How to check the performance of a car battery?

In this article we will tell you how to properly check the car battery for performance using a multimeter and a load plug, what methods exist for this.

Checking the car battery with a multimeter

For this a multimeter is required - a device for measuring voltage. If you do not have it, you can ask your friends or buy it in a store. The device itself is not expensive, and if you spend more than one renovation work with electrical equipment, then it will come in handy more than once.

Do not rely on measuring the battery voltage using on-board computer cars, because they may be wrong. This is because these voltmeters are not connected directly to the battery, which means that losses are possible. Therefore, the voltage on them may be shown less than on the battery itself.

Checking the battery with the engine running

We measure the voltage first on the running engine. Normal voltage should read 13.5V to 14.0V.

If the battery voltage with the engine running is greater than 14.2 V, this indicates a low battery charge and that the generator is operating in boosted mode to charge the battery. This does not always happen, for example, in winter, increased voltage is possible, because the battery may have run out a little overnight due to the cold temperature, or the electronics detect the air temperature and give more charge to the battery.

There is nothing wrong with the increased voltage on the battery. If everything is normal with the electrical equipment of the machine, then after 5-10 minutes the electronics will automatically drop the voltage to the usual: 13.5-14.0 V. If this does not happen, and the voltage does not gradually drop to the optimal value, then this may result in overcharging the battery. It will always work at maximum output and the electrolyte may boil off.

If the voltage is less than 13.0-13.4 V when the engine is running - this says the battery is not fully charged. You should not immediately run to the car service, for a start, the measurement should take place with all consumers turned off, which means turn off the music, headlights, heating, air conditioning and all energy consumption devices.

What is the current voltage on the battery when measured with a multimeter? During normal operation of the car electronics, it should be in the range from 13.5 to 14. If it is lower, then this indicates that the car generator is not working. Especially when the voltage with the engine running and the switched off consumers is less than 13.0 V.

Low voltage is also possible if the battery contacts are oxidized, so before going to the car service, check all the contacts and clean them with sandpaper.

How else to check the operation of the battery and generator, respectively? There is one way. For example, with the engine running and the power supplies turned off, the voltage on the battery is 13.6. Now turn on the low beam. The battery voltage should drop slightly - by 0.1-0.2 V. Next, we first turn on the music in the car, then the air conditioner and then other consumers. We do everything gradually and every time the consumers are turned on, the voltage on the battery should drop slightly.

If the voltage drops significantly after turning on the power sources of the car, this indicates that the generator may not be working in full powerthe generator brushes may have worn out.

Even with all the consumers turned on, the voltage on the car battery should not fall below 12.8-13.0 V. If it is less, then the battery is simply discharged, and it may need to be replaced and a new battery must be purchased, and how to check this is discussed below.

Checking the battery with the engine off

We check the battery voltage with the engine off using a multimeter. If the voltage at its terminals is less than 11.8-12.0, then the battery is discharged, the car may not start, and you will have to light it up from another car.

Normal battery voltage with the engine off should be approximately 12.5 to 13.0 V.

There is an old and very simple technique for motorists to find out the battery charge level by voltage. So, voltage 12.9 - says that the battery is 90% charged, voltage 12.5 - 50%, and 12.1 - 10 percent. Here is such an approximate method of measuring the battery charge level, but very effective, which is confirmed by our own experience.

There is one caveat when you measure the voltage on the battery when the engine is not running. If the measurement takes place immediately after the engine is turned off, then one reading is possible, and if the next morning, the voltage will be different. The best thing to do is measure the battery voltage before riding.

The battery charge level indicates its ability to hold voltage for some days. If the battery is fully charged, even if you haven't driven for over a week, the voltage will not drop much. Otherwise, if the car battery is discharged, the voltage will drop quickly and the battery charge will not last long.

We talked about a simple technique for measuring the voltage on a battery, but it is very approximate, although it is quite effective. If you want to know one hundred percent about the health of the battery, then we will talk about this in the next section.

Battery test with load plug

This battery test method using a load plug is a very effective way to test the health of a car battery. It is by its results that one can say whether the battery is charged or not.

How do I check the battery charge? To do this, connect the load plug, observing the polarity. The connection time should not exceed 5 seconds. At the beginning of the measurement, the voltage is 12-13.0 V. At the end of the fifth second, the voltage must be more than 10 volts. Such a battery is considered charged and capable of operating under load.

If, when checking load fork voltage drops below 9 volts, the battery is considered weak and unreliable. In this case, you will have to think about buying a new one (how to choose a battery for a car).

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All storage batteries (accumulators) are discharged during operation or become unusable. To prevent a malfunction from taking you by surprise, you need to periodically check the battery. In addition, there are several methods for performing verification. More details on how to check the car battery will be discussed in this article.

The storage battery plays an important role in the operation of the car, being one of the main elements of electrical equipment. The battery acts as a power source when the engine is not running. The battery's job is to perform several functions, including:

• supplying current to the starter when starting the car;
• power supply of all electrical devices when the engine is not running;
• power supply of all electrical devices together with the generator with the engine running.

On a note! The joint work of the battery with the generator allows you to provide transients that require a large number current. In addition, when working together in the car's electrical network, the current ripple is smoothed.

Principle of operation battery simple enough. Charged particles in the battery begin to move after being connected to the load. This leads to the formation of current. While the battery is being charged from a charger (charger) or a generator, particles begin to move in the opposite direction. This is due to the fact that the charging voltage exceeds the battery voltage, that is, its nominal value.

Symptoms of a Bad Battery

Some signs may indicate that your battery is dead or broken, including:

• the engine began to start very sluggishly (the starter does not turn well). As a rule, this indicates a low battery charge, which is not enough to ignite the fuel mixture, since the spark is rather weak;
• battery power is insufficient for a long time. Most often, motorists encounter such a problem in winter, when a fully charged battery is enough for only a few engine starts. Insufficient electrolyte level often indicates a rapid decrease in battery charge.

The car does not start well - a sign of a battery malfunction

These signs cannot be ignored, since the battery can fail at the most inopportune time, for example, somewhere far outside the city. Therefore, at the first signs of malfunctioning of the battery, diagnostics should be carried out immediately.

Common Causes

Reasons wrong work There can be many batteries. Let's consider the most common ones:

• inattention of the driver. Often, drivers leave their car with the electrical devices (radio tape recorder, indicators, bulbs), which is why the battery is quickly discharged;
• poor maintenance of the device. If you do not periodically clean the battery terminals, the risk of damage increases. It can also reduce the lifespan;
• long-term use. All car parts have a lifespan. This also applies to the battery. After the warranty period of the battery operation ends, various processes may occur in it (sulfation, oxidation, etc.);
• low quality electrical wiring. If a poor-quality wiring was installed on the car, then over time it can rot and wipe, which causes a short circuit or discharge of the battery;
• errors when connecting electrical appliances. This can degrade the performance of the battery and lead to a shortened battery life;
• poor generator performance. If the alternator is faulty, it will not charge the battery normally while the engine is running. To eliminate the malfunction, it is necessary to carry out diagnostics.

In most cases, battery problems can be prevented. To do this, you need to timely carry out maintenance and repair your car only in high-quality workshops.

Battery test methods

You can check the condition of the battery using various methods, including diagnostics using a load plug, a multimeter, a charger. Also, during the check, an external inspection of the battery and an electrolyte check are carried out. Now let's look at each of the methods separately.

Visual inspection

An external inspection is the first thing to do when checking a car battery. At this stage, you can identify mechanical damage to the case, oxidation of the terminals or contamination of the battery surface. Experts recommend that this check be carried out regularly, since the cleanliness of the battery can also affect its functioning. The inspection procedure does not take much of your time, so it can be done every time you raise the hood.

On a note! Particular attention should be paid to the battery terminals during inspection. Poor bonding in these areas can cause active oxidation. Also inspect the battery housing for mechanical damage, such as cracks.

If you find dust, dirt or oil on the surface of the battery, remove them with a rag. Without regular cleaning, the device will gradually lose its charge due to the formation of conductive deposits. This will lead to a deterioration in the performance of the battery. It will not be superfluous to check the reliability of the fasteners.

Load fork test

Step 1. Remove the battery positive terminal cover. This can be done by hand, without using any tools.

Step 2. Connect the positive lead of the load plug to the positive terminal of the battery (the one you exposed). As a rule, the positive wire on the device is colored red.

Step 3. Connect the negative lead of the load plug to the negative terminal of the storage battery.

Step 4. Connect the tip of the device (pin) to the positive terminal of the battery. In this case, you need to be extremely careful, since the metal pin can become very hot during operation.

Step 5. Check the reading on the voltage meter. If the battery is in good condition, the voltage should be between 12.4 and 12.7 volts. At the end of the procedure, you need to put the cover back on the positive terminal.

Electrolyte density check

Checking the electrolyte in the battery is another diagnostic method. To do this, disconnect the terminals from it and put the battery on a flat surface. Then unscrew all the caps of the electrolyte containers and look inside. Under normal circumstances, the liquid level should be slightly above the edge of the lead plates (about 10 mm).

For a more accurate measurement, use a hydrometer or a special graduated tube, which must be placed inside the battery to the very bottom. Then close the top of the tube with your finger and pull the tube out to measure the electrolyte level. The norm in this case is 10-15 mm. Checking with a hydrometer is much easier. To do this, simply take a sample of the electrolyte (this can be done absolutely from any jar). If everything is in order and the battery is fully functional, then the device should show a value in the region of 1.28 g / cm3. The recommended replacement frequency is 1-2 times a year.

With a multimeter

First you need to figure out what a multimeter is. This is a special device used to measure voltage. If you do not have such a device, then you can borrow it from friends or neighbors. It is worth noting that a multimeter is not expensive, so if you plan to independently repair electrical equipment on your car in the future, then it will come in handy. A digital multimeter is best suited for this purpose - it is more practical. So let's start checking.

Step 1. First you need to turn off the car and turn off the ignition.

Step 2. Remove the battery positive terminal cover. Check and clean the terminals from dirt, if necessary.

Step 3. Connect the positive lead of the multimeter to the positive terminal of the battery. As noted earlier, the positive terminal on the voltmeter is usually red.

Connect the plus of the multimeter to the battery

Step 4. Connect the negative lead of the multimeter to the negative terminal of the storage battery.

Now connect the "minus" of the multimeter to the battery

Step 5. Check the reading on the multimeter. If your battery is in good condition, the voltage should be between 12.4 and 12.7 volts. A reading of less than 12.4 volts means the battery needs recharging.

If the readings exceed 12.9 volts, then in this battery excessive stress. Turn on headlights and other electrical appliances to eliminate excess surface voltage. Typically, overvoltage indicates that the vehicle's alternator is overloaded with the battery. Replace the terminal cover after completing the procedure.

Using a charger

If your garage has a digital charger, you can check the battery level without using a voltmeter. The procedure is not complicated, everyone can handle it. The main rule of such a check is that the charger should not be plugged into an outlet, as this can affect the readings of the device.

To check the battery, you need to connect the charger to its terminals. Accordingly, connect the positive wire to the positive terminal, and the negative wire to the negative terminal. After that, turn on the device by pressing the special button on its body. This will start the test and then read the results.

Battery check without special devices

you can check car battery and without the use of various devices. Many manufacturers install special sensors on batteries to indicate the charge level. If you do not know how to use such a sensor, read the instructions. Often, manufacturers place the necessary information on the battery case itself.

Another test method is with headlights. Turn on the low beam on a cold (cooled) car for 5 minutes and watch the light. During this time, the brightness should not disappear. If the light still fades, then this usually indicates a battery malfunction. The same test, but using a horn instead of headlights. Turn on the ignition and wait 1 minute. Then beep several times - if the sound is loud, then everything is fine, if it is quiet, then you need to recharge the battery.

Important! If during the test the battery is very hot (for this, check it by touch), then using it further can be dangerous to the health of the driver. This is because a battery that heats up quickly can explode. In this case, it is better not to risk it and buy a new battery.

As a conclusion

After reading the instructions, you know how to check your car battery for serviceability and what you may need to do this. But in order to avoid various malfunctions of the battery, you need to follow some recommendations for care and operation:

• regularly diagnose electrical wiring, generator and other elements of the on-board network;
• monitor the electrolyte level and its density;
• periodically charge the battery using a charger (every 3 months);
• keep the battery clean, regularly remove accumulated dust, dirt, electrolyte and oil residues;
• clean the oxidized battery terminals, treating them after that with a special grease that is used for electrical contacts.

Checking the car battery without special devices

We hope that our article was useful to you, dear motorists, and you have emphasized something new for yourself. If you have any wishes or additions, then you can leave them below in the comments.

Video - Checking the health of the car battery

Without exception, all car owners will sooner or later have to face the problem of a malfunction of the battery used. During the operation of the car, the battery may fail or for some reason be discharged, not allowing you to use your car. There are various ways to test the battery, which we will discuss in this article.

Visual inspection of the battery

Before proceeding directly to measuring the voltage of the battery, it should be visually inspected. So, for example, you need to make sure the integrity of the case, which should not have mechanical damage. Pay attention to the absence of electrolyte leaks. The terminals must be clean, without light green or loose white deposits. With insufficient tightness of the terminals at the connection points, resistance increases, which negatively affects the values \u200b\u200bof the starting current. As a result, the engine does not start well, and the terminals can heat up to high temperatures. In the latter case, there is even a risk of wire fire and damage to the car. Be sure to keep your battery clean and tighten its terminals in time.

Checking the level and density of the electrolyte

This check can only be performed with serviceable batteries. To check the electrolyte level, remove the battery from the car, place the battery on a horizontal surface, then unscrew the plugs and visually inspect the electrolyte level, which should be a few centimeters above the lead plates. In the event that the electrolyte is below the plate level, it is necessary to add distilled water to the battery. The density check can be done with a special acid hydrometer. We carefully drain off some of the electrolyte and, using a hydrometer, check the corresponding density of the electrolyte, which should be 1.28.

Battery test with a multimeter

If for some reason the car cannot be started, then, first of all, the battery voltage should be checked. This work is done using a multimeter. To perform this check, you need to do the following:

Turn on the multimeter and set the DC voltage measurement mode.

We connect the black probe of the multimeter to the negative terminal, and connect the red probe to the positive terminal of the battery.

We fix the readings of the multimeter on the display.

When fully charged, the multimeter shows a voltage of more than 12.7 volts. If the battery voltage is fixed at 11.7 volts, the battery is completely discharged. In this case, it is necessary either to replace the battery or to charge it using special devices.

We check the battery with a multimeter with the engine running

Checking the battery with the engine running allows you to determine the presence of leaks in the network, and also identifies problems in the operation of the generator. With the engine running, the battery voltage should be in the range of 13.5-14 V. Note that an increased battery voltage with the engine running may indicate problems with the generator. In the event that such an increased battery voltage is kept with the engine running for a long time, it is necessary to carry out the appropriate diagnostics of the generator and the entire electrical system of the car. If the voltage indicators are 13 V or less, then this indicates a breakdown of the generator, which does not charge the battery while the car is moving.

We check the battery with a load fork

Checking the performance of the battery charge using a load plug allows you to establish the performance of the battery used on the machine. This load plug must be connected to the battery with the correct polarity. If the load plug shows the battery charge at 12-13 V, this indicates a high-quality battery charge and its ability to work under load. If, during such a test, the voltage indicator drops below 9 V, then such a battery is unreliable and is considered unusable.

Charging the battery

Charging the battery at home is not difficult. You can easily use special chargers that can literally fully charge the battery within 8-10 hours, which allows you to use your car without any difficulties. A special charger can be purchased at car dealerships or soldered on your own according to the appropriate schemes from the Internet.

Over time, all batteries deteriorate or discharge. In order not to face the problem of a faulty battery condition, it is necessary to periodically check it. There are several ways to check the car battery for performance.

Visual inspection

During an external examination of both a new battery and a used one, its various components are checked:

• for cleanliness. They should not have a greenish or white coating. If present, it is necessary to clean the terminals with fine-grained emery paper, and then grease them with petroleum jelly.
• The tightness of the terminals and contacts. A loose terminal may not charge the battery sufficiently and may make it difficult to start the vehicle. In order to seal the contact, it is necessary to tighten the nuts, but if the contact still remains loose after that, you can put a metal gasket.
• The integrity of the body. Even the slightest damage over time can lead to electrolyte leakage. If defects are found in the case, it is necessary to replace the battery with a new one.
• Dirt and moisture on the case. It is necessary to keep the housing clean, as this negatively affects. Dirt can be removed by wiping the housing with a mild alkaline solution.

Electrolyte check

In order to check the electrolyte level in the used battery, it is necessary to remove the terminals from it and place it on a horizontal surface. After that, you should unscrew the covers of all the capacitive battery cans, and look inside. The electrolyte level should cover the lead plates by about one centimeter.

For more accurate measurements, you can use a special graduated tube - a hydrometer, or you can take an ordinary glass tube and a measuring device. The tube is placed inside until it stops and closed from above with a finger, after which it must be pulled out and the level measured, normal indicators should be in the region of 10-15 mm.

The electrolyte density is checked with a hydrometer after fully charged at room temperature. To do this, you need to take a sample from any jar. Normal indicators should be around 1.28 g / cm 3. The density should be checked every six months.

The battery test with the load plug is carried out both without load and under it. For a no-load test, disconnect the terminals from the battery, then connect the load plug. With a fully charged battery, the voltage should be 12.7 V. A drop in readings of 0.2 corresponds to a discharge of 25%.

It is more important to make measurements under load, in ideal condition the indicators should be at the level of 10.2 V, if the indicators are lower by 0.6, then this corresponds to 75% of the battery charge, and during the measurement the voltage should not drop. If this happens, then it must be replaced.

How to use the load plug, see below:

Checking with a multimeter

One of the popular devices for checking the battery charge is a multimeter. This device allows you not only to measure the battery charge, but also to check the entire electrical system of the car. This device costs little in comparison with its capabilities. To check the charge, you need to put the multimeter in constant voltage mode and disconnect the negative terminal.

The procedure for working with a multimeter is presented in the video:

If there are no special devices

There are several reliable and at the same time simple ways checking the condition of the battery without various instruments. Modern batteries are equipped with a sensor that shows the charge level. In order to understand how to use the sensor, you can read the instructions, sometimes the information is placed directly on the battery.

You can also check the battery charge with the headlights. To do this, it is necessary that the car has time to cool down after use, it is best to do this in the morning, when the car has been standing all night. It is necessary to turn on the dipped headlights for 5 minutes, during which it is necessary to monitor it. The brightness of the light should not drop throughout the test. If the light dims, it's time to consider replacing the battery.

This is worth considering if you get poor results during the beep test. To check, first turn on the headlights on high beam and wait one minute. Then they click on the sound signal, if it is loud, then everything is in order, quiet - the battery needs to be changed. It is worth checking the temperature of the battery by touch, if it gets hot, then there is a possibility of its explosion.

All of these methods will help you avoid unpleasant situations both at home and away from it.

One of essential elements our car is a battery (accumulator). The main role, namely, the start of the car is performed by the battery. The engine is started by supplying current to the starter from the battery. Even with the engine off, all light and sound systems will work properly if the battery is good.

Battery charge rate

The car burglar alarm will also not function if the battery is “dead”. Even when the car is moving, if the generator cannot cope with the loads, the battery comes to the rescue. Certainly normal work onboard system the vehicle will not function properly if the battery is low. Therefore, in this article we will try to tell you which battery charge rate is the most optimal.

Battery charge rates

Voltage is the main parameter of the battery. Therefore, the owner of his car needs to know what voltage should be in the battery.

The voltage norm of the battery 6 CT (6 cans) in a charged state should be from 12.6 to 12.9 volts. From this it follows that the charge of one can should be between 2.1 and 2.15 volts. If the voltage is less, then your battery is discharged, but this does not mean that your battery cannot be used. You will hardly succeed in having a 100% charged battery at all times. On the table below you can see the dependence of the voltage and the state of charge of the battery.

Battery discharged

As practice shows, the critical voltage mark of a twelve-volt battery is a voltage of 10.8 volts. Such a discharge is called deep. Such a discharge is detrimental to the battery, it significantly reduces the service life of the car.

The table above shows how the state of charge is continuously related to the density of the electrolyte. The battery charge can be checked not only by the voltage at the terminals. You can also check the density of the electrolyte. The density of a fully charged battery should be between 1.27 and 1.29 g / kb.cm. The density of the electrolyte can be measured with a simple instrument - a hydrometer.

Checking the battery charge

A voltmeter or multimeter helps in measuring voltage. If you want to measure voltage with a multimeter, put it in voltage measurement mode. Then attach its contacts to the battery terminals and on the display you will see the charge of your battery. Polarity is optional. If you incorrectly applied the probes to the battery terminals, then the display will only show a negative voltage. The photo below shows the result of voltage measurement.

By means of a load plug, it is also possible to measure and monitor the battery charge. A voltmeter is built into the mechanism of such a device, which measures the voltage. The load plug not only determines the battery charge, but also monitors the battery condition itself. For this, the actual voltage is measured with resistance in closed circuit mode. The load plug emulates the start of the vehicle, and determines the load on the battery. But when carrying out such a check, the battery must be fully charged.

Before checking the battery charge with a load plug, connect the plug terminals to the battery terminals, and apply the load for 5 - 6 seconds. At the fifth second, remember the voltage on the voltmeter. If the voltage is less than 9 volts, then such a battery will not last long. If the voltage drops to 10 - 10.5 volts, then your battery is still in good condition.

Three main types of battery charging

• - accelerated. This charging mode is called Boost and is found on most modern car chargers (chargers). With such a charge, the battery does not receive a full charge, but it is enough to start the car. Such a charge is best used if you urgently need to drive your car and your battery is dead. Boost charge, accelerated by increasing the amperage;

• - charge with constant voltage. This type of charge must maintain a constant voltage at the battery terminals. This is an automatic battery charging that exists on all modern chargers. It is usually used when the battery is not fully discharged (at least 11.5 volts). This charging mode can be uncontrolled. The charger itself determines the required battery charge, and itself turns off the charging process;
• - charge with direct current... This charge supplies DC power to the battery. The process of such a charge is carried out in several stages, at which the supplied current gradually decreases. This mode is used for fully discharged batteries. A constant current charge most efficiently and evenly charges the battery. The downside is that such a charge must be constantly monitored, namely, the charge must be monitored, and when the charge is brought to the required norm, this process must be stopped.

Security measures

The whole process takes place in a well-ventilated area. Near the battery and charger, there should be no open flames or sparks. During the battery charging process, hydrogen is released, forming an explosive mixture when combined with oxygen!