Do I need to charge a maintenance-free battery before winter?

Is it possible to charge a maintenance-free battery? A regular charger at home or in an apartment

A maintenance-free battery is really different from its serviced counterpart, the point here is in its special structure. You will almost never know what it means to add an electrolyte, distilled water or measure the density. Hence the name maintenance-free, that is, it does not require any maintenance, it is completely autonomous. However, many of my readers are interested in how to charge it and is it possible to do this? After all, now there are a lot of different manufacturers of such batteries, and they are installed on new cars in 90% of cases...

THE CONTENT OF THE ARTICLE

Let me start with the fact that the battery can be recharged “any way”; I would even say that it is designed for this. Let's remember the structure of the car's on-board network. The battery (at start-up) transfers energy to the ignition system and the starter, which spins the engine (it starts). Then, after starting, the generator begins to generate electricity, which recharges our battery.

Maintained or unmaintained, this is the second question, the main thing is recharging, which replenishes the lost energy during startup. I will even say more - if you discharge an ordinary maintenance-free battery “to zero” (deep discharge), it will simply kill it after several such cycles. Therefore, the charge must always be present and in the normal phase, more details here.

Then what is the problem?

Many people are afraid not of car charging, but of so-called home charging. That is, with ordinary stationary chargers. What problems arise at this stage:

It is impossible to track the boiling of the electrolyte . YES, this is really a problem, because when it boils, we understand that charging is over. You just have to look into the jar, but you can’t look into the unattended one, because it’s simply closed (sealed). We don't see what's happening inside.

Density cannot be tracked . Again, for the reason that if in a serviced one you simply unscrew the plugs and measure the density with a hydrometer, then this will not work here.
Battery tightness . Also scary! What happens if the electrolyte boils, where will the vapors go? What if the hull ruptures?

These points are justified, which is why it is important to know how to charge such batteries.

How to charge a maintenance-free battery

Here the old antiquated methods (with bubbles in the electrolyte) will not work. It is important for you to know and understand how to charge a car battery, that is, the principles of charging (I already have a detailed article).

But for understanding, I’ll remind you a little - there are only two charging methods. These are constant voltage and constant current.

Constant tension. This is when you set a constant voltage, say 14.4 Volts, and the current is automatically adjusted. That is, at the beginning it can be 10 Amperes, and at the end of the charge 0.2A.
Direct current. Here, on the contrary, the tension can jump. We set, say, 2 Amperes, the current at the beginning of the charge will be 15 Volts, and by the end it may drop to 14.4 Volts.

Now all chargers are mostly automatic; they work according to the first point, that is, constant voltage, but the current varies.

By the way, regular serviced batteries are charged in the same way, but how long does it take to charge a maintenance-free one?

How to calculate charging time?

This is a more interesting question; the real inconvenience is that you need to clearly understand how discharged your maintenance-free battery is. That is, we calculate its capacity. But how to do that?

Again, it’s simple - you and I know that a 100% charge is a voltage of 12.7 Volts. But a completely discharged battery is 11.7 Volts. Of course, you can discharge even more, but this is not recommended; in general, 10 Volts is already a serious discharge.

If you calculate roughly, the difference is 1B, (12.7 – 11.7). If we divide “1” by 10, we get 0.10V, which is actually 10% of the charge.

Accordingly, 0.1 X 5 = 0.5. Now add 11.7 + 0.5 = 12.2V. This is a kind of discharge up to 50%.

Now a little about capacity, for batteries it is 55 – 60 – 75, etc. ampere*hour. That is, he can deliver this amount of current in one hour. If we have a 50% discharge, it means that we have used about half the capacity - for example, from 60 Amps it took 30, etc.

That is, to replenish 50% of the capacity, we need to supply a certain current and “fill” the battery. You can supply 30A in one hour (in our example), but this will kill the battery. The recommended charge is 10% of capacity. In our case, this is 6A. And since we need to replenish 30A, then 30/6 = 5 hours. That is, at this current we need to charge it for five hours.

I probably confused you, but the main thing is to learn how to determine the degree of battery discharge. Remember the lower limit is 11.7V, the upper limit is 12.7V.

Automatic charging stations

Of course, the automatic machines will do everything for you; there is no need to worry about what current to supply and adjust the voltage. He will do everything automatically. And to be honest, there has been no VOLTMETER or AMMETER there for a long time; they were removed as unnecessary.

Such a charger will supply the maximum current in the first hour, in the second hour the current is two to three times less, but in the sixth or seventh hour, the current can generally drop to a minimum, about 0.05A. Therefore, even if your maintenance-free battery is on such a charge, it will never boil, because the currents when “filling” are minimal, and I read somewhere that they may be completely absent, that is, they turn off.

What happens if you recharge?

Okay, we've sorted out the automatic chargers. But what will happen if you constantly recharge with an old “charger”, where you strictly set the current and voltage? That is, at 6 Amps you need to recharge, say, 6 hours, but you “crap”, 8 or even 10!

Of course, the electrolyte inside will boil, this is a purely physical principle. However, the battery will not burst (like a balloon), as many people think! It has a special valve inside, which in emergency cases is designed to relieve too much pressure. It opens exactly when you have a long and very powerful recharge, which, by the way, can also kill the battery - the case will survive, but some of the electrolyte will evaporate, you need to understand this!

I’m a teapot, I don’t want to calculate all sorts of amperes, what should I do?

I can understand, it’s not always easy to charge a maintenance-free battery - all you need is calculations of time and current. But even here the manufacturers took care of you, they made batteries with green windows (or many call them lamps) just for people like you. The principle is simple: when it is normally charged, the green indicator is on, when it is discharged, it is black, and if there is not enough electrolyte, it is white. We read here about the green window, there is a lot of detail there.

Can I charge at home?

Well, the last question - is it possible to charge at home? After all, let’s say the serviced brother is, to put it mildly, undesirable to use at home, because when boiling, harmful and even explosive gas is released.

About a maintenance-free battery, you can answer this way - if you are not going to recharge it for a long time (several hours), then you CAN charge it at home! Nothing bad will happen, its electrolyte will not evaporate into your room, it is “locked” inside. Therefore it is safe. Let me emphasize once again, you shouldn’t recharge it for a long time, maximum 15 – 30 minutes!

And if you have a version with an indicator, as soon as the “green window” lights up, turn it off immediately.

Now this is a useful video, be sure to watch it.

I’ll end here, there was a lot of information, but it was useful, sincerely yours, AUTOBLOGGER.

( 27 votes, average: 4.41 out of 5)

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Which battery is better maintained or maintenance free? Correct.

Charging a maintenance free battery

Old-style car batteries are being replaced with sealed batteries. The user may not understand how to charge a maintenance-free battery. Car owners are also concerned about whether frequent recharging will affect the service life of the product.

Types of maintenance-free batteries

The following types of maintenance-free batteries exist:

Lead-calcium-acid. The plates of this device are coated with calcium. They are resistant to corrosion and vibration. Calcium coating reduces the rate of electrolyte boiling and self-discharge.
A.G.M. It is an acid battery in which the electrolyte is placed in special fiberglass separators. This type of power supply is insensitive to critical discharges. The plate sulfation rate is reduced, so the battery operates uninterruptedly for 10 years.
EFB. A special feature of the structure of such a battery is the increased thickness of the electrodes made of lead. The use of material impregnated with an acidic composition helps reduce sulfation. They wrap the plates of the battery cans. The service life of the product is 7-10 years.
GEL. The liquid filler in such batteries is replaced by gel filler.

Why you need to charge maintenance-free batteries

It is necessary to charge the battery, especially during preparation for winter. Despite the long service life, the capacity of the power supply decreases over time. Other reasons for needing to recharge include:

Lack of energy at startup. A battery charged from a generator may not produce enough current to start the engine. This happens if the car is used to travel short distances. This time is not enough to restore the battery's energy potential. In this case, the battery is periodically connected to the charger.
Loss of charge in frosty weather. To start the engine at negative temperatures, a higher starting current is required. At the end of autumn, you need to fully restore the charge of a maintenance-free car battery. The maximum capacity provides enough energy to start the engine in cold weather.

Charging process

DC charging is used to restore the energy potential of a critically discharged battery. The process lasts several days and requires constant monitoring. The battery restores its capacity as much as possible. The procedure includes the following steps:

At this stage, the current strength is established. It should be 10% of the Varta battery capacity. For a battery with a capacity of 80 Ampere/hour, a current of 8 A is selected. Charging continues until the voltage at the battery terminals reaches 14.4 V. Chargers with built-in regulators help select the desired Volt and Ampere values.
At this stage, the voltage increases and the electrolyte boils. Reducing the current intensity by 2 times helps reduce the intensity of gas formation. The charging process continues.
After increasing the voltage at the terminals to 15 V, the current is again reduced by 2 times. The process of restoring the power of the car's battery continues. The user periodically measures the current and voltage. If the parameters remain unchanged, the battery is considered fully charged.

When a voltage of 14.4 V is applied, the battery will be charged to 80% within 24 hours. 100% restoration of energy potential during a 24-hour procedure is ensured by starting a current of 16 V.

Nuances when charging a maintenance-free car battery

When restoring the capacity of Varta power supplies or any other maintenance-free batteries, the following nuances are taken into account:

It is impossible to measure the density of the electrolyte in the battery.
The sealed case does not allow charging the battery with high current.
The power source is charged by placing it on a flat surface. This helps prevent the body from tipping over during the procedure.
Before applying current, the residual voltage is measured. A battery that has lost its charge must be charged with a stable voltage. The current on the charger needs to be adjusted. The voltage supplied to the terminals should be 14-14.5 V. The recommended starting current is 2 A.
When using non-automatic chargers, the charging process is controlled. When the charge power decreases to 0.2 A, the device is turned off.
It is impossible to supply a current of more than 15 A. It is not recommended to allow the voltage to increase to 15.5 V.
A deeply discharged battery must be charged for at least 24 hours.
Do not allow the electrolyte to boil for a long time. The release of large amounts of gases leads to an explosion or fire. If bubbling occurs, stop charging immediately. You cannot fill a maintenance-free battery with water.
Before charging begins, the battery is removed. The user must have access to a power source. This makes it possible to quickly de-energize. If charge restoration is carried out without dismantling, you need to disconnect the vehicle's on-board network from the battery.
Charging is carried out in a heated room. It is not recommended to connect the charger outdoors.

Charging at home

It is dangerous to charge batteries of the serviced type at home. When the electrolyte boils, toxic and explosive gases are released. Charging maintenance-free batteries does not pose a danger to humans. According to the instructions, the battery is placed away from heat sources in a ventilated area. Charge the power source by applying a voltage of 14 V. After 15 hours, the parameter is reduced to 13.2 V.

How to properly charge a maintenance-free car battery

Today, the usual lead-acid battery has been replaced by maintenance-free batteries, which are widely installed on new vehicles. A high-quality maintenance-free battery ensures uninterrupted operation throughout the entire declared service life (3-5 years) and ensures maximum ease of use during operation. The main advantage can be considered what lies in the name of such a battery - there is no need to maintain the car battery, that is, there is no longer a need to periodically measure the electrolyte density and add distilled water.

As a result, many car enthusiasts have a number of questions, the main ones being topics regarding maintenance and charging of maintenance-free batteries. Maintenance should be understood as maintaining the proper charge level to avoid deep discharge of the battery. Next, we will look at whether it is possible to charge a maintenance-free car battery and how to charge maintenance-free batteries correctly.

Read in this article

Charging maintenance-free car batteries

Let's start with the fact that charging a maintenance-free car battery is somewhat different from charging its lead-acid counterparts. The thing is that the manufacturing technology of maintenance-free batteries can be different. Such solutions may have a conventional electrolyte, which is poured into the housing, but the so-called “jars” are hermetically sealed, that is, there is structurally no access for adding water. The plate material also differs from the solutions used in lead batteries.

Another type of battery does not have liquid electrolyte inside the battery in the form in which many drivers are accustomed to seeing it. The electrolyte in the housing is held in a special material (polypropylene). There are so-called gel batteries separately. The design of such solutions requires the presence of an electrolyte that is mixed with silicon oxide. The specified silicon oxide is poured in the form of a powder, resulting in the formation of a gel inside the battery case. This gel fills the interior space of a maintenance-free gel battery.

As for recharging, a maintenance-free battery also needs to be periodically recharged, just like a regular one. In both cases, the charge from the generator alone is not enough, especially during short trips, when the energy spent on starting the internal combustion engine simply does not have time to be replenished. For this reason, it is simply necessary to recharge the battery with a special charger, especially before the onset of cold weather.

Any battery discharges faster at low temperatures, the lubricant in the engine itself thickens, and the fuel evaporates worse. It is quite obvious that it is much more difficult for the starter to crank the crankshaft in such conditions. Moreover, in cold weather, more starting current is supplied to the starter. If the engine started easily in summer even with a half-discharged battery, then in winter the battery may be discharged already on the second attempt to start. Taking into account these features, you should fully charge the battery, that is, increase the charge to the maximum battery capacity. In this case, winter operation will not cause problems for the owner, even if it is difficult to start the internal combustion engine in extreme cold.

Nuances when charging a maintenance-free car battery

When charging batteries of this type, pay attention to the following points:

inability to measure the density of the electrolyte using a hydrometer;
sealed case, which does not allow fast charging with high currents;

At the very beginning, you should place the battery on a flat, hard and securely fixed surface to prevent the possibility of tipping over during charging.

A slightly discharged car battery of a passenger car under such conditions will be fully charged in 3-4 hours. Note that in some cases, when using a charger, control over the charging process is necessary. Full charging occurs when the charging current drops to 0.2 A. Note that charging the battery with a current of more than 15 A is prohibited! Also, there is no way to allow the voltage at the terminals of a maintenance-free battery to increase above 15.5 volts.

In the case of a deep discharge (the battery is completely dead), it will take more time (about a day or up to 30 hours) to charge. Let us add that deep discharge is usually unacceptable for maintenance-free batteries. In practice, 1 or 2 such discharges do not greatly affect the performance properties of good quality batteries. The charger should be set to a voltage that is 1/10 V Ah of the total capacity of a particular battery.

Taking into account the risks described above, it is not recommended to charge the battery directly on the car, since the charging process (especially of a completely discharged battery) will require careful monitoring. In case of complications, there must be free access to the battery itself, and it must also be possible to quickly de-energize the charger. If you decide to charge the battery without removing it from the car, then be sure to turn off the power consumers that provide this possibility and remove the key from the ignition before starting the charging process. Let us add that it is better to use a warm room for charging, rather than connecting the charger to the battery via an extension cord directly outside at subzero temperatures.

How to charge a maintenance free battery

08/12/2019 admin Comments No comments

Today, all modern cars are equipped with maintenance-free batteries, which have replaced the long-proven lead-acid batteries. They provide the greatest ease of operation throughout the entire guaranteed service life. There is no need to constantly check the electrolyte density and monitor the level of distilled water. All that is required for uninterrupted operation of this type of battery is timely recharging.

Features of maintenance-free batteries

The charging process has some differences from recharging classic batteries. They consist in the fact that production technology can vary significantly, and therefore the nature of service. The following battery options are available:

The main difference is that the first option may contain in the case the classic electrolyte that we are used to seeing. But there the “banks” are sealed, that is, physical access is limited. In addition, even the material used to produce the plates has some differences from lead plates.

The second type of battery is not even that refillable. The electrolyte is contained in the housing in the form of a special material - polypropylene. Gel batteries can also be included in this group. In such devices, the electrolyte is placed in a slightly different format; it is paired with silicon oxides. Powdered silicon is poured into the body, resulting in the formation of a gel during the reaction. The resulting gel fills the battery space.

As for additional recharging, such batteries certainly need such manipulation, given the peculiarity of most (city) drivers to travel for short trips. That is, during such “travels” the battery does not even have time to charge in the standard way. Therefore, in fact, recharging is required, especially for cold continents and the winter period.

Any battery, regardless of the type and model of production, discharges much faster in cold weather. And if the oil is thickened, the starter is unlikely to be able to turn the crankshaft with a “dead” battery. In addition, especially in cold weather, increased current is always supplied to the starter. Keep in mind that the battery may die in winter even after a couple of unsuccessful starts. Therefore, taking into account such features, it would not be superfluous to charge the battery to maximum values. In such conditions, operation in winter will not cause serious trouble.

The nuances of charging a maintenance-free battery

When recharging, you need to consider some points:

It is not possible to analyze and measure the electrolyte using classical devices.
Due to its technological features, the sealed case does not allow charging with high currents.

Before charging, the residual voltage should be checked and clarified. Suppose the battery was only partially or completely discharged, in this case it is allowed to charge only with continuous current. Given this feature, you need to set certain values on the “charger”, namely 14-14.5 V, no less and no more.

Important! Remember an important point: the current should in no case exceed the permissible amperage of the battery.

A slightly “stressed” battery under such conditions can be charged after a couple of hours. Please note that in some cases it is necessary to monitor the process. You can simply find out that charging is complete if the charger current level drops to 0.2 A, then you can turn off the charger. Once again, I would like to remind you that exceeding the permissible current at the battery terminals of 15 A is strictly prohibited, and it is also prohibited to supply voltage above 15.5 V.

In cases where the battery is completely dead, it will take at least a day for a full recovery. Keep in mind that deep discharge is not advisable for such batteries. As a rule, a couple of times will not greatly affect the performance characteristics, but after five full discharges the battery will no longer hold voltage. In addition, remember that you must monitor the charging process, because during this the electrolyte heats up and can boil away.

Attention! If the battery type is sealed, then the acid can come out only in one way - an explosion. If you notice boiling or seething, immediately disconnect from the charger.

It is not recommended to charge directly when the battery is located in the car. Only in rare cases can you turn off all power and be sure to monitor the process personally.

Advice. It is better to carry out even small recharging in a warm room. Cold temperatures can negate all your efforts to restore battery voltage.

Instructions for charging a maintenance-free battery

Now let’s look in detail at what actions a car owner needs to take to recharge his “horse” and how to charge a maintenance-free car battery. Stages of work:

Connection. Remember that it is imperative to observe the polarity of both the battery and the charger.
We determine the amount of current required; as a rule, this value is determined by this calculation as 1/10 of the battery capacity. For example, we have a battery with 12 V and 70 A/h, in which case a current is supplied that does not exceed 7 amperes. The exception is when the battery is completely drained. During such periods, charging is performed with a low current of 1-2 A.
Remember that when connecting the charger terminals to the battery, the first must be disconnected from the network.
After all the manipulations, we connect the charger to the network, set the voltage to 14 V, and the current according to your characteristics.
During the entire charging, the current will decrease, thereby indicating that full charging is approaching, at which the current, as already mentioned, will decrease to 0.2 A.
In addition, I would like to separately remind you that in the case when the battery has been completely “depleted”, it is not recommended to give the maximum permissible voltage. It is better to reduce the value to 12 V. Also control the current strength so that at the very beginning it does not exceed 1/20 of the capacity. If the latter is greater, you need to further reduce the voltage.

This video shows charging a maintenance-free battery:

Differences between maintenance-free batteries and serviced ones

The main difference between maintenance-free batteries is their internal structure, which contains electrode grids made of an alloy of calcium and lead.

In previously used serviceable batteries, antimony was added to the lead plates, which served as a lead hardener and acted as a catalyst for water in the electrolyte. With the start of using antimony and replacing it with calcium, there was no need to add water.

A maintenance-free battery is a tightly sealed battery with no access to the plates. At the factory they are filled with electrolyte and sealed tightly. This technology allows you to retain the charge for quite a long time.

However, sometimes it is still necessary to check the voltage level, which should not exceed 12.5 volts. If the indicator is lower, then the battery should be recharged. According to the manufacturers' recommendations, this should be done approximately once every six months.

The main differences between a maintenance-free battery and a serviced one:

No plugs to check the electrolyte level. If there are any, then you have a serviceable battery.
The presence of a hydrometer to check the charge level and gas outlet.
Marking on the product body indicating all characteristics: battery type, starting current and others.

The differences between these types of batteries are described in this video:

Is it possible to charge maintenance-free batteries?

This type of battery, like all others, requires periodic recharging. Another thing is that you will have to do this much less often. Calcium batteries have very low water consumption. For plates doped with calcium, the onset of hydrolysis occurs at a higher voltage, which reduces water consumption.

The very principle of charging such batteries is practically no different from charging serviced batteries, but unlike serviced batteries, it is necessary to constantly monitor the charge voltage. It is very important that it does not exceed 14.4 V.

The thing is that if this indicator is exceeded, the water will decompose into oxygen and hydrogen, which will lead to a decrease in the electrolyte level, and there is no way to add water.

How to calculate the charging time of a maintenance-free battery

Before carrying out work, it is necessary to verify the degree of discharge of the battery. For this, manufacturers have provided 2 options:

The min/max designations are located on a special window of the case. When the indicator is located in the center, the battery is fully charged.
Digital indicator. The most convenient way to determine charge. For this, 3 types of colors are used:

red - indicates the battery is completely discharged;
white - indicates that recharging is recommended;
green - indicates that the battery is in good order.

However, it should be remembered that these readings are advisory in nature, and the actual charge level may be different.

For a more accurate determination, you need to use a multimeter. A reading of 11.7 means the battery is completely discharged; 12.7 - charging 100%.

Example: if the value is 12, then the battery charge is 30% (0.1 equals 10% charge. 12 - 11.7 =0.3=30%).

When charging with direct current, you will need the battery capacity indicated in the specifications (let’s take 60 A/hour)

We calculate the charging time: 70% of 60=42. Recommended current is 10% of capacity. Here - 6 A. It is necessary to divide 42 by the recommended current of 6 A (42/6 = 7). Time to full charge is 7 hours.

The charging time of the battery directly depends on the degree of discharge. With a completely “empty” battery, the time to fully charge can range from a day to 30 hours. If partial discharge is involved, then the time is reduced to 4-5 hours. Depending on the charger model, you may have to monitor the process, since full charging is achieved at a current reading of 0.2 A.

Important! For this type of battery, complete discharge is not recommended, as this sharply reduces the service life.

What happens if you recharge a maintenance-free battery?

The consequences of such a step can be very serious:

Boiling electrolyte corrodes internal parts.
The acid oxidizes the terminals, forming a coating.
The electrolyte escapes from the battery, destroying the plates, which leads to complete destruction of the battery.
The battery may explode.

But there is also good news. Currently, to prevent severe consequences, manufacturers have begun producing batteries that have a special valve inside designed to relieve pressure in extreme situations. In any case, overcharging the battery can lead to complete failure of the product.

A maintenance-free battery requires constant recharging. This is necessary to maintain all vehicle systems in working order. With proper care and proper use, the battery will not require replacement and will last its intended life.

At the end I would like to summarize the article. We have carefully analyzed the initial question - how to charge a maintenance-free car battery and now we know not only the detailed plan, but also the features and characteristics of the battery. Pay attention to the features of your specific battery and select a charger for it accordingly.

Useful video

This video explains how to properly charge a maintenance-free battery using CA/CA technology:

Proper Ways to Charge Maintenance Free Car Batteries

Thanks to numerous tests and innovations, developers began to use maintenance-free batteries instead of outdated lead-acid batteries, which have become widespread among new models. This type of battery makes it possible to use the car for a considerable period of time, since the service life of a maintenance-free car battery is 3-5 years, depending on the manufacturer, without creating any problems and without requiring attention. Just imagine, this design will free you from measuring the density of the electrolyte and adding distilled water, but these actions must be performed regularly.

Let us remind you about the features of servicing conventional batteries:

when the electrolyte is checked, a person may be injured because there is a spark nearby;
Adding water may cause acid to get on your hands, causing chemical burns.

Therefore, by choosing a maintenance-free model, you are taking care of yourself. In such a battery, in principle, access to its contents is not provided.

But any car owner will come to the moment when he will have to wonder what to do when the life allotted to the car battery expires, because it is very important to prevent the battery charge from becoming too low. Today we’ll talk about what to use and how to maintain this type of battery.

What are the differences between maintenance-free batteries?

From the very beginning, we will define this design in order to understand what a maintenance-free battery means. A maintenance-free battery is a battery that does not have a direct path to the cells and plates. Often the battery is calcium or hybrid.

Now we can calmly list its differences from its predecessors:

Impenetrable body. Therefore, it is impossible to open it, but only to charge it.
Holds a charge for a long time.
The design uses a lead-calcium alloy for the electrode grids.
Water does not evaporate, since it ends up in the tank after passing through the valves.
The electrolyte in models of this type is not in a liquid state. Its consistency is similar to a gel.

No matter what the manufacturers say, you will have to control the voltage level. It must remain above 12 and a half volts for stable operation. Hybrid grilles will reduce your visit to the battery to one check every 1.5 years, but calcium grilles will require attention every six months.

In general, there is another type of battery: low-maintenance. They are an order of magnitude lower in cost than the analogue we are considering, but you will have to check the charge level more often.

Which battery is better - serviced or maintenance-free? To be honest, a serviced battery brings much more trouble to the owner, thereby taking up a lot of his time. By choosing a maintenance-free model, you will definitely win, especially if this is your first car and you do not have the skills to maintain batteries. You may overpay, but when purchasing, remember that you are paying the difference in price for your time and long installation service.

Note: the main thing is to initially choose a good manufacturer, since many fakes can be found on the market today.

How to charge a maintenance-free battery

Due to the fact that the battery does not have enough charge from the generator, the driver sometimes needs to replenish the charge level using a charger. The need for replenishment increases with the beginning of the cold season. This is due to the fact that it is more difficult for the starter to crank the crankshaft, the lubricant in the engine freezes and becomes thick, and the fuel evaporates much worse. Accordingly, for a good engine start in winter, the charge volume must be increased to the highest point of the battery capacity. To check the charge level you will need certain equipment: a multimeter. If the indicator is from 11.7 to 12.7, then your battery is charged. It is impossible to know the exact value, unfortunately, but the battery itself is never fully charged.

There are a couple of peculiarities in the charging process due to the following criteria:

Electrolyte density cannot be measured using a hydrometer.
Charging with high currents is also impossible due to the external sealed coating.

Now let's move on directly to how to charge a maintenance-free battery.

To prevent the battery from falling, choose a flat surface on which it can be conveniently placed.
Measure the voltage remaining in the battery to set the required current on the charger. A voltage of 14-14.5 V is supplied to the terminals of a discharged or partially dead battery (the current strength is not higher than 2 amperes at the start).
You will understand when the process is finished by the charge current mark, it should be 0.2 A.

If you set the current indicator to 15 A or higher, this may cause the voltage at the terminals to increase, and you will be forced to purchase a new battery. The owner must constantly monitor the charging process, because if the electrolyte boils, it will not find a way out of imprisonment, since the structure is covered with a “shell”, which will lead to an explosion, from which both you and your property may suffer. Therefore, as soon as you hear extraneous sounds inside the battery, immediately disconnect the charger. Due to such conditions, you should not take risks and charge directly on the car.

When the charge reaches the highest point you need, do not forget to measure the voltage at the battery terminals.

How to check electrolyte level

There are two ways at your disposal to check the electrolyte level in a maintenance-free battery: by the marks on the structure and by the indicators. Let's look at each one separately:

The abbreviations “max” and “min” will tell you the charge level. They are written on a window specially designated for this purpose. The indicator located in the middle of the window tells the owner that the battery is fully charged. Sometimes there is no window for this, but the manufacturer leaves a transparent part of the case, which is usually made of plastic, for identification.
Indicators. Some developers have chosen this option, which also clearly communicates the electrolyte level to the driver. How do they do this? The answer lies in the color that the indicator itself produces. Color variations are limited to green, white and red. The first one notifies you that everything is fine with the battery and there is nothing to worry about. The second one is that it’s time to charge the battery. Well, the third color indicates the critical state of the battery: it is displayed when the acidity is increased and the water level has dropped. Of course, not all models use these exact colors, so read the instructions first.

As we have already informed you, there is no reliable source, so all indicators are approximate and it is better to pay attention to the indicators more often.

Sometimes a battery malfunction depends on the fact that the level of distilled water in it has dropped. The battery is a maintenance-free type, as the name implies, does not include a hole for external intervention by the owner to eliminate this breakdown. But there is still one way. So, how do you add distilled water to a maintenance-free battery?

Firstly, do not under any circumstances remove the battery cover: it is so secured that you most likely will not be able to put it back. So just peel off the sticker.
Secondly, through transparent areas we find banks and partitions. Using this picture, we determine where to fill water or check the density of the electrolyte.
Carefully make a passage using a tool like an awl.
Now, through the passage in the jar, where there is a density indicator, pour 5 ml of water. To make it more convenient for you, buy a disposable syringe for this operation. When the indicator turns white or green, add another 20 ml.
It is easier to determine the electrolyte level if you have a transparent battery case. Otherwise, resort to this method: plunge the syringe with a needle into the jar and pull the stem towards you. At the moment when electrolyte begins to flow into the cavity of the syringe, make a mark on the needle.
Next, you need to refer to this mark when you add water to the remaining jars.
The holes you made can be sealed with sealant, or you can cut out kind of plugs from rubber.
Shake the battery slightly to mix the newly added distilled water.

How to calculate charging time

This, of course, directly depends on how long you have managed to drain the maintenance-free battery. If the charge has fallen to the very bottom, the recovery process can take from 24 to 30 hours. It is very important to avoid such a situation. And on average, such analogues charge from 3 to 4 hours.

What happens if you recharge

Overcharging the battery can lead to dire consequences:

Boiling of the electrolyte will lead to corrosion of all internal parts.
The acid, spreading through the terminals, will oxidize them, and a green coating will form on them.
If the electrolyte begins to escape from the battery, the plates will appear on the surface of the case and then completely fall off. After such upgrades, you will take the battery to a landfill.
The percentage of the battery itself exploding is also due to the electrolyte.

Charge the products carefully, following the instructions above.

Using automatic chargers

You will see many automatic charger options, but frankly speaking, they are not always of the highest quality. Therefore, it is better to look at chargers in which you will be able to adjust all parameters. And don’t forget about how to properly charge a maintenance-free battery, we mentioned this above.

Can I charge at home?

Only by following all the tips and instructions that we have mentioned, you can carry out this operation at home. In any case, it is better to find a more suitable place for this, but when the range of options has narrowed to your home, do not despair. So to the question, is it possible to charge a maintenance-free battery at home, we answer positively.

In conclusion, we cannot talk about the bad sides of this type of battery, since it outperforms its rivals in many respects and is in line with new trends. Feel free to purchase cars with such batteries and save your time with them. Leave your comments and suggestions below, we will be glad to hear your opinions and preferences. Have a nice trip, and be careful on the roads.