How to test a battery with a multimeter: 3 diagrams in the form of instructions with pictures for the novice home DIYer

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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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Types of testing equipment

To choose the right device to determine the health of the battery, you must first make sure what exactly causes it to malfunction. Among the typical malfunctions of the batteries of various devices are the following:

• Fast charging and discharging.
• Inability to start charging.
• Leakage current.
• Broken power circuits or damage to plates immersed in electrolyte.
• Insufficient density of the electrolytic fluid.

The best choice for identifying most of these faults is a universal battery tester, which covers most of the car enthusiast's needs. But some parameters, for example, electrolyte density, cannot be measured by electronic devices; for this, other, hydrostatic equipment is used. Therefore, all possible measuring devices can be like this:

• Multimeter - can detect open circuits, measure the strength of the current supplied, the resistance of the plates and contacts, and the voltage produced by the battery at the terminals.
• A load fork is a device that allows you to set the rate of battery discharge, thereby determining the degree of its wear.
• Capacity meters - show the current presence of charge in the battery. They are used to understand how dry the contacts are and whether the electrolyte needs to be replaced with fresh one.
• Hydrometers are hydrostatic meters of the density of an electrolytic liquid. They determine the need for recharging and can help in deciding whether to replace the fluid itself or the entire battery.

Each type of measuring instrument can have several purposes, depending on the model. For example, with a hydrometer, in addition to the specific gravity of the electrolyte, you can measure the indicators of antifreeze, so it is better to consider each of the types and its most useful models in more detail.

Household and industrial multimeters

When choosing a device for a specific task, you need to decide on its type. Multimeters, for example, come in both analog and digital varieties. The measurement method does not change; all differences are solely in the display on which the results are displayed.

Analog multimeters are meters with a needle that moves along a scale drawn in the background. Depending on the position of the switch, which is located immediately below the display, one of the scales is selected, and the required indicators are already obtained from it.

Today, such devices are of little use for everyday use, since the accuracy of the results is relatively low. Therefore, even if the household has an analog multimeter, it is better to replace it with a digital one. We recommend: Types of Japanese car batteries FB

The electronic subtype makes working with it much easier. Instead of arrows and scales, the value of the value selected by the switch is simply displayed on the screen. In this case, you can determine its value to tenths or even hundredths, which increases accuracy and gives a much more correct idea of ​​the problem.

Each multimeter has additional functions that help in everyday life and repair of devices:

• "Squeaker." In reality, it is just a resistance difference meter, but it is used to detect electrical circuits and circuits that are in a short circuit state. At the same time, a squeak is heard, which gave this function its colloquial name.
• Thermocouple - special wires that can be connected to some models. Shows the current temperature on the surface to which it is applied.

Such features help a specialist or amateur quickly find out the cause of a breakdown or strange behavior of a device.

The most popular models of multimeters among radio amateurs and motorists are:

• DT-832 and its more modern modification DT-838. These are inexpensive and functional devices, which sometimes have a fairly high measurement error. But they remain indispensable for domestic use or in situations where more serious equipment is not at hand.
• Kemot KT30 - no longer uses AA batteries as power supply, but full-fledged nine-volt batteries of the Krona type. It has a low measurement threshold, the same price as the previous model, but boasts high accuracy - the error when using it does not exceed 1.2%.
• UNI-T UT 60 C is a more professional device. It has a built-in memory chip for storing a certain number of results of the latest measurements. Very durable body, resistant to any external influences. There is a display backlight for working in the dark.
• The Fluke 28-II is the ultimate tool for any professional. Expensive, reliable, accurate. Able to work in any temperature conditions, both cold and hot. Has built-in entry-level oscilloscope capabilities.

Of course, too expensive devices are not needed for everyday work; they can easily be replaced by a cheaper analogue. But if you often find yourself in unfavorable weather conditions, you should pay attention to those devices that are not afraid of the influence of the elements.

Hydrometers for electrolyte

The saturation of metal ions from the electrodes and free electrons greatly affects the performance of the car battery. To measure it, it is enough to use a hydrometer. Its action is based on the hydrostatic law, which postulates that the greater the density of a liquid, the more it tries to push an object floating in it to the surface.

We recommend: How to properly add distilled water to the battery

A flask with a sampling pipette on one side and a bulb creating negative pressure on the other serves as a reservoir for collecting such liquid.

The measuring element is a cylindrical glass float, which is equipped with a scale drawn on it. Measurements are taken using it as follows:

• The device is assembled, the meter is placed inside, and the bulb is put on.
• The pipette is immersed in the electrolyte.
• The pear collects a sufficient amount of liquid.

In this case, the floating part, under the influence of a small sinker in its lower part, is immersed in the liquid. Using the scale marked on it, you can find out the degree of discharge of the battery as a percentage. If the float is immersed too low, such a battery is considered completely unsuitable for operation. The contacts may be broken or the electrodes may be too oxidized.

Since acids act as electrolytes, you should take care of your own safety when working - wear thick rubber gloves, goggles and, if possible, a coarse linen apron. The respiratory tract is protected by a respirator. This helps to avoid the harmful effects of acid vapors on the lungs and nasopharynx. Therefore, this device for testing batteries should be used in a well-ventilated area.

Load forks

They are a combination of load resistance and voltmeter in the simplest configuration.
More advanced models can be equipped with an ammeter, a capacitance meter, and even attachments for checking ESR in capacitors.

Structurally, they look like a rectangular metal case with a handle-holder and a wire with a large cross-sectional area with a clamp at the end. The building contains:

• Load spirals.
• A cylindrical rod extending outwards.
• The voltmeter dial is mainly analog - with a scale and a moving needle.

The voltmeter contacts are connected to a rod (minus) and a wire (plus). Using a load fork as a battery tester is simple. The verification takes place in two stages:

1. Terminal voltage measurements without the participation of the load from the spirals. It is carried out only 5-7 hours after the car has been completely turned off or after the same period after the end of recharging. A terminal is connected to the positive contact, and you need to touch the negative one with a rod. The voltage readings obtained as a result of measurements are recorded.
2. Test with applied load. After submitting it, you need to do the same manipulations, but do not keep the chain closed for more than five seconds. In addition, there is a possibility of a spark jumping between the contacts, so do not worry about this.

The indicators at the second stage should not differ greatly from the battery’s passport data. If they differ from it to a lesser extent, such a battery can be safely replaced.

Universal instruments and capacity meters

These are tools for determining one of the most important characteristics that directly affects the further use of the battery.
Any battery has a nameplate capacity, which is measured in ampere-hours. We recommend: What to do if the car battery is dead

Over time, its value drops and such a device cannot maintain the charge level for the usual time. In this case, problems arise with the use of the product that is powered by a current source.

The passport capacity is always known, it is reported by the manufacturer and applied to a sticker that clings to the side wall. Therefore, to find its current value, you need to use one of the following devices:

• Pendant is a tester for testing domestically produced batteries. All measurements are saved in the permanent memory of the device. It can not only show the capacity, but also the voltage produced by the current source. During operation, it sends a short pulse, and based on the speed of receiving a response, it gives readings.
• Fluke is the most versatile tool available. Measures voltage, current, internal resistance of elements and capacitance. Can be used for temperature measurements.
• Skat-T Auto is a good device for use with twelve-volt batteries. Has limitations on battery capacity, will not work with those models that hold more than 120 amp-hours. All measurements are carried out within fifteen seconds.

It is worth remembering that each of these models has different measurement ranges. You need to carefully select them before use, since an incorrectly specified order of magnitude can negatively affect the results obtained.

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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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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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.

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