Maximum car battery charging current. How to properly charge a car battery

07.06.2018

Each car owner knows that the vehicle requires increased attention. It is necessary to change the oil in time, to carry out technical inspection of the car. And at the end summer season car owners have a question: how to properly charge a car battery? Let's consider this process in more detail.

The batteries are charged from a rectified current source. It is allowed to use various rectifiers that allow voltage regulation or charging current. There are 2 methods of charging the battery: at a constant voltage or at a constant current value. Both methods have the same effect on battery life. When choosing a device for charging car batteries, you must be guided by the information below.

Charging at a constant current value

Batteries must be charged with a current that corresponds to 1/10 of the rated capacity. To keep the current at the same level, you need to use a regulating device. This method has a disadvantage. Every 2 hours it is necessary to adjust the current strength, and at the end of the charge, abundant gas evolution is observed. To reduce it, you should step down the current strength when the charging voltage increases. Many drivers are interested in car battery charging time. If the nominal capacity is 90 Ah, it will take about 10 hours to charge.

If the voltage has reached 14.4 volts, then the charging current must be halved. If the battery has a capacity of 60 Ah, then the current strength will be 3 A. At this current strength, the charge continues until the moment when gas evolution begins. If the batteries do not have holes through which water can be added, then the current can be reduced by a factor of 2 at a voltage of 15 volts. The battery is 100% charged if the voltage and current during the charging process are unchanged for 1-2 hours.

Constant voltage charging

How to charge a car battery in this way? The battery voltage at the end of charging depends on charging voltage. If the voltage is 16 volts, then the battery will be almost completely charged in a day. When the current is turned on, its strength can be over 50 A. It all depends on how much capacity the battery has. That is why the charger has circuit solutions that keep the current limit in the range of 20-25 A.

During the charging process, the voltage at the ends of the battery becomes the same as the voltage of the charger. The charging current of the car battery is reduced, tends to zero. Thanks to this, the charging process takes place without human intervention. The criterion for the end of the charging process is a voltage of 14.4 volts at the ends of the battery. A green signal also lights up, which signals the completion of the process.

Part of the car battery charging circuit is a compound transistor. It may belong to the KT827 series. The output voltage is then determined by a variable resistor. The output current of such circuits is determined by the power, the type of transformer. Their minimum power is 200 watts. The transformer has 3 main terminals.

Some charger circuits are thyristor controlled. It passes due to the phase shift. Such schemes are quite simple. The design can be mounted in a conventional hardboard. Thyristors, as well as diodes, must be mounted on a heat sink. This is how it turns out charging a car battery with your own hands.

Charging with solar panels

The solar panel is installed on the dashboard of the car. It is connected to the cigarette lighter socket. Such a device is very useful during long-term parking vehicle to charge the battery. This is especially true in winter. Due to the correctly selected power of the module, a charge controller is not needed. To solar charge a car battery, a solar battery with a power of 6 watts is required; cable connected to the on-board network of the machine; decoupling diode.

Such a module can charge a battery, the capacity of which is not more than 75 Ah. A charge controller is not required.

If you need to recharge the battery all day, then you need to use a different module. Its power does not exceed 60 watts. For such cases, you need to use a charge controller. It will protect the battery from overcharging. Thus, the car battery will be properly charged.

The winding itself (which plays the role of the primary winding in an uninterruptible power supply) here we will have a step-down, that is, a secondary one. The transformer is a conventional step-down network transformer, in this mode of operation, an alternating voltage with a nominal value of 24 Volts 8-15 Amperes is formed at the terminals of the secondary winding, depending on the power of the transformer.

Battery charge on the car

When the battery is used in a car, it is charged at a constant voltage. Car manufacturers, in agreement with battery developers, set the charging voltage level to 14.1 ± 0.2 V, which is lower than the intense gas evolution voltage. With decreasing temperature, the charging efficiency at constant voltage decreases due to an increase in the internal resistance of the battery.

Therefore, the battery in a car does not always fully restore its capacity after a discharge. Typically, the state of charge of the battery in winter is 70-75% if the voltage at the battery terminals is 13.9-14.3 V with the engine running and high beam on. Therefore, in difficult conditions winters (when low temperatures, frequent and long starts of a cold engine and short runs) it is advisable to periodically (preferably at least once a month) charge the battery from a stationary charger and at a positive temperature.

For a fully charged battery, the density of the electrolyte is 1.28±0.01 g/cm3. Decreasing linearly as the battery is discharged, it is 1.20±0.01 g/cm3 for batteries whose state of charge has decreased to 50%. A fully discharged battery has an electrolyte density of 1.10±0.01 g/cm3.

If the density value in all batteries is the same (with a spread of ± 0.01 g / cm3), this indicates the degree of charge of the battery and the absence of internal short circuits. In the presence of an internal short circuit, the electrolyte density in a defective battery bank will be significantly lower (by 0.10-0.15 g/cm³) than in other cells.

To measure the density of liquids, hydrometers with interchangeable densitometers are used to measure the density of various liquids, for example, antifreeze with a density of 1.0 to 1.1 g/cm3 or electrolyte with a density of 1.1 to 1.3 g/cm3.

When measuring, the float must not touch the walls of the cylindrical part of the glass tube. At the same time it is necessary to measure the temperature of the electrolyte. The density measurement result is brought to +25°C. To do this, it is necessary to add or subtract the correction indicated in the special literature to the readings of the densitometer.

If during the measurement it turns out that the NRC is below 12.6 V, and the density of the electrolyte is below 1.24 g / cm3, the battery must be recharged and the charging voltage at its terminals should be checked with the engine running.

How to properly charge car battery(battery) charger. Instructions for dummies.

The battery should be recharged in the following cases:

• Battery low
• Once a year
• Before frost
• Have nothing to do

The battery should be charged if it turns the starter unsteadily,
the voltage on the battery of an unstarted car is approaching 12.0 volts,
indicator light (if present) indicates the need for charging.

small runs and insufficient voltage from the generator may not provide a full charge. Therefore, for prevention, it is recommended to fully charge the battery once a year.

Frost has a detrimental effect on the battery. The self-discharge increases. A discharged battery has a low electrolyte density. He may freeze. The liquid, as you know, expands when freezing, the frozen electrolyte can close and destroy the battery plates, after which the battery becomes unusable very quickly - it has a low capacity and can fail, even if it shows good voltage.

To charge the battery, you will need a charger, it can be voltage controlled, current controlled, allow you to select one of these options, or be fully automatic. We will consider a charge with current or voltage control.

If the battery was in the cold, it needs to warm up. It is not necessary to wait until it is completely warm to start charging. If the battery is not discharged to zero, you can start charging, but by the end of charging it should be at room temperature. If you do not have time to warm up - recharge after warming up. If it is discharged to 0, warm it up first.

We wipe the battery with a rag, unscrew the plugs, often they are under a removable plastic plate. Keep dirt out of the jars.

Check the electrolyte level. If it is below the marks on the body or even worse, it does not close the plates, add DISTILATED water to the required level.

Turn all knobs on the charger to the Min position. We throw a positive + terminal. Slightly rotate it from side to side - for good contact. We throw on the negative - terminal, turn it slightly from side to side. Plug the charger into the network.

We look at the marking with the capacity of the battery, for example 55 ampere hours. Multiply the capacity by 0.1 and get the battery charging current. 55 * 0.1 = 5.5 A

The charging voltage for 12V batteries should not exceed 14.7-14.9 volts.

So we got 2 values ​​\u200b\u200bnecessary for charging.

When charging, you need to control that the current and voltage do not go beyond these values.

DC charging
We set the appropriate current, maybe a little less. If the charger is automatic, it will maintain this current by itself by changing the voltage. The voltage will gradually increase. If the charger is old, not automatic, you need to monitor the devices and turn the knob increasing the voltage to manual, keeping the current at the required level. The voltage in this case should not exceed 14.9V.

Constant voltage charging
With this scheme, the charger holds a given voltage, for example 14.7 volts, but limits the current. The work process is similar. During such a charge, the voltage will be constant, and the current will drop. The automatic charger will automatically maintain the set current for the voltage. If the device is not automatic, you need to turn the knob so that at a voltage of 14.7 V, the current for our example does not exceed 5.5 A but is not lower than 1 ampere.

You can charge with lower currents, the charging time will increase. Currents higher than the capacity x 0.1 should not be charged, this has a detrimental effect on the battery plates.

The charge is over if, at a voltage of 14.9V, the current strength does not change within an hour. It will be less than 1 A. In the banks, at the same time, the release of bubbles will be visible.

If you have a hydrometer, it should show the density corresponding to the charged battery.

If the battery capacity does not suit you, you can try to train it.

Method 1 - discharge the battery with a light bulb to 11.9V and fully charge it

Method 2 - charge with a current of different directions. This eliminates the sulfation of the plates (a kind of plaque that prevents normal operation). For the second method, you need a special charger with a similar function. For example, the "cycle" mode. The meaning of the mode is that the charge voltage is periodically applied and removed. Read more about the mode in the instructions for the charger. If the device works semi-automatically in this mode - for example, you need to attach a light bulb and set the current yourself, then you need to make sure that during operation the voltage does not fall below 11.9 and does not rise above 15, if this is not provided for in the instructions.

Happy battery charging!

Every car owner who has to from time to time should know what kind of current. Inexperienced motorists think that in order to recharge the battery, you just need to connect it to the charger and turn it on, but this is not entirely true. This process requires compliance with certain rules, which we will discuss below.

General principles of battery charging

What should be used to charge a car battery 60A? Before proceeding with the charging procedure, you need to familiarize yourself with the technical characteristics of the battery used. You also need to study the characteristics of the charger. Regardless of the characteristics of the battery used, it is desirable that the charge current or voltage be constant. In the event that you do not know how to limit the signal yourself, you can add a rectifier element to the connection circuit, which is used to adjust the voltage value.

When buying or renting a charger, you should also carefully study all technical features and characteristics of the device. This is important because the memory may have certain capabilities. For example, if the charger is going to be used with a 12-volt battery, then most devices can increase the voltage to 16 volts if necessary. This is usually done to restore the performance of unserviced batteries.

Do-it-yourself ways to restore the charge

How to charge the battery with a small charging asymmetric current in accordance with the diagram? In practice, there are two methods to accomplish this task - either use a constant current or a constant voltage value. In this case, there are no special differences in these methods - each of the methods is considered complete and effective. Naturally, if during their implementation all the necessary points and nuances are observed.

Method 1 - at constant current

First, we suggest that you familiarize yourself with the first way to resume battery health by using constant force current. Distinctive feature of this method, it is considered that the owner of the vehicle needs to periodically monitor the value of the parameter on the charging device. And if necessary, the current will need to be adjusted. Usually, the process of diagnostics and verification is carried out once every 1-2 hours, but it is desirable not less often (the author of the video is the Nizhny Novgorod battery worker channel).

What is the best current to use to implement this method? The process itself is carried out taking into account a constant value - the value should be about 0.1% of the entire car battery capacity. At this current, the battery will be discharged within 20 hours. That is, if it is 75 Ah, then the amount of current to restore the battery charge should be about 7.5 amperes. How to limit this value - most modern chargers have a special regulator, you can use it to limit the value of the parameter.

It also needs to be said separately about maintenance-free batteries. When the operability of such a device is resumed, it is necessary to increase the voltage value when charging up to 15 volts, while simultaneously reducing the current value by 50%. That is, if the capacity of the device used is 60 Ah, then the current value should be set at 3 amperes. The fact that the car battery is fully charged can be recognized by the fact that for 1-2 hours when charging, all operating values ​​remain unchanged. If the device itself is out of service, then the recovery procedure can be completed when the voltage on the device is equal to 16.4 volts.

The second way - at a constant voltage

Another method - at a constant voltage, is not more difficult to implement and no less effective.

The charging procedure must be carried out for at least 24 hours:

1. The device is dismantled from the car, for this all terminals are disconnected and the clamps are disconnected.
2. The battery is removed, the probes of the charger are connected to its terminals.
3. Then, you will have to wait, as mentioned above, about a day. After that, you should check the parameters on the display of the memory (the author of the video is the Accumulator channel).

How to understand that the battery is charged:

• in the event that the voltage parameter is 14.4 volts, then over the next day approximately 75-85% of the battery charge can be restored, but in this case a lot depends on the characteristics of the battery;
• if the voltage parameter varies around 15 volts, this indicates that the battery is replenished by about 85-90%;
• when the voltage parameter is about 16 V, then we can conclude that the battery is approximately 95-97% charged, that is, its further operation, in principle, is already allowed;
• if you want the device to recharge to the maximum, then it will take no more than a day to complete this task, a voltage of 16.3 V can report a charge.

If you are the owner of a more modern charging device, then its case may contain special indicators- light bulbs - with which you can determine the completion of the process. When the battery is ready for use, the indicator will light up. in green. If its color is red, then the procedure is either not completed, or there were problems during the execution, more detailed diagnostics are required. Many battery experts claim that unattended batteries need to be recharged to approximately 95%, this option is considered the most relevant. In this case, the battery will be able to fully work out its entire service life, but at the same time it is necessary to ensure that the voltage parameter is not less than 14.4 volts.

Photo gallery "Battery malfunctions"

Conclusion

Everyone needs a boost modern battery, regardless of what its cost is and what manufacturer it was released by. Timely completion of this task will significantly increase the service life of the device used. It is especially important to perform such a procedure before the onset of cold weather, as well as after winter. Do not forget that when recharging a serviced battery, it is imperative to unscrew the plugs on its banks.

In the event that you do not do this, then high pressure may form in the banks, and this, in turn, can lead to an explosion. You should not completely remove the plugs directly, you can loosen them a little.

If you encounter a discharge problem too often, then you need to diagnose the device. First of all, it is necessary to check the case for damage, the operability of the terminals. In a device with a damaged case, there may be an electrolyte leak, which will lead to its constant discharge. It is also necessary to check the level of the electrolyte solution - ideally, the liquid should cover all the banks, if this is not the case, then distilled water must be added to the system. All this must be checked before starting recharging.

Video "How to increase the density of the working fluid?"

How to increase the density of the electrolyte in the banks of the device with your own hands and what is required for this - look for the answers in the video below (author - Denis Legostaev).

At first glance, it may seem that charging a battery is simple procedure. It would seem that there is such a thing - you just need to connect the battery to the network and wait until it is 100% charged. However, there are some nuances in this matter that must be taken into account. How much current should a car battery be charged? Below you will learn about it.

General principles of battery charging

In order for a charged battery to function for a long time, it is necessary to use a good and necessary current. The current strength of a 60 Ah battery in a car should not exceed the norm, otherwise the motorist may encounter certain problems. It should immediately be noted that charging car battery not so difficult, especially if you understand something in chemistry and physics. Before you charge the battery, you must carefully examine it operational features and properties.

It is also necessary to study the characteristics of the memory itself, but the most important point- is to know what current is better to charge the device at 60 Ah or any other. First of all, remember that in any case it must be constant. If you do not know how to limit this impulse, you can use special rectifiers. These devices are necessary to adjust the voltage and other indicators.

When buying or renting a memory, you need to carefully read its characteristics and capabilities. For example, the charger required to work with 12-volt batteries allows you to increase the voltage level to 16.6 volts, if necessary. As a rule, this is required in order to charge any maintenance-free device.

Methods for charging car batteries

So, if you decide to independently charge the charge current through the car battery at 60 or more Ah, it will be useful for you to familiarize yourself with the methods for carrying out the procedure. In practice, two methods can be used for this purpose - either at a constant current or at a constant voltage. Fundamental differences there are none in these methods - both methods are complete. Of course, when right approach and compliance with all technologies.

Method 1 - at constant current

To begin with, consider the scheme for charging the battery of a passenger car or truck with this parameter constant. One of distinctive characteristics This method is that the car owner needs to control the parameter on the memory from time to time and adjust it if necessary. As a general rule, the inspection and control procedure should take place every one or two hours, but not less frequently.

How much current to charge a car battery? The procedure for charging a car battery is carried out taking into account the constant value of the above indicator. This parameter is equal to 0.1% of the total capacity of the battery when it is continuously discharged for twenty hours. Accordingly, if the capacity is 60 Ah, then the current for charging the device should be 6 amperes. To maintain the constancy of this indicator throughout the process, it is necessary to use the regulator, which is equipped with many memory devices.

To make the vehicle battery charge level higher, experts advise using the stepwise reduction of the impulse strength function. The activation of the step-down function is relevant when the resistance indicator begins to increase.

Separately, recommendations regarding unattended devices should be highlighted. latest generation. In this case, you should increase the voltage parameter to 15 volts, while reducing the current parameter in the car battery by half. In other words, if the capacity of your device is 60 Ah, then the low current parameter should be set to 1.5 amperes.

After charging the battery with an asymmetric current, the device can be considered ready for operation when all parameters remain unchanged for one to two hours. In the event that the device is out of service, then the corresponding state will occur when the voltage level is 16.4 volts (the author of the video is Learning to drive a car. All secrets for beginners).

Method 2 - at constant voltage

What current to choose in this case? This method completely depends on the value of the above parameter provided by the device for charging.

If you recharge the battery throughout the day, the process will be carried out as follows:

• if the voltage level is 14.4 volts, then in 24 hours about 75-85% of the charge will be replenished, depending on the characteristics of the unit;
• if the above indicator is about 15 volts, then the device’s charge level will be about 85-90%;
• in the event that the parameter is 16 volts, the vehicle battery will be able to charge approximately 95-97%;
• to fully charge the device, it will take at least 20 and no more than 24 hours, while the voltage level should be 16.3 volts.

To understand that the device is fully charged, the main indicator for this will be the voltage level at the outputs of the device. This value should be 14.4 volts. If the charger is equipped with a light indicator, then it will inform the motorist about the end of the procedure with a green light. According to many experts, unattended batteries should be recharged to about 95% - in this way they can work out their entire service life, while the voltage should be at least 14.4 volts.

Remember that when charging a serviced device, it is advisable to unscrew all the plugs on it before starting the process. If the plugs are tightly tightened, this can provoke excessive pressure in the system, which in theory is fraught with an explosion. The plugs do not have to be completely unscrewed, just loosening them is enough.

Many car owners, faced for the first time with the problem of discharging a car battery and deciding to charge it on their own, ask next question: "What current to charge the battery?". In order to carry out this plan, first of all, it is necessary to have a starter-charger or charger that allows you to convert the current supplied from ordinary socket at 220V, into a current that has a much lower voltage - 15V. Measuring voltage parameters of 15V are considered optimal in order to carry out high-quality while not violating its system.

When answering the question of what current to charge the battery, first of all, it is necessary to decide on the choice of the method of charging the battery.

How to determine the total charge? As soon as it is charged, it will begin to emit gases. This is a sure sign that the battery is fully charged and ready for use. Another sign of a full charge is the stability of the voltage readings for an hour or more. The increase in charge efficiency will be higher the more the current is reduced at the end of the charge. To do this, before the battery is fully charged, it is necessary to gradually reduce the current strength (at a value of 14.4, a current of 3 Amperes is supplied). This effect increases the charging voltage.

When the battery is fully charged, as a rule, no excess gas is released, since the charge is up to 95%. Knowing what current to charge a car battery, it is important to choose the right effective regulating chargers for this method.

• There is another method - equalizing, which is used when the battery is already 95% charged and needs to be brought up to 100%. To the question of what current to charge the battery in this case, the answer will be the current strength equal to the following calculation. The current is equal to 3% of the battery capacity. In this case, not only 100% charging is achieved, but it is also equalized in all battery banks.

For experienced motorists who like to service their car on their own, the process of charging the battery does not cause any difficulties. Of course, this question is relevant specifically for beginners in the car industry: in order to properly handle the battery, it is important, first of all, to know exactly what current to charge the battery so that it lasts longer, with the best efficiency return.

What you need to know to properly charge your battery

In order to understand what current to charge a car battery with, first of all, you need to know what capacity it has and, based on this, set either the car battery charging current or voltage. It all depends on which method to choose and which charger will be used.

If, for example, the battery capacity is 60 Ah (Amp hours), the maximum current that can be supplied is 6 A (10% of the nominal battery capacity). If the capacity of the battery being charged is 75 Ah (ampere hours), the current is set to 7.5 A.

There are two known methods for charging the battery:

• constant current battery charging ;
• method constant voltage.

If the way direct current is activated by manual settings, then it will be necessary to control the charge current of the car battery every 2-3 hours. The current is set, as already mentioned, in the amount of 10 percent of the battery capacity. And then it is necessary to gradually reduce its value as the voltage indicator (U) increases. In this way, it is impossible to say for sure. This will take at least 10 hours.

The constant voltage method directly depends on how many volts the charger supplies to the battery. If you charge the car battery continuously for two days (as you know, it is with a long charging period that the best “pumping” of a deeply discharged battery is provided) - the battery will restore its capacity as follows:

• at U 14.4 V - from 75 to 80% ;
• at U 15 V - from 85 to 90% ;
• at U 16 V - from 95 to 97% .

If the battery is charged from 20 to 24 hours, and U at the same time is 16 V and a little higher, then you can count on a full charge. To complete the charging process, you need to wait for the voltage at the battery terminals to stabilize to 14.4 V. And if the charger is equipped with an indicator, it will light up in light green, signaling that charging can be completed.

At correct installation indicators and competent control of the process, both methods are equally good and will not harm the battery. By the way, many modern chargers are equipped with controllers and can work in safe auto mode.

A quick way to recharge the battery with high currents

The method of fast recharging the battery with high currents should be mentioned separately. It is quite common among those motorists who are in a hurry all the time and do not have enough time to give their battery a full safe charge time. In order for the batteries to be charged as quickly as possible, a current of 20 amperes and more is supplied to the battery terminals in the first hours of charging, and the process itself lasts no more than 5-6 hours. However, if you charge the battery with high current often and constantly, it will quickly fail due to too intensive chemical processes inside its "cans".

If a practical question arises, how much current to charge the battery and how many amperes is it better to supply the battery in exactly emergency situations - high currents it is allowed to use it when the motorist is in a hopeless situation: you need to urgently go somewhere, and the battery is dead. But you should always remember that the most optimal and safe car battery charge current should be no more than 10% of the battery capacity. And when "pumping" a deeply discharged battery with small currents - even less.

Charging a car battery with a modern charger

Of course, before you start charging your car's battery for the first time, you need not only to know what current is best to charge the battery. You also need to take care of purchasing the most suitable charger. There are many different memories. Including with the possibility of manual settings - for those who are well versed in how many volts or amperes should be set at a certain stage of charging.

For novice drivers and for those who especially do not want to go into the details of physics and electronics, there are portable and easy-to-use modern chargers for charging car batteries. In addition to manual, they have an automatic control system. A very good and compact “charger” T-1021 is offered by the Russian company Avtoelectric. It is affordable, and the quality is much higher than the Chinese counterparts that are popular in our time.

This device can charge car batteries with a capacity of 60 Ah and above. Its biggest advantage is the controller. With it, the entire charging process becomes absolutely safe. The controller will not allow high currents to flow into a partially charged battery. He will always prevent danger short circuits that can occur if the terminals accidentally touch each other.

To charge the battery using the T-1021, you need:

• connect plus ;
• connect minus ;
• turn on the device ;
• set the memory to the "automatic" position .

If the battery capacity is 60 Ah, the current should be set to 6 amps using the regulator. When the battery is charged, the arrow will automatically fall to zero. When trying to turn the current over high power(in case the battery is not completely discharged) the controller will not allow this.

If available enough time, and the battery is very discharged, it can be “pumped” to the full program in the same way, using automatic settings. The main thing is to initially correctly set the recommended current rate of 1 ampere. In this case, the battery will be charged for a long time, from 2 to 4 days. But a deeply discharged battery will recover almost completely. It all depends on how long he served.

Manual mode is more suitable for professionals, or for drivers with great experience. For beginners, it is better not to use it, since you need to be able to calculate the charge time and current strength.

When the battery is fully charged, the pointer will automatically drop to zero and the indicator will turn green.

In order to charge the battery yourself, it will be enough to know the basic indicators of safe current described above. It will be necessary to build on them when charging the battery. And modern chargers equipped with automatic system controls, will greatly facilitate this task for novice motorists.

The main reasons due to which a serviceable car battery can fail prematurely were considered. Here we will continue the topic of operating car batteries, and consider how to properly charge a car battery.

How does it usually happen? While the battery is working properly, few people pay attention to it - it works, well, okay. But as soon as interruptions begin in its work, for example, starting the engine in the morning is harder than usual, after some downtime, the starter turns the engine less vigorously than before, then many people begin to understand that it is time to devote time to the battery and take out the chargers. As they say, just don't be too late.

Let's start with the fact that the density of a working fully charged battery is 1.28 g / cc. Batteries, in which an electrolyte of this density is initially filled, are suitable for use in most regions of Russia. In the regions of the Far North, where winter temperature falls below 40 degrees, it is recommended in winter period use batteries with an electrolyte density of 1.30 g/cc. But even such a “high-density” battery in a discharged state can freeze at a temperature of “-15 degrees”. Therefore, for the state battery need to be monitored regularly. The density of the electrolyte is measured with a hydrometer.

When does a car battery need to be recharged?

It is believed that a decrease in the value from the initial density of the electrolyte by 0.01 g / cc means that the battery is discharged by about 6%. From this it follows that a decrease in density to 1.24 g / cc is equal to the discharge of the battery by almost 25%, i.e. for a quarter. In summer, such a battery will still work, but with the onset of cold weather or in winter, it will be hard for him. Based on the signs of the condition of the battery, given in, we can assume how long such a battery will last.

Therefore, we put a working battery on charge in the following cases:

• reducing the density to 1.25 g / cc, if the density is even lower - all the more you should not hesitate;
• if the density is different banks differs by more than 0.02 g/cc;
• if the battery was used and then was inactive for more than three months (for example, the car was stationary all this time). But this is on condition that the battery was stored properly (more on this below), in any case, you will need to check the density;
• periodically, in order to remove shallow sulfation of the plates with a small charging current.

The above cases are periodic charging prophylaxis for a working battery.

What should I pay attention to before putting the battery on charge?

Before proceeding with checking the electrolyte level and its density, it is necessary to wipe and clean the battery case from dirt and smudges, if any. Particular attention is paid to the places where the plugs of the filler holes fit to the body. Dirt usually accumulates there, which, at the moment the plugs are unscrewed, can get inside, i.e. into the electrolyte, which is undesirable.

In a working battery, albeit partially discharged, the electrolyte level will be within normal limits, i.e. plate grids will be completely covered. But it may turn out that in some of the cans, or maybe not in one, the level will be much lower, or the grates will be completely bare. Density in this case will be difficult to check. But, clearly, this is a sign that something is wrong in this bank or in these banks.

In this case, it is necessary to add distilled water not up to full level, but exactly enough so that it slightly covers the grid of plates, and then put the battery on charge. If the plates are closed, then nothing needs to be added yet! The fact is that during a natural discharge, the electrolyte level in the banks decreases, and during the charge it rises.

So it is necessary, if necessary, to add water in order to just cover the plates so that it does not happen that at the end of the charge the electrolyte level in the bank turned out to be much higher than the required value. Because of this can, the entire battery will have to be charged much longer, while in other banks the electrolyte level will already rise and the density will reach normal, i.e. the rest of the banks will already be charged.

Now, directly charging the battery with a charger.

You can charge a car battery without removing it from the car, if the wires from the charger are freely accessible to it. Only first you need to disconnect the regular wires "+" and "ground" from the battery. Instead, wires from the charger are connected: the positive wire is connected to the “+” of the battery, and negative wire- to the negative terminal.

How much current to charge a car battery?

The value of the charging current is taken as 0.1 of the nominal capacity of the battery. For example, if the battery capacity is 55 Ah, then the charging current should not exceed 5.5 Amperes, if the battery is 60 Ah, then the charging current is taken no more than 6 Amperes. It is not recommended to raise the charging current above these values, otherwise the battery can be damaged. High charging current can cause the plates to warp and the active mass to fall out of the grids. And this shortens the battery life.

But if you do not hurry, the most optimal charging battery will be a current equal to 0.05 of the value of the battery capacity (0.1 is divided in half). For batteries 55 and 60 Ah, these will be 2.75 and 3 Amperes, respectively. The lower the current, the deeper the charge. In this case, the time to full charge battery will increase, but the charge itself will be better. For the purpose of prevention, to remove the sulfation of the electrodes, it is recommended to take exactly these values ​​of the charging current.

To reduce the total charging time, the charging process can be divided into two stages. First, set the charging current equal to 0.1 of the battery capacity, and after the electrolyte density rises to 1.26 g / cc, reduce it by half (0.05) and continue charging to full.

How long does it take to charge a car battery?

A sign of the charging flow is the so-called "boiling" of the electrolyte - the release of gases. But this "boiling" should not be too intense. If gases are released too abundantly, then it is better to reduce the current a little. But when charging with low currents, the electrolyte may not “boil” at all, and the time of the charging process will increase. Therefore, in the process, it will be necessary to check the change in density several times. When the density of the electrolyte is restored to normal (1.28 g / cc), it is recommended to continue charging with a small current for about 1 hour, so to speak, to fix it. After that, the charging of the car battery can be considered finished.

It may turn out that during charging in one of the cans, the density of the electrolyte will increase more slowly, in comparison with other cans, and will stop at some value, i.e. will not reach the norm. This happens when the integrity of the active mass on the gratings is already broken. Perhaps this bank will soon completely fail, or maybe it will serve a little more. It will become clear in the course of further operation of the battery.

It is necessary to proceed from the fact that initially in all banks the electrolyte of the same density was filled. While the battery is new, the discharge-charge in all banks is approximately the same. Over time, the saturation of lead sulfate in the electrolyte in different banks will be different. And if you mix them with each other, by pouring from one can to another, then the density of the electrolyte in them will change from the original, and the battery will fail much faster.

What is wrong with overcharging the battery? When the battery charge comes to an end, another process begins in the battery - the electrolysis of water, which is part of the electrolyte. Water breaks down into oxygen and hydrogen and thus evaporates. When the electrolyte has already “gained” its density, and the charging current has not turned off (if the current is large, this is even worse), then the water from the electrolyte slowly boils away. This means that later it will be necessary to add distilled water to the electrolyte to the required level.

Now, a few words about maintenance-free car batteries. Everything related to inspection and maintenance, i.e. what is stated above in this article applies only to serviceable batteries for the simple reason that maintenance-free batteries do not have electrolyte fill holes. Therefore, it is impossible to check the density of the electrolyte and its level in the banks of maintenance-free batteries. However, such batteries also need care and periodic recharging.

The state-of-charge indicator that such batteries have does not give a complete picture. It often happens that the indicator shows that the battery is charged, and its capacity is barely enough for two attempts to crank the engine. This battery needs to be charged.

How long does it take to charge a maintenance-free car battery?

Charging time depends on how much the battery is discharged. Should be paid Special attention on the amount of charging current. It has already been mentioned above that a large charging current leads to the boiling of water from the electrolyte. It will no longer be possible to replenish water by topping up in such batteries, as well as to check the level, and a decrease in the electrolyte level, over time, leads to sulfation and battery failure. So having maintenance-free battery, you will have to check the operation of the generator more often.

When charging from an external charger, it is preferable to choose the value of the charging current equal to 0.05 of the battery capacity. Those. such that the electrolyte does not "boil". In this case, it will take more time to fully charge the battery, but the charge will be better, and the battery will eventually last longer.

For maintenance-free batteries (as, indeed, for any battery), it is better to use a charger on which it is possible to set the charge not for the current value, but for the constant voltage value. In this case, according to the laws of physics, as the voltage on the battery increases, the charging current will decrease. Thus, the operation of such a charger is identical to charging car generator, which is the most optimal mode for battery.

Very convenient - set the output voltage to about 13.8 volts and go do other things. As soon as the voltage at the output from the charger equals the voltage on the battery, which will increase during the charging process, the value of the charging current will drop to “0”, and overcharging will not happen. But if you are impatient to charge the battery quickly, or there is no time to wait, then you need to remember that the charging voltage should not exceed 14.5 volts, otherwise this may lead to water boiling off during the charging process, which will be impossible to replenish.

And finally, a few words about how to store a car battery.

There are no special tricks here. It is only necessary to remember that a car battery of any type is stored only in a fully charged state, dry and clean on the outside, preferably in a cold place. In a warm room, the natural process of self-discharge is enhanced. If the car is not used in winter, then it is better to leave the battery on the car, but first charge it and then do not connect the power wires (plus and ground), in order to avoid additional self-discharge. But if in your region the temperature drops below 40 degrees, then it is better to bring the battery to a “warmer” place. You can lubricate the terminals with technical vaseline. And let it be stored until the right time.

Lead acid batteries dominate in road transport as an onboard source of electricity, in emergency, backup uninterruptible power systems. For supporting long term service, you need to understand how to properly charge the battery. The life of the battery depends on the conditions of storage and charge, which can reach 5-8 years.

Storage Features

Lead batteries should be stored in cold rooms in a charged state. Temperatures above 30º and low level charge lead to rapid degradation with loss of performance. Long-term storage causes a gradual decrease in the charge level. At room temperature, it will need to be charged at intervals of once every 8 months, at -20º - once a year.

A bit of theory

Rechargeable batteries consist of cells connected in series with a voltage of ~ 2V. Thus, 6, 12 or 24V are obtained by connecting 3, 6 or 12 cells in series, respectively.

The normal voltage level of element 2.1 is -2.17V. A voltage below 1.8V indicates a full discharge and is critical.

The main parameter is the capacity, denoted by the Latin letter C. It characterizes the amount of accumulated energy in Amp-hours. Capacity C \u003d 50 A / h is the ability to give a current equal to 1 / 20C \u003d 2.5A for 20 hours.

Another important parameter- internal resistance Rin. It characterizes the ability of batteries to receive and give current. When the condition of the battery deteriorates, for example due to sulphation of the plates, the internal resistance increases. At very high values Rvn the battery stops receiving and giving current to the load, becomes unusable.

The main advantages that determine the widespread use of batteries are:

• ability to work at temperatures below -30 degrees;
• the ability to give large, over 10C currents;
• low self-discharge;
• ease of maintenance;
• relatively low cost;
• no need for complex chargers.

The ability to operate at low temperatures and deliver high currents are unique properties of lead-acid batteries.

How to properly charge the battery

Do not charge the battery in cold weather. Due to the increase in internal resistance at low temperatures, the voltage will have to be increased, and there is a risk of overcharging. It is best to do this at room temperature, in nominal modes. If there are filler plugs, they should be unscrewed, but not removed. In parallel, it is worth checking the electrolyte level. If the level is low, add distilled water.

Charge mode

Compliance with the modes is assigned either to the charger or to the person.

The diagram above characterizes the charge mode. At the beginning of the charge, the internal resistance Rin of the battery is low. It is important to limit the current to a safe level in order to prevent overcurrents that can cause plate warping - the horizontal section of the green curve. The charge voltage also gradually increases, and is limited at the nominal level in order to prevent overcharging. With an increase in the charge level, Rvn increases, I charge begins to fall (green graph) and the voltage remains at the nominal level (red graph). For automatic chargers, the end of charge signal is the achievement of minimum current charge, after which the charger turns off or goes into buffer support mode. Another visual signal of the completion of the process will be the abundant release of gases “boiling” of the electrolyte.

Voltage and current

The charge voltage should be limited to 2.4V per cell. For 12V batteries, the nominal charge voltage is ~14-14.4V and the current is 0.1C. at a temperature of 20ºС. For 50A\h capacity 0.1*50 = 5A.

However, there are times when there is no time to follow the rules, but you need to quickly start the car. In such cases, voltages with currents can be increased if the power of the charger allows. Such an afterburner will not bring anything good, but as a forced one-time measure it will not cause significant harm.

Charger types

According to the type of voltage conversion, they are divided into transformer and pulse (inverter).

Transformer ones have a larger mass, are simple and reliable. Due to the complexity of controlling the output voltage and current of a transformer, automatic models are rarely found, in best case they are equipped with a voltmeter, an ammeter with a simple voltage regulator. Control of parameters and time is carried out manually.

Switching memory devices are much more compact and powerful, as a rule, they support fully auto mode, are able to control currents, voltages, track the end of the process.

Which memory to choose

Undercharging and overcharging are equally harmful and shorten battery life. Best Choice will be fully automatic memory. Such a memory will relieve you of the need to manually control the charge parameters, track the time, and control the end of the process. Impulse devices have more high efficiency and reduced power consumption, including due to shutdown at the end of work.

In addition, advanced memory devices make it possible to provide such a useful mode as a charge-discharge cycle, which contributes to desulfation and restoration of battery capacity.

We charge correctly - we save money. Knowing the rules, charging and storage modes, along with choosing the right charger will help extend battery life.

Battery Charging Tricks: video

Battery Charging Methods

In practice, two methods of battery charging are used, or rather, one of two: battery charge at constant current and battery charge at constant voltage. Both of these methods are valid for proper observance their technologies.

Battery charge at constant current

A feature of this method of charging the battery is the need to monitor and regulate the charging current of the battery every 1-2 hours.

The battery is charged at a constant value of the charging current, which is equal to 0.1 of rated capacity Battery at 20-hour discharge mode. Those. for a battery with a capacity of 60A / h, the car battery charge current should be 6A. it is to maintain a constant current during the charging process that a regulating device is required.

For batteries of the latest generation without holes for topping up, it is recommended that by increasing the charging voltage to 15V, once again reduce the current by 2 times, i.e. 1.5A for a battery of 60A / h.

The battery is considered fully charged when the current and voltage remain unchanged for 1-2 hours. For maintenance-free battery this state of charge occurs at a voltage of 16.3 - 16.4 V.

Battery charge at constant voltage

This method is directly dependent on the amount of charging voltage provided by the charger. With a 24-hour 12V continuous charge cycle, the battery will be charged as follows:

• at a voltage of 14.4 V by 75-85%;
• at a voltage of 15 V by 85-90%;
• at a voltage of 16 V by 95-97%;
• the battery is fully charged when charging for 20-24 hours and the charger voltage is 16.3-16.4 V.

As a rule, the criterion for the end of the charge in the data chargers, is the achievement of voltage at the terminals of the battery, equal to 14.4 ± 0.1. The device signals green indicator about the end of the battery charging process.

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