These batteries come in different types: Liquid, Gel and AGM. Let's start with the fact that these are all acid batteries and the principle of their operation is no different from each other.

12 Volt Battery consists of six cells in which there are electrode blocks consisting of plates (grids) positive and negative with an active mass applied to them and separated from each other by a separator, all of this is filled with electrolyte. The process of formation (production) of electricity occurs through chemical interaction between the active mass deposited on the grids and the electrolyte.

Basics fundamental difference Conventional liquid, Gel (GEL) and VRLA or SLA batteries created using AGM technology lies in the physical state of the electrolyte:

• Conventional batteries have liquid electrolyte.
• Gel (GEL) - electrolyte thickened to a non-fluid state using special additives.
• VRLA or SLA, produced using AGM technology - the electrolyte is absorbed (soaked) into the separator.

The electrode grids that hold the active mass are doped with antimony and arsenic. Additives improve casting manufacturability, increase the hardness and corrosion resistance of electrodes. At the same time, antimony promotes increased consumption water and reducing 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 led to the emergence of low-maintenance batteries (low-antimony technologies), and the battery life also increased. Then calcium replaced antimony from the negative plates. “Hybrid” batteries appeared and began to require topping up even less often.

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

Gel batteries appeared with the beginning of space exploration. The gel obtained by adding silicon dioxide to sulfuric acid makes it possible to achieve complete sealing of the battery, since all gas evolution occurs inside the pores in the gel mass. Such batteries have no equal in resistance to deep discharges; they are much more durable than traditional ones. But gel batteries have not become widespread among motorists due to very high requirements for on-board electrical equipment and due to a sharp drop in starting current in the cold.

The most advanced technology (AGM) has returned to liquid acid, but now the electrolyte is held in the pores of a separator made of ultra-fine glass fibers. This design allows not only to seal the case, but also to maintain the functionality of the battery even if the outer shell is damaged. 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

Gel electrolyte fills the space between the battery plates, but a separator is not excluded. Recombination of gases in gel batteries has an efficiency of up to 97%. The gel more effectively fixes the material of the plates, reducing their wear in deep discharge modes, therefore the cyclic life 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 upside down) and have a slightly lower self-discharge, so it is preferable to use gel batteries in modes where the discharge is carried out at a low current for a long time.

In a gel electrolyte, ions have worse mobility (due to the higher density of the medium), which negatively affects the dynamic discharge and charging characteristics of gel batteries. Moreover, a temporary dip in voltage may occur with a sharp increase in load, which can lead to inappropriate behavior of the equipment; Therefore, caution should be exercised when using gel batteries in current control systems, etc. devices with switching 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 electrics allow 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’s not much better. And if the relay-regulator fails, then the gel battery can be thrown away immediately. It’s not for nothing that it says on it: the charge voltage is no more than 14.4 V. If it’s more, then the gel melts like jellied meat in the heat and is no longer restored. And here's another thing: real gel batteries, of course, can have a huge current, but only in the summer. The gel is already viscous, but in the cold it completely hardens. As a result, the characteristics drop by half or more.

Charging of gel batteries is limited to very low currents, otherwise there is a danger of “swelling” of the gel with excess gases due to lower recombination efficiency and limited thermal conductivity. It is preferable to power gel batteries from chargers with high quality voltage (stability, minimum ripple) to avoid overcharging and overheating, they cannot tolerate even short-term short circuits- any short circuit (for example, when installing a battery, you accidentally short-circuited two poles with a metal wrench for a split second) instantly disables the battery.

High vibrations cause the gel to liquefy and flow off the plates. As you can see, gel batteries are “better” (so to speak), only in terms of increased cyclic life and lower % self-discharge. In addition, this type of battery is the most expensive.

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

• VRLA(Valve Regulated Lead Acid) translated from English - Valve-Regulated Lead Acid;
• SLA(Sealed Lead Acid) - Sealed Lead Acid;
• AGM(Absorbent Glass Mat) is a manufacturing technology lead acid batteries, created by Gates Rubber Company engineers in the early 1970s. Porous glass fiber sorbent (AGM) is an absorbent separator used between the plates in a VRLA battery.

A special feature of VRLA batteries is the absence of the need to add water during the entire service life and the almost complete absence of the release of gases (hydrogen and oxygen) - products of electrolysis of water included in the electrolyte. Therefore, they are often called sealed maintenance-free. Minor maintenance, however, is necessary: ​​first of all, visual inspection, wiping off dust, tightening connections and checking stress.

Due to the design features and 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.

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

Advantages:

• Vibration resistant, can be installed in any position and requires no maintenance, high inrush current.
• Maintenance-free design.
• The design is sealed and valve-regulated, preventing acid leakage and terminal corrosion.
• Safer operation: with correct charging batteries eliminate the possibility of gas release and the risk of explosion.
• The sealed design allows the battery to be installed in almost any position (upside down installation is not recommended, however).
• Reliable operation at low temperatures (below − 40*C), low self-discharge (only 15 - 20% per year of inactivity), complete maintenance-free and long service life, up to 12 - 15 years.
• Increased vibration resistance increases service life.
• They provide a number of complete (70%) discharge cycles of about 500 times.

Flaws:

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

Batteries produced using AGM technology are manufactured in a spiral or flat-plate configuration. Spiral elements have a larger surface contact area, which makes it possible to produce high currents for a short time and charge faster. However, the downside is that the battery's specific capacity (the ratio of electrical capacity to size) is reduced compared to a flat configuration. Both technologies are promising. At the moment, the most common car batteries are AGM with a flat block configuration. SpiraCell spiral blocks are patented by Johnson Controls for the Optima series and cannot be used without their permission, unlike flat blocks. Spiral batteries have higher current output 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, made using AGM technology, appeared about 40 years ago - they were invented to operate in 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 motorsports. Firstly, again because of safety - now thanks to the completely sealed battery case, which prevents leakage of electrolyte in the event of an accident. And secondly, due to compactness - due to the low resistance of separators not insulating, but separators impregnated with electrolyte, they produce a large starting current with a smaller capacity, that is, with fewer plates in the package. AGM batteries appeared on conventional cars more than ten years ago. Currently, car starters AGM batteries are used as a power source for the “Start-Stop” system, which is equipped with a number of car models from leading manufacturers due to the ability to quickly both give and receive large amounts of energy, the ability to painlessly withstand deep discharges (with periodic discharges of more than 50% AGM - the battery will last four times longer than usual) and does not degrade during 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 cars with a Start-Stop system, such a battery can last four to five years, and not two to three years, like a regular “liquid” one.

A modern car cannot be operated without a mobile source of electricity. 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: serviced and maintenance-free. What a maintenance-free chemical source of electricity is will be discussed in detail in this article.

Contents

What is a maintenance free battery

A maintenance-free battery is a product that does not have the ability to top up 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 spillage of acid solution when tipped over.

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

Which one to choose, serviced or unserviced

Deciding on the type of battery to purchase can be very difficult. If the car previously had a serviceable battery installed, 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, you can easily restore the battery’s functionality 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.
• If you roll over on your side or drive too vigorously off-road, an electrolyte spill may occur.
• Higher leakage current, especially if electrolyte was spilled on the upper outer plane, between the terminals, during refueling.
• Additional time costs for preventive inspection and maintenance.

The maintenance-free battery has the following positive characteristics:

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

Flaws:

• If the battery fails, it will not be possible to restore its functionality.
• If the electrolyte boils away, it will not be possible to add distilled water without rough mechanical intervention;
• Critical to overcharging and deep discharges.

Attention! If the vehicle has serious electrical problems, then maintenance free battery won't 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 abnormalities in the vehicle’s on-board electrical network, then the most correct decision would be to purchase a maintenance-free device.

What types of maintenance-free batteries are there?

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

Lead calcium battery

A maintenance-free battery can be of the following types:

1. Calcium lead acid. The plates of this type of device are alloyed with calcium, as a result of which the material acquires properties such as vibration resistance and reduced corrosion effect. Also in calcium batteries there is a decrease in the process of self-discharge and boiling of the electrolyte.
2. A.G.M. Represents acid battery, in which between the plates the electrolyte is contained in special fiberglass separators. This type tolerates deep discharges more easily, and by reducing 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 battery is significantly increased compared to conventional products. To reduce each plate is wrapped special material, which is impregnated with an acidic electrolyte. Thanks to the use modern technologies service life ranges 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 established minimum limit for starting the engine.

Which chargers can charge maintenance-free batteries?

Considering the confined space in which the battery plates of a maintenance-free type are located, it is necessary to prevent significant overcharging of the battery.

Attention! To prevent the device from boiling, it is recommended to use an automatic charger.

The main advantage of this type of charger is the lack of human control during the entire charging time of the battery. The “smart” device itself will decide 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 a conventional 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 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 battery discharge level. Considering 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 diagnostics 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 charge 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, and the charge current should be 6 amperes.

It is easy to calculate how much time will be required when the discharge is 50% or when the battery capacity is reduced by 30%. To do this, you need to divide the total battery capacity by 100 and multiply by the charge reduction percentage, then divide the resulting result by 6 for a 60 A/h battery and by 5.5 for a 55 A/h battery.

GEL battery

How to restore a maintenance-free battery

If a maintenance-free battery fails before the service life recommended by the manufacturer, then, in many cases, it is possible to restore the battery's performance to acceptable values. Considering the inability to disassemble a maintenance-free battery, you will have to pierce the top battery cover with an awl in 6 places. This way you can gain access to 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 gas is released at a constant voltage of 14 V. When the charging process is completed, the battery is left for a while so that the lead plates are slightly cleared of the sulfate film.

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

Conclusion

The maintenance-free battery is ideal for use by novice drivers. Such a battery cannot be opened, so there is no danger of making mistakes during maintenance. For experienced drivers Those who know how and love to care for 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.

Correct operation of maintenance-free car batteries

Automotive battery technology has advanced significantly over the past couple of decades. If previously it was necessary to constantly check the electrolyte level in the battery, then modern models require significantly less attention to themselves. Manufacturers call these batteries maintenance-free, stating that they do not require constant monitoring of the electrolyte level. But the word maintenance-free can mislead the car enthusiast. After all, these batteries still require maintenance, which we will discuss in this article.

The concept of a maintenance-free battery has come into use since the advent of car batteries type Ca/Ca. In such models, positive and negative electrode grids are made from an alloy of lead and calcium. The so-called serviced models that were produced before had grilles made of an alloy of lead and antimony. Old car batteries had a high antimony content and were very high consumption water. Now they are no longer produced, and they have been replaced by models with a lower antimony content. They are also called low-antimony. The antimony content in the plates is less than 6 percent. In them, monitoring the electrolyte level must be periodic, since distilled water is constantly leaving it. Why? To do this, you need to consider the processes occurring in the battery.

When the battery is discharged, lead dioxide is reduced inside the car battery at the anode with sulfuric acid. At the same time, lead oxidation occurs at the cathode. When charging a battery, the process goes in the opposite direction. Antimony was added to lead plates in order to improve their strength characteristics. It is not possible to use electrodes made of pure lead due to its low strength. But adding antimony also brings a problem. Antimony acts as a catalyst for the hydrolysis of water from the electrolyte. Hydrolysis is the decomposition of water into hydrogen and oxygen under the influence of electric current. Outwardly it looks like boiling. This is why the expression “boiling away” of water from the electrolyte arose.

To solve this problem, manufacturers began to add calcium to electrode grids. This solution turned out to be very successful in terms of reducing water consumption.

With the advent of calcium-type car batteries, the concept of maintenance-free batteries appeared. And the lack of need for maintenance only concerns adding water to the battery.

Models without openings for access to banks began to appear in the product lines of battery manufacturers. To check the state of charge of the battery on such batteries you can often find a hydrometer or “peephole”. The hydrometer is designed to monitor the battery charge level. In the images below you can see a maintenance-free and a maintenance-free battery.

It is worth noting another category of maintenance-free batteries – gel batteries. The electrolyte is in a bound state. This may be an impregnation of fiberglass or a gel-like state. In most cases, such models are made in maintenance-free housings and do not require topping up water. Although in some cases distilled water is added to AGM batteries. For example, when .

Maintenance of maintenance-free batteries

Despite their name, maintenance-free batteries still require maintenance. Moreover, in a number of cases, maintenance-free performance, as they say, “backfires.”

Below are the main disadvantages of maintenance-free car batteries:

• It is difficult to control the electrolyte level;
• It is impossible to control the density of the electrolyte;
• They require flawless operation of the vehicle's electrical network and stability of the output characteristics.

As for the electrolyte level, some models of maintenance-free car batteries have minimum and maximum marks. For more information about what it is, read the article at the link.

In this case, the task of monitoring the electrolyte level is simplified. But on the other hand, what does knowing your electrolyte level give you? What if it is less than necessary? Still can't top it up. Of course, the water consumption is insignificant. And the covers of maintenance-free batteries are specially designed to ensure electrolyte recirculation. But distilled water still leaves, but you can’t top it up. And if the level drops to the point where the plates are exposed, then the life of the battery will begin to rapidly decrease. If you use the battery like this, you will need it very soon or it will go to the landfill.

Another problem with maintenance-free car batteries is the inability to measure the density of the electrolyte. And this characteristic is very important and gives an objective assessment of the condition of the battery.

At least just measure the density after the battery charging process for control. After all, without this, it is extremely difficult to understand the degree of charge and voltage here cannot be an objective indicator. To assess the state of charge of the battery, manufacturers build a hydrometer into maintenance-free car batteries. Car enthusiasts often call it the “peephole”.

A hydrometer is installed in one of the central banks of a car battery and monitors the density. Its action is based on the fact that the float rises when the density increases (charging) and falls when the density decreases (discharge). For ease of control, an appropriate color indication is provided. But here, not everything is so rosy.

Problems when using a hydrometer:

• If you believe the reviews of owners of maintenance-free car batteries, such hydrometers often fail, regardless of the model and manufacturer. And such a hydrometer begins to show data that is divorced from reality;
• Experts also say that the hydrometer provides information about the battery charge only when the battery capacity reaches 65 percent. And when it reaches 100 percent it will not be possible to find out, since the float does not give accurate values;
• The hydrometer measures the density in only one of the jars and what is going on in the others is unknown. It turns out that charge control is performed only on one can.

Now about charging maintenance-free car batteries. It is necessary to do it periodically for a number of reasons. The main problem is that when using a battery, including a maintenance-free one, in a car, it is not fully charged. In addition, due to a malfunction it may happen that . In this case, the car needs to be shown to an automotive electrician.

When the engine starts, the battery produces a powerful current and is discharged. To replenish the charge, you need to travel a fairly long distance. At the same time, the revolutions crankshaft must exceed 2000 rpm. Then the generator generates a sufficient amount of electricity both for consumers in the network and for charging the battery. When driving in urban conditions, it is difficult to ensure such a mode and constantly car battery undergoes a short-term surface charge.

That is, during such recharging, only the surface layers of the electrodes work. In order for the charge to penetrate the entire depth of the electrodes, a low current and a long charging time (up to a day) are required. It is impossible to provide such conditions in the vehicle’s on-board network. Therefore, periodically (preferably once every 3-4 months) you need to charge the battery from the mains charger. Which charging mode to set is described below.

How to charge a maintenance-free battery?

In the vast majority of cars, the voltage regulator in the on-board network sets a limit of 14.4-14.8 volts. The choice of this value is not accidental, since at large values ​​active hydrolysis of water begins and its consumption increases. When charging from a mains charger, you should also avoid exceeding the voltage above this value. In practice, you need to keep the battery voltage no more than 15.5 volts. More details can be found in the article at the link.

As for the charger, to charge a maintenance-free battery it is better to use a charger with automatic control. Then the charging process is ensured by special software embedded in the charger. In this case, commands to change current or voltage will be given by an algorithm, focusing on the electrical characteristics of the battery.

All you have to do is connect the charger “crocodiles” to the battery terminals, observing the polarity, and plug the device into the network. Additionally, you can read about.

Do not forget that when charging a battery, chemical reactions occur and harmful substances are released. Therefore, the battery should be charged in a well-ventilated area.

If you use a charger with manual adjustment of current and voltage, we recommend that you adhere to the following charging scheme for a maintenance-free battery. After connecting the charger to the battery, set the current to 0.1 of the battery capacity. That is, with a capacity of 55 Ah, this value will be 5.5 amperes. After this, set the voltage to 14.5 volts and turn on the charger. Read more about what it is.

Monitor the parameters during charging. The voltage will gradually increase during charging, and the current will decrease. When the battery voltage rises to 14.4 volts, the current should decrease to approximately 200 mA, which corresponds to the self-discharge current of the battery. The charging process will be completed.

			Battery charge level, %
Electrolyte density, g/cm. cube (+15 degrees Celsius)	Voltage, V (no load)	Voltage, V (with load 100 A)	Battery charge level, %	Electrolyte freezing temperature, gr. Celsius
1,11	11,7	8,4	0	-7
1,12	11,76	8,54	6	-8
1,13	11,82	8,68	12,56	-9
1,14	11,88	8,84	19	-11
1,15	11,94	9	25	-13
1,16	12	9,14	31	-14
1,17	12,06	9,3	37,5	-16
1,18	12,12	9,46	44	-18
1,19	12,18	9,6	50	-24
1,2	12,24	9,74	56	-27
1,21	12,3	9,9	62,5	-32
1,22	12,36	10,06	69	-37
1,23	12,42	10,2	75	-42
1,24	12,48	10,34	81	-46
1,25	12,54	10,5	87,5	-50
1,26	12,6	10,66	94	-55
1,27	12,66	10,8	100	-60

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 electrodes improves strength and casting properties, but increases the tendency to gas formation at high charging currents.
• The need for regular monitoring of the electrolyte level and density.
• High self-discharge value.
• Risk of shedding of the active mass of the electrodes.

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

• The stability of the onboard voltage must be high (no more than 0.1V).
• Deep discharge of the battery is not allowed.
• It is difficult to control the state of the electrolyte.

Based on the above, it is sometimes difficult to choose a serviced or maintenance-free battery for your car.

Maintenance-free car battery design

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

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

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

Flaws

Most significant drawback, which is inherent in maintenance-free batteries - high requirements to the stability of the on-board network voltage. This requirement is a consequence of 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 number of successive starts of the starter, the EMF level approaches the minimum permissible, and the generator voltage is reduced due to the 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 that the stability of the on-board network voltage does not go beyond the specified limits.

Even worse for these batteries high voltage. Toward the end of the charge, no matter what quality the batteries have, 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 a maintenance-free one?

If the car meets the listed requirements, then the answer is clear, the new calcium battery is much better. Such batteries relieve the car owner of some of the responsibilities and improve the reliability of starting the car.

Another thing is a car with an outdated on-board power supply system. Old domestic and foreign models with a relay voltage regulation system do not provide the necessary stabilization of the charge current at the battery terminals. As a result, either undercharging or overcharging occurs with all the ensuing consequences. Servicing new batteries is difficult or impossible. At the same time, batteries often do not work even guarantee period operation.

Maintaining a Maintenance Free Battery

To quickly monitor the condition of maintenance-free batteries, manufacturers equip them with a special indicator, which can be used to approximately estimate the degree of charge and electrolyte level.

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

It is important to know that the indicator displays the status of only one of the cans, mainly the central one. What happens in the remaining ones is unknown. If the indicator shows a low charge level, the battery must be recharged using a charger with good stability of output voltage and charging current.

The only accessible and reliable method for checking a maintenance-free battery is to measure the EMF with a load fork. Simply measuring voltage with a voltmeter does not provide the necessary accuracy, since it does not take into account the internal resistance of the battery. In the load plug, a load of high-resistance wire is connected in parallel to the terminals of the voltmeter. The load resistance corresponds to the rated discharge current of the battery.

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

Most conventional electrolyte monitoring methods void the product warranty because the sealed housing prevents access to the battery cells to determine their condition.

Adding water or electrolyte

In order to add water to a maintenance-free battery or measure the electrolyte density, you need to gain access to individual banks. Some manufacturers cover the caps of the jars with a decorative lid. In essence, such batteries are no different in design from classic, maintenance-free ones, and normal maintenance methods are applicable to them. If the cover is glued, it can be carefully removed from the body and then glued again.

It’s worse if the lid is welded monolithically to the body. In this case, opening a maintenance-free battery is much more difficult. You can make holes opposite the filler necks. After servicing, the holes are closed with hermetically sealed suitable caps.

Attention! When drilling holes, it is important to prevent chips from getting into the electrolyte. To do this, pre-drill holes with a drill of a smaller diameter.

It is safer to use a large volume syringe. When using a syringe, the diameter of the holes does not exceed 1 mm. In order to determine the electrolyte level, the syringe needle is gradually lowered into the hole, while simultaneously extending the rod. When electrolyte begins to be sucked into the needle, mark the level on the needle. The same actions are performed for all battery jars.

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 samples to measure the density with a hydrometer. We must remember to return the tested electrolyte to the same jar from which it was removed.

When the electrolyte level is low, distilled water is poured into the jars, and in the case when it is necessary to increase the density, for example, when switching to winter mode, then a correction electrolyte with a density of 1.4 g/cm3 is added. In this case, it may be necessary to select 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. Turning the battery over to drain the electrolyte or mix it is strictly prohibited, as the electrodes will short-circuit with 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 the electrolyte is a chemically active medium and reacts with most metals. The stainless steel from which the syringe needle is made is an exception.

Battery recovery

If necessary, you can try to restore both regular and maintenance-free batteries, since they have the same faults. The loss of capacity and uneven change in density in individual banks is restored in maintenance-free batteries through several cycles of charge and discharge with rated currents. Such actions help to dissolve large crystals of lead sulfate, which reduce the amount of active substance necessary for the chemical reaction to occur.

Gel batteries

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

Important! Repairing maintenance-free gel batteries with your own hands is almost impossible and impractical.

Conclusion

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

Modern automobile rechargeable batteries can last for years, providing your car with electricity. However, for this they need care and timely maintenance. We will talk about how to properly maintain the battery and what is needed for it to work as long as possible in this article.

How does the battery work?

To understand how electricity is generated in a battery, consider the processes occurring in a classic lead-acid battery.

Its working elements - a negative porous lead electrode, a positive electrode made of lead dioxide, as well as an electrolyte when connected to the load terminals, enter into chemical reaction, accompanied by the formation of lead sulfate on the negative plate, disintegration of the electrolyte, and accelerated movement of charged particles.

When the battery is charged, the completely opposite process occurs: lead is reduced at the negative electrode, and lead dioxide is regenerated at the positive electrode. At the same time, the density of the electrolyte increases.

Types of batteries for maintenance

Battery maintenance is usually divided into 4 groups:

• serviced;
• low maintenance;
• hybrid;
• unattended.

Serviced batteries

This group includes classic automotive power supplies that require systematic topping up with distilled water (after 5-7 thousand kilometers), as well as regular recharging. Some models even provide for replacement of working plates. With proper care, such a battery can last forever.

Today you can rarely find serviced batteries on sale, and such models are not cheap. As a rule, they are used for special equipment. For example, serviceable Varta batteries have found their application in agricultural and construction machines.

Low-maintenance batteries

Low maintenance batteries are the most common type of battery. We most often purchase them for our cars, and often confuse them with serviced ones. Electrolyte should be added to such power sources no more often than after 25 thousand kilometers, and charged as they are discharged.

Hybrid batteries

The hybrid is the same low-maintenance battery with increased performance characteristics. Due to the fact that their working grids are made of different metal alloys, their starting current is significantly higher, and the self-discharge current is practically absent.

Hybrid batteries are serviced in the same way as low-maintenance ones.

Maintenance-free batteries

As for maintenance-free batteries, this is new segment electrical products, which does not involve any intervention in their internal design at all. Their housing is completely sealed, and Newest technologies practically eliminate boiling and evaporation of the electrolyte. However, having purchased such a battery model, you should not forget about it, since it is still necessary to maintain a maintenance-free battery. It is necessary to systematically inspect it for mechanical damage, take care of the terminals, monitor the charge level, and periodically charge it.

What does service mean?

You can extend the life of your car battery only by caring for it and servicing it on time.

Battery care and maintenance, depending on its type, may involve several types of work:

1. systematic visual inspection for mechanical damage;
2. checking the electrolyte level and charge;
3. adding electrolyte;
4. charger.

How to maintain a gel battery

Gel batteries appeared relatively recently. They have a number of undeniable advantages over acidic ones. First of all, this concerns the service life - their minimum resource is 700 discharge-charge cycles. They are very resistant to sub-zero temperatures and physical impact. However, they also have some disadvantages. Firstly, the price is high, and secondly, they are very sensitive to overcharging.

The most important thing in maintaining gel batteries is to prevent the charging voltage from exceeding the threshold, which is usually 14-14.4 V, and is indicated by the manufacturers in the user manual. In addition, charging such batteries should be carried out exclusively with special chargers for gel batteries.

How to determine electrolyte level

Checking the electrolyte level is possible only in serviced and low-maintenance batteries. It is done quite simply. You need to unscrew the cap of one of the jars and lower a thin glass tube into it. It will immediately rest against the upper grid of plates. Having pulled out the tube, you need to measure the distance to which it is covered with electrolyte. If it is less than 10 mm, you need to add distilled water to the jar to the desired level. Measurements are carried out in all 6 banks.

How to understand when it's time to charge your battery

Timely recharging can also extend the life of the battery. Under no circumstances should you allow deep discharge. In this case, the working plates immediately fail, and the battery itself ceases to hold a charge.

Look at the instrument panel. There is a separate window that displays the process of charging the battery from the generator. At the slightest deviation from the norm, immediately contact an electrician. Don't be lazy to look under the hood. If you have a maintenance-free battery, monitor its charge using the indicator. Its green color means that the battery is charged, black means it is discharging, and white indicates that the battery is completely discharged.

If you use a serviceable battery, systematically check the voltage at the terminals with a car tester in voltmeter mode. It should not be lower than 12.5 V. At least once every three months, and be sure to check the density of the electrolyte in the battery banks when preparing the car for winter. This is the most accurate test that determines its performance. If the hydrometer shows less than 1.22 g/cm. cube, hurry up and charge the battery.

How to charge a serviceable battery

There are several methods for charging batteries:

• charging at a constant current;
• charging at a constant voltage;
• automatic (combined) charging.

Attention: before starting charging, you must unscrew the caps of all cans!

DC method

For charging method direct current The battery is connected to the charger, and a voltage of 16-16.3 V is applied to it. The required current value is determined based on the estimated charging time: for 20 hours - 1/20, for 10 hours - 1/10 of the battery capacity.

Constant voltage method

To charge using the constant voltage method, 16-16.5 V is supplied to the battery terminals. At the very beginning of the process, the current can reach 50 A, half of which the charger will automatically “extinguish”, and charging will occur at a rated current of 20-25 A. As the charge increases, the battery current will increase, trying to catch up with the charger current, and by the end it will drop to zero. Using this method, the battery is fully charged in 1-1.5 days.

Automatic charging

This method is considered the most correct. It combines the two methods described above, but this requires a special automatic charger.

At the very beginning of charging, a constant current equal to 1/10 of its capacity is supplied to the battery. After the battery voltage increases to 14.6-14.8 V, the device will switch the mode and begin charging with a constant voltage with an automatic decrease in current.

This method is also the fastest - the average serviceable Bosch battery is fully charged within a day.

If you have any questions regarding the selection, operation or maintenance of a particular type of battery, please contact us. Our specialists will always help you with this.