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How to Test Lithium Batteries – Methods and Steps

How to Test Lithium Batteries - Methods and Steps

Knowing how to test lithium batteries is a crucial part of their maintenance. It helps ensure they remain in good condition. In other words, you can tell when a problem arises — often due to age—and take action to keep your electrical system running. In this guide, you’ll learn the testing methods to use.

Can You Check Lithium Batteries?

Yes, you can. It helps you tell if you have a bad battery or not. Lithium battery problems can show up in various ways. For instance, it may take longer to charge or discharge too quickly than usual. Other issues include overheating or not charging at all.

You can check lithium-ion batteries by performing a visual inspection. Examine their casings and cables for corrosion or physical damage. Problems to look out for include breakage, dents, and cracks. Ensure the electrodes are clean, too, and not covered by corrosion.

In addition to visual checks, you should conduct physical tests to see if various parameters differ from those specified by the manufacturer. The following section explains how to test lithium-ion batteries.

How to check if a lithium battery is good with a tester
How to check if a lithium battery is good with a tester

How to Test Lithium Batteries

You can test lithium batteries in several ways depending on the required information. Let’s see how to conduct each testing method, the intended test purpose, and the expected results.

Note: some tests can damage your battery. Ensure you follow the correct steps and use the proper testing equipment. After each process, perform a visual check to see if everything is good.

1. Capacity Test

Battery capacity is the amount of charge it can store when charged and measured in Ampere Hours or Ah. The capacity drops with repeated use, usually because the various components age with each charge/discharge cycle. The following steps show how to test lithium-ion battery capacity:

Start by charging the battery to its full voltage. Record the charging information (current, voltage, and duration). Connect the fully-charged battery to a known load. Discharge it until it reaches its cut-off voltage. Record the discharge data.

To calculate capacity, use this formula: Capacity in Amp-hours = Current in A × Time in hours. For example, if you pulled three amps for 5 hours during discharge, the capacity is 15 Ah. If the load pulled 20 amperes for 4 hours, the capacity is 80Ah.

Compare the figure with that specified by the manufacturer: it should not significantly drop. If it does, the battery’s condition is not good and must be looked into or replaced.

2. Cycle Life Test

This test checks if the battery meets specified charge cycle requirements. Various standards, including IEC and UL, define the test and explain the process to use and the requirements to pass, either in a lab or during use.

You can use the cycle life test to predict the remaining useful life. It subjects the battery to a series of charging and discharging cycles performed under controlled temperature, DoD, or charging current. The IEC standard sets forth these steps:

Discharge the battery to its rated cut-off voltage at 0.2C. Charge it at 1C with constant voltage and current. Rest it for an hour, then discharge it at a 0.2C rate. Measure its capacity. Repeat the charge-discharge steps about 500 times or more.

Record the information for each cycle or use software to automate the process. Use this information to evaluate the cycle life. After 500 cycles, the capacity should be 60% of its rated value. (The manufacturer will usually indicate an acceptable capacity reduction rate).

3. Internal Resistance Test

There are two ways of measuring the internal resistance of a lithium battery: the open circuit method and the load test. The open circuit process measures voltage with no load attached. It’s a quicker and more straightforward method but less accurate.

The load test measures voltage with a resistor of known value connected. By mimicking a working condition, the load method provides better results.

Advanced methods like the AC test and electrochemical impedance spectroscopy (EIS) offer a more detailed analysis. However, they are complex to carry out and not accessible to many users.

Open Circuit Test

  • To conduct this test, ensure the battery has no load connected to it
  • Connect a multimeter (or internal resistance tester) across its terminals, then measure the voltage
  • Connect a resistor to the battery to discharge it, and then measure the voltage again
  • Use the resulting change of voltage to calculate the resistance

Load Test

  • For the load method, place a specified value on the circuit
  • Again, use the multimeter to measure the battery’s terminal voltage
  • Remove the resistor circuit, allow the battery to discharge briefly, and then measure the voltage
  • Use the voltage and current drop to calculate the internal resistance

4. Safety Test

In this test, you check the battery’s performance in extreme conditions. It involves the following actions: short-circuiting the terminals, overcharging and over-discharging, and thermal testing.

In all these tests, the performance should stay relatively high. It must largely remain stable and within specified limits. Here is how to go about it.

  • Short Circuiting: short the terminals. Check for issues that may develop, such as overheating or leaks
  • Overcharge: overcharge the battery and observe it. Look for signs that could cause concern, like swelling or leaking
  • Over-discharge: perform the over-discharge test. Again, monitor the battery’s behavior and note any unusual occurrence
  • Thermal Runaway Test: the thermal procedure involves subjecting the battery to a high-temperature environment and observing its response to the heat
How to test a lithium battery with a multimeter
How to test a lithium battery with a multimeter

How to Test Lithium Ion Batteries with a Multimeter

A multimeter is a simple-to-use device that you can use to test lithium batteries. It measures various parameters, including voltage, current, and resistance. Here is how to use it.

Voltage Test

  • To check voltage, rotate its dial to voltage (ensure the set voltage is higher than the battery’s).
  • Connect the multimeter probes to the terminals, the red probe to the positive terminal, and the black probe to the negative terminal. Monitor the readings.
  • A significantly low voltage indicates a damaged or discharged battery: it’s probably dead if the reading is less than half the rated voltage.

Current Test

  • Set the multimeter to DC within the estimated current draw value to measure current.
  • Connect the probes to their appropriate ports.
  • Connect one probe to the battery and the other to a resistor or bulb load.
  • Check the readings. The current should be proportionate with the resistor’s value.

Resistance Test

  • To measure resistance, set the multimeter to Ohms.
  • Again, connect it to the terminals and take the readings.
  • It should only indicate a few Ohms.
  • Disconnect the multimeter by removing the black probe first.
Using a battery tester
Using a battery tester

How to Test Lithium Battery without Multimeter

You do not need a multimeter to carry out the abovementioned battery-testing methods. Various other tools can help you assess it for damage. One of them is a voltmeter. Use it to measure the voltage. It works like a multimeter but offers fewer options.

You could also use a battery tester, which is a loaded voltmeter. The tester provides more accurate results by checking the voltage with the circuit connected to a known load (resistor).

Connect these tools to the –ve and +ve terminals as you would when checking voltage with a multimeter, then take the reading. The voltage should be within allowable levels. If not, you have a failing battery.

Li-ion battery analysis
Li-ion battery analysis

Interpreting Lithium Battery Test Results

You now know how to test lithium-ion batteries, but how do you interpret the results of the testing process? The answer is by analyzing and comparing them with the provided specifications. Any deviation is a possible problem.

Voltage and Capacity

A significantly low voltage (below the specified level) shows a faulty battery. The same applies if the capacity drops lower than the acceptable rate. Replace it if it shows significant drops for both.

Charging and Discharge

The battery is in good health if the capacity is within or close to the specified rating. If low, the problem could indicate deterioration, possibly due to aging and slow chemical reactions. On the other hand, a sudden capacity drop may indicate damage.

Internal Resistance

Resistance should be low enough and within specifications. If not, there could be a connection problem or an internal short. Erratic readings are often connection issues, while stable, high values indicate degradation that’s happened over time. 

Temperature Performance

Performance should not drop at higher temperatures. If it does, it cannot withstand heat. Replace faulty batteries that you cannot fix. Document your findings, too, including the actions taken. The information will serve as a reference in the future.


This guide examined how to test lithium batteries using various methods and tools. Lithium-ion batteries are generally safe and long-lasting. However, they can deteriorate due to age or wrong usage. Should that happen, you want to know how to check them so you can take repair or replacement steps.

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