Many car owners probably had to deal with the problem of incorrect battery operation. It happens that the car has stood for only a day, and after that it becomes impossible to start it. In this case, even a long battery charge does not help. Similar symptoms indicate a decrease. We will talk about what the density in the battery should be, why it falls, and how to raise it to the desired level in this article.
Electrolyte and its density
An electrolyte is a solution consisting of sulfuric acid and distilled water. These components are contained in approximately equal parts: water - 1 part, sulfuric acid - 1.25 parts. An indicator of 1.25 - this is the density of the battery battery directly depends on this indicator - the higher it is,
the lower its freezing temperature, and it is in a satisfactory working condition. Knowing what should be the density in the battery, you can judge the real state of your device.
Battery density measurement
Before checking the density of the battery, you should acquire a special device called a hydrometer. It is a device consisting of several rubber and glass elements.
Because The electrolyte is a dangerous chemical compound, before measuring its density, it is necessary to take precautionary measures, namely, to carry out work in rubber gloves, avoiding liquid contact with skin and clothing. It is strictly forbidden to smoke!
Open the neck of the jar, insert the tip of the device into it and use a pear to collect some electrolyte so that the hydrometer float floats freely in the body without touching the bottom, side walls and top. Wait for the liquid in the meter to calm down and, holding it at eye level, read the readings visually. Follow this procedure with all banks. If the density difference exceeds 0.01 g per cu. cm, then be sure to add distilled water or put the battery on an equalizing charge. With a decrease in density to 1.24 g per cu. cm or below the battery should be recharged.
It is important to know not only how to check the battery density with a hydrometer,
but also the rules for amending the reading of the instrument in specific temperature conditions. The optimum electrolyte temperature for measuring its density is +15 - +25˚С, but if you have to perform this procedure at a higher or lower temperature, then the readings must be corrected.
Electrolyte temperature (˚С) | Correction for hydrometer readings |
You should not find out what density is in the battery after you have recently
water has been added, or after repeated attempts to start the starter. After completing all procedures, thoroughly rinse the hydrometer with water.
How to increase the density in the battery?
The easiest way to maintain the required level of electrolyte in the battery is topping up. However, most car owners forget or do not know that it is necessary to periodically measure the density of the battery, because. water boils away over time, and with it the electrolyte, which leads to a decrease in density, sometimes to a critical level. When the battery is completely
refuses to work, then the burning question immediately arises: "How to increase the density in the battery?"
Using the instructions below, you can independently extend the life of the battery. However, remember that this procedure requires special attention and accuracy.
Precautionary measures
Be extremely careful when working with electrolyte: wear safety goggles and rubber gloves.
. When self-dilution of the electrolyte, be sure to add acid to the water, but not vice versa! These liquids have different densities and serious burns can result from a mistake.
. It is forbidden to turn the battery upside down, because. as a result, the active surface of the plates can crumble and cause a short circuit.
. Prepare containers in advance for draining the old electrolyte and preparing a new mixture.
. First check the plastic that you will use to seal the holes for electrolyte resistance.
. Remember that a charged battery will have a higher density.
Preparatory stage
In order to raise the density of the electrolyte in the battery, you will need:
. hydrometer;
. measured capacity;
. pear enema;
. soldering iron;
. drill;
. electrolyte;
. battery acid;
. distilled water.
How to raise the density of the electrolyte in the battery: detailed instructions
We measure the density of the electrolyte in each jar. Remembering how it should be
density in the battery, we compare our real indicators. So, if the density is 1.25-1.28, and the spread of values in each bank does not exceed 0.01, then the battery is fully functional, and it does not require any procedures. If the indicators vary at the level of 1.18-1.20, then the only option would be to add electrolyte with a density of 1.27.
Pump out the maximum amount of old electrolyte from one jar using a pear enema and measure its volume.
. Add fresh solution in an amount equal to half of the pumped out.
. Vigorously but gently shake the battery to mix the liquids.
. Measure density. If the value is not the same as the density in the battery should be, add another ½ of the electrolyte from the remaining amount. The operation should be repeated until you get the required indicators.
. Top up the rest with distilled water.
What to do at a critical density level
If the density index is below 1.18, then this problem cannot be solved by adding electrolyte. In this case, a battery acid having a significantly higher density will be required. This process is carried out similarly to the electrolyte addition scheme. If the desired results were not achieved at once, repeat the procedure as many times as necessary.
If the density in the battery is even lower than 1.18, then it is necessary to resort to the procedure for a complete replacement of the electrolyte. To do this, you immediately need to pump out the maximum amount of solution with a pear. Then, on the battery banks, seal the vent holes of the plugs. Put the battery on its side and alternately drill 3-3.5 mm holes in the bottom of each of the cans. Before making the next hole, drain the remaining electrolyte from the previous one.
Next, rinse thoroughly with distilled water. After that, solder the drilled holes with acid-resistant plastic (for example, you can use plugs from an unnecessary battery for this).
Having done all the preparatory procedures, you can start pouring fresh electrolyte. In this case, it is recommended to use a solution prepared by yourself, the density of which will be slightly higher than that provided for your climate zone. It should be noted that even a complete replacement of the electrolyte in an old battery will not be able to provide it with the same service life as a new battery.
Tip: if you want the battery to serve you as long as possible, do not forget to charge it on time and check its density periodically.
Few drivers have not had to deal with such a problem, so it will be useful for many to learn how to equalize the electrolyte density in battery banks. There are also owners who do not know at all that the battery also needs periodic maintenance.
In addition to the fact that it needs to be periodically recharged from an external current source, the level and density of the electrolyte in its banks should also be checked. Only careful attention to the battery will ensure its long service life.
We will try to convey to everyone how to equalize the density of the electrolyte in the battery banks in an accessible language, so that even the owner, who is far from “technology”, can independently perform such an operation. This does not require any special requirements or conditions, it is easily performed in a garage. Next, let's talk about why there is a need to adjust the density, how to do it correctly.
A few words about the battery device
Many years have passed since the appearance of the first rechargeable batteries. Despite the fact that it was constantly being improved, fundamentally new types of batteries were designed, the “old woman” lead-acid battery is still the most popular device. Probably, already from the name it became clear that it is based on lead for the manufacture of plates, and sulfuric acid for the electrolyte to impregnate these plates.
The battery consists of a plastic case that houses six individual battery cans. Each such section is capable of delivering a voltage of 2.1 volts, when connected in a series circuit, we get 12.6 volts at the output. In each such jar, a kind of package of negative and positive plates is installed. There must be a small gap between them for free access to the electrolyte solution.
It is made on the basis of concentrated sulfuric acid by adding distilled water to it. You can not use any other water, only pure chemically. By mixing acid and water, an electrolyte solution is obtained, the density of which should be 1.27 g/cm3. Battery operation consists of cycles of discharge and then recharging from a running car alternator.
Reasons for the decrease in density
There are many reasons for this, let's look at some of them. With the advent of cold weather for the battery, a period of its more intensive operation begins. It becomes longer to start the engine, driving with the lights on leads to the fact that the work of the generator is no longer enough to restore its capacity.
But an even more "insidious" reason lies in the self-discharge currents of the battery. Do not confuse them with the consumption currents of a watch or car radio in standby mode, they are incomparably small compared to self-discharge. In the process of recharging from a car generator, gas is released from the cans of electrolyte vapor. In the process of this, the condensate of these vapors and precipitation inevitably occur, including on the battery case. As a result of this, conductive paths appear from the “minus” of the battery to its “plus”, leading to self-discharge of the battery.
How to correct density?
To carry out such an operation, you must have the following devices and materials:
- Corrective electrolyte, its density should be from 1.33 to 1.4 g / cm3;
- Distilled water;
- Thermometer to measure its temperature;
- Densimeter, a device for determining the density;
- Glass tube for taking liquid from jars.
Next, you need to unscrew all the corks from the cans and measure the density in each of them with a densimeter. It can be high or low, which is equally bad for the battery and its service life. After that, using a glass tube, a certain amount of liquid from the cans is taken into a separate bowl. If the densimeter showed a value higher than recommended, then you need to add the same volume of water, and if it is lower, then a corrective electrolyte is added.
Now you need to put the battery for 30 minutes to charge at rated current, and then let it settle for a couple of hours. At this time, the liquids in the jars are completely mixed and they will become homogeneous. Again, you need to check the density and level of electrolyte in the banks and, if necessary, then carry out a correction again.
As can be seen from the description, the operation is quite simple and all car owners can perform it. We hope that it has become clear to everyone who has read this article to the end how to equalize the density of the electrolyte in battery banks. In order to carry out such an operation as rarely as possible, pay attention to the condition of the battery of your car more often.
The electrolyte in lead-acid batteries is sulfuric acid and distilled water. The density of the electrolyte is the ratio of these two components, which is measured using a special device called a hydrometer.
Density is a very important battery parameter, and any car owner must monitor its level and know how to raise it if necessary. Photo: onlinetrade.ru
What density is the norm
In lead batteries, the density can depend not only on the ratio of acid and water, but also on the temperature of the solution (at high temperatures, the density will be low and vice versa). The car owner must ensure that the electrolyte density indicators are always normal. It should be noted that these indicators are very dependent on the climatic region..
- The optimal density in areas with a cold climate, where the temperature can drop to minus thirty degrees and below, is from 1.26 to 1.30 gm / cm3,
- In zones with a moderate microclimate, this value should be about 1.24-1.26 gm / cm3. In a warm climate zone, the optimum density is 1.22-1.24 gm/cm3. And where the winter is especially cold and the temperature drops to fifty degrees, it is worth adhering to the value of 1.29-1.31 g / cm3.
The battery is usually charged only eighty to ninety percent of its total capacity, so the density in this case will be somewhat less than if the battery was 100% charged.
This is due to the fact that during charging, the battery absorbs water from the electrolyte and the density increases. In addition, the destruction of salts of sulfurous acid deposited on the plates is carried out. The battery, which is charged to the maximum, has a density of 1.26-1.28 g / cm3. After a while the battery starts to discharge and the value drops to about 1.17 g/cm3.
During the discharge of the battery, sulfuric acid is absorbed, and it, turning into sulfate crystals, eventually covers the entire surface of the plates. As a result, the capacity decreases, and the electrochemical characteristics of the battery decrease. This process is called sulfation and is one of the most common causes of battery failure.
Sulfation starts at a density of about 1.16-1.1.18, so in this situation it is necessary to immediately charge the battery.
How density affects battery performance
The density of the battery during operation is subject to constant changes. Thanks to the measurement of the density of the electrolyte, hydrometer, together with the measurement of voltage, you can determine the condition of the battery .
A significant decrease in the density level most likely indicates that one of the cells has a defect or indicates an open circuit or a strong discharge of the battery (in this case, all cells will have a low density).
It should be noted that the lower the density of the electrolyte, the longer the battery will be able to work. But at the same time, a low value often leads to sulfation of the plates. In addition, under such conditions, the battery may freeze completely, and after this, most likely, the battery will no longer be subject to recovery and you will have to purchase a new one.
- An increased level of electrolyte density contributes to a decrease in battery life. The reduced density in the batteries can lead to difficulties in starting the power unit.
If the battery stops holding a charge, it is necessary to check the condition of the liquid inside it. When the battery is in operation, water evaporates, causing the electrolyte to become concentrated, which also negatively affects the performance of the battery.
How to measure density
The density of the electrolyte is estimated, as a rule, using a hydrometer - a measuring device in the form of a glass flask with a hydrometer inside, a rubber pear at one end and a rubber tube at the other. Photo: akbshop.in.ua
To measure density, do the following:
- Before you start taking measurements, you need to press the pear to release air from it;
- After that, we lower the tube as deep as possible into the electrolyte;
- Then, slowly, we collect the contents from it, gradually unclenching the pear, while the hydrometer will begin to float without touching the bottom and walls;
- We install the device in a vertical position and look at the lower graduation, which will show the density of the electrolyte;
- At the end, we press the pear in order to drain the liquid back into the electrolyte;
- We perform this procedure with all the remaining banks.
You can also measure the density with a voltmeter. Connect an automatic tester to the battery terminals and measure the voltage. It should be twelve to twelve and a half volts. Then you should turn the key in the ignition and dial 2500 rpm. The voltage should jump to fourteen volts, but not exceed fourteen and a half. If there are no changes, then you just need to recharge the battery.
Most batteries that are produced today are equipped with a special color sensor.
A green gauge indicates that the battery is fully charged, while yellow indicates that there is very little charge left.
How to increase the density
To increase the density of the electrolyte, you can use the following methods:
- Change the electrolyte to a new one;
- Charge the battery;
- Add sulfuric acid;
- Fill in corrective electrolyte.
Before starting the process, we need to prepare everything that we may need, namely, a container for diluting the electrolyte, an enema pear, a drill, distilled water, and the corrective electrolyte itself.
At the very beginning, it is recommended to charge the battery and check its voltage. If after a set of revolutions nothing has changed, it is necessary to leave the battery to be recharged for about ten hours. In this case, the current should be 10 times less than the battery capacity, that is, if the capacity is sixty amperes / hour, a current of six amperes is enough.
This table will help you choose the battery density depending on the time of year and climate. Photo: prosdo.ru
You can reduce the values by half and charge the battery for another two hours. Due to this, the density of the electrolyte is evened out. If, when the power unit is running, the voltage becomes more than fourteen and a half watts, fill the battery with water and then recharge it.
If this does not help and the battery charge continues to drop rapidly, you will have to work with electrolyte.
To increase the density of the battery yourself, you need to follow these steps:
- Take some electrolyte from the battery bank;
- Add the same volume of corrective electrolyte, if necessary, to add density or water, if necessary, to lower it;
- Then charge the battery for about thirty minutes so that the liquid can mix;
- After charging, you need to wait 1-2 hours, this will allow the density of all cans to equalize. During this time, the temperature will also drop and all gases will come out;
- Next, you need to check the density and if it does not correspond to the norm, repeat all the steps again and measure it again.
Be sure to ensure that the density does not exceed 1.35 g / cm, otherwise the acid will begin to "eat" the plates.
You can find a video instruction on how to increase the density of the electrolyte here:
Outcome
So, density is a very important parameter that affects the functioning of the battery and can either extend its life or, on the contrary, reduce it. Therefore, the owner of any vehicle is recommended to regularly check the density of the battery and, if necessary, raise or lower its level.
Good day! All blog readers know that a serviced battery requires periodic checks. After all, the concentration of sulfuric acid in it decreases over time. Therefore, every self-respecting motorist should know how to increase the density of the electrolyte in the battery. About this, we will talk with you.
Why does the density of the electrolyte drop
Before we figure out how to increase the density of the electrolyte in the battery, let's find out the reasons for its fall.
For any battery, a change in density is normal. That is, the battery is discharged - its value has decreased. Charged - increased. But in some situations, the battery simply does not hold a charge. And this suggests that the concentration has fallen too much and it is time to raise it.
Why does the battery become low density:
- the battery is simply discharged;
- the battery was recharged, as a result of which the electrolyte boiled away;
- distilled water is added to the jars, and concentration measurements are not carried out. As a result, the density of the electrolyte gradually decreases;
By the way, if the battery will work for a long time in this state, this will lead to sulfitation of the plates. Therefore, it is better not to run it.
Preparation
So, if, as a result of checking with a hydrometer, a low density of the electrolyte in the battery was found, it must be raised. But before doing this, you need to make sure that some conditions are met:
- The battery is charged;
- the temperature of the electrolyte in the jars is in the range of 20-25 °C;
- in all banks, the liquid level is normal;
- whole battery. On the battery, cracks often appear near the current leads, due to loosening of the contacts. Therefore, you do not need to knock and make excessive efforts to. Better to spend a little more time and do it carefully.
If the car battery is discharged, then it is charged, and then the density is measured. Why is that? The fact is that with a low charge, the concentration of acid in the banks decreases.
If you pour a correction solution into an uncharged battery, the concentration of sulfuric acid can be increased to such an extent that the plates crumble in the banks.
It should be taken into account, and the fact that the car generator charges the battery only by 85-90%. Therefore, before measurements, battery charging must be carried out without fail.
Corrective battery charging
Sometimes, a situation may arise that after a full charge, the density of the electrolyte in the banks is different. In general, the difference in density is allowed no more than 0.01 kg/cm3. Otherwise, alignment is required.
To do this, you can carry out corrective recharge of the battery. The current strength decreases by 2-3 times (compared to the nominal value) and the battery is charged for 1-2 hours. If this does not help to equalize the density of the electrolyte, more drastic measures will be required.
Correction electrolyte
Corrective is called an electrolyte with a density of 1.40 kg / cm3. Remember, in no case should you just pour it into the battery. Those. first, you need to find out the reason for the drop in the liquid level, and then raise it.
Often there is a situation when novice motorists misinterpret the name "corrective". For example, when water evaporated from the cans. Those. you need to raise the fluid level, and here is just a corrective solution. The logic is simple:
- the battery is filled with electrolyte, and its level has dropped;
- corrective solution, which means it is designed to adjust the level of the liquid.
Unfortunately, this point of view is fundamentally wrong. In most cases, distilled water is poured into the battery to equalize the level.
A corrective electrolyte is poured in such cases:
- if the liquid has leaked out of the cans;
- if you poured too much distillate into the battery and lowered the density.
Therefore, it is not necessary to pour it if, for example, the battery is simply discharged, and, accordingly, the concentration is lower than required.
We raise the density of the electrolyte in the battery
So, let's figure out how to increase the density of the battery. I will say right away - although this is not a tricky business, it is quite painstaking and, moreover, takes a lot of time. Therefore, it is better to be patient in advance.
The normal density of the electrolyte should be in the range of 1.25-1.27 g/cm3. Moreover, this value should be the same for all cans. In order to raise the electrolyte concentration in the battery banks, a correction solution is used. If you want to prepare the mixture yourself at home, remember the sequence:
- distillate is poured into the container, and sulfuric acid is already added to it. If you do the opposite, the solution will begin to boil violently.
In addition, you will need:
- pear aerometer for pumping liquid from cans;
- glass container to drain the old electrolyte;
- beaker ;
- goggles, gloves.
It is also important to remember that the liquid may have different densities in jars. Therefore, it makes sense to make a simple plate where to enter the measurement results for each bank - otherwise you can get confused.
I will make one important clarification right away. Some comrades, advising how to increase the density in the battery, suggest completely pouring out the electrolyte and filling in a new one. And for this, they recommend simply turning the battery over, pouring out the liquid and rinsing everything with distilled water. And as a result of such manipulations, one or more cans stop working.
Why is this happening? The fact is that lead sediment collects at the bottom. And if the battery is turned upside down, pieces of lead can fall between the plates and short them out. Those. bank stops working.
So, when the density of the electrolyte has fallen, there are several effective methods to raise it painlessly. Let's take a look at them.
Adding correction electrolyte
To do this, you need a concentrated electrolyte.
How to increase density:
- liquid is pumped out of the jar using an aerometer or a conventional syringe;
- instead, the same volume of correction solution is poured;
- The battery is put on charge for half an hour - an hour, after which it is aged for 2-3 hours;
- control measurements are carried out;
- if necessary, the procedure is repeated.
When pumping out, care must be taken not to expose the surface of the plates.
Leveling with charger
Everything is simple here. The only condition is that you need a charger for a car with a tight adjustment of the output voltage. Automatic chargers that reduce the current strength when a full charge is reached will not work.
How to restore density:
- The battery is brought to full charge;
- when it's loaded and begins to boil - the current decreases to 1-2 Amperes;
- the logic is simple - the battery boils, the water evaporates, the electrolyte concentration rises;
- evaporation time depends on the specific case and can last more than a day;
- when the level dropped– electrolyte is added and the density is measured;
- if necessary, the operation is repeated.
Of the minuses, it is worth noting that it is long.
If the density is too low
How to equalize the density if it is too low? For example, if its value is below 1.18, the described methods will not work. You will have to drain the acid completely.
Let's see what to do in this case:
- the electrolyte is pumped out of the cans as far as possible;
- The battery is carefully turned over, and holes are drilled in the bottom in each jar.
- It is advisable to do this in some kind of container, for example, in a basin;
- after that, the battery is placed in a vertical position, and the remaining liquid is poured from it;
- the battery is washed with distilled water;
- the holes are sealed, and a new solution is poured.
Plastic for sealing holes must be resistant to sulfuric acid.
Sometimes there are situations when there is no density at all in old batteries. This indicates deep sulfation. In this case, more serious measures for recovery will be required.
In fact, if the electrolyte density in your battery has dropped, this is not such a big problem. And you can lift it without much difficulty. But, only if you determine the drop in concentration in time. If you do not take care of the battery, it will simply fail.
The density of the electrolyte in the battery is a very important parameter for everyone, and every car owner should know: what density should be, how to check it, and most importantly, how to properly raise the density of the battery (acid specific gravity) in each of the cans with lead plates filled with H2SO4 solution.
In the article on the density of the battery electrolyte, you will learn:
Checking the density is one of the points in the process, which also includes checking the electrolyte level and measuring the battery voltage. in lead batteries density is measured in g/cm3. She proportional to the concentration of the solution, A inversely dependent on temperature liquids (the higher the temperature, the lower the density).
By the density of the electrolyte, you can determine the condition of the battery. So if the battery does not hold a charge, That you should check the condition of its fluid in every bank.
The density of the electrolyte affects the capacity of the battery and its service life.
It is checked with a densimeter (hydrometer) at a temperature of +25°C. If the temperature differs from the required one, the readings are corrected as shown in the table.
So, we figured out a little what it is and what needs to be done regularly. And what numbers to focus on, how much is good and how much is bad, what should be the density of the battery electrolyte?
What density should be in the battery
Maintaining an optimal electrolyte density is very important for the battery and it is worth knowing that the required values \u200b\u200bare dependent on the climatic zone. Therefore, the density of the battery must be set based on a combination of requirements and operating conditions. Eg, in a temperate climate, the density of the electrolyte should be at the level 1.25-1.27 g/cm3±0.01 g/cm3. In the cold zone, with winters down to -30 degrees, 0.01 g / cm3 more, and in the hot subtropical - by 0.01 g/cm3 less. In those regions where the winter is especially severe(up to -50 ° C), so that the battery does not freeze, you have to increase density from 1.27 to 1.29 g/cm3.
Many car owners are wondering: “What should be the density of the electrolyte in the battery in winter, and what should be in summer, or is there no difference, and should the indicators be kept at the same level all year round?” Therefore, we will deal with the issue in more detail, and it will help to do this, battery electrolyte density table divided into climatic zones.
Point to be aware of - the lower the density of the electrolyte in a fully charged battery, the will last longer.
You also need to remember that, as a rule, the battery, being by car, charged no more than 80-90% its nominal capacity, so the density of the electrolyte will be slightly lower than when fully charged. So, the required value is chosen a little higher, from the one indicated in the density table, so that when the air temperature drops to the maximum level, the battery is guaranteed to remain operational and not freeze in the winter. But, regarding the summer season, increased density may threaten boiling.
The high density of the electrolyte leads to a decrease in battery life. The low density of the electrolyte in the battery leads to a decrease in voltage, making it difficult to start the engine.
The density table is compiled relative to the average monthly temperature in the month of January, so that climatic zones with cold air down to -30 ° C and moderate ones with temperatures not lower than -15 do not require a decrease or increase in acid concentration. All year round ( winter and summer) the density of the electrolyte in the battery should not be changed, but only check and make sure that it does not deviate from the nominal value, but in very cold areas, where the thermometer is often below -30 degrees (in the flesh up to -50), an adjustment is allowed.
The density of the electrolyte in the battery in winter
The density of the electrolyte in the battery in winter should be 1.27 (for regions with winter temperatures below -35, not less than 1.28 g/cm3). If the value is lower, then this leads to a decrease in the electromotive force and difficult starting of the engine in cold weather, up to freezing of the electrolyte.
Decreasing the density to 1.09 g/cm3 leads to freezing of the battery already at a temperature of -7°C.
When the density in the battery is lowered in winter, you should not immediately run for a correction solution in order to raise it, it is much better to take care of something else - a high-quality battery charge using a charger.
Half-hour trips from home to work and back do not allow the electrolyte to warm up, and, therefore, it will be well charged, because the battery takes charge only after warming up. So the rarefaction increases from day to day, and as a result, the density also decreases.
It is highly undesirable to carry out independent manipulations with the electrolyte; only adjustment of the level with distilled water is allowed (for cars - 1.5 cm above the plates, and for trucks up to 3 cm).
For a new and serviceable battery, the normal interval for changing the density of the electrolyte (full discharge - full charge) is 0.15-0.16 g / cm3.
Remember that the operation of a discharged battery at sub-zero temperatures leads to freezing of the electrolyte and the destruction of lead plates!
According to the table of the dependence of the freezing point of the electrolyte on its density, you can find out the minus threshold of the thermometer column at which ice forms in your battery.
As you can see, when charged to 100%, the battery will freeze at -70 °C. At 40% charge, it freezes already at -25 ° C. 10% will not only make it impossible to start the engine on a frosty day, but will completely freeze in 10 degree frost.
When the density of the electrolyte is not known, the degree of discharge of the battery is checked with a load plug. The voltage difference in the cells of one battery should not exceed 0.2V.
If the battery is discharged by more than 50% in winter and more than 25% in summer, it must be recharged.
The density of the electrolyte in the battery in summer
In summer, the battery suffers from dehydration., therefore, given that increased density has a bad effect on lead plates, it is better if it is 0.02 g/cm3 below the required value(especially in the southern regions).
In summer, the temperature under the hood, where the battery is often located, is significantly increased. Such conditions contribute to the evaporation of water from the acid and the activity of electrochemical processes in the battery, providing high current output even at the minimum allowable electrolyte density (1.22 g/cm3 for a warm humid climate zone). So, when the electrolyte level gradually drops, That its density increases, which accelerates the processes of corrosion destruction of electrodes. That is why it is so important to control the liquid level in the battery and, when it drops, add distilled water, and if this is not done, then overcharging and sulfation threaten.
Stably overestimated electrolyte density leads to a decrease in battery life.
If the driver or other reasons, you should try to return it to its working condition using a charger. But before charging the battery, they look at the level and, if necessary, top up with distilled water, which could evaporate during operation.
After some time, the density of the electrolyte in the battery, due to its constant dilution with distillate, decreases and falls below the required value. Then the operation of the battery becomes impossible, so that it becomes necessary to increase the density of the electrolyte in the battery. But in order to find out how much to increase, you need to know how to check this very density.
How to check battery density
To ensure the correct operation of the battery, electrolyte density should check every 15-20 thousand km run. The measurement of density in the battery is carried out using a device such as a densimeter. The device of this device consists of a glass tube, inside which is a hydrometer, and at the ends - a rubber tip on one side and a pear on the other. To check, you will need to: open the cork of the battery can, immerse it in the solution, and draw in a small amount of electrolyte with a pear. A floating hydrometer with a scale will show all the necessary information. We will consider in more detail how to correctly check the density of the battery a little lower, since there is also such a type of battery as maintenance-free, and the procedure is somewhat different in them - you will not need absolutely any devices.
The rarefaction of the battery is determined by the density of the electrolyte - the lower the density, the more discharged the battery.
Density indicator on a maintenance-free battery
The density of a maintenance-free battery is displayed by a color indicator in a special window. Green indicator testifies that Everything is okay(degree of charge within 65 - 100%) if the density has dropped and recharging required, then the indicator will black. When the window displays white or red bulb, then you need urgent topping up with distilled water. But, by the way, the exact information about the meaning of a particular color in the window is on the battery sticker.
Checking the density of the electrolyte, in order to determine the need for its adjustment, is carried out only with a fully charged battery.
So, in order to be able to correctly check the density of the electrolyte in the battery, first of all we check the level and, if necessary, correct it. Then we charge the battery and only then proceed to the test, but not immediately, but after a couple of hours of rest, since immediately after charging or adding water there will be inaccurate data.
It should be remembered that the density directly depends on the air temperature, so refer to the correction table discussed above. Having taken the liquid from the battery can, hold the device at eye level - the hydrometer must be at rest, float in the liquid, without touching the walls. Measurement is made in each compartment, and all indicators are recorded.
Table for determining the battery charge by electrolyte density.
Temperature | |||
Discharged |
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The density of the electrolyte must be the same in all cells.
A strongly reduced density in one of the cells indicates the presence of defects in it (in particular, a short circuit between the plates). But if it is low in all cells, then this indicates a deep discharge, sulfation, or simply obsolescence. A density test, combined with a voltage measurement with and without load, will determine the exact cause of the malfunction.
If it is very high for you, then you shouldn’t be glad that the battery is in order either, perhaps it was boiling, because during electrolysis, when the electrolyte boils, the density of the battery becomes higher.
When you need to check the density of the electrolyte in order to determine the degree of charge of the battery, you can do this without removing the battery from under the hood of the car; you will need the device itself, a multimeter (for measuring voltage) and a table of the ratio of measurement data.
** cell difference should not exceed 0.02–0.03 g/cm3.
*** The voltage value is valid for batteries that have been at rest for at least 8 hours.
If necessary, density adjustments are made. It will be necessary to select a certain volume of electrolyte from the battery and add corrective (1.4 g / cm3) or distilled water, followed by 30 minutes of charging with rated current and exposure for several hours to equalize the density in all compartments. Therefore, we will talk further on how to properly raise the density in the battery.
Do not forget that extreme care is required in handling the electrolyte, as it contains sulfuric acid.
How to increase the density in the battery
It is necessary to raise the density when it was necessary to repeatedly adjust the level with distillate or it is not enough for the winter operation of the battery, and even after repeated long-term recharge. A symptom of the need for such a procedure will be a reduction in the charge / discharge interval. In addition to correctly and fully charging the battery, there are a couple of ways to increase the density:
- add a more concentrated electrolyte (the so-called corrective);
- add acid.
How to properly check and increase the density in the battery.
To increase and adjust the density of the electrolyte in the battery, you will need:
1) hydrometer;
2) measuring cup;
3) a container for dilution of a new electrolyte;
4) pear enema;
5) corrective electrolyte or acid;
6) distilled water.
The essence of the procedure is as follows:
- A small amount of electrolyte is taken from the battery bank.
- Instead of the same amount, we add a corrective electrolyte, if it is necessary to increase the density, or distilled water (with a density of 1.00 g / cm3), if, on the contrary, its decrease is required;
- Next, the battery must be put on recharging in order to charge it with a rated current for half an hour - this will allow the liquid to mix;
- Having disconnected the battery from the device, it will be necessary to wait at least another hour / two, so that the density in all banks evens out, the temperature drops and all gas bubbles come out in order to eliminate the error in the control measurement;
- Re-check the density of the electrolyte and, if necessary, repeat the procedure for withdrawing and adding the required liquid (increase or decrease further), reducing the dilution step, and then measure it again.
The difference in electrolyte density between banks should not exceed 0.01 g/cm3. If this result could not be achieved, it is necessary to make an additional equalizing charge (the current is 2-3 times less than the nominal one).
To understand how to increase the density in the battery, or maybe vice versa - you need a decrease in the specifically measured battery compartment, it is desirable to know what the nominal volume is in it in cubic centimeters. For example, the volume of electrolyte in one can of a 55 Ah car battery, 6ST-55 is 633 cm3, and 6ST-45 is 500 cm3. The proportion of electrolyte composition is approximately as follows: sulfuric acid (40%); distilled water (60%). The table below will help you achieve the required electrolyte density in the battery:
electrolyte density formula
Please note that this table provides for the use of a correction electrolyte with a density of only 1.40 g / cm3, and if the liquid is of a different density, then an additional formula must be used.
For those who find such calculations very complicated, you can do everything a little easier by applying the golden section method:
We pump out most of the liquid from the battery can and pour it into a measuring cup to find out the volume, then add half that amount of electrolyte, shake it to mix. If you are still far from the required value, then add another fourth of the previously pumped out volume with electrolyte. So you should add, each time reducing the amount by half, until the goal is reached.
We strongly recommend that you take all precautions. The acidic environment is harmful not only when it comes into contact with the skin, but also in the respiratory tract. The procedure with electrolyte should be carried out exclusively in well-ventilated areas with extreme caution.
How to raise the density in the accumulator if it fell below 1.18
When the density of the electrolyte is less than 1.18 g/cm3, we cannot do with one electrolyte, we will have to add acid (1.8 g/cm3). The process is carried out according to the same scheme as in the case of adding an electrolyte, only we take a small dilution step, since the density is very high and you can skip the desired mark already from the first dilution.
When preparing all solutions, pour the acid into the water, and not vice versa.
If the electrolyte has acquired a brown (brown) color, then it will no longer survive frosts, since this is a signal for a gradual failure of the battery. A dark shade turning into black usually indicates that the active mass involved in the electrochemical reaction fell off the plates and got into the solution. Therefore, the surface area of the plates has decreased - it is impossible to restore the initial density of the electrolyte during the charging process. The battery is easy to change.
The average service life of modern batteries, subject to the rules of operation (to prevent deep discharges and overcharging, including through the fault of the voltage regulator), is 4-5 years. So it makes no sense to perform manipulations, such as: drilling the case, turning it over to drain all the liquid and completely replace it - this is complete "game" - if the plates have fallen, then nothing can be done. Keep an eye on the charge, check the density in time, properly maintain the car battery and you will be provided with the maximum lines of its work.
