1. Ensure normal operation during operation in closed ventilated rooms at temperatures from -40 to +45 ° С and without prejudice to performance characteristics to withstand during transportation and storage in packaging the temperature in the range from -50 to +50 ° С.
2. Provide seismic resistance when installed in accordance with the manufacturer's requirements. The battery must remain operational under seismic action with acceleration values \u200b\u200bof 0.9d and 0.6d - in the horizontal and vertical directions, respectively, as well as with their simultaneous action in the frequency range from 3 to 35 Hz.
3. Batteries must have a tight connection between the lid and the tank and the stopper, withstand an excess or reduced pressure compared to atmospheric pressure by 20 kPa, must have special sintered ceramic filter plugs to prevent gas, aerosols and electrolyte from escaping from the battery.
4. It is desirable that containers for low-maintenance batteries are made of transparent plastic, which will facilitate their maintenance.
5. Batteries in dry form (without electrolyte) must not be electrically conductive. The internal resistance of charged batteries must not exceed the specified values.
6. Sulfuric acid (H2SO4) must comply with TU for purity stipulated by BS 3031 and VDE 0510 standards, specific gravity of acid for batteries with Plante plates 1.20 kg / l ± 0.005 at +20 ° С and for other types 1.22 kg / l ± 0.005 at +20 ° С. The density of the electrolyte of a charged battery should be 1.24 kg / l ± 0.01 at +20 ° C.
7. Battery capacity must comply with DIN 40736 as well as IEC standard. A number of batteries of the same name should provide the ability to select the required capacity as accurately as possible.
8. Operation of batteries in a battery is carried out in a constant trickle charge mode with a voltage of 2.23 BxN + 1%, where N is the number of cells in the battery. In this case, the voltage deviation on individual cells can be +0.1 V ... - 0.05 V. It is allowed to operate a float charge of 2.23 BxN + 2%, while the battery life can be reduced by 15%.
9. Batteries must have 95% of the nominal capacity on the first cycle at 1 0, 5, 3, 1, 1/2, 1/6 - hour discharge modes and 100% capacity on the third cycle. The nominal capacity of the battery is considered to be the capacity for a 10-hour discharge to a final discharge voltage of 1.8 V per cell and an initial electrolyte density of 1.24 kg / l.
10. In order to avoid deep discharges, the batteries must not be discharged below the final voltages specified in the documentation for this type of battery. Batteries must be capable of short-term discharges up to an end voltage of 1.35 V per cell without compromising their performance. Batteries must provide a short-term (1 min) discharge with a current of 1.39 A, the final voltage on the battery must not be lower than 1.45 V.
11. Self-discharge of fully charged batteries with 30-day inactivity should not exceed 3% at a temperature of +20 ° C and double with an increase in temperature for every + 10 ° C.
12. The batteries must be capable of operating in accordance with the values \u200b\u200bspecified by the manufacturer. Battery life is related to parameters such as float current, float voltage, ambient temperature, charger characteristics, quality of service.
13. During the entire service life, the occurrence of failures affecting the performance of batteries is permissible, on no more than one battery per year out of 10,000 in operation.
14. The storage of batteries without electrolyte (in their original packaging) from the date of manufacture until they are put into working condition must be at least four years.

A modern car cannot be operated without a mobile power source. The battery not only allows you to start the car engine, but also takes on the main load, at low generator speeds.

There are 2 main types of batteries: serviceable and unattended. What constitutes an unattended chemical source of electricity will be described in detail in this article.

Curbing

What is a maintenance-free battery

The maintenance-free battery is a product that cannot be refilled with distilled water. Such devices are safer during operation and charging, due to the reduction in the release of explosive gas, as well as the spill of acid solution when overturning.

As for the internal filling, a maintenance-free battery is no different from a maintenance one. You can visually determine whether the battery belongs to the category of maintenance-free products by the absence of filler plugs.

Which to choose, serviced or unattended

Deciding on the type of battery to purchase can be very difficult. If a serviced battery was previously installed on the car, then many car owners prefer not to change their habits. Serviced batteries have the following advantages:

• It is possible to check the electrolyte level and its density.
• If the level is insufficient, the battery can be easily restored by adding the required amount of distilled water.

Unfortunately, this type of battery also has many disadvantages:

• Evaporation of water in hot weather and when the battery is overcharged.
• Electrolyte spillage may occur if you roll over on its side or drive too hard off-road.
• Higher leakage current, especially if electrolyte was spilled on the upper outer plane between the terminals during refueling.
• Additional time spent on preventive inspection and maintenance.

The maintenance-free battery has the following positive characteristics:

• Set it and forget it;
• No need to add water.

Disadvantages:

• If the battery is out of order, then it will not work to restore its performance.
• If the electrolyte boils away, then it will not be possible to add distilled water without rough mechanical intervention;
• Critical to overcharge and deep discharges.

Attention! If the car has serious electrical problems, the maintenance-free battery will not last long. In this case, it is better to purchase a serviced battery and carefully monitor the quality and level of electrolyte.

If there are no deviations in the car's on-board electrical network, then the most correct solution would be to purchase a maintenance-free device.

What are the maintenance-free batteries

If you decide to buy a maintenance-free battery, then you need to know that these devices differ not only in capacity and strength of the discharge current.

An unattended battery can be of the following types:

1. Calcium lead acid. Plates of this type of devices are doped with calcium, as a result of which the material acquires such properties as: vibration resistance, reduced corrosion effect. Also in calcium batteries, a decrease in the self-discharge process and electrolyte boiling is observed.
2. AGM. It is an acid battery in which the electrolyte is located between the plates in special fiberglass separators. This type is easier to tolerate deep discharges, and due to a decrease in the intensity of sulfation of the plates, the service life can be increased to 10 years.
3. EFB. Design features This type of battery is that the thickness of the lead is significantly increased compared to conventional products. For lowering, each plate is wrapped in a special material that is impregnated with an acidic electrolyte. Thanks to the use of modern technologies, the service life is from 5 to 10 years.
4. GEL.Unlike other batteries, these have helium inside.

The above types of maintenance-free batteries will work without any complaints only with properly organized recharging, when the battery capacity drops below the set minimum limit for starting the engine.

What chargers can be used to charge maintenance-free batteries

Considering the closed space in which the maintenance-free battery plates are located, it is necessary to avoid significant overcharging of the battery.

Attention! It is recommended to use an automatic charger to prevent the device from boiling.

The main advantage of this type of charger is the lack of human control during the entire battery charging time. The “smart” device will decide for itself what voltage and current to apply to the battery terminals at the beginning of charging, in the middle of the cycle and at the last stage.

In the absence of an automatic device, you can restore the capacity with an ordinary charger, but, in this case, you will need to fully control the process.

For calcium batteries, you can use any standard charger, for gel batteries and you need a special charger.

How to charge a maintenance-free battery

Before charging a maintenance-free battery with a conventional charger, it is necessary to correctly determine the level of battery discharge. Given the fact that it is not possible to open such a battery to check the electrolyte level and its density, the degree of discharge is measured using multimedia. Many batteries are also equipped with a charge indicator.

This device allows you to measure DC voltage with an accuracy of hundredths of a volt. If during the diagnosis the voltage at the terminals is more than 12.6 V, then there is no need to charge the battery. When the voltage drops to 12 V, the battery charge will be only 50%, and if the voltage is less than 11.7 V, the battery is considered completely discharged.

The charging time when the battery is completely discharged is easy to calculate. The recommended charging current for all car batteries is 10% of the battery capacity. For example, if you need to restore a completely discharged battery with a capacity of 60 A / h, you will need to turn on the charger for 10 hours, while the charge current should be 6 amperes.

It is not difficult to calculate how much time it will take with a 50% discharge or with a 30% decrease in the battery capacity. To do this, divide the total capacity of the battery by 100 and multiply by the percentage of charge reduction, then divide the result by 6 for a 60 A / h battery and 5.5 for a 55 A / h battery.

How to repair a maintenance-free battery

If a maintenance-free battery fails before the manufacturer's recommended service life, then, in many cases, it is possible to restore the battery to acceptable values. Given the inability to disassemble the maintenance-free battery, you will have to pierce the top battery cover in 6 places with an awl. In this way, you can access the electrolyte, which must be carefully drained from the battery.

At the next stage, distilled water is poured into the holes to the required level. Then the battery is charged, until the gas evolves, with a constant voltage of 14 V. When the charging process is completed, the battery is left for some time so that the lead plates are slightly cleaned of the sulfate film.

After a few days, the battery charging procedure is repeated, after which the water is drained and the working mixture of sulfuric acid and water is poured. After charging, the battery can be installed on the vehicle. The holes in the top cover should be sealed with any acid resistant sealant.

Conclusion

The maintenance-free battery is ideal for novice drivers. Such a battery cannot be opened, so there is no danger of making mistakes during maintenance. For experienced driverswho know how and love to take care of their iron horse, it is better to purchase a regular serviced battery, because carrying out infrequent and simple activities will significantly extend the battery life.

Have you ever had maintenance-free battery? Share your experience in the comments, this will help make the article more complete and useful.

Serviceable and maintenance-free battery. What to choose?

The battery stores and stores energy that can be used like electricity. It is impossible to deliver a car without it. If this element fails, most often it needs to be replaced. Charging only helps to postpone the purchase of a new device for a short while, and here car owners have a question - what type of battery to choose?

Serviced battery

This name of the battery is because you can actually unscrew the plugs from the cans and see what is inside, as well as check the level and condition of the electrolyte, density, condition of lead plates, the presence of sulfate crystals, and boiling during charging. This is a rather significant plus - you can control the battery and make the right decision in a timely manner.

Maintenance-free battery

This battery is maintenance-free. The device does not have unscrewed plugs - it will not work to examine its "insides". It is a sealed design with six cans, each containing a plate and filled with electrolyte - all of which are in a completely sealed space. When heated and then boiled, the electrochemical liquid goes up in the form of vapor. However, it does not come out of the sealed housing, but condenses on the walls and falls back down.

There are several different types of batteries of this type, for example:

• with liquid electrolyte - have sealed holes into which distilled water is added;
• gel - with thickened, dried silica gel, permeated with microcracks, which do not allow electrolyte vapors to escape;
• AGM - with absorbed electrolyte, emitting almost no gases during operation, developing high discharge currents and requiring no maintenance during the entire service life;
• EFB - improved acid batteries with a thin layer of hygroscopic fiber applied to the positive plate, which prevents the active mass from shedding.

What's better?

It is quite difficult to give an unequivocal answer about which battery is better. The calmness and safety of not only the car, but also nervous system its owner. Studying the assortment of the store, you need to clearly understand what you expect from the new device, as well as know what characteristics of the battery are needed in your particular case.

Of the clear advantages maintenance-free batteries it can be noted that they do not require constant verification and control. In such models, the electrolyte boils away significantly less than in the service ones. They also have a longer lifespan and deliver more starting current when the vehicle is started.

The advantages of maintenance-free batteries include their low self-discharge. Any battery is discharged during long storage. However, these batteries lose only up to 2% of their charge per month, and serviced ones lose up to 20% of their charge in the same period of time. Therefore, the installation of the former excludes the possibility that the car will suddenly become unusable due to a frozen or discharged battery.

The charging process of this battery has one important feature that must be taken into account when purchasing it. This is the need to use only a special charger, which excludes manual adjustment of the current power. The use of a conventional device is fraught with the squeezing out of the boiling electrolyte from the battery with an incorrectly set current through the emergency valve. Subsequently, this affects the density of the liquid in the battery and reduces the battery life.

For all the benefits of maintenance-free batteries, maintenance-free batteries are still in production. The fairly high demand for them is largely due to their low price, compared to models without service. Also, high-quality operation of maintenance-free batteries requires good automotive electrics, which is difficult to achieve, for example, in cars. domestic production... Short circuit or overcharging is not allowed, the device must be charged at a constant, even voltage, without surges, in a strict range: from 13.9 to 14.4 Volts. When discharging, you cannot use a conventional charger - to replenish the energy of such a battery, a special charge is required that holds d.C. at the terminals.

Maintenance of the battery is necessary if, as a result of use, the performance of the battery has decreased (the starter turns too slowly, the car does not start, etc.). The main reason is the deviation of the battery from the operating parameters. The service includes:

• topping up with distilled water (electrolyte);
• cleaning the case from white bloom and dirt;
• recharging with a charger.

High-quality battery maintenance reduces the likelihood of its rapid failure and increases the reliability of starting the engine in the cold season.

Thus, there is no definite answer which battery is better - each type of device has its own disadvantages and advantages. For car enthusiasts, owners of new vehicle with modern electronics, the best option are maintenance-free products, and experienced car owners can select and service models.

Whichever device you prefer, you should only purchase it from reliable car dealerships that provide checks and warranty coupons. This will save you from high costs for repairing or replacing the battery in the event of a breakdown: an examination in the service center will determine the factory defect and become the basis for a free battery replacement.

The term "maintenance-free batteries" appeared with a significant change in the production technology of lead-acid batteries. Classic batteries have the following disadvantages:

• The presence of antimony additive in the composition of the electrodes improves the strength and castability, but increases the tendency to gas formation at high charging currents.
• The need for regular monitoring of the level and density of the electrolyte.
• High self-discharge value.
• Risk of crumbling of the active mass of the electrodes.

The replacement of antimony in the alloy with calcium and other metals helped to reduce the negative qualities. Calcium maintenance-free batteries do not require regular monitoring, but they have a number of disadvantages:

• The stability of the on-board voltage must be high (no more than 0.1V).
• Deep discharge of the battery is not allowed.
• Control of the electrolyte state is difficult.

Based on the foregoing, it is sometimes difficult to choose a serviced or unattended battery for your car.

Maintenance-free car battery device

There are no fundamental differences in the design of lead-acid batteries. Only the production technology differs. Maintenance-free batteries are made of high-purity materials with a change in the alloy composition of the electrode plates.

Due to the fact that it was possible to reduce gas evolution (electrolytic decomposition of electrolyte water), it became possible to seal the battery case. As a result:

• no losses due to water evaporation;
• surface self-discharge is reduced to a minimum
• additional cavities under the electrodes prevent crumbling sludge from short-circuiting the plates.

disadvantages

The most significant drawback inherent in maintenance-free batteries is the high voltage stability requirements of the on-board network. This requirement is due to the fact that calcium batteries do not allow deep discharge, thereby losing their capacity.

Systematic undercharging during short trips in winter leads to the fact that after a series of sequential starts of the starter, the EMF level approaches the minimum allowable, and the generator voltage is reduced due to a large number of consumers (heated mirrors and seats, headlights, heater operation). Before installing a maintenance-free battery in a car, you should make sure that the generator has the necessary power reserve, and the stability of the on-board network voltage does not go beyond the specified limits.

The high voltage is even worse for such batteries. Closer to the end of the charge, whatever the quality of the batteries, the moment of electrolysis of water in the electrolyte comes. In a sealed case of maintenance-free batteries, this can lead to swelling of the case, cracks, and leakage of electrolyte.

Which is better, a regular battery or maintenance-free?

If the car meets the listed requirements, then the answer is unequivocal, the new calcium battery is much better. Such batteries remove some of the duties from the motorist, improve the reliability of starting the car.

Another thing is a car with an outdated onboard power supply system. In old domestic and foreign models with a relay voltage regulation system, the necessary stabilization of the charge current at the battery terminals is not provided. As a result, there is either undercharging or overcharging with all the ensuing consequences. Servicing new batteries is difficult or impossible. In this case, the batteries often do not work out even warranty period exploitation.

Maintenance-free battery

For operational monitoring of the state of maintenance-free batteries, manufacturers complete them with a special indicator, which can be used to approximately estimate the state of charge and electrolyte level.

Attention! By the presence of an indicator (eye), you can distinguish maintenance-free battery from the usual.

It is important to know that the indicator displays the state of only one of the cans, mainly the central one. It is not known what happens in the remaining ones. If the indicator shows low level charge, the battery must be recharged using a charger with good stability in output voltage and charging current.

The only available and reliable method for checking a maintenance-free battery is measuring the EMF with a load plug. A simple voltage measurement with a voltmeter does not give the required accuracy, since it does not take into account the internal resistance of the battery. IN load fork a load from a high-resistance wire is connected in parallel to the terminals of the voltmeter. The load resistance corresponds to the nominal discharge current of the battery.

A reduced voltage level with normal indicator readings indicates a malfunction in one of the cans.

Most of the usual methods for monitoring electrolyte result in a void of product warranty, as the sealed enclosure makes it impossible to access the battery banks to determine their condition.

Topping up water or electrolyte

In order to add water to a maintenance-free battery or measure the density of electrolyte, you need to get access to separate banks. Some manufacturers cover the jar caps with a decorative lid. In fact, such batteries do not differ in design from the classic, maintenance-free and conventional maintenance methods are applicable to them. If the cover is glued, then it can be carefully detached from the case, and then glued again.

Worse if the lid is integrally welded to the body. In this case, opening a maintenance-free battery is much more difficult. Holes can be drilled opposite the filler openings. After servicing, the holes are closed with hermetically suitable caps.

Attention! It is important when drilling holes to prevent chips from entering the electrolyte. For this, holes are pre-drilled with a drill of a smaller diameter.

It is safer to use a large syringe. When using a syringe, the hole diameter does not exceed 1 mm. In order to determine the electrolyte level, the syringe needle is gradually lowered into the hole, while the stem is extended. When electrolyte is sucked into the needle, mark the level on the needle. The same actions are performed for all battery cells.

To check the density, part of the electrolyte is drawn into a syringe and poured into a suitable container, from which it is convenient to take a sample for measuring the density with a hydrometer. Remember to return the tested electrolyte to the same jar from which it was removed.

At a low electrolyte level, distilled water is poured into the banks, and in the case when it is necessary to raise the density, for example, when switching to winter mode, a corrective electrolyte with a density of 1.4 g / cm3 is added. In this case, it may be necessary to take a part of the electrolyte so that the final level does not exceed the permissible level.

After manipulating the electrolyte, the battery is charged in order to naturally mix the liquid medium. It is strictly forbidden to turn the battery over to drain the electrolyte or stir it, since the electrodes will be closed by the crumbling sludge.

The containers in which the electrolyte will be located must be made of glass, ceramics or plastic. The use of metal utensils is not allowed, since electrolyte is a chemically active medium and reacts with most metals. The stainless steel of which the syringe needle is made is an exception.

Battery recovery

Both conventional and maintenance-free batteries, if necessary, can be tried to be restored, since they have the same malfunctions. Loss of capacity and uneven change in density in individual banks is restored in maintenance-free batteries after several charge and discharge cycles with rated currents. Such actions help dissolve large crystals of lead sulfate, which reduces the amount of active substance required for a chemical reaction to proceed.

Gel batteries

Batteries in which the electrolyte is condensed to a jelly state stand apart. Such batteries are distinguished by high reliability due to low electrolyte fluidity, withstand lower temperatures, but they are even more critical of the stability of the on-board voltage and have a high cost.

Important! It is almost impossible and impractical to do the repair of maintenance-free gel batteries with your own hands.

Conclusion

It is impossible to say unequivocally which battery is better maintained or unattended, in which car a maintenance-free battery can be installed. It depends on many factors. Under favorable conditions and compliance with all requirements, the service life of calcium batteries is at least 5-7 years, which is slightly higher than that of conventional batteries.

These batteries are of various types: Liquid, Gel and AGM. To begin with, that's all acid batteries and the principle of their work does not differ from each other.

The 12-volt battery consists of six cells, in which there are electrode blocks consisting of positive and negative plates (grids) with an active mass applied to them and separated by a separator, all of which is filled with electrolyte. The process of formation (production) of electricity occurs during chemical interaction between the active mass applied to the lattice and the electrolyte.

The main fundamental difference between conventional liquid, Gel (GEL) and VRLA or SLA batteries created using AGM technology is the physical state of the electrolyte:

• Conventional batteries have a liquid electrolyte.
• Gel (GEL) - a thickened electrolyte to a non-flowing state with the help of special additives.
• VRLA or SLA, produced by AGM technology - the electrolyte is absorbed (absorbed) into the separator.

The grids of the electrodes holding the active mass are doped with antimony and arsenic. Additives improve the processability of casting, increase the hardness and corrosion resistance of electrodes. At the same time, antimony promotes increased consumption water and a decrease in the EMF of the battery during operation.

Further development led to a decrease in the proportion of antimony in the composition of the alloy from which the gratings are cast. This has led to the emergence of low maintenance batteries (low antimony technologies), and the battery life has also increased. Then calcium displaced antimony from the negative plates. "Hybrid" batteries have appeared, and they require topping up even less often.

The use of calcium in positive and negative plates (calcium technology) has resulted in batteries that theoretically do not require topping up throughout their entire service life. However, such batteries fail from deep discharges. To increase the resistance, silver was added to the lead-calcium alloy of the positive plates. The use of labyrinth covers and plugs that condense the remaining evaporation of water and return it back to the battery has led to the emergence of completely maintenance-free batteries throughout their life.

Gel batteries appeared with the beginning of space exploration. The gel resulting from the addition of silicon dioxide to sulfuric acid makes it possible to achieve complete tightness of the battery, since all gas evolution occurs inside the pores in the gel mass. Such batteries have no equal in terms of resistance to deep discharges, they are much more durable than traditional ones. But gel batteries did not get widespread among motorists due to very high requirements for onboard electrical equipment and due to a sharp drop in starting current in the cold.

Most modern technology (AGM) reverted to liquid acid, but now the electrolyte is trapped in the pores of an ultrafine glass fiber separator. This design allows not only to seal the case, but also to maintain the battery's performance even in the event of damage to the outer shell. AGM batteries are insensitive to temperature fluctuations, very resistant to deep discharges, durable, vibration-resistant and can work even while lying on their side, but are afraid of overcharging.

FEATURES OF GEL BATTERIES

The gel electrolyte fills the space between the battery plates, but the separator is not ruled out. Recombination of gases in gel batteries has an efficiency of up to 97%. The gel fixes the material of the plates more efficiently, reducing their wear in deep discharge modes, therefore, the cyclic resource of gel batteries is 2-3 times higher than that of conventional ones, so it is advisable to use them in cases where such an application (cyclic mode with deep discharge) is in demand. Gel batteries can also be used in any position (except inverted), have a slightly lower self-discharge, therefore gel batteries are preferably used in those modes where the discharge is performed with a low current for a long time.

In a gel electrolyte, ions have the worst indicators of mobility (due to the higher density of the medium), which negatively affects the dynamic discharge and charging characteristics of gel batteries. Moreover, there may be a temporary voltage dip with a sharp increase in load, which can lead to inadequate behavior of the equipment; therefore, care should be taken when using gel batteries in current control systems, etc. devices with switching of rapidly changing currents. Gel batteries are very sensitive to the quality of charging. Batteries with gel inside can only be used where the on-board electrical system allows very precise maintenance of the charge mode. Where there, on domestic cars even with a working relay-regulator, the voltage "walks" from 13 to 16 volts! And on most foreign cars it is not much better. And if the relay-regulator fails, then the gel battery can be thrown away immediately. It is not for nothing that it says: the charge voltage is not more than 14.4 V. If it is higher, then the gel melts like a jelly in the heat and cannot be restored back. And here's another thing: real gel batteries, of course, can have a huge current, but only in summer. The gel is already viscous, but in the cold it completely freezes. As a result, the characteristics drop by half or more.

The charging of gel batteries is limited to very low currents, otherwise there is a risk of "swelling" of the gel with excess gases due to the lower efficiency of recombination and limited thermal conductivity. Gel batteries are preferably powered from chargers with high quality voltage (stability, minimum ripple) in order to avoid overcharging and overheating, they do not tolerate even short-term short circuits - any short circuit (for example, when installing the battery, you accidentally closed two poles for a split second with a metal wrench) instantly disables the battery.

High vibrations cause the gel to liquefy and run off the plates. As you can see, gel batteries are "better" (if I may say so), only in terms of increased cyclic resource and lower% of self-discharge. Moreover, this type of battery is the most expensive.

LEAD-ACID SEALED VALVE RECOMBINATION BATTERIES (VRLA or SLA)

• VRLA (Valve Regulated Lead Acid) in English - Valve-Regulated Lead Acid;
• SLA (Sealed Lead Acid) - Sealed Lead Acid;
• AGM (Absorbent Glass Mat) is a lead acid battery technology developed by engineers at the Gates Rubber Company in the early 1970s. Porous fiberglass sorbent (AGM) is an absorbent separator used between the plates in a VRLA battery.

The peculiarity of VRLA batteries is that there is no need to add water during the entire service life and the almost complete absence of gases (hydrogen and oxygen) - products of electrolysis of water that is part of the electrolyte. Therefore, they are often called sealed maintenance-free. Minor maintenance is nevertheless necessary: \u200b\u200bfirst of all, visual inspection, dusting, tightening of connections and stress control.

Due to the design features and the composition of the materials of the plates, separators and electrolyte, the products of water electrolysis - hydrogen and oxygen molecules - in batteries of this type recombine, turning into water molecules and returning to the electrolyte composition.

The recombination coefficient under normal operating conditions is quite high and can reach\u003e 99%. Therefore, only a very small part of non-recombined gases accumulates inside the accumulator housing and then, when the set pressure level is exceeded, is released into the atmosphere through special valves.

Benefits:

• Vibration resistant, can be installed in any position and without the need for maintenance, high starting current.
• Maintenance-free design.
• The design is sealed and valve regulated to prevent acid leakage and terminal corrosion.
• More safe work: at correct charging batteries exclude the possibility of gas evolution and the risk of explosion.
• The sealed design allows the battery to be installed in almost any position (however, upside-down installation is not recommended).
• Confident work with low temperatures (below - 40 * C), low self-discharge (only 15 - 20% per year of downtime), complete maintenance-free and long, up to 12 - 15 years, service life.
• Increased vibration resistance increases service life.
• They provide a number of complete (70%) discharge cycles of about 500 times.

Disadvantages:

• Should not be stored in a discharged state, voltage should not fall below 10.8 V. Extremely sensitive to overvoltage charging.
  To charge batteries made using AGM technology, it is advisable to use a special charger with appropriate charging parameters that differ from the charging of classic batteries with liquid electrolyte. AGM batteries are not as "capricious" as gel batteries, but they also require attention to the condition of the generator and relay-regulator. The fact is that there is very little electrolyte in batteries of this type, and if it boils away, then it is impossible to top up.
• High price.

Batteries manufactured with AGM technology are manufactured in spiral or flat configuration. The spiral elements have a larger surface contact area, which makes it possible to deliver high currents for a short time and charge faster. but reverse side is a decrease in the specific capacity of the battery (the ratio of electrical capacity and dimensions) in comparison with a flat configuration. Both technologies are promising. Currently, the most common car batteries AGM with flat block configuration. SpiraCell spiral blocks are patented by Johnson Controls for the Optima series and cannot be used without permission, unlike flat blocks. Spiral batteries have higher current-transfer characteristics and lower internal resistance due to the larger working surface of the plates at the same external dimensions batteries. In simple terms, they are more powerful.

Lead-acid batteries with bound electrolyte, manufactured using AGM technology, appeared about 40 years ago - they were invented for operation in a buffer mode in stationary uninterruptible power supply systems. Such batteries are good from a safety point of view, since they practically do not emit gases formed during charging into the atmosphere. In the 90s of the last century, AGM technology took root in motorsport. First, again because of safety - now thanks to a completely sealed battery case, which prevents electrolyte leakage in an accident. And secondly, due to their compactness - due to the low resistance of separators impregnated with electrolyte, they give out a large starting current with a lower capacity, that is, with a smaller number of plates in the package. AGM batteries appeared on conventional cars more than ten years ago. At the moment, AGM car starter batteries are used as a power source for the "Start-Stop" system, which is equipped with a number of car models of leading manufacturers due to the ability to quickly give and receive a large number of energy, the ability to painlessly withstand deep discharges (with periodic discharges more than 50% AGM - the battery will last four times longer than usual) and not degrade with frequent discharge-charge cycles. After all, fiberglass mats, in addition to everything, mechanically hold the active mass on the plates, preventing it from crumbling. That is why on machines with the "Start-Stop" system, such a battery can work for four to five years, and not two or three years, as a normal "liquid" one.