How to check a battery with a multimeter - detailed instructions

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04/09/2017 1422

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Determining the suitability of used batteries for further operation is a real “headache” for owners of devices that operate on such batteries. How can you tell whether a battery will last indefinitely in remote controls or watches after most of its charge has been used up in toys or flashlights? The simplest option, which is to install them in the device itself and check it, does not work when it comes to dozens of different batteries. In this collection, we have collected 7 inexpensive battery testers from Aliexpress, most of which are multi-format, that is, compatible with various types of batteries from tablets and pinky batteries to high-current 18650 batteries.

• Sliding tester
• Tester with LCD screen
• Vertical charge meter
• Digital battery tester
• Universal tester BT-768
• Tester in keychain format
• Device for checking the charge of button batteries

Sliding tester

This tester has the simplest design imaginable, which is fully reflected in its extremely low cost. One of the contact pads here is made in the form of a folding leg, which allows you to install batteries and accumulators of AAA, AA, CR2032, as well as 18650 and several other most popular formats. For Krona batteries, there are 2 separate contacts on the opposite side. The level of remaining charge is displayed on an analog scale, where the green and yellow zones indicate the battery’s expiration date, and the large red sector indicates the need to replace them with new ones or charge them.

$3.13 | Buy

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Safety precautions

Since work is carried out with electrical equipment operating with high current levels, it is worth taking into account the negative effects on the human body. Electrical current can cause several types of injuries. Among them:

• Thermal burns.
• Muscle cramps.
• Failure of internal organs.

Therefore, when working with devices that involve connecting terminals and taking measurements with current passing through them, you must follow the rules of safe operation. Take care to protect your hands, grounding, and dry the ground on which the person stands. It is best to use shoes with rubberized soles and avoid getting them wet.

You can ground yourself using a thin wire or piece of wire connected at one end to the device and the other to a battery or other external metal structure.

When working with batteries, do not allow them to overheat. Some alkali metals are flammable and burn for a long time even in open air. Therefore, you should always keep powder fire extinguishers within reach.

Tester with LCD screen

The structure of this device for determining charge involves installing batteries on its side, by fixing them between the contacts using a sliding slider. To display charge information, the device uses a tiny LCD screen that displays values ​​in volts. A cheat sheet consisting of control values ​​is printed on the back of the case in the form of an indelible microrelief. The tester is compatible with batteries with voltages from 1.5 to 9 volts. Contacts for checking elements of the “Crown” type are located on the opposite part of the housing.

$3.52 | Buy

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What is a battery and what electrical characteristics determine its performance?

The popular name battery is assigned to galvanic cells or chemical current sources that generate electricity to power household appliances and electronic gadgets.

They are usually produced in finger form with dimensions AA or AAA or in the form of tablets.

Functionally, they may or may not have the ability to charge after intended use (batteries). In the first case, the inscription “Rechargeable” is placed on their body.

In the instructions for other models they write that they cannot be charged, that is, they work one-time until they are completely worn out. This must be taken into account, because when they are installed in a charger under voltage, they can explode.

There was such a case in my practice when a neighbor on the top floor damaged her landline phone. She had nickel-cadmium batteries in her tube, which became unusable after a few years.

She replaced them with batteries of the same shape, talked, and placed the handset on the base... she had to buy a new device.

Be careful not to repeat such mistakes.

The performance of a battery is determined by the amount of electrical power that it is capable of delivering to a connected consumer. At the same time, a potential difference is formed at its terminals in the open state - a voltage that, when connected to any resistance, produces an electric current of a certain strength.

It cannot flow indefinitely, but acts only for that period of time for which the energy stored in the chemical current source is sufficient. All of these processes are interconnected, summarized by the term “battery or accumulator capacity” and described by mathematical formulas.

For example, a car battery has a capacity of 60 amp-hours.

This means that at a load current of 1 ampere it should work for 60 hours, and at 60 amperes it should last only an hour.

The same requirement applies to batteries, only their power is much less. Their capacity is marked in milliamp-hours.

The main electrical characteristic of a battery is its capacity . It determines the duration of operation of the chemical current source, that is, its resource.

Its value constantly decreases during operation, and the rate of decrease strongly depends on the connected load.

The results of one of the verification tests of four identical batteries at different consumer currents showed the following results.

In life, we constantly encounter this: the larger the connected load, the faster the chemical current source fails. Therefore, for each electrical device, its own galvanic element is selected according to its power.

2 factors that can damage a battery from the factory before use: you need to know them

These include:

1. time;
2. freezing.

I will dwell on them in more detail, because in some cases you won’t even have to use a multimeter.

Storage time and service life of a chemical power source

My neighbor in the country bought a wireless mouse for his laptop. She successfully worked for him for six months, and then refused. He came to me with a question.

We looked at the batteries, there are two AAA ones. They have completely exhausted their charge: they need to be replaced. The neighbor asked his friend, who was traveling to the city, to bring him similar ones.

The next day he asks me again: the power supply has been replaced, but the mouse does not work. I removed the AAA from the case: they have the year of manufacture 2013 on them, when it is now the height of summer 2022. The expiration date has long expired.

It is indicated on the packaging (usually 3 years), and the date of manufacture is indicated directly on the body of the galvanic cell.

This is explained simply: it is almost impossible to completely eliminate self-discharge currents. They are taken into account by their expiration date.

Why you need to pay attention to storage conditions

Let's say we bought batteries for my neighbor at a kiosk on the street. In our country, the period of negative temperatures lasts for six months, and in more northern regions it lasts even longer.

During frost, the capacity of any chemical current source is subject to greater self-discharge; it loses its service life before the specified time.

Considering these two factors, I generally do not buy batteries at kiosks and always check their release date, which I advise you to do.

Vertical charge meter

Like the previous model, this tester uses a sliding platform that allows you to install a battery of any size from tablets to large lithium batteries. But the scale for determining the suitability of batteries has been slightly improved. The charge is displayed in the form of stripes on an elongated display, along the edges of which various values ​​​​are applied to determine the voltage. Switching the battery to the red sector means its unconditional write-off. The device's compact dimensions of 8.9 x 2.7 cm allow it to be used as a daily tool that can easily fit in your pocket.

$7.74 | Buy

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Full discharge/charge

Today, complete discharging and charging is the only direct and most reliable way to determine the battery capacity. Specialized battery discharge/charge monitoring devices (UKRZ) allow deep discharge and subsequent full charging of the battery with constant capacity monitoring. However, this procedure takes a very long time: 15-17-20-24 hours, sometimes more than a day, depending on the capacity and current state of the battery. Although the method gives the most accurate results, its use is limited due to the time required.

Digital battery tester

In general, this tester resembles the previous one, but has a number of significant differences from it. The body of the device turned out to be more voluminous, which made it possible to place an informative screen on it, which displays not only the voltage scale, but also digital and percentage values. Additional information on charge levels was included on a colored sticker. A sliding slider with contacts allows you to check the vast majority of formats of current battery types. The device itself requires 2 pinky batteries to operate.

$6.32 | Buy

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Diagnostic methods

If you don’t know how to test a battery with a multimeter yourself, then we suggest you familiarize yourself with the testing methods.

First, let's look at the control discharge method; it is carried out in several steps:

1. First of all, the car’s battery will need to be fully charged and then discharged. During execution, it is important to maintain the current or power at the same level.
2. After you can achieve the desired voltage parameter, the discharge procedure will need to be stopped, and the time must also be recorded. Ultimately, the results of the control discharge will need to be compared with the main technical parameters of the battery. If you have also tested the device previously, then the results need to be compared.
3. If the battery takes a long time to discharge under load, this will indicate that its capacity is high.

This testing method is not suitable for everyone, since to perform it, the car owner must not only approach the task correctly, but also have free time. So for testing you can use a simple tester. With such diagnostics, the load size must be such that it can take 50% of the current that is needed for the normal functioning of the battery. This testing method is relevant when the battery is fully charged (video published by the Avto-Blogger.ru channel).

To discharge the device, you can use a regular incandescent light bulb, to which two wires are connected, and which is subsequently connected to the battery. If during the diagnostics you see that the light produced by the lamp has become too dim, this indicates that the battery is discharged. If the testing ultimately shows that the voltage reading is 12.4 volts, this indicates that your battery has good capacity.

Universal tester BT-768

The complex and angular shape of the contact pad of this tester allows it to work with batteries and accumulators of any size and voltage up to 9 volts - you just need to choose the appropriate niche. Voltage values ​​are displayed using a scale on an elongated electronic screen. For reference, 3 stripes are applied parallel to it, consisting of red, yellow and green sectors. The device runs on a single AAA battery, to install which you need to remove the cover located on the front side.

$4.59 | Buy

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Multimeter functions

A multimeter is a portable multifunctional electrical measuring instrument. It is also called a tester; it is easy to use and useful in everyday life. The tester can be found in almost every home. The device is small, lightweight, portable, and runs on a Krona battery.

In the minimum set it includes the functions of a voltmeter, ammeter and ohmmeter.

A multimeter will help:

• check the serviceability of any electrical equipment;
• test the diode or transistor;
• find the area of ​​damage to the electrical wiring;
• measure the voltage in the network;
• ring - measure the resistance value;
• find out the voltage frequency;
• determine the battery capacity;
• measure the voltage in the battery

and do much more.

Tester in keychain format

The very compact body structure of the BC-06 model allows it to be used as a keychain and worn on a chain along with keys. There is only one contact pad, and therefore the voltage can only be measured on button cell batteries, for example LR44. Despite its modest dimensions, the creators of the device managed to equip it with an LCD screen and percentage markers to determine the suitability of elements for further use. The case also has a hidden compartment for storing batteries. It is accessible by sliding the cover on the back wall of the device.

$6.96 | Buy

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Device for checking the charge of button batteries

Another specialized tester for tablet batteries has slightly larger dimensions, which made it possible to place on the case 3 niches with contacts for batteries of various diameters, including CR2032 and LR44. The scale for displaying voltage is made in the simplest analog version, but the markings on it are perfectly readable and understandable to any user. But there are no polarity tips on the contact pads, so the buyer himself has to guess the correct position of the “plus” and “minus”. The body of the device is entirely made of plastic, weighs 47 grams and is painted in a cheerful green color.

$2.27 | Buy