The battery is a relatively short-lived product that must be replaced after a certain mileage. To extend the service life helps to control the level of electrolyte, its density, charge level.
Without the use of special tools, you can only control the electrolyte level, in order to check the rest, it is better to contact specialists or pay attention to indirect indicators of the operation of electrical equipment.
How should it be normal?
Lead battery is a rechargeable source of electrical current. It has been produced for more than 100 years, as it has a simple design, is popular and is easily produced by modern industry. Over a hundred years, it has undergone many changes, but even now new technological solutions are emerging. 
The operation of the battery is most often based on redox reactions occurring between lead plates and a solution of sulfuric acid. When discharging, the electrons of sulfuric acid bind to the atoms of porous lead, when charging, lead is released back, the number of ions in the acid solution increases, and the density of the electrolyte increases.
The ratio of distilled water and sulfuric acid in automotive battery is selected for the most optimal passage of charge-discharge processes. The best density should be 1.27 g/cm 3 . A discharged battery has a much lower density - in winter, the battery can even freeze if it is heavily discharged. But in general, the density fluctuates around a value of 1.27 g / cm 3.
When working inside the battery, the density and electrolyte level are interrelated. The smaller the electrolyte volume, the higher the density, and vice versa. If the electrolyte level is not regularly checked, it may fall below the level of the lead plates.
Important! Operating a battery with bare lead plates will result in permanent damage.
What level should be normal? — The normal electrolyte level is 10-15 mm above the lead plates. It is enough for the plates to be completely immersed in the electrolyte when the car is moving. When the electrolyte level changes, the balance of reactions is disturbed, which leads at least to rapid wear of the battery. A low electrolyte level is almost always a sign of increased electrolyte density.
Reasons for changing the volume of liquid
Due to the characteristics of the battery, the level and density of the electrolyte decreases over time. This happens almost always, even in maintenance-free batteries. In most cases, the density increases over time, because sulfuric acid is not subject to evaporation or hydrolysis, unlike water. In fact, the level of water in the electrolyte changes.
This happens for the following reasons:
Important! Measure the density and level only after a full charge.
A low level adversely affects battery performance - concentrated acid easily corrodes lead and its salts settle on the plates and bottom, sulfating the battery and shorting the banks. To prolong battery life, you need to periodically monitor the density and level of the electrolyte.
How to check?
Properly servicing the battery with your own hands is not difficult, it does not require expensive devices. Checking the electrolyte level is a simple and straightforward procedure, but there are some nuances here.
Attention! Acid splashes can damage the skin, mucous membranes, the surface of the eye! Use goggles, respirator, rubber gloves. In case of damage to organs or electrolyte splashing, it can be neutralized with a weak solution of baking soda. If there is no soda at hand - any soda soda.
When handling batteries, do not allow sudden movements, throws, shocks. All work should be done carefully and with the right tool.
Video on checking the electrolyte level
Visual instruction.
How to determine in a maintenance-free battery?
The status of maintenance-free batteries is carried by several types - gel, fiberglass and with a labyrinth cover. Only the latter can be serviced by drilling holes in the lid for access to the jar. If the label has the letters GEL or AGM, tampering with the battery may result in battery failure.
Often, special “eyes” are provided to check the electrolyte level, and how to use them is explained in detail. 
After intervention, the operation of the labyrinth lid will be disrupted, and the battery becomes normal. After checking the level, the holes are plugged with suitable plastic plugs. When drilling holes, do not allow chips to enter the can. You can read about how to do it right.
It is impossible to carry out maintenance of high-tech batteries for no apparent reason - only if there are complaints about the work and you still have to buy a new one - only in this case you can open sealed cans.
What to do if the level is low
If the level is slightly lower, you can simply add distilled water to the level and put the battery on top of charge. Do not add drinking or mineral water - this will significantly reduce the life of the battery.
But with a strong drop in level, be sure to measure the density of the electrolyte. This is done with a special device - a hydrometer, and about how to determine the level of density, separate article. 
Depending on the hydrometer readings, distilled water, regular battery electrolyte or concentrated electrolyte should be added, bringing the density to 1.27 mg/cm 3 .
The density and level in all banks should be the same, this indicator is extremely important for the operation of the battery.
Conclusion
As you can see, the electrolyte level affects the efficient operation of the battery. A “poured” or “empty” battery spins the starter much weaker, does not perceive charging well, and discharges on its own during parking.
Its control helps to understand the condition of the battery, extend its service life and avoid sudden breakdowns.
In one of the previous materials on charging car batteries, we already wrote that a certain advantage of serviced batteries is the ability to monitor the state and electrolyte level, which allows you to extend the battery life and even reanimate it after a long idle time without a charge. This issue is worth considering in more detail - although more car owners are choosing maintenance-free batteries, the demand for batteries of the classic design remains. Checking the electrical parameters of the battery is relevant for all types.
What is the meaning of diagnostics?
The main parameters that are important for the owner are how the battery behaves under real load (voltage drops, maximum current) and its real capacity. Even a fully charged battery (according to a voltmeter or roughly - according to the built-in "eye") does not guarantee a confident start - with significant deviations in the level and density of the electrolyte, "crumbled" plates, it will be unable to maintain normal starter speed, slowly gain charge. Diagnostics will help to determine exactly what the cause of the problems is - in the battery, poor contact of the ground wire, or in the starter itself.
Already relying on knowledge about the incorrect operation of the battery, you can (if, of course, it is serviced) find out if the malfunction is fixable - after spending some time, you may be able to save a tangible amount. There is a special meaning in checking the electrolyte density in winter - for example, a fully charged (that is, having a normal electrolyte density) battery will freeze at a temperature of about -54 degrees, and if the density decreases by only 0.15 g / cm 3 - already at -8.
Video: How to do battery maintenance
How to Check the Electrolyte Level
The composition and quality of the electrolyte largely determine both the efficiency of the battery and its life. By itself, the electrolyte is dilute sulfuric acid, which participates in chemical reactions on the surface of the plates: when discharged, it is consumed (lead sulfate is formed), and when charged, it is restored.
For the correct course of the reaction and to achieve the desired resource, the density of a fully charged battery is normalized at the level of 1.27-1.28 g / cm 3 for a temperate climate, for a colder climate it is customary to increase the density, thereby compensating for the slowdown in the course of chemical reactions in frost (up to 31 g/cm3).
During battery operation, the electrolyte level inevitably drops: the inevitable electrolysis of water, which occurs at , reduces the level and increases the density. With a long discharge, part of the acid remains consumed in the form of large crystals of lead sulfate, which will not be restored during subsequent charging - the density will drop.
Video: How to check the electrolyte level in the battery
Equally important is the level of electrolyte in each bank - the electrolyte must cover the plates with a margin in order to fully use their usable area even during fluctuations (banks, sharp accelerations or braking). It is easiest to check it - in batteries with translucent walls, marks are usually even applied, by which you can see the minimum and maximum levels. In opaque batteries, you can use any transparent tube by unscrewing the plug and releasing the tube into the hole until it stops against the plates: by pinching the top edge of the tube with your finger and pulling it out, you can see how much the electrolyte is higher than the plates. Normally, this excess should be 10-15 millimeters.
Is the level low? Well, it's worth replenishing. In theory, it is enough to add distilled water, since it is consumed first of all. But in practice, especially if the battery has already worked for a long time, such topping up can lead to a drop in density - as we wrote above, part of the acid will be spent on undissolved lead sulfate. Therefore, you need to make sure exactly what the density of the electrolyte is at the current moment.
How to find out the density of an electrolyte?
To control the density of the electrolyte, a simple device is used - a hydrometer. This is a transparent tube with a pear for electrolyte sampling, in which a pointer weight of a predetermined density floats. Opposite this weight, a scale is graduated - accordingly, depending on the ratio of the densities of the weight and the electrolyte being tested, it will indicate different divisions of the scale, which is what we need. Approximately the same, but much more crudely, the built-in "eyes" work - a green ball floating in a dense electrolyte becomes visible in the indicator light guide, but if it sinks (density has dropped) - blackness in the eye.
Hydrometer device
Since the density of the electrolyte is significantly dependent on its temperature, it is best to measure it on a warm battery. If this is not possible, the following amendments are adopted:
| Temperature | Density correction |
| -55…-41 | -0,05 |
| -40…-26 | -0,04 |
| -25…-11 | -0,03 |
| -10…4 | -0,02 |
| 5…19 | -0,01 |
| 20…30 | 0 |
| 31…45 | +0,01 |
Density measurement is started when the battery is fully charged. The nose of the hydrometer is lowered into the jar, then the electrolyte is taken into it with a pear. The current density is determined by the pointer. If the level is within the normal range, then the density should correspond to normal.
Video: How to check electrolyte density
With a significant decrease in the electrolyte level, the composition of the topping up is determined by the density: if it is above the norm, then distilled water is added, if it is lower, then acid will also have to be added. However, how to determine the right amount of it, not knowing how much electrolyte is left in the bank? The most optimal and reliable method is to completely drain the electrolyte from the can and replace it with a ready-made one with a normalized density.
It is safest to drain the electrolyte into a wide plastic basin filled with several liters of water - in this case, water will be sprayed, not acid, and the final concentration of acid will be low enough for safe disposal. Draining the electrolyte will allow you to simultaneously check the presence of sediment in the bank: it will clearly indicate the destruction of the plates. Having found a sediment in one of the cans, you need to drain the electrolyte from all, then rinse all the cans, filling them two or three times with distilled water, and only then fill them with fresh electrolyte.
Battery level control
Density control is convenient in that it allows you to assess the condition of each battery cell. But not everyone has a hydrometer, and this method is not applicable to maintenance-free batteries. Knowing the characteristics of a lead-acid battery, you can roughly estimate its charge with a voltmeter - without load, its readings should be in the range of 12.8-13.2 V, since there are 6 cans connected in series in a 12-volt battery, and when fully charged, each has a voltage at the terminals of 2.2-2.4 V. The battery is considered discharged if the voltage on the bank drops below 2.03 V (that is, 12.18 V in total).
Video: Checking the battery charge with a load plug
The roughness of this evaluation method is that the voltage on all banks is summed up, regardless of their condition. For example, if five out of six cans are fully functional and charged, and a short circuit occurs in the sixth, then we will see 10.75V on the voltmeter - it would seem that the battery is in deep discharge, but attempts to charge it will only lead to the “boiling away” of the electrolyte in serviceable cans .
But even if the voltage at the terminals is normal, it is not a fact that the battery will be able to deliver the required current. To control current output, load devices are used - in the simplest case, this is a conventional load plug, consisting of a powerful low-resistance resistor and a voltmeter, the most complex devices (used, in particular, in dealer auto technical centers) have built-in electronic circuits, based on the voltage drop at a less powerful load from a pre-entered nominal capacity that determine the condition of the battery. Since the price of such devices makes their purchase unjustified for an ordinary motorist (in particular, the Micro 568 battery tester costs about 16 thousand rubles), we will focus on load plugs of a traditional design.
By connecting the plug terminals to the battery, you can see the voltage on it - based on the above values, you can roughly determine its degree of charge, many devices have color markings for convenience (green / yellow / red range). By pressing a toggle switch or a button on the case, we connect a load to the battery, the resistance of which is tenths of an ohm - thereby, it simulates the inclusion of a starter with a power of about a kilowatt. At this point, the voltage at the terminals will drop sharply and begin to decline even more. A healthy battery can be considered if the load does not cause a voltage drop of more than 2 volts (for commonly used batteries at 55-65 Ah, the larger the capacity, the less the drawdown should be), and a further decrease in voltage occurs slowly and smoothly. A sharp drop in voltage is a clear indication that the battery is no longer able to deliver high current, and its rapid decrease within a few seconds means a significant drop in battery capacity.
Car batteries need regular recharging and maintenance. Checking the density and level of electrolyte in a car battery can extend the life of the device.
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Electrolyte and its role in a car battery
Lead-acid batteries are used in passenger cars equipped with internal combustion engines. The plates of the battery are in a special liquid capable of conducting electric current - electrolyte. The battery electrolyte is a solution of hydrochloric acid in distilled water.
Foreign impurities in the electrolyte are not allowed, since they worsen the characteristics of the liquid - density and electrical conductivity.
In a lead battery, three components are used to pass current-generating processes:
- lead dioxide PbO2, located on the positive contact (cathode);
- spongy pure lead present on the negative contact (anode);
- electrolyte.
As the battery discharges, pure lead at the anode is converted to PbSO4 sulfate. In this case, the substance changes color and gives two electrons to the electrical circuit. Electrons are absorbed at the cathode and lead dioxide is converted to sulfate. The movement of electrons is carried out through an external circuit.
The device and principle of operation of a lead battery
During the formation of lead sulfate at the cathode, sulfuric acid is consumed from the electrolyte solution, which leads to a decrease in density. If the battery is put on charge, then the processes go in the opposite direction. The charge goes up to a certain point, after which the density of the solution does not increase further. This moment is considered the point of full charge of the battery. Further charging leads to the decomposition of water into oxygen and hydrogen, which are released from the electrolyte in the form of gas bubbles. This process is called battery boiling.
Density and level of electrolyte in the battery
Since the electrolyte is an integral part of the electrochemical process occurring in the battery, it is necessary to maintain its parameters. To assess the state of the solution, the concept of liquid density is used. The battery provides the required voltage only at a certain value of this indicator. With an increased or decreased parameter, the current source does not work correctly and fails. The level of liquid in the banks ensures the functioning of the entire surface of the plates. When a part is exposed, the element undergoes intense destruction, which will quickly disable the battery.
Why is it necessary to check the electrolyte level and its density?
To maintain the working condition of the battery, it is necessary to ensure the density and level of the electrolyte within the specified limits. Exceeding the tolerance standards leads to the destruction of the plates and loss. By changing the parameters, one can indirectly judge the health of the generator installed on the car.
Electrolyte level control
Control of the electrolyte level on serviced batteries is carried out by a special meter. may have marks on the side of the minimum and maximum amount of liquid. It is impossible to restore the level on such sources. When the volume goes beyond the range, the owner should be prepared to buy a new battery.
How to check the electrolyte level in the battery?
Steps for measuring the electrolyte level in a car battery:
- Wipe the battery cover with a clean cloth.
- Open ventilation plugs. To unscrew, a coin is used, which fits snugly into the grooves of the plugs.
- Lower the glass measuring tube (with a diameter of 5-6 mm) into the jar until it stops in the plates or safety net.
- Pinch the top of the tube, and then remove it from the jar.
- View the received value. The norm is the level within 12-15 mm above the surface of the plates.
Level measurement with a tube Why does the electrolyte level drop?
There are reasons for the drop in the electrolyte level:
- evaporation of water from the solution;
- battery recharge due to a faulty relay regulator;
- solution flow through cracks in the body.
If the battery has a low electrolyte level - what should the car owner do?
Depending on the cause of the level drop, various methods are used to restore the amount of electrolyte in the battery.
The owner can restore the amount of liquid:
- If there are no traces of electrolyte leakage on the battery, then the level is restored by adding distilled water. After that, it is necessary to wait some time and measure the density of the liquid. If a parameter deviates from the norm, it must be restored. Density adjustment techniques are shown below.
- To check the voltage, a tester is used, which is connected to the battery terminals. The voltage in the on-board network with the engine running should not exceed 14.4 V (at any crankshaft speed).
- If damage is found on the case, you can try to solder them using acid-resistant plastic. After that, electrolyte with the same density is poured into the jars.
A video tutorial on raising the density of the electrolyte is provided by the Denis MECHANIK channel.
Consequences of incorrect electrolyte level in the battery
Incorrect fluid level leads to negative consequences:
- A lower level leads to the exposure of the edges of the plates, which begin to collapse. Fragments of elements crumble inward, forming conductive bridges. Because of this, an active internal discharge of the battery begins, leading to a drop in capacity. Constant self-discharge additionally destroys the plates, which quickly renders the battery unusable. Restoring such a voltage source is impossible.
- With an increased amount of electrolyte, fluid leaks onto the body and subsequent corrosion occurs. Electrolyte drips form conductive paths that close the terminals. Eventually, the capacity of the battery starts to drop.
Electrolyte density control
Checking the density of the electrolyte is one of the main ways to monitor the condition of the battery. Measurement is performed using a special device - a hydrometer. Based on the results of the measurement, it is possible to draw a conclusion about the state of the battery and the level of charge.
Procedure for measuring density in serviced devices:
- Wipe the battery cover with a clean rag and open the plugs.
- Wipe the hydrometer and collect liquid from the jar.
- Wait 1-2 minutes and check the density value.
- Drain the liquid back.
- Take measurements for the rest of the banks. The norm is considered to be a density in the range of 1.25-1.29 g / cm³ (for the southern and northern regions of Russia, respectively).
Maintenance-free batteries can be equipped with a viewing eye for a rough estimate of the charge level. The peephole can be unscrewed from the lid (not on all types of batteries) and measure the density in the jar. The remaining banks are not available for measurement, so the state of the battery will have to be judged by one measured value.
Battery electrolyte density table
Below is a table of correspondence between density and charge level, compiled for a temperature of 20-25 ºС. You can clearly see the dynamics of the voltage drop as the battery is discharged. Voltage data may vary on batteries from different manufacturers.
Correspondence table for density and charge level.
| Charge degree, % | Discharge degree, % | Density, g/cm³ | Terminal voltage, V |
| 100 | 0 | 1,277 | 12,73 |
| 90 | 10 | 1,258 | 12,62 |
| 80 | 20 | 1,238 | 12,50 |
| 70 | 30 | 1,217 | 12,37 |
| 60 | 40 | 1,195 | 12,24 |
| 50 | 50 | 1,172 | 12,10 |
| 40 | 60 | 1,148 | 11,96 |
| 30 | 70 | 1,124 | 11,81 |
| 20 | 80 | 1,098 | 11,66 |
| 10 | 90 | 1,073 | 11,51 |
| 0 | 100 | 1,060 | 11,40 |
How to check the density of the electrolyte in the battery?
When self-measuring density with a device, you must follow the rules:
- measurement is carried out in each bank;
- during the measurement process, it is forbidden to try to equalize the density value by turning the battery over;
- ventilation plugs, battery surface and hydrometer must be clean;
- the battery being measured must be fully charged;
- the battery must be kept for 3-4 hours at room temperature.
Density measurement is only possible on serviced batteries. On maintenance-free batteries, banks do not have inspection holes.
How to increase the density of the electrolyte in the battery?
The first step in increasing the density of the electrolyte is the dissolution of lead sulfate deposited on the plates. For this, special chargers and cyclic charging and discharging of the battery are used. The method helps to dissolve part of the substance, which will increase the density of the electrolyte. After that, you need to re-measure the parameter. The spread of values among banks should not exceed 0.01 g/cm³.
If a density is found in the range of 1.18-1.20 g / cm³, then it is necessary:
- Pump out some of the electrolyte in the jar with a rubber bulb.
- Add liquid with a density of 1.27 g / cm³ to the norm.
- Wait a few hours for the full mixing of liquids. You should not shake or shake the battery to speed up the procedure.
- Re-measure the value.
- Carry out the pumping and topping up procedure again.
At a density below 1.18 g/cm³, the procedure for restoring the density is to top up with clean battery acid.
Since the electrolyte has an aggressive effect on the skin, it is recommended to carry out operations to increase the density of the liquid with rubber gloves.
There is another recovery method, which involves recharging the battery:
- Pump out the electrolyte from the cans with a rubber bulb.
- Close plugs.
- Lay the battery on the side. Turning the battery 180º is not recommended, as there is a risk of shedding of the active mass and short circuits inside the cans.
- Drill holes in the bottom of the cans with a drill with a diameter of 3-4 mm. Drilling is done carefully so as not to damage the plates.
- Put the battery in its normal position and rinse the jars with running distilled water.
- Solder the holes with plastic similar to that used for battery cases. Usually they use old plugs or debris from broken batteries.
- Pour electrolyte into the jars to the norm. Some owners add liquid with a slightly increased density.
This density recovery technique prolongs the life of the battery for a short time. If sulfation processes have begun in the battery, then the car owner must prepare to purchase a new power source.
Modern car batteries practically do not require care and maintenance - this is the opinion of most motorists and driving school instructors. In fact, this is not entirely true, and in order for the purchased battery to honestly work out its due date, certain measures are still necessary. Especially with prolonged use of the car in high temperatures.
The first thing to do constantly is monitor the cleanliness of the battery, because if conductive dirt accumulates on its cover, short circuits between its terminals are possible. The second is to constantly ensure that the battery is securely fixed in its socket. And thirdly, it is enough to regularly check the electrolyte level in the battery, since its changes have an extremely negative impact on the performance and the overall life of the battery.
At the same time, both a decrease in the level and its excess are not allowed. This is done in any battery, while most do not know how to check the electrolyte level in a maintenance-free battery, although this does not require complex manipulations - they have special indicators. Regardless of the type of indicator and its name, they allow you to check the electrolyte level in the battery quickly and with a high level of reliability.
Why check the electrolyte content
The battery manufacturer clearly defines the required solution level. When it is normal, all the plates located inside the battery are completely covered with it, which ensures that the battery can function normally and correspond to the declared capacity. Any changes make bad adjustments to the “working” process of the battery, and many problems appear - from rapid self-discharge to short circuits and destruction of internal plates. In the latter case, resuscitation of the old battery may be completely impossible.
The electrolyte level in a car battery must be constant, as well as its density. In addition, the poured solution must be clean, i.e. free of foreign impurities. Their role can often be played by various chemical elements that significantly change the process of normal operation, reducing the life of the battery. By regularly checking the electrolyte level in the battery, you can independently determine the presence of some contaminants. So, if the electrolyte becomes crimson during recharging, this indicates the presence of manganese, and if the solution is contaminated with copper, there will be excessive gas formation.
How to check the level correctly
Before checking the electrolyte level in the battery, it is necessary to determine the room, which must be fireproof and have good ventilation. The procedure after that will be as follows:
All these manipulations are only relevant if there are no min-max marks on the battery. So, the electrolyte level in the glass tube should vary within 12-15 mm. operation of the battery with a level below 12 mm is strictly not allowed. You can see how this parameter is checked in the video:
Attention! Wear thick rubber gloves before checking the electrolyte level in the battery, as acid from the electrolyte can cause severe burns to the skin.
Why does the electrolyte level drop?
Can be distinguished 4 main reasons for the decrease in the level of electrolyte in the battery.
The decrease in the electrolyte level occurs as a result of boiling water - the acid remains in place due to the fact that it is heavier than water. Accordingly, if it needs to be restored, only distilled water should be added, and nothing more. A common mistake made by many inexperienced drivers who do not know what to do when they find a low electrolyte level in the battery is topping up with new electrolyte. This only leads to an increase in its density, which negatively affects its performance and service life.
If the question - what should be the electrolyte level in the battery and how to check it - is quite simple, then the question of determining the density is not so simple. After the electrolyte level is restored, the battery must be charged. And only after that you can start measuring the density of the electrolyte. To do this, you need to use a special device - a hydrometer. After some time has passed since the end of charging, the battery is placed on a flat surface and all plugs are unscrewed.
The rubber pear of the hydrometer is compressed to force all the air out of it, and its tip is immersed in the first can of batteries. After releasing the pear, you must wait until the device is filled with liquid. The float located inside the flask will show the density. As a rule, most devices have color scales - the float in the green sector will correspond to the normal value. If the density is lower, a concentrated solution should be added to the battery, if higher - distilled water. Repeated measurements should be carried out after 3-4 hours, when all the liquid acquires the same density. You should not shake and “flounder” the battery to force the process. More details about the test are described in the video:
Consequences of an incorrect electrolyte level
If the electrolyte level of the car's battery is not checked or the results are ignored, the consequences will not be long in coming. As mentioned above, the normal level in the battery is 12-15 mm. If it turns out to be less, and the operation of the battery continues, the plates will be the first to suffer. They begin to slowly collapse and crumble, causing the formation of sludge. Subsequently, this threatens the formation of the so-called. bridges between the plates, which, due to their current conductivity, become a source of constant short circuits, seriously impairing battery performance, reducing its power, making starting the engine more and more difficult.
If you drive with a high electrolyte content, this will also negatively affect the plates, which will be corroded by too high an acid content. In addition, it will begin to actively splash out of the battery, including through the holes designed to let the gas out. As a result, they may become clogged. Liquid that gets on the battery cover quickly causes oxidation of the contacts, as a result of which the contact is broken and the car is difficult to start. In addition, it threatens the same closures.
Responsible for starting the engine and ensuring the operation of the vehicle's on-board network. Most motorists use batteries (batteries), which, subject to the rules of operation, require practically no maintenance. In general, the owner of the car is required to keep it clean and regularly, two or three times a year, check the degree of its charge. The degree of charge of the battery largely depends on the level of the filled electrolyte and its density.
ELECTROLYTE LEVEL AND ITS DENSITY
The electrolyte level in the battery affects the durability of its work. Excess solution contributes to the oxidation of the battery output terminals, which can disable the entire vehicle electrical system. If the liquid level in the battery is lower than necessary, then it is destroyed. In this case, the battery fails completely. Therefore, car owners often ask themselves the question: “What electrolyte level should be in the battery and how to check it?”
CAUSES OF ELECTROLYTE LEVEL CHANGES
The amount of liquid in the battery is not a constant value. It is considered normal if the upper edge of the battery plates is under a layer of solution 12 ... 15 mm thick. Determine the electrolyte level in the battery is determined visually. To do this, unscrew the filler plugs and look inside. The solution must be in contact with the lower end of the tube of the filler neck of each can. At the same time, a meniscus should be visible at the point of contact (a curved surface of a liquid between closely spaced walls; from the Greek meniskos - a crescent).
Regardless of which battery is used, the electrolyte level in it is constantly decreasing. This is due to the evaporation of water during operation. As a result, its reserve stock located above the plates decreases, which leads to an increase in the concentration of sulfuric acid and an increase in density. As a result, a low level of electrolyte in the battery leads to the destruction of the plates and a decrease in its working life. The speed of this process depends on:
- Serviceability of the elements of the electrical circuit of the car;
- Vehicle operating conditions;
- Driver's driving style.
Due to a combination of adverse factors, the fluid level can drop to a critical value even within one month. That is why, with the appearance of even the most minor failures in the operation of the on-board electrical network, experts recommend checking the electrolyte in the battery.
ELECTROLYTE LEVEL CHECK
There are two ways to check the electrolyte level in the battery:
- If there are max / min marks on the translucent battery case, then looking at the liquid level, you can decide what to do next (add or reduce the amount).
- If there are no marks on the case, then a glass tube with an inner diameter of 3-5 mm is used. Having opened one of the plugs, insert the tube into the hole until it stops at. Then, closing the outer hole with your finger, take it out of the hole. The column of liquid remaining in the tube indicates its level in one can.
Important! The height of the electrolyte column in the tube should be in the range of 12-15 mm.
This procedure must be performed for all cans, after which a decision can be made on further actions. Excess fluid must be drained (syringe, douche). If the electrolyte level in the battery is insufficient, then you need to add distilled water to each jar (to the lower edge of the filler neck), and its temperature should be within 15 ... 25 degrees Celsius.
Helpful advice! Only distilled water should be added to the battery. Using tap water or stream water will drain the battery completely.
ELECTROLYTE DENSITY CHECK
When adding distilled water, one should not forget about such a parameter as density. Density is measured with a special device - a hydrometer. It is made in the form of a float equipped with a scale graduated in units of density. In the upper part of the device there is a bottle with which the solution is sucked into the pipette. Its free movement of the float in a vertical position. The line along which the hydrometer comes into contact with the liquid indicates the density of the electrolyte. Density measurement must be carried out for all battery cans.
Important! The value of the density of the electrolyte in the battery should not go beyond the range of 1.25 ... 1.3 g / cc.
If measurements have shown that the density is too high, then you just need to dilute the solution with distilled water, while simultaneously controlling the density and level of the liquid.
In the case when the measurements showed a reduced density value, a special corrective electrolyte is used for topping up (density 1.4 g / cm3). It is used to increase the density of the solution filled into the battery.
Important! Measurement of the density of the electrolyte in order to determine the need for its adjustment is carried out only on a fully charged battery.
The density adjustment process is quite complex and must be performed by a trained technician.
At the factory, a clean, transparent electrolyte is poured into the battery. However, during operation, it becomes cloudy. This is due to:
- ingress of dirt;
- topping up tap water with impurities of chlorine and iron;
- overcharging of the battery due to the alternator, severe operating conditions, as well as when using homemade chargers.
In addition, the gray tint of the liquid means that the battery needs to be recharged. A full charge returns the liquid to its original transparency.
Attention! The black electrolyte in the battery indicates that the coating from the plates has almost completely crumbled, the battery has become unusable and needs to be replaced.
