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:
The car battery provides power to the elements of the car. During its movement, it is charged using a generator. However, he will not be able to fully replenish the energy. Therefore, maintenance of the battery is periodically necessary. To do this, you should know how to properly charge a car battery with a charger at home.
Charger selection
The defining parameters are the characteristics of the battery - voltage (6, 12 or 4 V), battery type (flooded, dry-charged, gel and lead acid). For the latest quality, it is recommended to choose universal models suitable for all types of batteries. Additionally, the nominal capacity indicator is taken into account - Ah. 
By their functionality, the memory devices are divided into two classes:
- Chargers. Designed only to restore the battery's performance, it is possible to maintain the current charge at the required level.
- Start-up chargers. A significant charge of current is required to start the vehicle systems. If the battery has not had time to charge by this time, the starter-charger can replace it at this stage.
For beginners, it is recommended to buy simple charger models, without additional functions for adjusting parameters. If the car enthusiast has a lot of experience, he will need a professional charger with indication, the ability to adjust the current and voltage. Any model must have an option to protect against overheating, incorrect connection.
How often should the battery be charged
The frequency at which a battery is charged determines its useful life. Ideally, it should be connected to the memory no more than once a year. But in fact it depends on many external factors. If the frequency is incorrectly selected and there is no control over the current state of the battery, the opposite effect will be observed - a rapid decrease in capacity. 
Facts affecting the battery charging frequency:
- Temperature overboard. It does not affect if the indicator is more than + 5C. As soon as there is a decrease, the battery capacity can drop by 1.5-2 times.
- Possible malfunctions of the power plant. These include problems with compression, improper functioning of the fuel equipment.
- Full load frequency of the battery with the motor off.
The minimum battery charge for starting the power plant is individual. But usually it shouldn't be less than 12.3 volts. If this value is less, the charge will not be enough, you will need to connect to the charger. On average, 70-75% of the maximum charge is sufficient for normal battery operation. It is recommended to restore it to 100% once a year, before the beginning of the winter period.
Car battery charging methods
There are two main ways to charge a battery - by changing the DC current or voltage. The choice depends on the functionality of the charger, the need to control the process, its speed and the degree of charging. 
Before starting, you must fulfill the following conditions:
- Preliminary check of the actual capacity of the battery.
- Correct connection of terminals by polarity - "plus" to "plus", as well as "minus". Otherwise, there will be a reverse process - discharge.
- The minimum conductor cross-section is 1 mm2. The braided diameter should be about 1.3 mm.
- Cleaning the surface of the battery from acid residues, dirt.
- Unscrew the acid filler plugs.
- Checking the electrolyte level. If it is not enough, distilled water is added.
After that, you can start the charging process. It is recommended to do this in a room with room temperature and good ventilation. In the process of increasing the charge, electrolyte vapors will be released.
Constant current regulation
The essence of this method is to control the current value by regulating it depending on the current battery charge. For novice motorists, it is difficult, since changes in the indicator depend on the actual state of the battery. It is recommended to use it if it is possible to continuously monitor the process. 
It is best to consider the essence of this method using the example of a battery, the capacity of which is 60A * h. Recommended procedure.
- Set the current value to 6A, from a ratio of 0.1 to the rated capacity.
- After the start of electrolyte gas evolution, it is necessary to reduce the indicator by half. With a battery charge value of 14.4 V, the amperage should be 3 A.
- As soon as the charge indicator reaches 15 V, the current decreases to 1.5 A.
In this way, you can charge the battery to a level of 70% to 100%. In the latter case, it is necessary to control the value of the battery charge level and current strength. If the former remains unchanged for two hours, this is a sign of a full charge.
DC voltage change
The best way if there is no way to constantly monitor the process. It should be borne in mind that the value of the battery charge in this case is proportional to the supplied voltage. For a preliminary calculation of the time, the applied voltage must be divided by 1.11. 
Let's consider this process using the example of a standard 12 V battery, depending on the required state of charge for a duration of 24 hours:
- 75-80%. In this case, the supplied voltage must be 14.4 V;
- 85-90%. The optimum value is 15 V;
- one hundred%. The voltage parameter must be at least 16.3 V.
Important - the value of the charging current should not exceed 25 A. For this, the charger must be equipped with a circuit that limits this parameter. It is present in all factory models, but if a homemade device is used, this moment needs to be tracked.
Checking the battery charge level
In addition to the values of the parameters on the charger and the battery terminals, it is recommended to additionally monitor the density of the electrolyte. This is done using a special device - a hydrometer. 
For a standard battery, the following electrolyte density values are adopted, depending on the state of charge:
- 100% - 1.28 g / m3;
- 75% - 1.25g / m3;
- 50% - 1.20 g / m3.
It is important to check this indicator in all banks. If, for any reason, a short circuit occurs in one of them, the value of the density of the electrolyte will be much less than the rest. It is also necessary to take into account the error of the hydrometer, the degree of its suitability for verification, the range of measured values. Additionally, this device can be used to monitor the condition of the coolant.
Alternative ways
A proven method of restoring the battery performance without using a special device is "lighting" from another battery. It is important that the values of the current strength are the same for them. Otherwise, the fuses or part of the car's wiring will fail. 
This can be done according to the following algorithm.
- Direct connection to the battery of another car, observing the polarity, as when using a charger.
- After starting the engine, you need to wait 3-5 minutes and only after that you can disconnect the terminals. First from the "donor", and then from the battery of your car.
- The trip takes 20-30 minutes. The best charging will be when activating higher or lower gears. The recommended number of crankshaft revolutions is from 2900 to 3200.
This method will be effective if the charging level in the battery is not lower than the critical one. Otherwise, starting the engine and on-board systems will be impossible.
It is also not recommended to use homemade chargers made on the basis of household charging blocks from a laptop or mobile phone. It is practically impossible to monitor the main values of current and voltage during the charging process. This can lead to negative consequences. It is best to purchase a cheap but reliable factory model of the charger.
It is very important for every car owner that the power supply to his car is reliable. For this, a special device is intended - a battery, which needs periodic recharging. Those who do not know how to charge the battery on their own need to heed the advice of professionals. If you visit a battery store, you will get expert advice. You will learn the principle of operation of this unit, whether its capacity is sufficient for your machine, whether it has a long service life.
The main features of the charging process
Do you want to learn how to charge the battery without assistance? Then you need to observe some parameters, the implementation of which is mandatory.
First, determine the nominal energy capacity of the device. The optimal current strength should be no more than 10% of the nominal value. At the charging terminals, the permissible voltage level is + 10% of the nominal value of the battery.
If you want to charge the battery at an accelerated rate, do not use this solution, as the device will be damaged. This process is performed by currents of high values of 20-30 A.
Gel batteries should be charged without exceeding the critical voltage for this type of battery - 14.2 V.
These criteria are fundamental to efficiently charging a car battery.
A cycle of preparatory actions
First, make sure that the battery is really discharged. Discharge can occur due to operating errors or damage to the case. If the integrity of the device is violated, the electrolyte will leak out, and the chemical reaction will not occur. A damaged battery cannot be used. Therefore, before charging the battery, it is removed from the niche, cleaned, and carefully examined.
A color indicator is installed on the cover. It is used to determine whether the resource has actually been exhausted. There is a sticker next to this identifier explaining what the colors in the picture mean.
The condition of the battery can also be checked by measuring the voltage at the terminals with a conventional tester. The discharge of the battery will be indicated by a voltage indicator with a value lower than the nominal.
It is also necessary to check the condition of the electrolyte, its amount. The liquid must be clean and transparent. Its level should be slightly higher than the plates. If it is lower, you need to top up the distalate.
The ventilation hole on the battery cover must be clean, otherwise vapors cannot escape.
We carry out charging correctly
Be aware of harmful electrolyte fumes before charging the battery. It is not recommended to carry out these works in a residential area.
First, the charging is connected to the battery, and then to the network. This must be done correctly, otherwise the charger fuses will fail.
The charging procedure is performed in 2 ways. At the first time, work is performed at a constant rate of 14-16 V. But since the current strength is a variable value, at the beginning of the process it can be at around 25-30 V, and then gradually decrease.
The second option is a little more complicated. It is performed with a varying voltage with a constant amperage, a device that operates in a constant voltage manner.
The current strength of 10% of the battery energy capacity is set by the regulator. The signal about the complete recovery of the battery will be the arrow on the ammeter in the "0" position. This operation will take about 13 hours.
The method of recharging with such a device requires special attention: with the given parameters, the battery must be charged to a value of 14 V, then the current is reduced by 2 times. After that, the charge level should be 15 V, and the current is reduced by another half. Holding the pointer on the indicator scale at the same level for about 1 hour indicates the end of the process.
Having mastered the information on how to charge the battery, you must also understand that the full charge of the battery can be checked with a load plug on the terminals. If this device is not available, install the battery on the car. The starter should briskly start the power plant.
Each battery store in Minsk, which is easy to find with the TAM.BY catalog, will be glad to offer you a wide selection of batteries and chargers.
Does every car enthusiast know how to properly charge a car battery? Of course, anyone can say: what can be a layer here ...
From Masterweb
25.04.2018 23:01During the movement of the vehicle, a generator serves to power the on-board network. However, when the engine stops working, the entire load is transferred to another device, referred to as a battery (accumulator). And in order for such a source of electrical energy to last as long as possible, it is necessary to properly charge the car's battery.
Within the framework of this article, we will analyze such points as: the need to properly charge the battery, what types of it exist, and also touch upon, in fact, the charging rules themselves.
A little theory won't hurt
The car battery serves as the main source of energy for starting the starter motor, which in turn “turns on” the engine. It also maintains the efficiency of the on-board network when the generator is not running.
In the summertime, the start of the power unit is also possible with a 50% charged battery. However, in winter, the battery capacity is half as much due to the fact that the grease thickens, and this leads to an increase in starting currents.
Therefore, such a storage battery is unlikely to be able to start the engine, except to use the method of lighting it from another vehicle. For this reason, the car battery must be charged by the charger before the cold weather sets in. But what, in fact, is the reason for the need for proper charging? This will be discussed further.
What is the need to properly charge the battery?
A battery with a working car can last 2 or 3 years, which usually ranges from 70 to 100 thousand kilometers. Keeping the battery charged can increase its service life. At the same time, it is recommended to charge the battery when it is discharged by half or more.
It is worth remembering that the storage battery itself does not generate electrical energy, but accumulates it and subsequently feeds the vehicle's on-board network. While the vehicle is moving, the charge is restored, and a generator driven by the crankshaft of the engine serves as a source for recharging the battery.
Excessively frequent discharging and charging cycles of the vehicle battery adversely affect its technical condition. Not only does the charge level decrease, but the battery is gradually discharged. And over time, this charge is no longer enough to start the engine. Then it becomes necessary to charge the battery, due to which the efficiency of the power source is restored. For this, a charger (charger) is used.
However, before proceeding to familiarize yourself with all the subtleties, it is worth studying what types of batteries exist, what main characteristics they have, what is the feature and operation of the chargers. We will also touch on some equally important points and what is not recommended to do.
Varieties of battery
The following batteries are currently produced:
- Alkaline.
- Acidic.
- Gel.
Moreover, each of them has its own characteristics of charging a car battery. In alkaline devices, it consists in using a nickel-iron or nickel-cadmium tandem, which is used for the production of plates. The cavity of the battery housing is filled with caustic potassium. But due to the lower current strength, such batteries are practically not used, unlike other analogs.
The electrodes of acid batteries are made from lead and a number of impurities. This decision has a good reason - this metal can deliver more current for a short period of time. Plus, it has excellent energy capacity. An acid solution acts as an electrolyte here. As practice shows, such batteries are popular among a large number of vehicle owners.
Gel batteries can be considered a kind of innovation. In fact, this is the same acidic version, only the electrolyte is in a jelly-like state. And in fact, charging a car battery at home of this type is practically no different from the procedure with acid analogs.
Such know-how of the automotive industry holds much more promise. At the same time, its widespread use is limited by a number of factors. And this is mainly due to technological features. In addition, not every car enthusiast likes their cost, which is too high for most consumers.
Serviced and unattended batteries
In addition, rechargeable batteries are divided into two more types:
- Maintenance-free - these include closed-type batteries, and their cases are completely sealed. Due to this, there is no access to the internal parts: it will not work to unscrew something or just look. At the same time, if you accidentally turn it over during operation or when charging a car battery at home, electrolyte will not leak out. As a rule, these are gel batteries.
- Serviced - as you might guess, these are the batteries that have access to the contents of the cans. To do this, each of them has a twist-off plug. This category includes acid batteries.
More than a century has passed since the very first battery appeared (about 140 years), and in our modern world it is impossible to imagine how to do without such power sources. Indeed, in addition to cars, this type of battery power a variety of devices: from phones and gadgets to complex systems in various spheres of human activity, including space.
Something about the charger
What is the charging of the car battery? When we are faced with the need to buy a charger for a mobile phone, we usually do not have such a question. It would seem that it is the same with car analogs, and the problem of choice as such simply does not exist. However, this was relevant 2 decades ago. Then the chargers differed from each other only by the brand and the body.
Now everything is different, and the differences between modern devices are more pronounced. And the first thing I want to note is the way of charging the car battery. According to this feature, the battery can be:
- With manual adjustment.
- Automatic.
Despite the fact that hand chargers are already a classic, many car enthusiasts still prefer them. In this case, it is always possible to control the entire process and, if necessary, intervene, adjusting the current based on the state of the battery. But, in addition to charging the car battery with a charger, it is possible to perform sulfation recovery.
About automatic chargers, and so everything should be clear. The restoration of the battery capacity takes place without human intervention. The simplest and, accordingly, inexpensive chargers are even devoid of measuring instruments, and the end of the procedure is signaled by an LED. For those car owners who prefer to rarely look under the hood, this is the best solution. But here it is worthwhile to understand that working in accordance with the given algorithm, the state of the battery is not taken into account. In addition, the cost of such devices may not be affordable for everyone.
Also, the chargers can be separated depending on the design:
- Transformer - made on the basis of a familiar voltage transformer with a minimum number of active elements. This made it possible to achieve high reliability and increase in size.
- Pulse - due to the alternating current of charging the car battery with a high frequency, it became possible to significantly reduce the dimensions of the devices. On the one hand, this is an undoubted advantage, but on the other, the high cost and complexity of the entire structure.
The simplest charger consists of a step-down transformer and a diode bridge. It will not be difficult to understand the principle of operation: the primary winding takes on an alternating voltage of 220 V, after which it is reduced (converted) and directed to the diode bridge.
At the output, we get the required 14-16 Volts, which is enough to charge the battery.
Basic but important rules
To be successful in charging your car battery, there are important points to keep in mind:
- In order to determine the level of the charging current, the capacity of the battery can be guided. As a rule, 10% of the nominal battery rating is enough. For example, if the battery capacity is 55 Ah, therefore, 5.5 Amperes is the charging of the car battery.
- It takes a certain amount of time to fully charge the battery. However, do not resort to quick options using a current rating of 20-30 amperes. Ultimately, this only leads to the destruction of the battery.
- For gel batteries, the limit is 14.2 Volts, it is highly not recommended to exceed it.
- Before connecting the charger, it must be disconnected.
- When connecting, observe the polarity (plus to plus, minus to minus), otherwise both devices (battery and charger) may fail.
It is also necessary to ensure that the voltage at the charger terminals exceeds the battery rating by 10%. For a better understanding, let's give an example: if the voltage of the battery terminal is 12.8 Volts, then it must be maintained within 14.08 V, which is these 10% (12.8+ 1.28).
Knowing these basic rules, you can avoid many mistakes when charging a car battery at home. Do not forget about safety precautions, because this event is a chemical process, during which an explosive mixture of gases (hydrogen and oxygen) is released. In this regard, you need to be careful.
Battery check
Before proceeding to charge the battery, you need to make sure that it is completely discharged. There are several ways to do this. Most batteries have a special indicator, which is, in fact, a hydrometer. He independently measures the density of the electrolyte and, depending on this, one or another ball floats up. This is what we see, mistaking it for a light bulb. And when everything is normal, a green "light" is visible, otherwise it will be red.
Another way to check the battery before charging the car battery is to use a multimeter. A fully charged battery has a terminal voltage of about 12.6 volts or more. Other values correspond to:
- 12,5 – 90%;
- 12,42 – 80%;
- 12,32 – 70%.
- 12,2 – 60%;
- 12,06 – 50%.
- 11,9 – 40%;
- 11,75 – 30%.
- 11,58 – 20%;
- 11,31 – 10%.
- 10,5 – 0%.
But a more reliable method is a load plug, which will show the voltage drop under load. In other words, you can see the real indicator of the battery charge level.
This device can be found in every auto electrician, or in any store that sells batteries. Most likely, such a check can be done for thanks, nothing more.
From theory to practice or preparing the battery for charging
After the complete discharge of the battery has been determined, it is worth going directly to practice. But before that, a small preparatory stage is needed. The first step is to remove the battery from the car, but if there is not much time to charge the car battery, then you should disconnect it from the on-board network.
At the same time, you can diagnose it, examining its condition well, simultaneously cleaning it from dust and other contaminants. In this case, it is worth paying attention to whether there are cracks and electrolyte leakage. If any, further operation of such a battery is highly discouraged.
If everything is in order, it is worth cleaning the terminals to ensure good contact. You can also wipe the battery case with a cloth soaked in a solution of ammonia (10%) or soda ash. After that, you need to unscrew the plugs or remove the plugs. Electrolyte vapors will escape unhindered to avoid overpressure.
Charging the vehicle battery correctly
There is nothing complicated in the battery charging procedure itself, but not everyone knows how to do it in the right way. It is advisable to carry it out in a room with good ventilation, away from open flames.
In this case, you can go in two ways:
- Constant voltage (14-16 Volts) with alternating current. At first, its value is 25-30 Amperes, but subsequently gradually decreases as the battery is charged.
- The voltage changes, but the current remains unchanged. Only this approach is quite complicated, because accuracy is important here.
The first method is very easy to implement and all that is needed is to set the required current value, which is 10% of the battery capacity. As a rule, this parameter is indicated in the passport or in the plate on the case. As the battery charges, the current will decrease. On average, the time it takes to fully charge a car battery is 10 to 13 hours.
The second method is already more complicated, and it is necessary to clearly understand how everything is done. The first step is to set the current value (10% of the battery capacity). It should be adhered to until the voltage reaches 14 volts. When this is achieved, the current should be halved until it is already 15 volts. And as soon as this voltage is established, the current must be reduced three times. A full charge of the battery will be indicated by a constant voltage level on the indicator.
At the end of the procedure, it is advisable to check the battery with a load plug. If it is absent, you can make sure that the battery is working properly by installing it in place and connecting it to the on-board network. Success will be to start the engine.
Service and maintenance issues
In order for the battery to serve for a long time, it is not only necessary to properly charge it, but careful care of it is also important. And this requires regular maintenance. The first step is to understand one proven fact: in the summer, liquid from cans evaporates more intensively. And if the battery case is translucent, then a decrease in the electrolyte level below the normal range will be clearly noticeable. Of course, if the driver is interested not only in what should be the charging voltage of the car's battery, but even occasionally looks under the hood.
As a rule, there are special marks on the car battery: "MIN" and "MAX", which allow you to control the amount of liquid. However, there are batteries where they are not available, or for some reason it is impossible to visually determine the electrolyte level. Then you should use a simple method:
- Unscrew the caps from each jar and, in turn, lower the glass tube into each of them. Its length must be at least 10 cm.
- After the tube rests against the mesh, it is worth pinching its end with your finger and pulling it out.
- Measure the resulting distance. Normally, it should be from 10 to 15 mm. If it is less, then you need to add distilled water to the required level.
In addition, the density of the electrolyte should be measured, for which a hydrometer is used. This device looks like a large graduated pipette. There is a float inside that can move freely. A rubber bulb is attached to one of its ends.
To measure the density of the electrolyte, you first need to squeeze the pear - all air will be removed from it. The other end is immersed in a jar of liquid, after which the pear can be released without haste. The float will begin to float, and the division at which it stops will be the value of the desired density. In addition to this, there are other hydrometer designs.
Now with regard to directly the values of the density of the electrolyte. It is different for each climatic zone. In summer, for the central regions, the optimal density value should be in the range of 1.27-1.19 g / cm3. For the southern and northern ones - 1.25-1.17 g / cm3 and 1.2-1.21 g / cm3, respectively. Lower density values indicate the need to charge the vehicle battery. If they are higher, then you need to add distilled water.
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New car owners don't care about battery power. Of course, if the equipment is operated in accordance with the instructions. But after 3-5 years, the battery wears out and can fail at the most inopportune moment.
Or you've been listening to music in the garage for too long with the engine turned off. Or maybe they left the headlights on for the night. There are enough reasons for an unplanned battery discharge.
And it is far from always possible to "light up" from another car, and restore performance from a standard generator. To do this, you will have to drive several hundred kilometers at high speeds.
There is no need to despair. You can always charge the car battery with a charger, even if the voltage level has dropped below a critical one. Therefore, such a device should be in the arsenal of a motorist.
How to properly recharge the battery?
There is no universal answer to this question. The general rule is as follows: Continuous charging with a lower current is more beneficial for the battery than boost charging with a high current. However, such a regime is not always possible. Sometimes it is necessary to urgently restore working capacity before leaving.
How long does it take to charge the car battery so as not to overcharge? Details in this video
And the standard charging system is far from perfect: even with normal operation of the voltage regulator, the duration of the trip is different. As a result, the battery on the operated car is charged in jerks, haphazardly.
There are several ways to charge autonomously
Optimal charge current
Should not exceed 10% of the battery capacity. That is, if you have a 60CT battery (60Ah capacity), the correct charge current should not exceed 6A. With this current, you charge the battery if there is a lot of recovery time.
Important! Allowance must be made when charging maintenance-free batteries. Since the electrolyte vapor outlet valve is too small, the current should be reduced to 5% of the capacity. Otherwise, in case of boiling, the battery may crack.
Express method
If you need to quickly charge the battery with the charger (urgent departure), you can quickly restore the capacity sufficient to start the engine.
In this case, the charge current is 25-40% of the capacity. You will inform the battery of the required charge in 30-50 minutes. But this method actually kills the battery plates. Therefore, it can be used only in exceptional cases.
Important! With an accelerated charge with high currents, the plugs of the battery cells must be unscrewed. It is dangerous to charge maintenance-free sealed batteries in this way.
Minimum current
Just enough to overcome the internal resistance of the battery. With this current, you can charge the battery for several days, or maintain the charge level during storage.
Important! With any charging method, it is unsafe to leave the battery unmonitored. Even if you have a smart charger, the automation can fail.
How to determine the charge capacity? By voltage at the contacts of the battery.
Battery EMF table in volts at temperature:
+20 ... + 25 ° С -5 ... + 5 ° С -10 ...- 15 ° С Battery charge level,% 12,70 – 12,90 12,80 – 13,00 12,90 – 13,10 100 12,55 – 12,65 12,65 – 12,75 12,75 – 12,85 75 12,20 – 12,30 12,30 – 12,40 12,40 – 12,50 60 12,00 – 12,10 12,10 – 12,20 12,20 – 12,30 25 11,70 – 12,00 11,80 – 12,00 11,90 – 12,10 no charge
EMF is measured without load on the battery contacts. Be sure to consider the temperature. The readings in the table may differ slightly, this is not essential. By determining the percentage of discharge, you can correctly calculate the charging time and current.
For example, a 60 Ah battery. At a temperature of + 5 ° C, the EMF at the contacts is 12.4 volts. This means that the battery has lost 50% of its capacity. With a charge current of 6A, it will take 5 hours to charge.
Set the value of the current on the device and note the time. At the end of the calculated set of capacity, measure again. Just let the battery cool down a little to determine the exact value of the EMF.
The electrolyte heats up during charging, and with a thermometer you measure the temperature of the surrounding air.
Another way to determine the residual capacity of the battery is to measure the density of the electrolyte.
| Electrolyte density | Charge rate% | Freezing temperature ° С |
| 1,27 | 100 | -60 |
| 1,23 | 75 | -42 |
| 1,19 | 50 | -24 |
| 1,15 | 25 | -13 |
| 1.11 and below | -7 |
The value of the freezing temperature is no less important than the voltage at the battery contacts. As the discharge proceeds, the temperature of the transformation of the electrolyte into ice rises.
If a fully charged battery can withstand frost of -60 ° C, then with a charge of 25%, the electrolyte will freeze already at -15 ° C. A crack will form on the case and the electrolyte will enter the engine compartment.
