How To Test 18650 Battery With A Multimeter

Lithium-ion rechargeable batteries are known as 18650 batteries. Its official name is a 18650 cell. There are two different types of 18650 batteries, each rated for 3.7v or 1800mAh to 3500mAh (milliampere-hours).

In addition to their voltage range being from 2.5 and 4.2 volts, or 4.2 volts for charging, 18650s have 3.7 volts as a nominal voltage. 18650 batteries take about four hours to charge on average. Batteries and chargers vary in power and voltage, which affects how long they take to charge.

18650 Batteries – Steps for Testing With a Multimeter

Using a multimeter, you can determine whether a 18650 battery is functioning properly. Even if a battery cannot be used to measure its milliamp-hours, it is feasible to check whether a battery is functioning using the multimeter. Multimeters can be used to measure the mAh rating and resistors can act as a load. A stopwatch will be required to represent the elapsed time. Below are the following steps:

1) Prepare the meters battery

The first thing you need to do is check the meter battery and set the multimeter dial at the battery checking level. In order to continue the process, you’ll need to replace a dud one.

2) Use a multimeter to attach the clips

Ensure that the battery is correctly positioned. Alligator clips should be placed on the probe tips of the meter. To select the correct resistor, you will need to know what voltage the battery has.

3) Terminal connection

Your stopwatch should now be reset. A positive terminal from the 18650 cell should be connected to a positive terminal on the resistor.

4) Set up the multimeter

To measure direct current, turn the multimeter’s knob to direct current. To locate the unconnected resistor lead, clip the positive probe to its red lead. Then attach the black probe, which is a negative probe connected to the negative terminal of the battery. Ensure you have a positive reading on the meter which is the sign that it is working.

5) Set the stopwatch

Set your stopwatch to one hour intervals and check your current reading every hour. Stop the watch when the current reaches 30%.

6) Determine the readings

By multiplying the first current reading on the meter by the number of hours recorded on the stopwatch, you can calculate the battery’s mAh rating.

Testing 18650 batteries in Alternative ways 

Cellular batteries with an 18650 battery have a diameter across of 18mm and a height of 65mm.

The removal of cells

Firstly, it is necessary to remove the battery case in order to remove the batteries. It is possible to use a variety of methods. Wear gloves and safety glasses to prevent your eyes and hands from harm. There are sharp edges and the plastic case can fly off. The nickel tabs that join the cells together are very sharp and may cause serious harm. Listed below are three methods that can be used to remove the cells.

  1. It is best to twist the plastic casing to break it away.
  2. Then, with a durable set of wire cutters and then break off the corners.
  3. The easiest way to remove the cells from of the pod is by hitting it against the ground. Even though some of the cells may be damaged, this is one of the fastest ways to remove them.

Checking the initial voltage

In order to confirm that all cells are free, first perform a voltage test. For devices that measure more than 2 volts, the cells can be directly charged in TP4056 chargers.

Detection of Self Discharge

In order to verify that the batteries are at full charge, allow them to sit for 24 hours before testing their voltage again. This will work to get rid of any cells that discharge just by sitting for some time. Finally, if any of the cells are below 4V after charging, they are considered to be self-discharging and should be removed.

Testing Capacity

Those cells that pass the first tests are then tested for their capacity. After charging the battery first and discharging it, the charge will be low and it will have to be recharged again after measuring its capacity. In order to determine the cells’ capacity, these are sorted and then marked.

People Might ask

How long will a 18650 battery last?18650 batteries can take 45 minutes up to 250 hours to complete a project, but there can be some variation. Furthermore, assuming you don’t use it too frequently, 2 hours of runtime might mean it will last about a month or three.

Is it possible to recharge a dead lithium battery?In certain situations, you may need to replace the battery if reviving doesn’t work. Give the reconditioned Lithium battery a full charge by placing it in the lithium charger, which should take about 3 hours depending on the type of battery.

What is the best way to test a lithium battery with a multimeter?If you want to test the battery of a device, consult the owner’s manual. Firstly connect your voltmeter to the power source. Make sure you are measuring in volts. Determine your lithium ion battery’s positive and negative terminals.

Can 18650 batteries be charged overnight?18650 batteries are among the most commonly used batteries. An 18650 battery may require up to four hours to fully charge using a separate charger. Recharging 18650 batteries overnight is never a good idea since this can permanently damage the batteries.


Cells made of 18650 rechargeable batteries are used in motor vehicles and electronic devices. Batteries can be very reliable when in good condition, but they need to be in good condition otherwise they will not be reliable. As we have discussed, there are different methods for testing 18650 batteries with a Multimeter. It is possible to test the battery without using a multimeter if you do not want to spend money on a multimeter, as explained above. Maintenance is essential for their longevity and for providing the best performance when you need it.

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