How to properly charge a completely discharged car battery

The battery plays a major role in all cars because it starts the engine in the vehicle.

The starter begins to work due to the torque, which sets the crankshaft in motion and the engine starts.

There are situations when this becomes an excellent replacement for a non-working generator. But this is only for a short time. While driving, the battery is charged from the generator.

However, despite all this, it is recommended to replenish its energy through other devices. This requires special knowledge of how to properly charge the battery in order to avoid its premature breakdown and maintain its original capacity.

Attention! Under no circumstances is it recommended to completely discharge the battery. This will lead to a decrease in its original characteristics.

How to charge a severely discharged car battery

Most often, this situation is typical for winter. A battery whose age has exceeded 3 years usually regularly supplies the necessary energy at above-zero temperatures, but when winter comes, it refuses to function normally. To successfully operate the car, you will need to reanimate the battery. How to charge a completely discharged car battery? First, make sure that the starting problems are related to the battery.

Video

We invite you to watch a video on how to properly charge a car, the devices used, and how to properly prepare the equipment for restoration.

The generator supplies the vehicle with energy while driving. When the engine stops, the battery takes over the “feeding” function.

The service life of this unit lasts on average 2-3 years (equivalent to 80-100 thousand kilometers). The battery stores energy rather than generating it. At the moment when it is at least half discharged, you should think about recharging. Here are some tips.

How can you tell if your car battery is completely discharged?

There are a number of methods for checking the battery. The most basic one involves the presence of an eye indicator on the product. If it is greenish, this indicates that the battery is ready to start the engine. However, this information is very approximate: the contacts may have the required voltage value, but the starting current (capacitance) for cranking the crankshaft will be small. This is usually caused by sub-zero temperatures, when the chemical solution in the jars stops reacting with the plates made of lead. There are other ways to determine the health of the battery:

It should be noted: measurements are carried out using a voltmeter with minimal error. A variation of parameters of only 1–2% leads to errors in determining the battery charge level of up to 20%.

The reason for battery discharge is most often incorrect operation of the product. This refers to improper feeding. After all, how do car owners generally try to charge a dead battery? Either they completely discharge the battery, or, conversely, they keep it connected to the charger for a long time. All this leads to disruption of the internal structure of the battery. In the latter case, the positive terminal (or even both) oxidizes; in the first, lead paste slides off the plates. Such troubles can be avoided if you use calcium batteries rather than lead-acid batteries, which simply do not charge more than 95%.

Another reason for an “unauthorized” discharge is the forgetfulness of the car owner. These are side lights left on overnight, fog lights, ignition on, doors left open. Is it possible to charge a completely discharged car battery? If the car has been parked for a long time or under a roof, and the voltage on the battery has decreased to 2 volts, then it is impossible to revive the latter.

How to charge a completely discharged battery

An elementary way is to light a cigarette from the car of an acquaintance, friend, or neighbor (no need to remove the battery). But first, look at the contacts: if they are covered with a whitish coating, it needs to be removed. If your battery has not yet died completely, then further charging will occur from the generator. It is worth noting: the battery can be restored to 100% after driving hundreds of kilometers. At home (in the garage), before charging a very discharged car battery, test the density of the chemical electrolyte solution and the serviceability of the cans. How to check and charge the battery after a deep discharge? This is done using a glass instrument - a hydrometer.

How to properly charge a dead car battery? First you need to check the density of the electrolyte, its optimal value is 1.28. If it does not meet the standard, distilled water should be added. The chemical solution is rarely added when there is none at all. Next you need to measure the voltage at the battery terminals. If it is 10–12 V, there is sulfation in one of the cans. Sometimes the problem is resolved during the charging process. Finding a faulty jar is not that difficult. To do this, unscrew all the plugs and, with the charger running, carefully (it is better to wear special glasses) look inside the cans. In the one that is faulty, gas formation and bubbling do not occur. Then connect the negative “crocodile” of the charger (charger) to the can, and the second one to the battery contact. Turn on low current to the charger. If the battery gets very hot or hisses, you will have to purchase a new one.

How to properly charge a completely discharged car battery and what to do if it is impossible to get to the cans? Then connect a small load (for example, a light bulb) and discharge the battery to a voltage of 7.2 V. Then leave the product alone for 24 hours to allow the electrolyte to cool. After that, charge again. Repeat the procedure 2-3 times. Another way to get to the cans is more radical: you just need to drill holes above them with a diameter of 10–12 mm (pick up the plugs in advance).

Lighting a cigarette from a charged battery

The most popular way to “reanimate” a battery. When connecting batteries to each other, remember the diagram:

• We connect the wire for lighting one end to the positive on the operating unit;
• with the other end we also connect it to the positive on the non-working battery;
• with the second wire we do the opposite (first we connect the wire to the negative of the failed battery, and then we connect to the negative of the charged battery).

What to pay attention to when charging a car battery

The first point: choosing a device. How to charge a battery if it is completely discharged using devices sold in stores? The market offers a fairly wide range of these products, which can be:

The first two varieties are the most popular, which is due to their high reliability, relative simplicity of design (in case of breakdown, self-repair is sometimes possible) and affordable cost.

How to charge a car battery that is completely discharged? When charging the battery, observe the polarity. If the wires are mixed up, the battery will be discharged, but not restored. Next, find out from the label the capacity of your battery, which is indicated in ampere hours. You need to charge with a current of 1/10 of the capacity. Example: if the battery has a capacity of 55 ampere-hours, for charging you need to supply a current of 5.5 A. In this case, the time to restore the battery will be 5.5 hours. You can increase the current strength (it is not recommended to set more than 15 A), but then you will have to control the charging process: if gases are released rapidly, reduce the energy supply to 0.5 A and leave the battery in this position for another couple of hours. In this case, you must unscrew the plugs (if the battery is serviceable). But still, the best option is to use a small current for charging.

What to do with maintenance-free batteries and how to charge a car battery after a deep discharge? The sealed housing of such devices does not allow checking the density of the electrolyte. Charging must be carried out using a charger whose current is set to 2 A. In this case, the voltage at the battery terminals should not exceed 15.5 V. When the device readings reach 0.2 A, the procedure can be considered complete.

Zheka147 › Blog › How to properly charge a car battery

Surely, every car owner who has been using his car for at least five years has had problems when a dead battery could not start the engine, or, to be more precise, the voltage was not enough to turn the starter. If you have never had such a problem in several years, then you can say that you are very lucky, since the average battery life is about 3 years. Although it is possible that with careful treatment and operation, the battery can last 4 or even 5 years.

General rules and safety tips when charging car batteries

Safety precautions when performing such procedures should come first, since non-compliance with them can cause an increased risk to health.

It is highly not recommended to perform this work in a residential area; it is better to use a garage or other place for this. The room in which the battery is charged must be well ventilated so that the released gases do not accumulate in one place. Do not smoke or use other fire or spark-producing elements in the vicinity as this may cause an explosion. The battery is first connected to the device, and only after that it is connected to the network. The wires are connected red to positive and black to negative. Do not leave the process unattended, even if you are using an automatic device. The caps of each can must be unscrewed, and if they are not, then be sure to read the recommendations below for maintenance-free A.B. What device is needed to charge a car battery?

A few days ago, in one of the previous ones, I talked about buying a charger for a car battery. So there were a few words about the parameters that you should pay attention to. But here I will try to tell everything in even more detail.

First, you need to know what voltage your battery is: 12 or 6, or maybe 24 or even 48 Volts? The weakest ones at the moment can be found in old Soviet motorcycles. More powerful ones are used, for example, in large agricultural machinery, etc. But the most common is a battery with a voltage of 12 Volts. Accordingly, you need to choose a charger that will maintain the voltage of your battery. Pay attention to the current the device produces. Here, first of all, you need to start from what the battery capacity is. If, for example, you have installed A.B. 60 Ampere hour, then you need a device that will produce at least 6 Amperes. After all, when charging, the optimal current value is 0.1 of the full capacity of the battery. It is best to use devices that have a fully automatic charging mode. These are the majority now. For example, you connected the device to the battery, set the required current value, and the voltage will be supplied automatically depending on the degree of current battery charge. When the battery is fully charged, the device automatically reduces the current and voltage to a minimum, which prevents overcharging. How to determine the level of discharge of a car battery?

In most cases, the battery is not completely discharged, that is, the voltage drops to the minimum permissible when it is impossible to turn the starter. Usually in this case, the lighting devices still continue to function, although not at full power.

But there are also more dangerous cases when the battery is completely discharged and the voltage drops to such a level that even the lighting devices refuse to work at all. This happens, for example, when you forgot to turn off the headlights at night, or left the radio on even without sound. Below is a table that clearly shows the degree of battery discharge according to the output voltage at the terminals at a certain air temperature.

What current and voltage are needed to properly charge a car battery?

As mentioned above, the device must be selected so that it can fully charge the AB. and below will once again be given a list of current and voltage values.

The optimal charging current should be 1/10 of the full battery capacity. That is, in other words, if your battery has a capacity of 55 Ampere-hour, then the required current is 5.5 Amperes. These are recommendations from manufacturers of both the devices themselves and storage devices. But the ideal option would be to run less current to the battery terminals. That is, in a similar case, supply a current of not 5.5, but already 2.75 Amperes. Of course, the process will be a little slower (twice), but the quality will only increase. As for voltage, most chargers that are sold now have an automatic mode. But, you should pay attention to the orientation of the battery: some devices have a switch that changes the voltage for different types of batteries: 6, 12, 24 Volts. Accordingly, you need to choose the mode necessary for your battery. And then the charger will do everything for you, that is, at first the voltage will be supplied stronger, and when the charge reaches 75%, it will automatically decrease, ultimately to a minimum value, in order to prevent the battery from self-discharging. How to charge maintenance-free car batteries?

A considerable number of modern batteries are so-called maintenance-free. That is, during the entire service life there is no need to add electrolyte or check its density in the jars. Moreover, it is not possible to do all these operations, since there is no access to banks, there are simply no traffic jams.

Of course, if such an AB is dead, then it is possible and even necessary to charge it, but it should be borne in mind that due to the absence of plugs, gas formation inside the case may be increased, which may pose a risk of explosion. In this regard, manufacturers of such units strongly recommend using a rated charge current of no more than 1/20 of the battery capacity. In other words, if the capacity is 50 Ampere hour, then the current needs to be supplied not 5, but 2.5 Amperes.

How long does it take to charge a car battery?

Many technical manuals say that with a completely discharged battery, it must be charged for 15 hours (with a current of 1/10 of the capacity) to 100%. For example, the “patient” has a capacity of 50 Ampere hour, which means that it needs to be “driven” for 15 hours with a current of 5 Amperes.

Microwave oven charger

Some car enthusiasts use a transformer from a broken microwave oven. But this transformer will need to be redone, since it is a step-up transformer, not a step-down transformer.

It is not necessary that the transformer be in good working order, since the secondary winding in it often burns out, which will still have to be removed during the creation of the device.

Remaking the transformer comes down to completely removing the secondary winding and winding a new one.

An insulated wire with a cross-section of at least 2.0 mm is used as a new winding. sq.

When winding, you need to decide on the number of turns. You can do this experimentally - wind 10 turns of a new wire around the core, then connect a voltmeter to its ends and power the transformer.

According to the voltmeter readings, it is determined what output voltage these 10 turns provide.

For example, measurements showed that there is 2.0 V at the output. This means that 12V at the output will provide 60 turns, and 13V will provide 65 turns. As you understand, 5 turns adds 1 volt.

Scheme.

Well, then everything is done as described above - the diode bridge is made, all the components are connected and the functionality is checked.

It is worth pointing out that it is better to assemble such a charger with high quality, then place all the components in a case that can be made from scrap materials. Or mount it on a base.

Be sure to mark where the “positive” wire is and where the “negative” wire is, so as not to “over-plus” and damage the device.

How to charge a completely dead car battery

Your battery is discharged, probably because you did not clean the terminals from oxidation, perhaps you left the headlights on overnight. Oops, I'm off topic. So, how to charge a completely discharged car battery? Now I will tell you everything completely.

The battery itself constantly gives its charge to the car. For example, to start the engine or play music for you. And it only receives a charge when the generator is turned on. It is he who supplies your electricity. The generator starts together with the engine, that is. That is why this method of charging the battery is not suitable now. First, let's look at when does the battery need to be charged in a car?

If you are too lazy to read, watch a good video. In it you will learn:

When does your car battery need to be charged?

In order to determine when the battery needs to be charged? We will use two methods:

1. It is necessary to measure the voltage by connecting to the terminals. We then use the table to determine the state of charge of the battery.

That is, if your terminal voltage is 12.24 V and the battery temperature is approximately 0° , then the charge is 30% .

2. Determining the battery charge by electrolyte density is a more accurate method. This method can only be used if it is possible to remove the plugs on your battery and gain access to the electrolyte.

An electrolyte is a mixture of distilled water and a sulfuric acid solution, the density of which changes as the battery charge changes.

The lower the density, the less charge on your battery. To determine the density of the electrolyte, we use a special tool - an aerometer .

To take a measurement you need:

In this case, the density should be equal between all banks. The norm will be if the density is 1.27 g/cm3. To find out the charge, we use a table of the degree of charge of the battery based on the density of the electrolyte.

Charge level in %	Electrolyte density at temperature 20…25°	Electrolyte density at temperature +5…–5°	Electrolyte density at temperature -10… –15°
100	1,27±0,01	1,30±0,01	1,31±0,01
75	1,24±0,01	1,27±0,01	1,28±0,01
50	1,20±0,01	1,22±0,01	1,23±0,01
25	1,15±0,01	1,17±0,01	1,18±0,01
1,00±0,01	1,03±0,01	1,04±0,01

table for determining the degree of battery charge by electrolyte density.

You can use the graph to determine the degree of charge of the battery based on the density of the electrolyte.

How to properly charge a dead battery

First of all, how to start charging the battery, you need to prepare it. Clean it from dirt and oxidation, unscrew the plugs, but do not remove them. This way the gas will escape and the interior will not be contaminated by dust. Don't charge it in the car, disconnect the battery and bring it home.

How to properly charge a dead battery? In order to charge a battery with a capacity of 65 Ah . It is necessary to charge it with a charging station, which will supply it with a constant current of 6.5 Amps. It will charge for 15 hours.

It is important to know. When charging in this way, the voltage increases, thereby releasing a lot of sulfuric acid gas. To avoid this, we will step-by-step reduce the supplied current 2 times as soon as the voltage becomes 14.3 and 15 V. The downside of this charging method is that it must be monitored so that the battery is charged successfully.

A simpler, but slightly longer than the previous charging method. It does not need to be controlled like the previous one. In this method we will charge the battery with constant voltage. To do this, you need to set the voltage to 14.5 V, in turn, the current will itself change in order to maintain the voltage value. With this approach, charging time will be approximately a day. True, you won’t be able to fully charge, but only 90–95%.

Remember safety precautions. Charging is also dangerous, because the battery contains a solution of sulfuric acid, which evaporates as a gas. Charge the battery while wearing gloves and in a room with open windows. Also, do not use objects that could cause a spark or fire.

Moving the battery to your home

It happens that a driver rarely drives a car in winter. In this case, experienced drivers strongly recommend removing the battery and storing it in a dry, warm room. The recommendation is supported by the fact that a non-working battery at low temperatures quickly deteriorates in its characteristics. Sometimes this even leads to irreversible damage to the battery.

During such storage, it is important not to forget to charge the battery at least once every 3 months. Then he will always be in “combat” readiness.

In conclusion, we emphasize: be attentive to the car and to yourself. Many unpleasant situations will not happen if you think about your safety in advance. Proper use of the battery will allow you to avoid malfunctions. Careful preparation of the car before a long journey will allow you to get to your intended destination without unnecessary incidents.

How long to charge a dead car battery?

The battery charge is constantly being wasted, even when you are not using the car. First of all, it is spent on starting the engine, on a constantly working alarm and locks in the car, on a generator, and a starter. Replenishes its charge using a generator. Your battery does not always receive the charge it needs while the generator is running. And after the trip, in order to start the engine, you may not have the required amount of charge. How can you find out how long it will take to charge a dead battery?

Charging the battery takes 10 – 20 hours. You need to charge 1/10 of the current from the battery capacity.

To quickly charge a dead battery, you can use a mode with a current of 8 A for 3 hours and another hour with a current of 6 A.

In conclusion, I will say, try to avoid a complete discharge, because this is harmful and reduces the battery capacity.

Source

Main factors affecting battery performance

Discharge of the device may occur due to improper use. Sometimes this is affected by unstable battery power: it is either discharged too much or is kept connected to the charger for too long.

The reason for battery discharge is most often incorrect operation of the product.

If the battery is severely discharged and left in this state for a long time, then the process of sulfation begins when spongy lead turns into lead salts. This process resembles cirrhosis of the liver, where living active cells turn into connective tissue.

On the other hand, you cannot often use “fast charging”, which is not recommended by manufacturers and can only be used in the rarest cases. Otherwise, the active mass of the battery will crumble.

Another common cause of deep battery discharge is the negligence of the car driver. Motorists often forget to turn off their headlights, fog lights, and ignition. In this condition, the car can sit in the garage for several days. It is important to note that if the car has been parked for too long and the charge has dropped to 2 volts, it will most likely not be possible to bring the battery back to life.

Safety measures when restoring battery capacity

When batteries boil, they release toxic substances, so a house or apartment is not the best place to charge. If there is no other room, try to do this in a well-ventilated area.

When working with the device, you must wear goggles and gloves. The battery contains acid and there is a risk of serious injury. The battery must be charged away from open flames, as the release of hydrogen can cause an explosion. Also take care of the fuses in your home electrical system.

Maintaining the operating condition of the battery depends on proper use of the device, compliance with all manufacturer’s recommendations and monitoring external signs of wear. Timely maintenance will save not only money, but also the motorist’s time.

What to do if the battery is completely discharged

Many automakers claim that one full charge will have a worse effect on battery performance than several full discharges. Of course, you don’t need to constantly bring the battery to this state, but you shouldn’t despair if it’s completely dead either.

When charging the battery, it is important to observe the polarity

It is possible that after a deep discharge the battery will lose part of its capacity, but its performance will still remain. For deep discharge, you will need a professional level charger or a sufficiently qualified specialist. Therefore, the safest solution to the problem would be to contact a car service center, where professionals will resuscitate the battery.

If the battery goes out while driving away from home, you can try to light it from the battery of another car. However, before this you need to pay attention to the contacts and ensure a quality connection. If there is a whitish coating on the terminals, it must be removed.

Next, the charge will occur from the generator. However, it is better to try to restore the battery at home, using modern chargers that do not require outside intervention and control the process themselves.

Battery charging requirements

Before carrying out the procedure for making a homemade battery charger, you must pay attention to the following requirements:

1. Providing a stable voltage of 14.4 V.
2. Device autonomy. This means that a homemade device should not require supervision, since the battery is often charged at night.
3. Ensuring that the charger turns off when the charging current or voltage increases.
4. Reverse polarity protection. If the device is connected to the battery incorrectly, the protection should be triggered. For implementation, a fuse is included in the circuit.

Polarity reversal is a dangerous process, as a result of which the battery may explode or boil. If the battery is in good condition and only slightly discharged, then if the charger is connected incorrectly, the charging current will increase above the rated one. If the battery is discharged, then when the polarity is reversed, an increase in voltage above the set value is observed and, as a result, the electrolyte boils.

How to properly charge a dead battery at home

It is not difficult to charge the battery at home. The main thing is to follow step-by-step recommendations, take your time and follow safety rules.

Preparing the battery for charging

Before charging, you must remove the battery from the car, make sure that the car battery is clean, there is no damage or leakage of electrolyte. The next step is to check the consistency of the electrolyte.

In conventional lead acid batteries, the charging current is set to 1/10 of the capacity

It must be free of foreign objects, clean, transparent, without plaque, sediment or flakes. Only after all these preparations can you start charging: first, the positive and then the negative terminal are connected, and then a current of 1/10 of the capacity is started.

Step-by-step instructions for resuscitation

First you need to determine how much the battery is discharged. Sealed batteries have an indicator in the form of a float, which floats up when the electrolyte density is normal, showing a certain color.

So, green means that there is enough charge, and red means that there is not enough charge. Such data are very approximate and have a number of errors. You can also use a voltmeter: if the voltage is below 11.8 V, the battery is completely discharged.

The start of charging must correspond to the mode recommended by the device manufacturer

Most often it is recommended to start with a power of 0.05-0.1 of the total battery capacity. In this mode, as a rule, you will need to charge at least 15 hours.

It is necessary to complete charging only if the voltage at the terminals does not change within 1 hour when the same charge is applied. Any voltmeters are suitable for monitoring, but a constant value should be measured.

An important indicator when recharging a battery is the density of the electrolyte. Normally, it should correspond to 1.25-1.27 g/cm3. Under no circumstances should you add electrolyte when charging, only distilled water. The electrolyte level should be approximately 1.5-2 cm below the edges of the battery.

How long does it take to recharge?

The charging speed depends on the characteristics of the battery itself and the features of the charger. Thus, the time will be affected by:

Fast charging takes up to 4-5 hours. Drivers use it in cases where they urgently need to go somewhere. However, you should not abuse it in this way - it significantly damages the battery and reduces its service life.

When applying constant voltage, charging can last a day, and with continuous current this procedure will take a little more than 10 hours. Everything is very individual and there is no universal indicator.

Extending the life of your car battery

The average battery life is 3 years. Sometimes device manufacturers can promise up to 5 years of operation. If you treat the battery with care, you can use it much longer. To increase service life, it is not recommended to use the battery if it is already sufficiently discharged. This is especially true in winter, when the load increases.

When working with batteries, you should use protective gloves and goggles.

The battery terminals must be cleaned periodically and ensure that there are no electrolyte leaks, dirt or debris on the housing. You should also clean the vents from time to time. Pay attention to how well the device is fixed, since batteries do not tolerate vibration well, and as a result, the active mass falls off the plates.

Experts recommend that you always monitor for current leakage. Modern cars are equipped with a huge number of gadgets and various electronics, which are powered by a battery. Of course, such devices are developed taking into account the fact that they must consume a minimum amount of electricity.

To save battery charge, unnecessary equipment should be turned off if it is not needed.

One of the new ways to extend battery life is to use a thermal case. It will help maintain temperature in winter and prevent hypothermia. But it is worth noting that such a thing will be useful only if it is heated.

Charger for AA batteries

Today, many devices run on batteries. The main disadvantage is that it is difficult to track how soon the charge will run out. And if at the most inopportune moment the batteries run out, and you don’t have time to go to the store for new ones, you can use a homemade battery.

To make your own AA battery charger, you will need:

• flux;
• solder;
• soldering iron;
• tweezers;
• tester;
• screwdrivers.

A tester is needed to check the performance of radio components for comparison with standard indicators.

You will also need a battery compartment and case. We take the compartment from any children's toy (for example, from Tetris, which was very popular in the 90s). Any plastic case will also work.

The process then looks like this:

• We attach the battery compartment to the case with screws. You can use a game console board as a basis. We cut everything out according to this pattern and leave the power socket.
• We connect the parts with a soldering iron, focusing on the diagram. Don't forget to take into account polarity: plus is soldered to plus.
• For the cord, you can use a cable from a computer mouse with a USB input.
• Check the voltage from the cord. The tester will display a reading of 5V.
• Set the charging current. We connect the tester so that the minus is connected to the battery, and the plus is connected to the diode.
• We set the current mode to 200 mA and plug it into the network. The LED lights up, which means you did everything right.
• Now you need to set the charging current indicator by changing the resistance. We make the second AA battery in the same way.