When operating a car with serviceable electrical equipment, problems associated with the battery of this car usually do not arise. Of course, if you do not leave powerful consumers of electricity on for a long time when the car engine is not running. But it is worth blowing the fuse that protects the excitation circuit of the generator, and the next attempt to start the car engine will not be successful. After that, a previously irrelevant question will arise before the owner of the car: “how to charge the battery correctly?”. With the availability of a charger, it is not difficult to properly charge a car battery at home. Charging the car battery with an automatic charger is the simplest and does not need to be controlled over the process.
The car battery (ACB) is used to start the car engine and as an auxiliary source of electricity when the car engine is not running.
Battery Status Assessment
The fact that the car's starter turns "sluggishly" is not necessarily a consequence of the fact that the car's chemical source of electricity is depleted. Therefore, before dragging the car battery for charging, it is recommended to check it.
Measurements are taken when the car's engine is not running. A fully charged car battery has an electrolyte density of 1.27 to 1.29 g / cm 3 and a terminal voltage of 12.3 to 12.9 V. When 70% of the charge remains in it, its electrolyte density will be from 1.23 to 1.25 g / cm 3, and the voltage is from 12.0 to 12.1 V. A half-discharged current source will have an electrolyte density of 1.16 to 1.18 g / cm 3 and show a voltage of 11.8 to 12, 0 V. Fully discharged, it will have a density of 1.11 to 1.13 g / cm 3, and the voltage will drop below 11 V.
Preparing the battery for charging
In order to properly charge the battery at home, follow this sequence:
Charge Methods
There are three ways to properly charge a battery:
The first two ways to charge the battery have both their pros and cons. The first method is to connect the battery to a source of electricity with a constant current strength of no more than 16.2 V. The current strength when charging for 20 hours can be calculated if the battery capacity is divided by 20 hours. For example, if your car has a 50 Ah battery, then 50 Ah / 20 hours = 2.5A. With a 10 hour charge, to determine the strength of the battery charge current, the capacity is divided by 10 hours. That is, to properly charge the same battery in 10 hours, you need a charging current of 5 A. One of the most important advantages of this method is that the battery is fully charged. Among the shortcomings, one can note the need to stabilize the current strength, a significant release of gases, and heating of the electrolyte.
Charging in this way is recommended to be carried out in two stages - first, make the charging current equal to 1/10 of the rated capacity, and after reaching the voltage of one bank of 2.4 V, reduce it by 2 times. The end of charging is determined by the appearance of intense gas formation - "boiling" of the electrolyte.
Alternative
The second way is to stabilize the charging voltage, while the current varies depending on the resistance of the battery. This technique allows you to charge the battery up to 85-90%. Advantages of the method:
- fast bringing the battery to working condition;
- most of the energy consumed at the beginning of the process is spent on restoring the active mass of the plates.
The main disadvantage is the strong heating of the electrolyte due to the high current strength at the beginning of charging. Equalizing charging is designed to eliminate the consequences of deep discharges. Eliminates the increasing sulfation of electrodes very well.
The forced technique is used to quickly restore the operating state of the source after a deep discharge. Allows an increase in current at the beginning of charging up to 70% of the nominal capacity, but not longer than half an hour. The next 45 minutes, the charging current is reduced to half the rated capacity. For another 1.5 hours, the charge goes on with a current that is 30% of the rated capacity. This charging requires mandatory monitoring of the electrolyte temperature. If the temperature rises to 45 ◦ C, charging should be stopped.
Use the battery boost method as little as possible, as its regular use significantly reduces battery life.
About battery capacity
There is an opinion among car owners that it is unacceptable to install a battery with an increased capacity on a car, since with a larger capacity, the car battery allegedly will not have time to charge. However, the amount of energy spent on starting a car engine does not depend on the capacity of the battery. Therefore, with a working generator, it will be replenished in a battery of a larger and smaller capacity in the same time. This means that installing a battery with a capacity greater than the recommended one on a car will not do any harm. 
Charging device
The charger (charger) is used to charge electric batteries from the AC mains. The charger consists of a voltage converter (transformer or pulse rectifier), a voltage stabilizer, a controller that regulates the charging current, and sometimes an indication unit consisting of pointer or LED ampere-voltmeters. Chargers differ in the type of rechargeable batteries, their operating voltage and capacity.
The designation of the charger for car batteries: X B/C, where X is the name of the charger, B is the maximum capacity of the battery being charged in Amp-hours, C is the maximum operating voltage of the battery being charged in volts. If the charger has a B value greater than 170 Ah, then it can be used not only for charging, but also to help start the car engine.
If you ask a similar question to anyone who has at least some idea about a car and a battery, you can get the most detailed advice. For some reason, many believe that this question is so trifling that it is even a shame not to know. However, statistics show that more than half of the batteries do not withstand the service life declared by the Manufacturer and they have to be replaced prematurely with new ones.
And the main reason is improper charging during the operational period. Let's figure out how to still charge the battery, and do it CORRECTLY.
Let's clarify one point right away. It is believed that if the car's generator runs smoothly, and the car is used regularly, then this is quite enough to maintain the proper battery charge level. This opinion is fundamentally wrong, and here's why. According to its technical characteristics, the generator is not able to provide 100% charging, that is, the battery will be partially charged all the time, which significantly reduces its service life.
Remove battery from car
Often, motorists neglect this and charge the battery without removing it from the car. But in vain, and here's why.
Firstly, the battery needs a systematic inspection, and from all sides, and not just from above. Electrolyte splashing is possible (corrosion of the “landing” socket frame will appear), a crack in the case (the result of constant vibration and unreliable fixation at the location).
Secondly, the product must be cleaned of dirt and dust. The fact is that the “plaque” formed on the case, between the terminals, is conductive, which means that the degree of self-discharge of the battery increases, which negatively affects its service life.
Therefore, before putting the battery on charge, it should be serviced. Accumulated dirt, in which acid is present, is good to collect with a swab dipped in a weak soda solution. If foaming occurs, this indicates that not all acid has been removed from the surface of the housing.
By the way, the terminals also need periodic maintenance, since lead oxidizes, and therefore more current is required when starting the engine, which leads to increased battery discharge.
If, nevertheless, the battery is charged at the installation site, then suitable (network) wires must be removed from its terminals.
Remove corks from jars
The need for their maintenance should also not be forgotten. In the center of each there is a small through hole through which the products of gas formation, which occurs during operation, are removed. If it is clogged with dirt, then the accumulated gas can simply break the case.
In addition, you need to make sure that the electrolyte level is normal. If necessary, add water (distilled).
Connect charger terminals
Here you need to pay attention to the polarity. "Plus" is connected to the "+" of the battery, "negative" - to the "-".
Charging process
This largely depends on the type of device. However, many motorists prefer to produce it manually. The current is set to the maximum (depending on the nominal capacity of the battery), and as the voltage decreases, it is added.
It should be noted right away that a lot depends on how the battery is operated, to what extent it is discharged, how often the owner puts it on charge from an external device. The "quality" of the car's generator also affects.
The most optimal is the mode of charging with small currents. More on this below. It remains to add that it is necessary to systematically control this process. Sometimes a motorist simply puts the battery on charge and leaves for several hours. This is fraught with the fact that the battery can be charged earlier (and the process of recharging will begin) or even “reset” the current to a minimum. Then you have to increase it and still wait for a full charge to occur.
With what we now know, we can answer some common questions that beginner motorists have.
How do you know the battery is fully charged?
The voltage at its terminals can be different (from 14.5 to 16.1 V). It depends on many components (electrolyte density, capacitance, and a number of others). The main criterion is the constancy of the output voltage at its terminals with the ongoing charging process for 1 hour. It is measured by any type of voltmeter, regardless of its accuracy class.
Is it possible to charge at a negative air temperature?
Yes, since an electrolyte with the proper density never freezes. Example - the car is operated not only in summer, but also in winter, and, nevertheless, recharging from the generator is not interrupted.
Do I need to disconnect the battery from the on-board network when charging from an external source?
Necessarily. Quite often, the battery is put on charge without removing it from the installation site. But here it must be taken into account that any electronic device can be connected to the network, even with the ignition off and the "ground". There are so many different features of engineering solutions in modern car models that it is impossible to foresee everything, especially since not all Manufacturers describe in detail such nuances in the documentation for a “car”. Therefore, it is better not to take risks and play it safe, otherwise a larger than expected “voltage” of the charger can damage something.
How often should the battery be recharged if it is removed from the car?
Many motorists do not operate their "iron horses" in the winter. A zealous owner removes the battery for this time and stores it separately, in a warm room. But any device, characterized by such a parameter as electric capacitance, gradually self-discharges.
Naturally, the electrolyte begins to react to low temperatures, and in a discharged state, in a cold room, the banks can simply freeze. Such a battery is no longer subject to recovery. By the way, that is why it is necessary to remove it for the winter and put it in “warmth”. Recommendations for the frequency of recharging vary. In order not to be mistaken, it should be done about once every 3 months (provided that the battery is stored at a positive temperature).
If the battery is not removed from the car, and it is not in use, then you need to charge it more often - once every 1.5 - 2 months. This is due to the fact that it is possible to increase the self-discharge current through the on-board network. And if the wires are removed from the terminals, but it is cold in the garage, then at least 1 time in 2 weeks. So more reliable.
What current to set and how long to charge?
There is such a criterion that is applicable to all types of batteries - the value of the charging current is 10% of the nominal capacity of the product. The most common batteries are 45 A / h (for passenger cars). Therefore, the optimal charge current is 4.5 A. If the discharge is complete, then at least 12 - 15 hours. In other cases - until fully charged. How to determine above.
Since it is impossible to determine the degree of rarefaction "by eye", then if the battery is not completely discharged, experts recommend using the "sparing" mode, that is, setting the current 2 times less than the calculated one (for example, instead of 4.5 A, set 2.5). Naturally, it will take more time to charge, but the service life of the product will also increase.
Sometimes, to reduce the charge time, motorists specifically give increased current. Yes, it will charge the battery faster. But at the same time, the fact that the chemical processes occurring in this case begin to proceed more intensively is not taken into account, and this entails an increase in the temperature of the electrolyte. Overheating the battery significantly reduces its shelf life.
Motorists with experience prefer such a "technology" - a current of about half an ampere, and let it "worth it". Although longer, it is quite safe for the battery. In this case, charging is achieved 100 percent.
It remains to add that if you do not allow the systematic discharge of the battery to a critical minimum (10.5 V), then the product will reliably serve not only 5 guaranteed years, but even more. The normal density of the electrolyte within the normal range is 1.25 - 1.27; voltage at the terminals - depending on the type of battery.
After buying a new battery for a car, the owner has many questions regarding charging time and operating conditions. In some cases, motorists do not know how to prepare a source of electric current for work and whether there is a need for such an event at all. In this article, we will talk about whether you need to charge a new car battery, how long it takes to fully charge, and give recommendations on operation that will help extend battery life.
Experts agree that even a new battery must be charged. In most cases, the battery lies in the manufacturer's or seller's warehouse for a long time, which leads to a natural decrease in its capacity. In order not to be mistaken, it is better to check with the seller the date of manufacture of the battery and, based on the information received, decide whether to charge the battery or not.
There is an opinion that modern battery production technologies make it possible to minimize self-discharge. This statement is relevant only if the storage conditions are observed in the warehouse. The following factors can affect the degree of self-discharge:
- air temperature in the room (norm 5-20 0 С);
- air humidity;
- the presence or absence of dust and dirt.
If the first parameter in warehouses is more or less observed, then few people monitor air humidity and dust. As a result, after 2 months, the loss of battery capacity can reach 20-40%.
As you can see, the question of whether to charge a new battery or not disappears. It is better to play it safe and charge it, even if the seller swears that the goods are fresh from the factory.
How to charge a new car battery correctly?
In fact, there are almost no differences between charging a new and a used battery - both elements must first be prepared. But there are differences between the duration of the charge of a serviced battery and an unattended one.
In each case, a certain voltage supply method is applied, which determines how much you need to charge a new car battery.
Charging with variable voltage
This method is useful for charging a new, serviceable battery. This technique allows you to somewhat reduce the degree of "boiling" of the electrolyte, which has a positive effect on the operation of the battery in the future.
It is advisable to charge a new car battery.
If you decide to charge the battery in this way, use the instructions.
- Remove the battery from the car, make sure that the temperature of the electrolyte does not exceed 35 0 C.
- Install the charger rheostat so that a voltage of 10% of the battery capacity is applied to the terminals.
- Wait for the appearance of bubbles in the electrolyte, measure the voltage at the contacts.
- If a value of 14.4 V is obtained, reduce the supplied current by 2 times.
- Periodically check the voltage, once it reaches 16V and does not drop for three hours, the battery is charged.
It is difficult to say with accuracy how much time it will take to charge. This procedure usually takes up to 14 hours. Therefore, do not forget to check the voltage in order to turn off the charger in time.
There is another way by which you can make sure that the battery is charged. Check the density of the electrolyte with a hydrometer. If it does not rise within three hours, the process is over.
Be careful! If during the charging process you find that the battery temperature has risen to 45 0 C and above, turn off the charger or reduce the supplied current by 50%.
Constant voltage charging
This method is best used to charge a new, maintenance-free battery. The difference from the previous method is the constant supply of voltage without changing the current strength. This approach makes it possible to reduce the heating of the electrolyte.
For charging, a modern charger is used, equipped with a charge indicator and an automatic relay that regulates the supplied voltage depending on the parameters of the battery electrolyte.
Already an hour after connecting the charger, the battery capacity will rise to half, and after 4 hours - up to 95% of the declared by the manufacturer. There is no need to guess how long it takes to fully charge. This takes about 5 hours, after which the charger will turn on the full charge indicator.
Operating a new car battery
In order not to have to go to the car shop again in a year, you need to know how to prepare the battery for work and operate it in the future. For those who have a vague idea of what to do with a new battery, we have prepared two instructions.
First of all, you need to choose the right battery - it must correspond to the parameters specified by the car manufacturer. Otherwise, our recommendations will be useless.
Proper battery charging.
Preparation of the battery for work consists in the following actions:
- Remove the packaging, wipe the case with a clean cloth.
- If the battery is serviced, remove the plugs and measure the density of the electrolyte (should be 1.27-1.28 kg / cm 3).
- Charge the battery.
- Clean the contacts with sandpaper, wipe with a clean cloth.
- Carefully, avoiding sparks, connect the terminals.
If you have an old car that does not have on-board electronic devices (radio, alarm, computer, etc.) - use the instruments to check for possible current leakage. Normally, the value should not exceed 15 mA.
On modern cars, current leakage can not be checked - even a turned off radio tape recorder can consume electricity and you will not be able to remove reliable indicators.
Battery Rules
- Immediately after the first trip with a new battery, check the voltage at idle and with the power consumers turned off (the norm is at least 13.5 V).
- Periodically inspect the case for mechanical damage that may occur due to improper operation or the influence of severe frosts.
- Once a month, remove accumulated dirt from the surface of the case.
- Be careful while "lighting up" another car. There is a risk of burning the wiring when the ignition is on.
- Regularly check the electrical equipment of the car: even a minor malfunction of the generator or relay can adversely affect battery performance.
- Do not allow the battery to be critically discharged (less than 30% capacity) - do not turn on the headlights or radio for a long time when the internal combustion engine is not working.
- Check the quality of the battery fastening to avoid mechanical damage to the case.
If you are not confident in your skills, contact a specialist once every six months to inspect the battery and possible technical work. It's better to leave it to someone who knows than to try and fix the problem yourself and ruin the battery.
As you can see, the operation of the new battery is not particularly difficult. The main thing is to periodically look under the hood and check the condition of the battery.
Rules for charging a new battery
If you become the owner of a classic lead battery, then take precautions when installing or recharging. Remember that there is acid inside the battery, which can pose a threat not only to health, but also to life.
Acid burns are very painful and leave scars for life, therefore, when servicing a new battery, it is recommended to work with special gloves that prevent the dangerous substance from getting on the skin.
This advice is especially relevant for those craftsmen who carry out battery maintenance or repair at home.
Keep in mind that during charging, chemical reactions occur in the battery, as a result of which explosive explosive gas (a mixture of oxygen and hydrogen) is released. Keep the battery away from open flames, do not touch the terminals to avoid sparks.
Summing up
Now you know how to properly charge a new car battery, follow our recommendations so that the power source lasts a long time and does not cause electrical equipment to fail. If during operation you have any problems with the battery, and you do not know how to solve them, go to the service station. As practice shows, the cost of the services of a master is much lower than the price of a new battery.
Many car owners are worried about the battery in cold weather, because it is discharged. They are interested in: does the battery charge at idle? The Internet is filled with various answers. After all, when starting the car, a large charge is spent. Does the alternator charge the battery when not traveling? At what RPM will it not charge? We will answer these and some other questions in our article.
The principle of operation of the generator and why does it always produce energy when the engine is spinning?
The units are connected using a drive belt, which transmits the engine speed from the crankshaft to the generator pulley. The generating device converts the mechanical energy that occurs when the engine is idling and when driving, into electrical energy. Magnets attached to the shaft, together with the copper windings of the generating equipment, create an electric field. When this charge is transferred to the generating unit, the battery is recharged.
It is fundamentally wrong to think that the process of replenishing the battery capacity occurs constantly. This is wrong. The power source will take as much electricity as it has spent, and then simply will not consume it. Constantly charging the battery from the generator will cause it to boil away. Stopping the transmission of current is carried out using a voltage relay located in the generating unit.
During engine operation, the generator takes on the maximum consumer load - it is he who supplies electricity to the entire vehicle system. The use of battery energy begins when the load on the equipment that generates electricity increases. Therefore, the operation of this node and the power source must be coordinated and uninterrupted.
Is there always enough energy generated by the generator?
The maximum performance values of the generator system are set by the manufacturer and are indicated on the device case. Fully serviceable and compliant generating equipment will generate as much energy as necessary, subject to all conditions: the health of the car's electrical system and the battery capacity corresponding to the make of the car.
On the dashboard of any vehicle with an internal combustion engine there is a battery charging light. When the ignition key is in the pre-start position, all indicators should light up for a while, then they go out. If the battery light is on, then this indicates its low charge - it is worth checking the equipment.
Interesting! Idling is an individual indicator for each model of the machine, which is laid down by the manufacturer and indicated by him in the operating book or under the hood. You can find cars with idle about 500 rpm, and there are - with 1500 rpm.
The number of crankshaft rotations depends on many parameters:
- engine size;
- injection type;
- type of gearbox;
- air temperature;
- machine condition, etc.
Accordingly, depending on the number of revolutions of the crankshaft at idle, the generator produces a different amount of energy, which can almost double on two brands of cars with different idle speeds.
Charging the battery from idle in winter (features)
Under idling, it is customary to understand such an operation of a car engine without load, during which the voltage in the system ensures that processes are maintained only in the internal combustion engine. This mode is necessary for the car to warm up all fluids to operating temperatures. Each car has its own idle speed. If their value is lower than those indicated by the manufacturer, then this indicates an imbalance in the operation of the internal combustion engine.
Does the battery charge at idle in winter? The principle of operation of the generator does not depend on the season and temperature conditions - when the engine is running, it produces a certain amount of electricity. Therefore, in winter, the car battery is recharged. However, it is worth remembering that in conditions of low temperature, the battery takes an electric charge very poorly. The activity of this process will increase as soon as the engine warms up and it becomes warmer in the engine compartment.
The cause of problems with starting the car during the winter months is short-term trips, during which the battery does not have time to fill the capacity, or a malfunction in the electrical system. In order not to face the problem of a non-rotating engine one day, we recommend periodically diagnosing the battery.
Energy consumption table for different equipment.
Charging the battery is necessary in cases where it takes on part of the load of the power supply system. How much power does the equipment in a car need?
Table 1. Electricity consumption in the car with additional equipment.
By simple calculations, we get a total consumption of 1070 watts, which, when translated into amperes, will be approximately 90A. Such a load for many automotive generators, namely, they are the first to take it upon themselves, is at the limit of equipment capabilities. When a certain threshold is reached, the system will transfer part of the load to the battery. Therefore, it is necessary to carefully calculate the characteristics of the generator and battery.
Briefly about the power of generators in different machines.
The ratio of the work of the generating equipment and the time during which it performs it is called the generator power. To charge a car battery, generating equipment must provide it with the necessary voltage and current for a certain amount of time. Traditionally, passenger cars use equipment with a power of about 1 kW.
But it is worth remembering that each car has personal energy consumption needs, which depend not only on the parameters of the engine system, but also on additional sources of consumption. Therefore, we recommend choosing a generator following the manufacturer's instructions and taking into account the additional costs.
Will the battery charge at idle?
Very often on the Internet you can find discussions in which participants are trying to find out if the battery is charging at idle or not? Some believe that the battery is charged only while the wheels are spinning, someone defends a different position, arguing that there is no connection between trips and battery charging. Let's figure it out.
As we said above, the operation of the generator is correlated with the movement of the crankshaft. It works with the engine. It doesn't matter if it's idling or driving actively - there is physical energy in the car, regardless of the mobility of the wheels. It is her generator that converts it into electricity and transfers it to the power source, if necessary, to recharge it.
Therefore, we can safely say that the battery is charging at idle. Another question is how long it will take to recharge the battery capacity on a car.
How long does it take for the battery to charge at idle?
Remember that the generator produces a different amount of current and voltage depending on its characteristics and the discharge of the battery? Therefore, it is impossible to unequivocally answer the question: how long will it take to charge the battery at idle engine speed.
If the battery is slightly discharged, and other consumers are turned off, then the battery can be charged relatively quickly. In the case of a strong discharge of the power supply, the time will be slightly longer.
How to calculate charging time
The amount of time it takes to recharge a car battery from a generator is not easy to know. If we take an ideal situation, then to carry out such calculations, a formula is needed: the amount of energy required to restore the full charge of the battery (A / h) must be divided by the amount of free current that the generating equipment produces (A).
Free current refers to the energy that is not spent on additional sources of consumption (headlights, stoves, heaters, wipers, etc.)
However, it should be understood that in these calculations we do not take into account the ambient temperature and engine speed.
In conclusion, I would like to note that a large amount of unknown data does not make it possible to clearly answer the question: how long and does the battery charge at idle? Calculations require information about the consumers of electricity in the car system, the battery charge, the production capabilities of the generator, and the idling of a single motor. Of course, it would be easiest to use a universal formula, but, unfortunately, there is none. Therefore, the most important thing is to understand the essence of the issue and the ability to apply knowledge in practice.
We hope that this article has helped you understand the equipment that provides energy to the car, and the principles of its operation. We strongly recommend that you monitor the battery capacity and select power supply devices that meet the requirements. Then the operation of the car at any time of the year will not cause you trouble. Remember that you should not recharge the battery - this will shorten its life.
How do you charge your car battery from a generator? How long did it take to recharge? Share your experience with readers in the comments. We love reading your stories and answering your questions.
A maintenance-free battery is really different from its serviced counterpart, the point here is in a special structure. You almost never know what it means to add an electrolyte to it, or measure the density. Hence the name maintenance-free, that is, it does not require any maintenance, it is completely autonomous. However, many of my readers are interested in how to charge it and is it possible to do this? After all, now there are a lot of such batteries from different manufacturers, and they are installed on new cars in 90% of cases ...
To begin with, the battery can be recharged “by any means”, I would even say that it is designed for this. Let's remember the structure of the car's on-board network. The battery (at start-up) gives energy to the ignition system and the starter, which spins the engine (it starts). Further, after starting, the generator begins to generate electricity, which recharges our battery.
Serviced or unattended, this is the second question, the main thing is recharging, which replenishes the lost energy during start-up. I’ll even say more - if you discharge an ordinary maintenance-free battery “to zero” (), then it will simply kill him, after a few such cycles. Therefore, the charge must always be present and moreover in the normal phase, .
Then what is the problem?
Many people are not afraid of car charging, but the so-called home charger. THAT is the usual stationary chargers. What problems arise at this stage:
- Electrolyte boiling cannot be monitored . YES, this is really a problem, because when it boils, we understand that charging is over. One has only to look into the jar, but you can’t look into the unattended one, because it is simply closed (soldered). We don't see what's going on inside.
- Density cannot be tracked . Again, for the same reason, if in a serviced one, you simply unscrew the plugs and measure the density with a hydrometer, then this will not work here.
- Battery tightness . Also scary! What will happen if the electrolyte boils, where will the vapors go? What if the hull breaks?
These points are justified, which is why it is important to know how to charge such batteries.
How to charge a maintenance-free battery
Here, the old-fashioned methods (with bubbles on the electrolyte) will not work. It is important for you to know and understand how to charge a car battery, that is, the principles of charge ().
But for understanding, I will remind you a little - there are only two charge methods. It is constant voltage and constant current.
- Constant voltage. This is when you set a constant voltage, say 14.4 volts, and the current is automatically regulated. That is, at the beginning it can be 10 amperes, and at the end of the charge 0.2A.
- DC. On the contrary, the voltage can jump. We set, say, 2 Amperes, the current at the beginning of the charge will be 15 Volts, and by the end it may drop to 14.4 Volts.
Now all chargers are mostly automatic, they work according to the first point, that is, a constant voltage, but the current strength changes.
By the way, ordinary serviced batteries are also charged, but how long does it take to charge an unattended battery?
How to calculate charge time?
This is a more interesting question, the real inconvenience is that you need to clearly understand how discharged your maintenance-free battery is. That is, we calculate its capacity. But how to do that?
Again, it's simple - you and I know that a 100% charge is a voltage of 12.7 Volts. But a fully discharged battery is 11.7 Volts. Of course, you can discharge even more, but this is not recommended, in general 10 volts, this is already a serious discharge.
Accordingly, 0.1 X 5 \u003d 0.5. Now add 11.7 + 0.5 = 12.2V. This is a kind of discharge up to 50%.
Now a little about the capacity, for batteries it is 55 - 60 - 75, etc. ampere*hour. That is, this amount of current, he will be able to give in one hour. If we have a discharge of 50%, it means that we have lost about half of the capacity - for example, 30 Amperes have gone from 60, etc.
That is, in order to replenish 50% of the capacity, we need to supply a certain current and “fill” the battery. It is possible to apply 30A in one hour (in our example), but this will kill the battery. The recommended charge is 10% of capacity. In our case, this is 6A. And since we need to replenish 30A, then 30/6 = 5 hours. That is, at this current, we need to charge it for five hours.
I probably confused you, but the main thing is to learn how to determine the degree of battery discharge. Remember the lower limit is 11.7V, the upper limit is 12.7V.
Automatic charging stations
Of course, the “automatic machines” will do everything for you, there is no need to “steam” what current to supply and regulate the voltage. He will do everything automatically. And to be honest, there has long been no VOLTMETER or AMMETER, they were removed as unnecessary.
Such a charger will give the maximum current in the first hour, in the second hour the current is two to three times less, but in the sixth or seventh hour, the current can generally drop to a minimum, about 0.05A. Therefore, even if your maintenance-free battery is on such a charge, it will never boil, because the currents during “filling” are minimal, and I read somewhere that they may be completely absent, that is, it turns off.
What happens if you recharge?
Okay, we figured out the automatic chargers. But what will happen if you constantly recharge with the old “charger”, where you set the current and voltage rigidly? That is, you need to recharge at 6 Amperes, say 6 hours, and you “fuck”, 8 or even 10!
Of course, the electrolyte inside will boil, this is a purely physical principle. However, the battery will not burst (like a ball), as many people think! It has a special valve inside, which in case of emergency is designed to relieve high pressure too much. It opens just when you have a long and very powerful recharge, which, by the way, can also kill the battery - the case will survive, but part of the electrolyte will evaporate, you need to understand this!
I'm a teapot, I don't want to calculate all sorts of amperes, what should I do?
You can understand, it’s not always easy to charge a maintenance-free battery - everyone needs time and current calculations. But even here the manufacturers took care of you, they made batteries with green windows for people like you (or many people call them lamps). The principle is simple: when it is normally charged, the green indicator is on; when it is discharged, it is black; if there is not enough electrolyte, it is white. , it's very detailed.
Can you charge at home?
Well, the last question - is it possible to charge at home? After all, let's say a served fellow - to put it mildly, because when boiling, harmful, and even explosive gas is released.
