How often should you charge a car battery?

How to properly charge a car battery

The battery is one of the most important parts of a vehicle: it allows you to start the engine and replace the alternator if it malfunctions. Recharging a car battery can be done with a working generator device (in the car) or from a charger (indoors).

To extend the battery life and avoid damage, you need to choose the right car battery charging parameters and follow safety precautions.

How often to charge your car battery

The frequency of charging the battery is determined individually. The battery consists of 6 sections-cans that contain the electrolyte reagent and electrodes. The most common type of car battery is WET. It uses acid as a reagent and lead as a material for electrodes.

During operation, the battery capacity decreases due to several factors:

• contamination and reduction in reagent quality;
• acid evaporation;
• sulfation of lead electrode plates.

Reducing the battery capacity increases the required charging frequency, but shortens its duration. When using the battery for a long time, it is recommended to regularly check the voltage of the device.

The normal battery charge value in the warm season is >50% of the nominal value, and in the cold season - >75%. This is due to the difference in electrolyte density, the load on the battery and the degree of risk of it turning off at different temperatures.

Motorists and service center technicians recommend charging the battery to 100% at least 2 times a year, one of which is immediately before the onset of cold weather.

Checking the car battery

There are several ways to check the battery charge:

1. Using an indicator on the case. Some batteries are equipped with a hydrometric indicator. It allows you to evaluate not only the charge, but also the fullness of the reagent. When the indicator is green, the charge and acid level are normal; when it is white, the device requires recharging; and when it is red, the charge is at a minimum and/or the reagent needs to be topped up.
2. Using a multimeter. The diagnostic device is set to voltmeter mode and connected to the battery terminals. At the same time, the engine must be turned off: otherwise the driver will receive a charge from the generator, not the battery. When there is no load, the voltage at 100% charge is 12.66 V, at 75% - 12.42 V, at 50% - 12.18 V, at 0% - 11.7-11.8 V. Considering the small difference in indicators, The multimeter must have a minimum measurement error.
3. Using a load coil. This diagnostic device is a resistance element (18-20 mOhm), to which a voltmeter is connected in parallel. The coil is connected to the battery outputs for a few seconds, and then the readings are taken from the measuring device. Load tests are carried out mainly in car repair shops or at the point of sale of car batteries.

The charge level is measured no earlier than 8-9 hours after turning off the engine or removing the battery.

Experienced motorists identify an additional method of checking the battery: by ear. If the charge is at a sufficient level, the car starter rotates normally. When the charge decreases, the power system starts with effort, and the starter spins more slowly and with noticeable attenuation.

In service centers, the charge is often measured when starting an internal combustion engine (ICE) or lighting devices (dimensions and high beams).

When starting an internal combustion engine, the voltage norm is 9.5 V or more. If the voltmeter readings are below this value, this indicates a discharge of the battery or a malfunction of the starter. For differential diagnostics, a guaranteed working and fully charged battery is installed in the vehicle.

When measuring against the background of lighting devices, the battery voltage should be at least 11.2 V.

How to prepare a battery for charging

Preparing the device for charging is carried out according to the following algorithm:

1. Remove the battery from the car or disconnect it from the on-board network, disconnecting both wires or at least the negative wire. In the cold season, you need to bring the battery into a room with a temperature of at least +10°C and leave it for several hours so that the electrolyte has time to warm up.
2. Clean the terminals from oxides, sulfides and grease. Wipe the surface of the battery with a rag moistened with a solution of soda or ammonia (10%).
3. If the battery is a serviceable type, unscrew the caps located on the banks and place them next to each other. Drain off some of the electrolyte to check the color and presence of impurities. If the battery is maintenance-free, then remove the plug from the ventilation hole on the device. This will ensure the free release of reagent vapors and make the procedure safer.
4. Serviceable battery plugs allow you to add water to the sections. If the plates in the jar are immersed in the reagent by less than 0.5 cm, then it is necessary to add a little distilled water into it and level the level in other sections. This procedure is not carried out for a maintenance-free device, because the reagent remains at the required level throughout the entire service life.

Safety precautions

In the process of preparing and charging the car battery, the following rules must be observed:

• charge the device in a well-ventilated area (garage, service station, or at least on the balcony);
• if there are small children in the family, you cannot exercise in the apartment;
• It is prohibited to smoke, set fire to anything or cut metal in the immediate vicinity of a charging battery;
• Do not charge the device in a room with high humidity;
• connect the terminals and clamps of the charger only when the charger is disconnected from the network;
• use safety glasses and gloves during work to prevent the dangerous effects of acid fumes;
• When working with a battery, keep a solution of 10% bicarbonate or sodium carbonate (soda) nearby.

A soda solution is suitable both for wiping the battery case from reagent fumes, and for neutralizing acid in case of careless handling of the electrolyte.

How to charge the battery

To start charging, you need to correctly connect the “crocodiles” of the charger to the “plus” and “minus” of the battery. In most cases, manufacturers mark the positive terminal in red and the negative terminal in black. However, before starting the process, it is recommended to clarify the polarity by finding the “+” and “-” signs on the battery case.

Connecting a battery to a charger under voltage may result in sparking at the terminals and ignition of gases that are released during electrolysis of distilled water.

There are 3 main ways to charge a battery: automatic, constant current (I) and constant voltage (U). They differ in duration and effectiveness. Despite the corresponding names, in the absence of automatic control systems, it is necessary to control both charge parameters (U, I).

You should check the battery charge level and temperature from time to time. When the reagent boils, you must immediately reduce I to recharge at low values.

DC charging

Charging at constant I is carried out as follows:

1. The current value is set at 1/10 of the battery's rated capacity. The standard capacity is 55 or 60 ampere hour. This means that I on the charger should not exceed 5.5-6 A, respectively. By manually setting this value on the charger, you must continue charging until the voltage measured at the terminals reaches 14.4 V (permissible error - 0.1 V).
2. When the battery is deeply discharged, it should be charged not with the nominal, but with the minimum I (1.5-2 A). This will avoid strong electrolysis of water and gradually increase the density of the electrolyte due to the decomposition of lead sulfate.
3. Once the specified U value is reached, the current should be reduced to 1/20 of the capacity. At 60 A*h it corresponds to 3 A. Reducing the charging intensity allows you to reduce the heating rate of the reagent and continue recharging to the maximum.
4. When U reaches 14.5-15 V, it is necessary to reduce I by half again. At the final stage of the process, you need to charge the battery until both charge parameters (I, U) reach a constant value. The final value of I should be within 0.2 A, which corresponds to self-discharge of the battery. The whole process takes from 8 to 12 hours.

Upon completion of charging, you need to allow the released gases to escape, wipe the battery case again with soda solution, tighten the caps on the cans or return the ventilation plug to its place.

If you neglect to neutralize the surface, the battery will quickly discharge again due to current loss to the electrolyte layer on the case.

Constant voltage charging

To charge at constant U you need:

1. Set the voltage to the nominal charging level - 14.4 V (permissible error - 0.1 V). Strict voltage control is necessary when charging maintenance-free batteries.
2. Observe the current value. It should be about 0.1 capacity (for maintenance-free batteries) or 0.05-0.1 capacity (for maintenance-free ones). I more than 20% of the capacity is harmful to the battery.
3. With a deep discharge, recovery should begin with U no more than 12-13 V. The value of I should not exceed 5% of the battery capacity. If I rises, then the voltage needs to be reduced even more.

Recovery at constant voltage is a longer process than at constant current. At nominal U, the battery restores 75-85% of its charge per day, at 15 V - up to 90%, at 16 V or more - 95-100%. In addition to these data, it is necessary to take into account the limitation of the charging voltage: for a battery U above 15.6 V is dangerous. If the discharge is severe, the recovery time for the device can be up to 3 days.

Accelerated battery charging

To quickly charge the battery, you need to apply I to it at 10-15 A, which corresponds to 20-25% of the device’s capacity. In 15-20 minutes of intensive recovery, the battery will acquire a sufficient charge to start the car.

Regularly using this charging method is harmful, because... High charger current shortens battery life.

Dependence of battery charge and electrolyte density

The charge and density of the electrolyte are interdependent quantities. If the battery is severely discharged, the driver will not be able to quickly restore battery function, because the reagent density in the sections will be minimal. The relationship between the density of the acid solution and the degree of charge of the battery is presented in the table.

10 Tips on How to Charge a Car Battery

The generator supplies the vehicle with energy while driving. When the engine stops, the battery takes over the “feeding” function.

The service life of this unit lasts on average 2-3 years (equivalent to 80-100 thousand kilometers). The battery stores energy rather than generating it. At the moment when it is at least half discharged, you should think about recharging. Here are some tips.

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1. Make sure the battery is low

Several ways to understand that the battery is not charged:

• look at the indicator (red means the battery needs to be charged);
• use a multimeter (charged battery voltage at the terminals is not lower than 12.6 V);
• The load plug will show the voltage drop under load.

2. Follow safety precautions

Almost everyone understands that you should not unscrew a hot battery with your bare hands. But not everyone knows that the battery contains poisons. The battery contains toxic substances: sulfuric acid, lead, arsenic, hydrogen. It's easy to find information about them.

Below are tips that we strongly recommend following when working with the battery:

• Manipulations with the battery must be carried out in a ventilated non-residential area;
• the ambient temperature where you are working with the battery must be at least +10 °C (if the battery is from the cold, then first it must be allowed to warm up);
• work only in rubber gloves and safety glasses, the skin should be covered with clothing (drivers often do not pay attention to such recommendations, thereby exposing themselves to the risk of, for example, getting a chemical burn);
• you cannot pour water into the acid, you can only do the opposite (otherwise there will be a strong reaction with the release of heat, which can lead to trouble);
• You cannot smoke, light anything, or use devices that produce sparks (the battery produces gases that can ignite);
• this advice is related to the previous one: be sure to let the gases evaporate before charging the battery in order to minimize possible risks;
• After handling batteries, be sure to wash your hands with soap and warm water.

3. Charging process (step by step instructions)

The process itself is simple: connect the charger wires to the battery terminals, observing the polarity (plus to plus, minus to minus) and insert the plug into the socket.

It is important to understand that there are two methods: direct current charging (do not remove the battery) and constant voltage charging (remove the battery).

Charging with direct current is more efficient, is carried out in several stages, and requires control. This method is more difficult. The process itself is like this:

1. we charge the battery with a current that is 10% of the total capacity of the battery (if the capacity is 60A/h, then we charge no more than 6 A), wait until the voltage at the terminals is 14.3-14.4 V;
2. to reduce boiling, the next step is to continue charging, reducing the current by 2 times (in this example to 3 A);
3. The result is a full charge in approximately 10 hours.

Constant voltage charging is easier, but only provides 80% charge. The voltage is kept between 14-16 V. The current gradually decreases as the battery charges. Here the algorithm looks like this: set the voltage in the range of 14.4-14.5; We wait a day, we get the battery charged to 80%.

4. How long to charge the battery

The battery recharging time depends on several factors: the type of device and the amount of current. Less current means more time to recharge.

It takes 15 minutes for the battery to start the engine. Then you need to drive around until the battery is fully charged, while it is recommended to use additional devices that consume current (stove, radio, etc.) to a minimum.

So how long does it take to charge the battery? It takes 10-12 hours to charge the battery.

5. Signs of successful battery charging

The end of charging is accompanied by boiling of the battery. You can also determine the state of battery charge using an ariometer: the full battery charge shows 1.26-1.28 depending on the season (a little lower in winter, a little higher in summer).

6. Emergency measures for charging the battery in winter

In the cold season, a situation may arise when the battery “died”. In this case, we recommend removing the battery and moving it to a warm place for half an hour.

You can speed up the process by placing the battery in slightly warm (this is a prerequisite) water. The terminals must remain dry. This is a dangerous method and may shorten the life of the battery. If, for example, the water is too hot, the electrolyte will expand.

Using household appliances such as hair dryers and heaters inappropriately can damage the battery.

7. Lighting a cigarette from a charged battery

The most popular way to “reanimate” a battery. When connecting batteries to each other, remember the diagram:

• We connect the wire for lighting one end to the positive on the operating unit;
• with the other end we also connect it to the positive on the non-working battery;
• with the second wire we do the opposite (first we connect the wire to the negative of the failed battery, and then we connect to the negative of the charged battery).

8. Prevention

There won't be any particularly long explanations here. We recommend that you carry out maintenance charging of the battery 2 times a year so that the likelihood of sudden battery failure is minimal.

9. Buy a special battery revitalization kit

• starting charger;
• adapter for charging from 220 V;
• adapter for recharging from a cigarette lighter;
• USB cable (not always included);
• power clamps for starting the engine.

10. Moving the battery to your home

It happens that a driver rarely drives a car in winter. In this case, experienced drivers strongly recommend removing the battery and storing it in a dry, warm room. The recommendation is supported by the fact that a non-working battery at low temperatures quickly deteriorates in its characteristics. Sometimes this even leads to irreversible damage to the battery.

During such storage, it is important not to forget to charge the battery at least once every 3 months. Then he will always be in “combat” readiness.

In conclusion, we emphasize: be attentive to the car and to yourself. Many unpleasant situations will not happen if you think about your safety in advance. Proper use of the battery will allow you to avoid malfunctions. Careful preparation of the car before a long journey will allow you to get to your intended destination without unnecessary incidents.

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How to properly charge a battery - useful tips “Behind the Wheel”

Filling a jar with electricity is an expression from V.I. Dahl’s dictionary: this is how he explained the meaning of the word “charge.” It fits perfectly into modern six-cell car batteries. True, the banks turn out to be different - both in design and in condition. How to fill them with electricity?

All batteries can be divided into low-maintenance, maintenance-free and completely maintenance-free. The oldest of them are low-maintenance, with gratings made of lead-antimony alloy, the coolest are completely maintenance-free, with gratings made of the purest lead. It should be noted that “maintenance-free” means extended intervals for adding water or the complete absence of this procedure throughout the entire service life. But any maintenance-free battery requires periodic monitoring along with other car components. Contrary to popular belief, there is no significant difference in charging these three types of batteries.

Should I charge it or not?

Is it possible to charge in the cold?

How to charge when traveling infrequently?

Charger or generator – which charges better?

Under normal operating conditions, a charger is not needed. The battery must be charged from the generator. And a charge at a constant voltage of a working car is the most correct and useful for the battery.

The task of a stationary charger is to restore the battery, albeit not completely, but enough for the generator to recharge to 100%. When charging with direct current, in order to avoid overcharging and “boil-off”, that is, the consumption of water from the electrolyte, the stationary charger interrupts operation at a level of 14.4 V, switching to recharging mode with a minimum current during storage. This usually prevents the battery from being fully charged. And the generator charges it in constant voltage mode.

Depending on the settings of the vehicle's power supply system, the voltage regulation range is 13.8–14.5 V. The charge current is determined by the internal resistance of the battery, which characterizes its current state, and decreases as the voltage at the battery terminals approaches the generator voltage. That is, a stationary charger produces a specific current in accordance with its algorithm, and the battery takes the current it needs from the generator. This is why a charger cannot charge as well as a generator.

What should the charge mode be?

When the NRC drops below 10.5 V, this is already an ultra-deep discharge. If the battery is drained in a short time, it can be quickly charged with a high current of 10–20 A (10% of the rated capacity) from a stationary device within a few hours. If the battery was chronically undercharged and died slowly, the charge must be started with a minimum current at a constant voltage. To do this you will have to contact a specialized service.

Should I remove the battery from the car to charge it?

Can I “light up” from another car?

Opinions on this matter often differ, but the debate is only about the safety of the vehicle’s electrical equipment and its compliance with the operating instructions. One thing is certain: the battery will definitely not be damaged! In our opinion, “lighting” is safe if a simple scheme is followed: we connect the positive terminals of the donor and acceptor to each other, and place the negative terminal of the donor on the body of the “lighting” car.

The editors would like to thank Dmitry Tishchenko, an expert from the National Association of Power Source Manufacturers, for his assistance in preparing the material.

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How to properly charge a calcium battery

How often you need to resort to this operation depends on the ratio of the power of the car's generator and the power of consumers, as well as on driving conditions. In the summer, almost any car can do without additional battery recharging. The engine starts easily, consumers always turn on the ignition, electric fuel pump (approximately 8-10A), radio (3-4 A), headlights with dimensions (13 A). Even at idle, a working generator produces 40-45A, which is almost enough to power a minimum number of consumers. And at operating speeds, when driving along the highway, for example, the 60-70A supplied by the generator is enough to power consumers and charge the battery.

The operating conditions for the battery in winter are much more difficult. Negative temperatures reduce the battery capacity, impair the ability to accept a charge, and starting a cold engine requires a large amount of energy. New powerful consumers are turned on on board: heater (5-7 A at first speed and 10-11 A at second), heated windows and mirrors (16-20A), heated seats 5A. The total current consumption is more than 50 A. At idle, the generator can no longer cope with powering consumers; most of the energy is taken from the battery. And even in operating modes, the ability of the generator to recharge the car battery turns out to be very modest; in addition, at negative electrolyte temperatures, the battery does not accept a charge. All this leads to the battery becoming chronically undercharged. The user may not notice this, because even a partial charge is usually enough to start the engine. But chronic undercharging leads to sulfation of the plates, which reduces capacity and increases internal resistance. This in turn shortens the battery life and worsens starting performance. Therefore, in winter you need to systematically recharge the battery.

How often should you recharge your car battery?

The frequency of recharging depends on the car, weather, and travel conditions. For cars with a well-regulated starting system, in mild winter conditions with daily trips over short distances, accompanied by systematic standing in traffic jams, it is enough to charge about once every month or two. Of course, if frosts approach -30°, and each start is accompanied by repeated activation of the starter, then it makes sense to check the battery charge level more often.

And, of course, the battery must be immediately charged if you have discharged it “to zero” with unsuccessful attempts to start the engine. Precisely “immediately”, since the density of the electrolyte in a discharged state is low and there is a possibility that it will freeze, damaging the battery. On the other hand, keeping a lead battery in a discharged state leads to sulfation of the plates.

How to properly charge a car battery

Experienced drivers are familiar with the situation when, when trying to start the engine, it turns out that the starter turns weakly. To restore the functionality of the vehicle, you will need to charge the car battery. It is important to carry out this operation correctly, not forgetting simple precautions.

How often to charge your car battery

In the automotive industry, acid-type batteries are used; they can be serviced or maintenance-free. First, you can independently check the level and density of the electrolyte solution. In a working car, the battery is constantly recharged. This function is performed by the generator. The relay-regulator process controls the process, through which the voltage supplied to the terminals is supplied.

If the generator unit is working, the battery capacity is sufficient and the outside temperature is positive, recharging is not required. If the relay is faulty and under difficult climatic conditions, the battery will receive insufficient voltage and will begin to gradually discharge.

At negative temperatures, the battery capacity decreases, so standard charging is not enough. In addition, in cold weather, engine oil becomes thicker and the battery experiences increased load during startup, and it does not have time to be fully recharged.

Therefore, the recommended charging frequency with working equipment is once a year in late autumn. If part of the battery capacity is lost or the relay-regulator gives a charge less than normal, then recharging should be carried out as needed.

If the ignition system malfunctions, you have to turn the starter for a long time when starting. This requires energy consumption and causes the battery to drain quickly, so you will have to use the charger often.

Checking the car battery

Most modern models have an indicator on the top cover of the case. The design of this indicator is extremely simple: a green spherical float floats in a glass flask.

If the density is sufficient, the float floats up and can be seen in the indicator window. When the battery is discharged, the density of the electrolyte in its banks drops, the ball drops down and is not visible.

However, not all batteries have such an indicator, so you have to use other checking methods. One way is to use a multimeter. This device measures the voltage at the terminals. The measurement results are compared with the data in the table: