What is battery internal resistance? Accurate method of measuring battery internal resistance using a multimeter

Concept of battery internal resistance? Need to learn about battery internal resistance why

The internal resistance of a battery is a measure of the resistance of current inside the battery, or in other words, it is the level of resistance between the two terminals of the battery, measured in milliohms. In the field of digital applications, low battery internal resistance is considered an important fundamental factor. Low internal resistance means the battery is able to provide energy more efficiently.

For the battery charging process, low internal resistance helps extend usage time and minimizes the temperature generated on the battery. In cases where the battery is charged and discharged daily over a long period of time, if the internal resistance increases, the battery performance will gradually decrease, and this may lead to the battery no longer being able to charge. This causes a voltage drop on the battery when in use, especially when the internal resistance is high, leading to a rapid decrease in battery voltage, causing the phenomenon of virtual battery capacity.

What is the formula for calculating battery internal resistance?

After understanding the internal resistance of the battery, below is an extremely important formula to apply and calculate accurately in daily work. 

r = (V - Vt)/Vt . Rt

In there:

- r is the battery internal resistance,

- V is the initial voltage of the battery without load,

- Vt is the voltage across the two terminals of the battery when under load,

- Rt is the resistance of the load.

Using this formula will help users accurately calculate and evaluate the battery's internal resistance in different situations, from which they can adjust and optimize battery performance in technical applications. digital device, which improves user experience and ensures the longevity of electronic devices is extended.

How much battery internal resistance is required?

The internal resistance of a battery depends on many factors such as size, chemical properties, lifespan, temperature and discharge current of each specific battery type. In the current era of 4.0 technology, with the diversification of measuring devices, a series of tools have been created to measure battery internal resistance. This makes battery maintenance increasingly important, because the performance of many digital devices depends directly on the age and operating state of the battery.

During use, the battery continuously goes through charging and discharging cycles, leading to the battery's performance gradually decreasing over time and possibly leading to a situation where the battery can no longer be charged. This has the potential to cause sudden system problems. Therefore, measuring battery internal resistance to check battery condition is an indispensable part of the maintenance and operation of any battery-powered device.

Steps to measure battery internal resistance

To measure the internal resistance of batteries, the process requires using an electrical measuring device such as a multimeter, and the steps are as follows:

Step 1: Prepare complete equipment including a multimeter, 1 battery that needs to measure internal resistance, 1 light bulb or load suitable for the battery, and pen and paper.

Step 2: Connect the battery to be measured to the multimeter by inserting the red probe into the low voltage jack and the black probe into the COM pin jack.

Step 3: Adjust the scale on the multimeter to the 1-way voltage scale and select the appropriate voltage level for the battery.

Step 4: Select the battery voltage measurement range by touching the black probe to the (-) terminal of the battery and the red probe to the (+) terminal of the battery. Select the battery voltage measurement range with normal discharge current and record this value.

Step 5: Measure the battery voltage by connecting the light bulb to both poles of the battery, paying attention to connecting it in the correct direction. Measure the voltage across the 2 terminals of the battery and record this value.

Step 6: Measure the resistance of the load by switching the scale on the multimeter to the resistance scale and measuring the resistance of the light bulb or load. Record this value.

Step 7: Apply the formula to calculate the battery internal resistance using the measured values. Usually the value will be very small, about 0.0xx V, then convert it to milli Ohm units for convenience in calculation.

What type of multimeter is good to buy to measure battery internal resistance?

You can refer to the following multimeter models to measure battery internal resistance quickly and most accurately:

Kyoritsu 1009 multimeter

Kyoritsu 1009 multimeter brings many outstanding features. With a wide measurement range from 400Ω to 40MΩ for resistance, and the ability to measure AC/DC voltage up to 600V, and the ability to measure AC/DC current up to 10A/600V.

In addition, Kyoritsu 1009 is also capable of performing frequency, capacitance, diode testing, and continuity testing with high accuracy. This helps users save time and effort in performing complex measurement tasks.

To optimize user experience, Kyoritsu 1009 provides many benefits such as the ability to store measurement values, a 4000-point display, and 2 functions of automatic measurement and self-adjustment. This provides high working efficiency and productivity for electrical experts, maintenance engineers, and professional electronics repairmen.

Hioki DT4254 multimeter

Hioki DT4254 is a multimeter belonging to the world-famous Hioki brand. Hioki is famous for providing a variety of electrical measuring devices such as Hioki clamp meters and Hioki multimeters. This device is designed to be compact and lightweight for easy use and measurement of electrical equipment, current, and electrical systems. Hioki DT4254 is equipped with many measurement functions such as measuring AC voltage from 600mV to 1500V, measuring AC current, measuring resistance, and measuring frequency. This product meets CAT IV 600 V and CAT III 1000 V standards, making it popular in many fields from professional to residential. The multi-function and high safety features of Hioki DT4254 help users perform measurement tasks.

Hioki DT4254  is a multimeter belonging to the world-famous Hioki brand. Hioki is famous for providing a variety of electrical measuring devices such as Hioki clamp meters and Hioki multimeters. This device is designed to be compact and lightweight for easy use and measurement of electrical equipment, current, and electrical systems.

Hioki DT4254 is equipped with many measurement functions such as measuring AC voltage from 600mV to 1500V, measuring AC current, measuring resistance, and measuring frequency. This product meets CAT IV 600 V and CAT III 1000 V standards, making it popular in many fields from professional to residential. The multi-function and high safety features of Hioki DT4254 help users perform measurement tasks.

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Above is information to answer questions about battery internal resistance as well as how to measure battery internal resistance with a multimeter. If you need to buy a multimeter, please contact us immediately at the EMIN store via hotline for advice and to receive the best quote. We are always happy to assist you with all your needs related to electronic measuring equipment.