weather. If you have been using the battery for 3-4 years and everything is fine in the summer, then with the onset of cold weather there will definitely be problems. To prevent this from happening, watch the forecast and recharge the battery from the mains charger before the arrival of negative temperatures.

That's all on the topic. We hope that now you understand why your car battery drains overnight. If you have additions or questions, leave them in the comments. Vote in the poll below and rate the article!

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What should you do if your car battery runs out quickly?

Which motorist has not found himself in an unpleasant situation with a dead battery? You open the car, get in, turn on the ignition and... nothing. The battery died and the car became completely useless. Again, look for another car to either drag it home to recharge. Again, a lot of nerves were spent, being late for work or an important meeting. A familiar situation, isn't it? So, why does the car battery drain so quickly? We will look into this in this article.

There are four main reasons for rapid battery drain:

• Battery. Natural wear and tear of the battery or its premature failure;
• Generator. Due to a malfunction of the generator, the charge when the car is moving may be absent or insufficient to fully charge the battery;
• On-board network. Worn wiring or current leakage in the electrical equipment of the machine can lead to rapid battery discharge;
• Driver. Often the car driver himself becomes the reason why the car battery quickly runs out.

Now, let's look at these reasons in more detail.

Worn or faulty battery

You can check the battery for serviceability at a service center or yourself.

A load fork is used for this. This is a device that includes a voltmeter and a load resistance. The load fork simulates the situation with the battery that occurs when the engine starts.

If you have such a device, you can check the battery yourself. First, check the battery voltage without load. It should be at least 12.7 volts. This corresponds to 100 percent charge. After this, to check the condition of the battery, you need to measure it with a load.

Load the battery using the device's resistance, wait 5 seconds and take voltmeter readings. On a working battery, the voltage value should be at least 10.2 volts. If the battery shows a voltage of more than 12.7 volts without a load (that is, fully charged), and the load test does not pass, then it’s time to get ready to buy a new one.

Below is a video demonstrating how to test a battery with a load fork.

There may be several reasons why a battery becomes unusable. Here are some of them:

• Short circuit;
• Shedding of active mass;
• Causes related to electrolyte.

Short circuit

A short circuit can be caused by both improper operation and manufacturing defects. The reason for this phenomenon is the short circuit of plates of different polarities.

A short circuit can be diagnosed by intense “boiling” of the electrolyte and a drop in voltage at the battery terminals. The total battery capacity is also reduced. Reasons why a short circuit may occur:

• Violation of the integrity of separators;
• Warping of plate grids;
• Formation of growths on the electrodes;
• Entry of foreign elements into the battery;
• Sludge at the bottom of the battery.

If we were talking about old serviceable batteries, then the short circuit problem in them was solved simply by replacing the faulty battery element. This cannot be done with modern low-maintenance or maintenance-free car batteries. On the Internet you can find examples of eliminating a short circuit as a result of passing a large current through the battery. As a result, the short circuits are burned out. But this requires certain equipment and skills in handling it. Therefore, for inexperienced car owners in this case, we can recommend replacing the battery.

Shedding of active mass

When using a car battery, shedding of the active mass of the plates occurs gradually. This process can be accelerated by increased shock and vibration loads. For example, when driving off-road. Accumulating at the bottom of the battery, crumbled active mass can cause a short circuit of plates of different polarities.

But even if this does not happen, shedding will reduce the performance of the battery. In particular, these are capacitance and inrush current. As a result, the capacity is reduced so much that the battery practically does not gain a charge and quickly runs out. As you understand, only replacing the battery with a new one will help here.

Below you can watch a video about the shedding of the active mass of the plates:

Causes related to electrolyte

There can be two problems with the electrolyte: a decrease in the level due to water consumption and a density that does not meet the norm. These problems are fixable, but it is necessary to monitor the condition of the battery and carry out regular maintenance. You must check the electrolyte level and not allow it to drop below the top level of the plates. In general, the normal level is 10-15 millimeters above the surface of the electrodes. In the hot season or when overcharged, the electrolyte may boil away. You can read about why this phenomenon occurs in the article at the link.

The density of the electrolyte should be monitored with a hydrometer. With increased density, everything is quite simple ─ add distilled water. The reason for water consumption is often the electrolysis process, and in the summer heat, evaporation is also added.

But if the density is low and the battery is fully charged, then you will have to tinker with bringing it back to normal. It is necessary to select the old electrolyte, gradually diluting it with a new one with a density of 1.27-1.29 g/cm 3 . In this case, the electrolyte must settle for mixing and then measure. If the density is insufficient, then everything repeats itself.

Problems with the generator

After you have verified that the battery is in good working order and charged, you should turn your attention to the generator. The problem with it is that it may not charge the battery or provide a charge insufficient to restore the battery capacity. In this case, after parking the car for a short time, you will have to think about.

If so, then you should contact a car electrician to find out the reasons. There it will become clear what the reason is, and also whether to change it or repair it.

In the second case, the generator does not produce enough electrical energy. One of the reasons for this may be a loose alternator belt. It is very easy to diagnose. When a car starts with a loose alternator belt, a piercing whistle is heard. This can be corrected by additional tension on the alternator belt. You can easily handle this on your own. You will need a pry bar and an appropriate wrench to loosen and tighten the generator mounting nut.

If the alternator belt tension is loose, correct the problem as quickly as possible. Otherwise, undercharging during a trip will cause the battery to drain quickly. Especially during the cold season.
Additionally, you can read the article about.