How to Check the mAh of a Battery with a Multimeter

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Most people today own a mobile phone. Nonetheless, many of them most likely do not totally understand all of its components. For example, how much do you understand about your battery?

You see, the battery offers life to your phone. Without it, your phone and other devices would make a costly paperweight. It’s about time that you move one step closer to learning the mysteries of keeping this small powerhouse charged by understanding the basics.

One of the basic terms which come up with talking about rechargeable phone batteries is mAh. But what is it, by the way? Allow us to bring you one step closer to learning this electric extension of you. 

What Does mAh in Battery Means? 

In case you didn’t know, mAh or milliamp hours is the unit for calculating the capacity of a battery or the amount of stored energy. These are the units electricians or technicians utilize to measure the useful operating lifetime of a battery or how long the battery will last when it powers an average electrical load.

You could measure a battery’s mAh rating with the use of a multimeter, a stopwatch to keep track of the elapsed time, and a resistor to function as a load. 

How Does mAh Impacts Battery Life? 

Most often utilized to measure the battery’s energy capacity: the higher the mAh, the more energy it could store that converts to a longer battery life. To measure the battery’s life, you would need to divide the battery’s capacity by the current needed by the object it powers.

For example, you have a mobile phone with two batteries: the first battery has a capacity of 1,000 mAh and the second battery has a capacity of 2,000 mAh. Your phone needs a current of 200 mA to function properly. 

The first battery—along with the 1,000 mAh—would power your phone for only five hours (as 1,000 divided by 200 is equivalent to five). Nonetheless, the second battery would power your phone for ten hours (as 2,000 divided by 200 is equivalent to ten).

How Do You Measure the mAh of a Battery? 

It will help if you identify the capacity of a battery in mAh to understand how much charge it holds once full. Bear in mind that the mAh unit specifies a milliamp multiplied by an hour unit of time.

That suggests that dividing its mAh rating by the milliamp current draw of the device leads to how many hours the battery would last once the capacity of a battery is determined. 

Make sure you fully charge the battery you plan to test, especially if it’s rechargeable. Or else, you can also utilize a new non-rechargeable battery.

To help you measure the mAh of your battery using a digital multimeter, just follow the steps below. 

  1. Grab your digital multimeter and turn it. Switch its measurement dial to the direct current (DC) measurement setting. Keep in mind that all batteries generate DC current. That setting is indicated by the capital letter A along with straight lines on top of it. Take note that the letter “A” there stands for the basic unit of current, which is the amp. 
  1. Insert the red test lead of your digital multimeter into the positive port. Attach the black probe of your meter into the negative port. The negative port might be labeled “COM” for common ground. 
  1. Attach the digital multimeter’s red probe to the negative terminal of the battery. Attach the black multimeter test lead to the positive terminal of your device powered by the battery with the help of an electrical wire exposed at both ends.

Now, attach the negative terminal of your powered device to the battery’s positive terminal. You can do that by using a small piece of electrical wire exposed at both ends. Make sure you take note of the current reading from the meter’s LCD and begin your stopwatch. 

Do you get a reading in amps? You can multiply that by 1,000 to convert to milliamps. For instance, let’s say the current reading was 200 milliamps. 

  1. Stop your timer after the device being powered by the battery shuts off. At this point, your battery is totally drained. Take note of the time in hours needed to drain the battery. For instance, it took you fifteen hours to exhaust the energy of the battery. 
  1. Multiply the current reading by the time to arrive at the capacity of the battery in milliamp-hours. Finishing off our example, you have 200 milliamps then multiplied by fifteen hours. To sum up, your battery has a capacity of 3,000 mAh.

You may be thinking, is a higher mAh rating better? Well, the answer to that question is, it depends. A higher mAh battery could power your phone for a longer period compared to a phone that uses the same quantity of energy from games, Wi-Fi, apps, mobile data, and other usages, but a lower mAh capacity. 

That is better if you want a battery to last. Nonetheless, the higher the mAh rating, the bulkier and heavier your battery would be. 

When it comes to calculating the milliampere-hours, you need to consider both the current load within the circuit and the battery capacity in mAh. For that, you need to use the formula below:

Battery life = Battery capacity in mAh / Load current in mAh 

Hence, your calculation will look like this if your phone has a capacity of 2,500 mAh and has a 500 mAh load: 5 hours = 2,500 / 500 mAh. That means it will die in five hours if you charge the phone to full capacity. 

Final Thoughts

Understanding your phone or any device’s specifications could help you make a smart decision the next time you purchase a new one. The battery capacity of your phone will identify how well the device serves you.

Now, you can answer other people when they ask you, “how to check the mAh of a battery using a digital multimeter.” We hope you find this guide educational and useful. Are you now ready to test your battery’s functionality?

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