There are many methods of charging batteries nowadays. There are more modern ones that require special chargers, and there are also simple, classical charging methods that have been known since the inception of rechargeable batteries and are still popular today.

Today we will look at two classic methods of charging a battery.

1. Battery charge at constant charging current. I = const.

2. Charge the battery at a constant charging voltage. U = const.

Today we need the following devices:

1. Level gauge tube (if any)

2. Hydrometer.

3. Voltmeter (multimeter or built-in charger).

4. Charger.

Before starting charging the battery, you need to make sure that this is necessary, that is, check the battery and prepare it for charging, for this we need:

1. Clean the battery case, terminals from oxides, unscrew the filler plugs

2. Check the electrolyte level using a level tube and if a reduced level is observed (less than 10-12 mm), it is necessary to top up with distilled water.

3. Measure the density of the electrolyte using a hydrometer

4. Measure the voltage (EMF) of the battery with a voltmeter or multimeter.

And it is desirable to write down or remember these values; we will need them to control the end of the battery charge.

Based on the measured values ​​of the density and voltage of the battery, evaluate whether it still needs charging or not.

The density of the electrolyte in a fully charged battery measured at a temperature of + 25 ° С, depending on the climatic zone, must correspond to the values ​​indicated in the table.

The voltage on a fully charged battery must be at least 12.6 volts.

Do not charge the battery unless necessary, as this will shorten its life by overcharging the battery.

The principle of battery charging is that the voltage from the charger is connected to the battery, and for the charging current to occur, that is, to start the battery charging process, the charging voltage must always be more battery voltage.

If the charging voltage is less than the voltage on the battery, then the direction of the current in the circuit will change and the battery will begin to give its energy to the charger, that is, to discharge to it.

So, let's look at the first method of charging a battery.

Battery charge at constant charging current.

Charging a battery with a constant charging current is the main universal charging method. You need to know that when using this method, unlike some others, the rechargeable battery is charged to 100% of its capacity.

With this method, the value of the charging current is kept constant throughout the entire charge.

This is achieved either by using special chargers with the function of setting the set value of the charging current, or by including a rheostat in the charging circuit, but in the latter case, it is necessary to change the resistance values ​​of the rheostat to achieve a constant charging current during the charging process on your own.

The point is that during the charging process, the resistance of the battery and the voltage across it change, which leads to a decrease in the charging current. To maintain the charging current at a constant level, it is necessary to increase the value of the charging voltage using the aforementioned rheostat.

I will say again that in modern chargers, the charging current value can be maintained automatically.

The charging current is usually chosen equal to 10% of the battery capacity, which is indicated on the battery case. In the literature, this capacity is referred to as C20, which is a 20 hour discharge capacity. Just remember this.

In this case, the charging time of the battery depends on the degree of its discharge before the start of charging. If the battery has been completely discharged but not lower than 10 volts, then the approximate charge time will be within 10 hours.

If you are not limited by the charging time, then it is better to charge the battery with a current of 5% of the battery capacity, while the charging process is better and the battery is charged at 100% of its capacity, and the charging time increases.

The battery is charged until abundant gas evolution, constant voltage and electrolyte density are achieved for 2 hours.

The voltage of the charger connected to the battery usually reaches 16-16.2 volts at the end of the charge.

It should be said that at the end of the battery charge by the method of constant charging current, there is a significant increase in the temperature of the electrolyte in it. Therefore, when the temperature reaches 45 degrees, the charging current should be reduced by 2 times, or the charge should be interrupted altogether to reduce the temperature to 30-35 degrees.

So, we take the charger, connect the positive and negative terminals to the battery terminals, set the knob for setting the charging current to a minimum, that is, to the extreme left position, connect the charger to the network.

Next, we set the charging current equal to 10% of the battery capacity and every 2 hours we control the density of the electrolyte, the voltage on the battery, which in the process of charging the battery will increase and, if possible, the temperature of the electrolyte, or at least indirectly, touching the battery case with your hand.

If the charger does not have the function of maintaining a constant charging current, then we maintain it manually by changing the charging voltage and monitoring the charging current every half hour using the charger's ammeter or an ammeter connected in series to the charging circuit.

When the voltage reaches approximately 14 volts, we control the density and voltage every hour.

When observing signs of charge (boiling, constancy of density and voltage), disconnect the charger from the network, disconnect the clamps from the battery.

Our battery is charged.

Disadvantages of the charging method:

1. Long battery charging time (when charging with a current of 10% of its capacity about 10 hours, when charging with a current of 5% of its capacity - about 20 hours, provided that the battery is completely discharged).

2. The need for frequent monitoring of the charging process (charging current, voltage, density and temperature of the electrolyte).

3. There is a possibility of overcharging the battery.

Battery charge at constant charging voltage.

Charging the battery while maintaining a constant voltage across it is a faster and easier method of putting the battery into operation.

The essence of this charging method is as follows.

The charger is directly connected to the battery and a constant value of the charging voltage is maintained during the entire charge. In this case, the voltage is set in the range of 14.4-15 volts (for a 12-volt battery).

With this method of charging, the value of the charging current is set, one might say, automatically, depending on the degree of discharge, the density of the electrolyte, temperature and other factors.

At the beginning of the battery charging, the charging current can reach large values, even 100% of the battery capacity, since the EMF of the batteries has the smallest value, and the difference between this EMF and the charge voltage is the greatest. However, in the process of charging the EMF of the battery, the difference between the EMF of the battery and the charging voltage decreases, thereby reducing the charging current, which in 2-4 hours can reach about 5-10% of the battery capacity. Again, it all depends on the degree of battery discharge.

Such high charge currents are the reason for faster battery charging.

At the end of the battery charging process, the charging current decreases to almost zero, therefore, it is believed that when charging by maintaining a constant value of the charging voltage, the battery will only charge up to 90-95% of its capacity.

Thus, when the value of the charging current is close to zero, the charge can be stopped, the battery can be restored to its original state and installed on the car.

By the way, the battery charge at a constant value of the charging voltage is implemented in the car.

If the voltage on the battery is less than 12.6-12.7 volts (depending on the car brand), then the relay regulator connects the generator to the battery to recharge it. Moreover, the voltage from the generator corresponds to the value of 13.8-14.4 volts (the standard value, in foreign cars, the generator voltage is slightly higher than the specified value).

1. We connect the charger to the battery,

2. We set the charging voltage within 14.4-15 volts,

3. Controlling the battery charging current

4. Remove the battery from charging when the current value is close to zero.

Disadvantages of the method:

1. The rechargeable battery is not charged up to its full capacity, but on average up to 90-95% of its value.

2. Large overload of the charging voltage source at the beginning of the charge, due to the large charging current (relevant when charging the battery from the car generator).

Upon completion of charging the battery by any of the methods, you must:

1. Make sure that the voltage across it has a value of at least 12.6 volts,

2. The density of the electrolyte is within 1.27 g / cm3

3. Electrolyte level 10-12 mm above the plates

4. Eliminate possible electrolyte drips and install the battery on the vehicle.

And now a question. In some videos on YouTube and in articles on sites, I have come across this advice on connecting the charger to the battery: first we connect the plus, then the minus. So I would like to know your opinion is this statement correct or the sequence of connecting the wires of the charger does not matter?

Write your opinions in the comments.

I propose to watch a detailed video in which I explain how to charge the battery using two classic charging methods:

During engine operation, the battery (), regardless of the type (serviceable or maintenance-free battery), is recharged from the car generator. To control the battery charge, a device called a relay-regulator is installed on the generator.

The very operation of a car in winter often involves short trips, the inclusion of a large amount of energy-intensive equipment (heated mirrors, glass, seats, etc.) The load on the battery increases significantly. At the same time, the battery simply does not have time to charge from the generator and compensate for the losses spent on starts. Considering the above, it is optimal to fully charge the battery with a charger to 100% at least once a year before the onset of cold weather.

We add that in case of problems with starting the engine due to the presence of engine malfunctions (problems with fuel equipment, etc.), the owner has to turn the starter much longer and more intensively. In such cases, you will need to charge the battery with an external charger much more often.

Charging the battery with a charger

To know how to charge a maintenance-free car battery with a charger, as well as to charge a service-type battery, certain rules must be followed. The charger (charger, external charger OVC, starting charger) is actually a capacitor charger.

The car battery is a constant current source. When connecting the battery, it is imperative to observe the polarity. For this, the positive and negative terminals are marked with a plus and minus sign ("+" and "-") on the battery. The terminals on the charger have a similar marking, which allows you to correctly connect the battery to the charger. In other words, the "plus" of the battery is connected to the "+" terminal of the charger, the "minus" on the battery is connected to the "-" output of the charger.

Note that an accidental reversal of polarity will result in the battery being discharged instead of being charged. It should also be borne in mind that a deep discharge (the battery is completely seated) can in some cases damage the battery, as a result of which it may not be possible to charge such a battery using a charger.

It should also be borne in mind that before connecting to the charger, the battery must be removed from the car and thoroughly cleaned of possible contamination. Acid streaks are well removed with a damp cloth, which is moistened in a solution with soda. To prepare the solution, 15-20 grams of soda is enough for 150-200 grams of water. The presence of acid will be indicated by foaming of the specified solution when applied to the battery case.

As for the serviced batteries, the plugs on the acid cans should be unscrewed. The fact is that during charging, gases are formed in the battery, which must be provided with a free exit. You should also check the electrolyte level. When the level drops below the norm, distilled water is topped up.

What voltage to charge the car battery

To begin with, charging a battery involves supplying it with a current that is not enough for a battery to fully charge. Based on this statement, you can answer the questions of how much current to charge the car battery, as well as how much you need to charge the car battery with the charger.

In the event that a battery with a capacity of 50 Ampere-hours is 50% charged, then at the initial stage, a charging current of 25 A should be set, after which this current must be dynamically reduced. By the time the battery is fully charged, the current supply should stop. This principle of operation is the basis of automatic chargers, with the help of which a car battery is charged on average in 4-6 hours. The only drawback of such chargers is their high cost.

It is also worth highlighting semi-automatic chargers and solutions that involve completely manual configuration. The latter are the most affordable and widely available for sale. Considering that the battery is usually 50% discharged, you can calculate how much to charge a maintenance-free car battery, and also understand how much to charge a car battery of a serviced type.

The basis for calculating the battery charging time is the battery capacity. Knowing this parameter, the charging time is calculated quite simply. If the battery has a capacity of 50 Ah, then for full charging it is required to supply such a battery with a current of no more than 30 Ah. The charger sets 3A, which will take ten hours to fully charge the battery with the charger.

To be 100% sure that the battery is fully charged, after 10 hours, you can set the current to 0.5 A on the charger, and then continue charging the battery for another 5-10 hours. This charging method is not dangerous for car batteries, which have a large capacity. The downside is the need to charge the battery for about a day.

To save time and quickly charge the battery, you can set it to 8 A and then charge for about 3 hours. After this period has expired, the charge current is reduced to 6 A and the battery is charged with this current for another 1 hour. As a result, it will take 4 hours to charge. Note that this charging mode is not optimal, since it is advisable to charge the battery with a small current of up to 3 A.

Charging with high currents can overcharge and overheat the battery, resulting in a significant reduction in battery life. We also note that the use of battery charging methods, which are aimed at minimizing the negative process of plate sulfation, in practice do not have noticeable positive results.

Correct operation of the battery, depending on its type (serviced and unattended), the elimination of deep discharge and timely charging with the help of a charger allow an acid battery to work properly for 3-7 years.

How to assess the condition and charge of a car battery

Proper charging and a number of conditions that must be observed during the operation of a car battery can ensure normal engine start even in extremely low temperatures. The main indicator of the state of the battery is the degree of its charge. Next, we will answer how to find out if the car battery is charged.

To begin with, some battery models have a special color indicator on the battery itself, which indicates whether the battery is charged or discharged. It should be noted that the indicated indicator is a very rough indicator, by which it is possible, with a certain degree of probability, to determine only the need for recharging. In other words, the charge indicator can indicate that the battery is charged, but the starting current at negative temperatures is insufficient.

Another way to determine the degree of battery charge is to measure the voltage at the battery terminals. This method also allows a very approximate assessment of the state and degree of charge. To measure the battery, you need to remove it from the car or disconnect it from the charger, after which you need to wait an additional 7 hours. The outside temperature is not critical.

• 12.8V-100% charge;
• 12.6V-75% charge;
• 12.2V-50% charge;
• 12.0V-25% charge;
• A voltage drop of less than 11.8 V indicates a complete discharge of the battery.

It is also possible to check the state of charge of the battery without waiting. To do this, the voltage at the battery terminals must be measured by the load using the so-called load plugs. This method is more accurate and reliable. The specified plug is a voltmeter, a resistance is connected in parallel to the terminals of the voltmeter. The resistance value is 0.018-0.020 Ohm for a battery with a capacity indicator of 40-60 Ampere-hours.

The plug must be connected to the corresponding outputs on the battery, then after 6-8 seconds. fix the readings that the voltmeter displays. Next, you can estimate the battery voltage level using a load plug:

• 10.5 V - 100% charge;
• 9.9 V - 75% charge;
• 9.3 V - 50% charge;
• 8.7 V - 25% charge;
• Indicator less than 8.18 V - full battery discharge;

You can also take measurements in the absence of a load plug without removing the battery from the car. The battery must be connected to the vehicle electrical system. Then you will need to load the battery by turning on the dimensions and high beam of the head optics (for cars with standard halogen lamps). The headlight bulbs have a power of 50 W, the load is about 10 A. The voltage of a normally charged battery in this case should be about 11.2 V.

The next method that allows you to check the battery charge is to measure the voltage at the battery terminals at the moment when the internal combustion engine is started. These measurements can only be considered reliable if the starter is working properly.

At the moment of start-up, the voltage indicator should not be below the 9.5 V mark. A voltage drop below the indicated mark means that the battery is severely discharged. In this case, it needs to be charged using a charger. This test method also allows you to identify problems with the starter. A known serviceable and 100% charged battery is installed on the car, after which the measurement is taken. If the voltage at the battery terminals at the time of starting drops below 9.5 V, then problems with the starter are obvious.

Finally, we add that measurements in different ways involve fixing fluctuations in fractions of a volt. For this reason, increased requirements are imposed on the voltmeter. The accuracy of the device is extremely important, since the slightest error of even one or two percent will lead to an error in measuring the degree of battery charge by 10 -20%. For measurements, it is recommended to use devices with a minimum error.

How to charge a fully discharged car battery

A common cause of deep battery discharge is banal inattention. It is often enough to leave the car with the included dimensions or headlights, interior lighting or a radio tape recorder for 6-12 hours, after which the battery is completely discharged. For this reason, many car owners are interested in the question of whether it is possible to restore a completely discharged battery.

As you know, a complete discharge of a battery has a strong effect on battery life, especially when it comes to maintenance-free batteries. Manufacturers of car batteries indicate that even one full discharge is enough to damage the battery. In practice, relatively new batteries can be restored at least 1 or 2 times after their complete discharge without significant loss of operational properties.

First, you need to determine how much the battery is discharged using one of the above methods. You can also put the battery on charge right away. Further, a completely discharged battery must be charged in the mode recommended by the battery manufacturer. The standard is to supply a charge current at 0.1 of the total battery capacity.

A fully planted battery is charged with this current for at least 14-16 hours. For example, consider charging a 60 Amp-hour battery. In this case, the charge current should be on average from 3 A (slower) to 6 A (faster). A fully discharged car battery should be properly charged with the smallest current, and as long as possible (about a day).

When the voltage at the battery terminals no longer increases for 60 minutes. (assuming the same charging current is supplied), then the battery is fully charged. When fully charged, maintenance-free batteries assume a voltage value of 16.2 ± 0.1 V. It should be borne in mind that this voltage value is a standard, but at the same time there is a dependence on the battery capacity indicator, charge current, electrolyte density in the battery, etc. Any voltmeter is suitable for measurement, regardless of the error of the device, since it is necessary to measure a constant, not an exact voltage.

How to charge a car battery if there is no charger

The easiest way to charge the battery is to start the car using the “lighting” method from another car, after which you need to drive the car for about 20-30 minutes. For the efficiency of charging from the generator, either dynamic driving in higher gears or driving on "low" is assumed.

The main condition is to maintain the crankshaft speed at around 2900-3200 rpm. At the specified speed, the generator will provide the required current to recharge the battery. Note that this method is suitable only if the battery is partially and not deeply discharged. Also, after the trip, you will still need to fully charge the battery.

Quite often, car enthusiasts are interested in what else you can charge a car battery, besides the charger. Most often, as a replacement, it is supposed to use chargers that charge mobile phones, tablets, laptops and other gadgets. We note right away that these solutions do not allow charging a car battery without a number of manipulations.

The fact is that the main condition for supplying current from the charger to the battery is that a voltage must be present at the output of the charger, which will be higher than the voltage at the outputs of the battery. In other words, when the voltage of the battery outputs is 12 V, the output voltage of the charger should be 14 V. As for various devices, the voltage of their batteries often does not exceed 7.0 V. Now, imagine that you have at hand a charger from a gadget that has the required voltage 12 Q. The problem will still be present, since the resistance of the car's battery is measured in whole ohms.

It turns out that connecting charging from a mobile device to the battery outputs will actually be a short circuit of the terminals of the charging power supply. The protection will operate in the unit, as a result of which such a charger will not supply current to the battery. In the absence of protection, there is a high probability of failure of the power supply from a significant load.

It should be added that the car battery should also not be charged from various power supplies that have a suitable output voltage, but they structurally lack the ability to adjust the amount of current supplied. Only a special charger for a car battery is a device that has at its output the required voltage and current for charging the battery. In parallel with this, it is possible to control a constant current value.

Homemade charger for car battery

Now let's move from theory to practice. Let's start with the fact that you can make a charger for a battery from a power supply from a third-party device with your own hands.

Please note that these actions pose a certain danger and are performed solely at your own peril and risk. The administration of the resource does not bear any responsibility, the information is presented for informational purposes only!

There are several ways to make a charger. Let's take a quick look at the most common ones:

1. Making a charger from a source that has a voltage of about 13-14 V at its output, and is also capable of providing a current of more than 1 Ampere. For such a task, a laptop power supply is suitable.
2. Charging from a regular household electrical outlet of 220 volts. To do this, you will need a semiconductor diode and an incandescent lamp, which are connected in series in a circuit.

It should be borne in mind that the use of such solutions means charging the battery through a current source. As a result, constant monitoring of the time and moment of the end of the battery charge is required. This control is carried out using regular measurements of the voltage at the battery terminals or counting the time for which the battery is put on charge.

Remember, overcharging the battery leads to an increase in the temperature inside the battery and the active release of hydrogen and oxygen. Boiling of the electrolyte in the "banks" of the battery causes the formation of an explosive mixture. The battery may explode if an electrical spark is generated or other sources of ignition occur. An explosion like this can lead to fires, burns and injuries!

Now let's focus on the most common method of self-manufacturing a charger for a car battery. We are talking about charging from a laptop PSU. To accomplish the task, certain knowledge, skills and experience in the field of assembling simple electrical circuits are required. Otherwise, the best solution would be to contact a specialist, purchase a ready-made charger or replace the battery with a new one.

The scheme for manufacturing the memory itself is quite simple. A ballast lamp is connected to the PSU, and the outputs of a homemade charger are connected to the outputs of the battery. A lamp with a small rating is required as a "ballast".

If you try to connect the power supply unit to the battery without using a ballast lamp in the electrical circuit, then you can quickly disable both the power supply unit and the battery.

You should select the right lamp step by step, starting with the minimum ratings. To begin with, you can connect a low-power turn signal lamp, then a more powerful turn signal lamp, etc. Each lamp should be tested separately by daisy-chaining. If the light is on, then you can proceed to connecting an analogue of greater power. This method will help not to damage the power supply. Finally, we add that the burning of the ballast lamp will indicate the battery charge from such a self-made device. In other words, if the battery is charging, then the lamp will burn, even if it is very dim.

The new battery must be fully charged and functional, that is, it must be immediately installed on the car to start further operation. Before purchasing, it is necessary to check the battery for a number of parameters:

• the integrity of the case;
• measuring the voltage at the outputs;
• checking the density of the electrolyte;
• date of manufacture of the battery;

At the initial stage, it is necessary to remove the protective film and inspect the case for cracks, streaks and other defects. If the slightest deviation from the norm is found, it is recommended to replace the battery.

Then the voltage is measured at the terminals of the new battery. You can measure the voltage with a voltmeter, while the accuracy of the device does not matter. The voltage should not be lower than the 12 volt mark. A voltage reading of 10.8 volts indicates that the battery is completely discharged. This indicator is unacceptable for a new battery.

The density of the electrolyte is measured using a special plug. Also, the density parameter indirectly indicates the battery charge level. The final stage of the check is to determine the date of release of the battery. Batteries that were released 6 months. back or more from the day of the planned purchase should not be purchased. The fact is that a battery ready for use has a tendency to self-discharge. For this reason, the battery must be prepared in advance for long-term storage, but in this case, the battery can no longer be considered a new finished product.

It turns out that the answer to the question whether it is necessary to charge a new battery for the car will be negative. There is no need to charge a new battery. If the battery planned for purchase is discharged, then it may simply be old, used, or there is a manufacturing defect.

Other questions about car battery charging

Very often during operation, owners try to charge the battery without removing the battery from the car. In other words, the battery is charged without removing the terminals directly on the car, that is, the battery while charging remains connected to the vehicle's network.

We draw your attention to the fact that when the battery is charging, the voltage at the battery terminals may be around 16 V. This voltage indicator strongly depends on what type of charger is used for charging. We add that even turning off the ignition and removing the key from the lock does not mean that all devices in the car are de-energized. The security complex or alarm system, multimedia head unit, interior lighting and other solutions can remain on or in standby mode.

Charging the battery without removing and disconnecting the terminals may result in too high supply voltage applied to powered devices. The result is usually the breakdown of such devices. If your car has devices that cannot be completely de-energized after turning off the ignition, then it is prohibited to charge the battery without disconnecting the terminals. Before charging, in this case, it is necessary to make a mandatory disconnection of the "negative" terminal.

Also, do not start disconnecting the battery from the positive terminal. The negative terminal on the battery is connected to the vehicle's electrical system through a direct connection to the body. An attempt to turn off the "plus" first can have dire consequences. Unintentional contact of a wrench or other tool with metal parts of the car body / engine will cause a short circuit. This situation is quite common in cases where the positive terminal is unscrewed from the battery output with the help of keys, while the negative is not removed.

As for charging the battery in the cold or indoors in winter without heating, the battery can be safely recharged in such conditions. During charging, the battery heats up, the temperature of the electrolyte in the "banks" will be positive. In parallel with this, bringing the battery into heat for charging is required if the electrolyte has frozen inside the battery and the battery has been completely seated. It is necessary to charge such a battery strictly after the frozen electrolyte thaws.

The maintenance-free battery really differs from its serviced brother, the point here is in a special structure. You almost never know what it means to add electrolyte to it, or measure the density. Hence the name maintenance-free, that is, it does not require any maintenance, it is completely autonomous. However, many of my readers are interested in how to charge it and can it be done? Indeed, now there are a lot of such batteries from different manufacturers, and they are installed on new cars in 90% of cases ...

To begin with, the battery can be recharged "anyway", I would even say that it is designed for this. Let's remember the structure of the car's on-board network. The battery (at start-up) gives energy to the ignition system and the starter, which spins the engine (it starts). Further, after starting, the generator begins to generate electricity, which recharges our battery.

Serviced or unattended, this is the second question, the main thing is recharging, which replenishes the lost energy during start-up. I will say even more - if you discharge an ordinary unattended battery "to zero" (), it will simply kill it, after a few such cycles. Therefore, the charge must always be present and, moreover, in the normal phase,.

Then what is the problem?

Many people are frightened not by car charging, but by the so-called home charging. That is, with conventional stationary chargers. What problems arise at this stage:

• It is impossible to trace the boiling of the electrolyte ... YES, this is really a problem, because when we boil, we understand that charging is over. One has only to look at the bank, but you cannot look into the unattended one, because it is simply closed (sealed). We do not see what is going on inside.

• Can't track density ... Again, for the same reason, if in a serviced one, you simply unscrew the plugs and measure the density with a hydrometer, then this will not work.
• Battery tightness ... Also scary! What happens if the electrolyte boils, where will the vapors go? What if the case breaks?

These points are reasonable, which is why it is important to know how to charge such batteries.

How to charge a maintenance-free battery

This is where the old old-fashioned methods (with electrolyte bubbles) will not work. It is important for you to know and understand how to charge a car battery, that is, the principles of charging ().

But for understanding, I will remind you a little - there are only two charging methods. It is constant voltage and constant current.

• Constant voltage. This is when you set a constant voltage, say 14.4 Volts, and the current is automatically adjusted. That is, at the beginning it can be 10 Amperes, and at the end of the charge 0.2A.
• Direct current. Here, on the contrary, tension can jump. We set, say, 2 Amperes, the current at the beginning of the charge will be 15 Volts, and by the end it may drop to 14.4 Volts.

Now all chargers are mostly automatic, they work according to the first point, that is, constant voltage, but the current strength is changing.

By the way, ordinary serviced batteries are also charged, but how long does it take to charge an unattended one?

How to calculate charging time?

This is already a more interesting question, the really inconvenience is that you need to clearly understand how discharged your maintenance-free battery is. That is, we calculate its capacity. But how to do that?

Again, it's simple - we know that a 100% charge is a voltage of 12.7 Volts. But a fully discharged battery is 11.7 Volts. Of course, you can discharge even more, but this is not recommended, generally 10 Volts, this is already a serious discharge.

Accordingly, 0.1 X 5 = 0.5. Now add 11.7 + 0.5 = 12.2V. This is a kind of discharge up to 50%.

Now a little about the capacity, for batteries it is 55 - 60 - 75, etc. ampere * hour. That is, this amount of current, he will be able to give in one hour. If we have a discharge of 50%, it means that about half of the capacity has gone away - for example, it took 30 from 60 Amperes, etc.

That is, in order to replenish 50% of the capacity, we need to supply a certain current and "fill" the battery. It is possible to supply 30A in one hour (in our example), but this will kill the battery. The recommended charge is 10% of the capacity. In our case, this is 6A. And since we need to replenish 30A, then 30/6 = 5 hours. That is, with this current, we need to charge it for five hours.

Probably, I confused you, but the main thing is to learn how to determine the degree of battery discharge. Remember the lower limit is 11.7V, the upper limit is 12.7V.

Automatic charging stations

Of course, the "automatic machines" will do everything for you, there is no need to "steam" what current to supply and regulate the voltage. He himself will do everything automatically. And to be honest, neither VOLTMETER nor AMPERMETER has been there for a long time, they were removed as unnecessary.

Such a charger will supply in the first hour - the maximum current, for the second hour the current is two to three times less, but at the sixth - seventh hour, the current can generally fall to a minimum, about 0.05A. Therefore, even if your maintenance-free battery is on such a charge, it will never boil, because the currents during "filling" are minimal, and I read somewhere that they may be absent altogether, that is, it turns off.

What happens if you recharge?

Okay, we figured out the automatic chargers. But what will happen if you constantly recharge with an old "charger", where do you rigidly set the current and voltage? That is, you need to recharge at 6 Amperes, say 6 hours, and you "crap" 8 or even 10!

Of course, the electrolyte will boil inside, this is a purely physical principle. However, the battery will not burst (like a ball), as many think! He has a special valve inside, which in emergency cases is designed to throw off - through the "chur" high pressure. It opens exactly when you have a long and very powerful recharge, which, by the way, can also kill the battery - the case will survive, but some of the electrolyte will evaporate, you need to understand this!

I'm a kettle, I don't want to calculate all sorts of amperes, what should I do?

It is possible to understand you, it is not always easy to charge a maintenance-free battery - all calculations of time and amperage are needed. But even here the manufacturers took care of you, they are exactly for people like you who made batteries with green windows (or many call them lamps). The principle is simple: when it is normally charged, the green indicator is on, when it is discharged, it is black, if there is not enough electrolyte, it is white. , there is a lot of detail.

Can I charge at home?

Well, and the last question - is it possible to charge at home? After all, let's say the serviced brother - to put it mildly, because during boiling, harmful, and even explosive gas is released.

When buying a new battery or removing a discharged battery from a car, car owners ask themselves: how long does it take to charge it? No specialist will tell you exactly how many hours you need, since the time depends on a number of factors. He will only give recommendations on how to charge.

Preparing the car battery for the charging process

Any car battery (either purchased or removed from the car) must be prepared for charging. An electrolyte of the required density is poured into the new one to the specified level.

The battery removed from the vehicle is prepared as follows. First, you need to thoroughly clean its output contacts from dirt and oxides. Then it is advisable to wipe the car battery with a soft clean cloth moistened with a solution of soda (preferably soda ash) or ammonia. This completes the preparation of the maintenance-free battery. If the battery is serviced (with plugs on the banks for filling electrolyte), then the top cover, together with the screwed plugs, must be thoroughly cleaned - otherwise, when opening the cans or during charging, dirt may get into the electrolyte, which will lead to an early battery failure. Only then are the plugs turned out. Then check, as well as its density. If necessary, the level is brought to the required level. Distilled water or electrolyte with such a density is added to obtain the desired density in the cans. After this operation, the plugs are left open so that the car battery "breathes" during charging. If you close them, the battery can burst with gases that will be released during the charging process. In addition, it will be necessary to periodically monitor the temperature of the electrolyte in order to prevent it from overheating and boiling.

Now you can connect (charger) to the terminals of the car battery. In this case, it is imperative to observe the polarity (do not confuse the "minus" and "plus") and the following sequence: first connect the charger wires to the "crocodile" terminals and only then connect its power cord to the mains and turn on the charger. At the end of charging, we do everything the other way around: first, turn off the charger, and then disconnect it from the car battery. This is necessary to avoid an explosion or ignition of the oxygen-hydrogen mixture from sparks generated when connecting and disconnecting crocodiles. All chemical reactions in the electrolyte solution are accompanied by the evolution of hydrogen, the battery banks are open, and oxygen is present in the air.

How and for how long to charge a car battery with constant current

There are two ways to charge the battery: constant current and constant voltage (meaning the constant value of the electrical quantity). The first method is most widely used.

A prepared car battery is switched on for charging when the electrolyte temperature in it is not higher than 35 ° C. For a new and heavily discharged battery, first set the charging current equal to 10% of the battery capacity (for 60 Ah - 6 A). If the charger does not automatically support the current value, then this is done manually using a rheostat or a special switch. The car battery is charged before the start of gas evolution in its banks - this will correspond to the achievement of the voltage at the output contacts of the battery of 14.4 V (that is, 2.4 V on each of its sections). After that, the current is reduced for a new battery by 2 times, and for a used one - by 2–3. Further, the battery is charged with a reduced current until abundant gas evolution occurs in all of its banks. This two-stage method allows you to speed up the charging process and reduce the intensity of gassing, which destroys the electrodes (plates) of the battery.

A slightly discharged battery must be charged in one-stage mode. The entire charging cycle is carried out with one current equal to 10% of the nominal battery capacity. A sign of completion of charging, as in the two-stage method, will be the onset of abundant gas release. The end of the charge, in addition to the abundant gas release in the battery banks, is characterized by the following features:

• the density of the electrolyte does not increase within three hours;
• the voltage at the output contacts of the battery has reached 15-16.2 V (2.5-2.7 V at the contacts of each of its sections) and does not increase for three hours.

During the charging process, every 2-3 hours you need to check the density, as well as the temperature of the electrolyte in the battery banks.

During charging, the temperature should be no more than 45 ° C.

If this value is exceeded, it is necessary to reduce the current by 2 times or stop charging for the time that is necessary for the temperature to drop to 30–35 o C. If the charge has not been interrupted, then the current should be increased to the previous value after the temperature has dropped during charging. During charging, the electrolyte level must be monitored.

The first charge of a new (uncharged) battery can last for a relatively long time: 25-50 hours (depending on the state of the battery). How long a used battery will take to charge depends on its discharge rate, operating time and condition. A highly discharged battery may take 14-16 hours or more.

A maintenance-free battery is best charged using the constant voltage method. In any case, the voltage at the output contacts of the battery should not be allowed to exceed 14.4 V. The charge will be completed when the current drops to 0.2 A.

How and for how many hours to charge a car battery with constant voltage

To charge the battery in this way, it is necessary that the charger stably maintain a voltage of 13.8-14.4 V. In this case, the value of the charging current is set automatically based on the state of the battery (degree of discharge, electrolyte temperature, and so on). Practice has confirmed that with a constant voltage of the current source within the specified limits, a car battery can be charged in a state of any degree of its discharge and it will be automatically charged without abundant gas evolution and without dangerous heating of the electrolyte. The maximum charging current, even with a completely discharged battery, does not exceed its nominal capacity.

At a positive electrolyte temperature, the level of battery charging in the first hour increases to 50–60% of its capacity, in the second - up to 15–20%, in the third - up to 6–8%. In 4–5 hours, the battery should be charged to 90–95% of its nominal capacity. However, in each individual case, the time may be different. Battery charging will be completed when the current drops to 0.2 A.

It is impossible to charge up to 100% by this method due to insufficient voltage, since for the complete end of the charge, as indicated above (in the method with constant current), it is necessary to increase the voltage at the output contacts of the battery to 16.2 V.

The advantages of this method:

1. Provides a boost charge.
2. Ease of carrying out - it is not necessary to adjust the current during charging and you can charge the car battery on the car without removing it.

When operating on a car, the battery is also charged at a constant voltage (from the generator). Therefore, in "field" conditions, when the battery is planted, you can try to charge it from the mains of another car, if its owner does not regret the generator and the battery, the load on which will increase. However, this is a more gentle way to start than "lighting". How long it will take for such a charge to be enough to start depends on the outside temperature and on how much you have already managed to "torture" your own battery.

Expert opinion

Ruslan Konstantinov

Automotive expert. Graduated from ISTU named after M.T. Kalashnikov with a degree in Operation of Transport and Technological Machines and Complexes. More than 10 years of professional car repair experience.

During operation, many motorists try to charge the battery directly on the car, without bothering to remove it. Moreover, some do not remove the terminals at all, leaving the battery connected to the vehicle's on-board network while charging. Depending on the selected charger, the voltage can vary greatly and exceed 15 V. Even if you turn off the ignition and remove the key from the lock, this does not mean that all electricity consumers are de-energized. For example, car alarms and interior lighting remain fully functional even without the ignition on.
If you do not remove the terminals from the battery, increased voltage can be supplied to devices in standby mode, which, as a result, leads to their malfunction. If there are such devices in the car (and it certainly is in any car), charging is prohibited without removing the terminals. At the very least, you should throw off the negative terminal. When disconnecting the terminals, you do not need to first remove the positive one, the fact is that the negative one is connected to the vehicle's on-board network by connecting directly to the body. If you first throw off the "plus" the consequences can be the most dire. Any contact of metal tools with body parts can cause a short circuit. This is especially true when motorists unscrew the positive terminal fasteners without removing the "minus".
If you need to charge the battery at a negative temperature in a room without heating, then a similar procedure is allowed. During the charging process, the electrolyte in the jars heats up. However, if the battery was very discharged and the electrolyte in the banks froze, you first need to warm up the battery in a warm place and, if there is no damage (electrolyte leakage), start charging.

I periodically receive questions on my blog regarding charging a fully charged car battery. For example, I put the battery on preventive charging and forgot about it, the charger is not automatic and it took a very long time to charge the battery! What will happen, what are the consequences? Another popular question - the car generator always "feeds" the battery, even when fully charged, and if the trip is long, what will happen then? How does it all work? As you understand, today we will talk in relation to the car. I will answer all questions at once, as usual the video version at the end ...

Lead-acid batteries are installed on cars. Of course, now there are a huge number of technologies for their production (there are also options that are the most advanced now). However, charging a battery that is fully charged is not worth it, this can drastically reduce the product's life. There are a number of reasons for this.

Device

If the charging current is applied again, the sulfates are destroyed, and the density begins to rise again. Actually, this happens in a circle, this is a classic scheme of work.

Of course, now the electrolyte can be locked in special mats (AGM) or gel (GEL), but the essence remains the same. Lead plates are electrolyte.

What happens if you charge 100%

Bubbles begin to appear in the electrolyte, many say that it boils! However, this is not entirely correct (if you do not go into the theory of physics now and say everything in simple words), then - when the full charge and electrolyte density of 1.27 g / cm3 are reached, a working battery should begin to emit bubbles. This comes out "HYDROGEN" and "OXYGEN", which are released from the electrolyte during a chemical reaction. IT IS POSSIBLE TO REMOVE THE BATTERY FROM CHARGING!

That is, in simple words, it is water that begins to decompose, but not sulfuric acid. If the battery is left to simmer for a long period of time, the density will increase even more.

Over time, lead sulfates form on the plates, which must be broken.

Generator operation

Many wrote to me - after all, the generator always recharges the battery (this is how we figured it out badly for a fully charged one), so this system cripples itself?

Not quite right. Now in modern generators, and in older models, there was a very effective overcharge elimination system. Installed, which reduced the charge when reaching 100% (then it generally tends to zero). In modern systems, there is such that generally the supply of recharging stops and after the discharge, it is resumed again.

Therefore, on cars, it does not happen CHARGING AN ALREADY CHARGED BATTERY (in simple words, overcharge), it is completely cut off by the electronics (in this case, the relay). But if this happens, it means that the relay-regulator is not working properly.

That is why the batteries of normal manufacturers (how to choose) can go for a VERY long time. 5-7 years old

Put it on charge and forget

I don't know how this is even possible - YOU NEED TO BE CAREFUL ! YES, and now it's worth taking advanced chargers (at least the same one), they will automatically turn off when they reach 100%.

BUT it also happens - the charger is old (that is, it does not automatically turn off), and you forgot to turn it off. That is, the battery is charged, but the charge is all "figchet" and "figchit". Is it bad or not?

The very first thing is that it all depends on the capacity of the battery and the current strength. For example, if you charge a 200Ah battery with a current of 1-2A, then you will charge it for a VERY LONG time! But if it's 40 or 45 Ah, that's a little different.

The second - of course, overcharging is bad, but again, depending on what current you put it on, and how long it already costs. It usually happens that they bet on 1-2A (for 55Ah) and thus it costs a long time (for example, two days). Such a weak current cannot do anything terrible in a day. Well, the electrolyte will boil, well, a small part of it will boil off, you add distilled water to the norm and that's all. There won't even be an intense warm-up.

But if the current strength is 5-10 Amperes, then it is really already dangerous! Such a current can not only contribute to the "boiling away" of most of the electrolyte - exposure and strong heating of the plates (in a really short period of time, I am already silent about the days) - which will actually shorten the battery life (or even disable it). BUT, and most of the released hydrogen can provoke an explosion (as I also call cotton), because hydrogen burns quickly and strongly.