How to properly recharge your 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.

Let's charge the battery! Instructions for beginners and blondes

Car batteries stay charged by using the extra power from the car's engine. Most can last for five years without needing to be replaced or recharged. But even the best batteries will eventually die prematurely if you leave the lights on for too long. It is a very inconvenient situation when the battery suddenly runs out. But even an inexperienced car enthusiast can easily recharge the battery using the instructions that we at 7vaz.ru have prepared for you.

Preparatory work

Wear suitable protective equipment

Safety is of the utmost importance whenever you service or operate your vehicle. Start by wearing safety glasses to protect you from sparks or battery fluid. It is also recommended to use gloves. Make sure that the room in which work is performed is well ventilated and sufficiently lit.

Gloves are not required. But they can protect you from minor pinches and cuts while working on your car.

Make sure there are no children nearby while you are charging your car's battery, as a spark may occur if the positive and negative cables accidentally touch each other.

Determine what kind of battery you have

To properly charge your battery, you must first determine the type of battery you have. You can usually find a description somewhere on the battery. Sometimes you may need to visit the manufacturer's website if the label is too worn to read the information on it.

You should also check the battery voltage on the label or in your vehicle's owner's manual.

Buy a car charger

Choose a charger that is suitable for your battery. Most chargers are universal and suitable for all types of batteries except gel ones. There are fast chargers that can charge your battery quickly and even give you a jump start. There are also inkjet chargers that charge slowly, but at a higher quality.

Many modern devices have a microprocessor installed that allows you to control the degree of battery charge. This is very convenient as the process stops automatically after the battery is fully charged.

Simpler and older models must be stopped manually to prevent dangerous overcharging. You should not leave them unattended for a long time in the connected state.

• Read your charger's instruction manual to ensure you are using it correctly.
• Even modern digital models must be carefully monitored during charging to ensure they are functioning properly and stopping before recharging the battery.

Disconnect and remove the battery

It is important to disconnect the battery before recharging it. Often circumstances allow you to charge the battery without removing it from the car. But many car enthusiasts still take the device out of the engine compartment and take it home or to a room where there is an electrical outlet.

Attention! Always disconnect the negative terminal first and then the positive terminal.

Clean the terminals

Any dirt on the battery terminals can prevent the charging cables from making a strong connection to the battery cells, so it is important to clean them thoroughly. Use baking soda and a damp cloth or sandpaper to remove any dirt or rust. Make sure the metal terminals are completely clean before moving on to the next step.

• Sometimes you may find that the battery is fully charged, but dirty terminals are simply preventing electricity from flowing through.
• Do not handle the terminals with bare hands, especially if there is white powder visible on them. This may be sulfuric acid, which can burn your skin if it comes into contact with it.

How to properly charge the battery

Place the charger on a stable surface

Never place the charger directly on the battery as it may connect the negative and positive terminals, causing damage to the battery and charger and possibly even causing a fire. Instead, place the charger on a stable surface as far away from the battery as the cables will allow. Before connecting the charger to the wall, make sure the room is well ventilated. Open your garage door or window if you are indoors.

• Make sure the surface you place the charger on is sturdy to prevent it from falling or becoming detached from its terminals.
• Use the full length of the cables to place the battery as far as possible from the charger.

Connect the charger to the battery

Connect the black cable from the charger, marked with a negative sign (-), to the negative terminal on the battery, marked with the same symbol. Then connect the red cable with a positive sign (+) to the positive terminal on the battery with the corresponding symbol. Be sure to check the connections before connecting or turning on the charger, as mixing positive and negative terminals can damage the battery or even cause a fire. [8]

• Some vehicles may mark the positive terminal with the letters POS instead of the positive (+) symbol and NEG instead of the negative (-).
• Make sure the cables are securely connected to allow electricity to flow from the charger to the battery.

Set up your charger

Digital chargers can show the voltage level in the battery and allow you to set the desired voltage level. Older models only allow you to turn the charging process on and off.

Speed ​​chargers also give you the ability to choose the speed at which you want to charge the battery (often depicted as a turtle for a slow charge and a rabbit for a fast charge).

Fast charging is good for a car battery that recently died because you left a light on or something like that. If the battery has been discharged for a long time, it may require a longer charging process before it can be used.

• If the device allows you to set the desired battery voltage, set the value indicated on the label.
• Never put your charger into fast charge mode if you plan to leave it unattended.
• If the slow charging mode is selected, the battery can be left unattended overnight.

There are two charging modes: constant current or constant voltage. The first method is considered more effective, because it does not require control. The second method is simpler, but allows you to charge the battery only up to 80 percent.

Some expensive charging models make it possible to use a combined method, thanks to which human participation is minimized.

How to charge with DC current

1. Set the voltage to 10 percent of the battery capacity and charge until the voltage rises to 14.4 V. For example, if the battery capacity is 60 Ah, then charge it with a current of about 6 Amperes.
2. Then you need to reduce the current by half (in our example to 3 Amps) to lower the boiling point.
3. As soon as the voltage level reaches 15 V, we again reduce the current by half and continue the charging process until the current value and voltage stop changing.

How to charge with constant voltage

The charging process is much easier. You just need to set the voltage level to 14.5 V and wait. The charging process can last up to 24 hours, the battery capacity will only be replenished to 80 percent. But there will be no need to control the process and be nearby.

Check the battery

After the battery is charged, check if it works. Some digital chargers provide information about whether the battery is holding a charge properly and whether it needs to be replaced. This can often be stated as a percentage. For example, a value of 100% means that the battery has 100 percent charge.

You can also use a voltmeter to measure the voltage in the battery after disconnecting it from the charger. To do this, touch the positive and negative cables from the voltmeter to the corresponding terminals. If the battery is still in the car, the surest way to check its functionality is to plug it back in and try to start the car.

• If the voltmeter shows the number of volts that corresponds to the battery, the charger is fine and can be used to start the vehicle.
• If the voltmeter shows that the battery is draining quickly or the car will not start, this indicates other problems or the need to replace the battery.

In some cases, there is no way to wait, and you need to start the car as quickly as possible. In this case, you can “light” it from another car. How to do this is described in detail in the step-by-step guide on the website 7vaz.ru

Battery Troubleshooting

Check battery performance at an auto parts store

If you have charged your battery using a battery charger or another vehicle and your car still won't start, remove the battery (if you haven't already) and take it to your local auto parts store. There you can charge the battery and check whether it works normally, whether it can be serviced or whether it is better to replace it with a new one.

If the battery is maintenance free, you will have to replace it if it won't hold a charge.

• If the battery is bad, you will need to purchase a replacement.
• If the battery is fully charged and operating normally, but the car does not start, check the battery cables to make sure they are not damaged and connect them securely to the terminals.

Check the generator

A faulty alternator can prevent your car from charging its battery enough to start the car again. Sometimes it doesn't produce enough electricity to even keep the car moving.

You should check if the alternator has any problems. To do this, start the car and then disconnect the positive terminal of the battery. A properly functioning alternator will produce enough electricity to keep the car running without a battery. But if the engine stops working, the generator most likely needs to be replaced.

• Sometimes you can detect a problem with the generator by paying attention to the interior lighting. If the lights start to brighten when you press the gas pedal, and then dim again when you remove your foot, the generator is not working well.
• If you remove the alternator from your car, many auto parts stores can check it to see if it needs replacement.

Listen to the sounds

If your car won't start but makes an audible click when you try, the battery probably doesn't have enough charge to start. This could be because it is not charged properly or the battery is too worn out to hold a charge. Try starting the car again or check the battery.

• Make sure you have a good connection to the battery while charging, otherwise the battery will not be able to start the car.
• A clicking sound indicates that there is some electricity in the battery, but not enough to start the engine.

If the car stalls

If the car starts after charging the battery but stalls shortly after starting, it may be due to the alternator. If it starts again or continues to spin but fails to start, the problem is not electrical. Most likely, problems arose with the delivery of fuel or air.

• For an engine to operate properly, it must receive not only electricity, but also fuel and air.
• You will most likely need to take your car to a mechanic to determine the source of the problem and fix it.

How to properly charge a car battery

The life hacker explains which way to approach a discharged battery, as well as how and, most importantly, how to charge it.

It doesn’t matter how the battery died: whether you forgot to turn off the lights, were too carried away listening to music in the parking lot, or went on vacation for the whole summer. To charge the battery, you need to have an understanding of the theory and follow a few simple rules.

A little theory

Cars mostly use lead-acid batteries (WET). Their operating principle is based on the chemical reaction of lead plates with an electrolyte, which results in the generation of electricity. Over time, sulfation and destruction of the plates inevitably occur, as well as boiling away of the electrolyte, which reduces the capacity of the battery. And the battery can run out at the most inopportune moment.

How to check the battery

The easiest way is to use the built-in charge indicator, which is found on most batteries. This is the same “light bulb”, which in reality is not a light bulb at all, but a green float ball moving in a transparent flask. When the level and density of the electrolyte is sufficient, the ball rises and we see a green indicator. If the float is not visible, you need to check the electrolyte and recharge the battery.

Another option is a multimeter. With its help, you can measure the voltage at the terminals and understand whether the battery is discharged or not. A fully charged battery should have 12.6 V or more. A voltage of 12.42 V corresponds to 80% charge, 12.2 V - 60%, 11.9 V - 40%, 11.58 V - 20%, 10.5 V - 0%.

The most reliable way is to check with a load fork. It can show the voltage drop under load, that is, the real charge level and, accordingly, the capacity. Any auto electrician or a store that sells batteries has such a device. And most likely they won’t even take money from you for this check.

How to prepare a battery for charging

Having determined that the battery is indeed discharged, you can begin charging, but first you need to prepare.

1. It is advisable to remove the battery from the car. If you don’t have time for this, disconnect it from the on-board network by disconnecting the negative wire.
2. After this, you need to clean the terminals of grease and oxide for good contact.
3. It doesn’t hurt to wipe the surface of the battery with a dry cloth, or better yet, one moistened with a 10% solution of ammonia or soda ash.
4. Also, do not forget to unscrew the plugs on each of the battery cans or remove the plug to ensure the free release of electrolyte vapors and to prevent excess pressure inside.
5. If the electrolyte level in any of the jars is insufficient, you need to add distilled water so that it completely covers the plates.

How to charge the battery

The charging principle itself is simple: you just need to connect the wires from the charger to the battery terminals in accordance with the polarity and plug the plug into the socket. However, first you need to decide on the charging method. There are two main methods: constant current charging and constant voltage charging.

The first is more effective, but takes place in several stages and requires control. The second is simpler, but only charges the battery up to 80%.

There is also a so-called combined method, in which participation on the part of the car owner is minimized. The disadvantage of this method is the need for a special charger with a fairly high cost.

DC charging

1. We set the current to 10% of the nominal capacity of the battery and charge until the voltage at the battery terminals rises to 14.3-14.4 V. For example, a battery with a capacity of 60 Ah should be charged with a current of no more than 6 A.
2. Next, we reduce the current by half (to 3 A) to reduce the intensity of boiling, and continue charging.
3. As soon as the voltage rises to 15 V, you need to halve the current again and charge the battery until the voltage and current values ​​stop changing.

Constant voltage charging

Everything is much simpler here. You just need to set the voltage within 14.4–14.5 V and wait. Unlike the first method, with which you can fully charge the battery in a few hours (about 10), constant voltage charging lasts about a day and allows you to replenish the battery capacity only up to 80%.

Precautionary measures

Since charging a battery is a chemical process that releases an explosive mixture of hydrogen and oxygen, you need to be very careful and follow the rules:

1. Charge the battery in a well-ventilated area.
2. Do not use open flames or carry out any work that produces sparks.
3. If it is not possible to remove the battery from the car, disconnect the negative cable, or better yet, both.