Testing Batteries With Multimeter

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Introduction: Testing Batteries With Multimeter

Find out how much power is left in your batteries using a multimeter. Here I test AA batteries but you can test AAA and other size batteries.

This was done using the multimeter device at TechShop San Jose. They have an electronics workstation with multimeters, soldering iron and other tools for working on electronics.

Set up the multimeter by turning it on. Plug the black probe and red probe into the spots shown in the photo. Turn the knob to 20 V- as shown in the photo.

To test a battery, hold the probes, one in each hand. Touch the metal tip of black probe to the battery's ground or negative end, marked with "-". Touch the metal tip of the red probe to the battery's positive end, marked with a "+". Make sure the probes have good contact with the ends. You can use your fingers to press the metal tips of the probe to the battery.

The voltage read out will display on the multimeter. See the attached photos for examples of battery test results.

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My multimeter has 3 places to plug in the two probes. Which ones do I use?

7 Comments

Helpful tip! I have my own Battery Tester which I am very satisfied with. I bought the unit at www.gainexpress.com and used the code 10SPECIAL to avail 10% off.

Lead acid batteries should test at 2 volts per cell but you should still load test them. I understand that you can't properly test lithium ion batteries without special equipment.

Is your multi meter cheaper than this: http://www.uobd2.net/wholesale/mst-2800b-intelligent-automotive-digital-multimeter.html

I used the one at TechShop.

Sorry but this method isn't accurate. You need to have a load in series with the battery, for instance a 100 ohm resistor. Check out this youtube video, the 5 minute mark, to see how this plays out. The bad battery reads 9V unloaded, 3V loaded. https://www.youtube.com/watch?v=HcikzMG7mMU


There are some meters like the Amprobe BAT200 that apply a load to the battery then give an indication of how much life is left. This will just give you an arbitrary good/bad indication but since it is based on loading the battery under test, it is generally a more reliable test than just a voltage indication. It is inexpensive also.

You may find voltage reads OK but there isn't enough current to do any work
After testing and sorting 'good' or 'bad' batteries, connect to a small (1.5~3v) flashlight bulb or similar
Battery may still work an LED even if bulb is too much current draw