How to test the battery life of rechargeable batteries

Updated July 05, 2018

There are many types of batteries used for a variety of home, office and outdoor electronics. There are rechargeable batteries that are designed to replace single-use batteries such as AAA, AA, C, and D batteries. Other products such as cameras, laptops and MP3 players rely strictly on rechargeable batteries with no single-use batteries available. Even though a battery is rechargeable, there will still be a day when the battery needs to be replaced. Testing the life of your battery requires evaluating the charge time.

Determine the expected life of the battery charge. This is done by reading packaging or using the following equation: capacity /current drain = approximate battery life. The capacity is expressed in Ampere hours. Current drain refers to the load of the battery. For example, a AAA battery has a one Ampere capacity or 1000 mAh. These batteries are generally designed for 10 ma of drain capacity. This means the expected life of the battery is 100 hours. Check battery packaging and labels for capacity and drain; it may state the expected run time.

Plug the battery into the charger. Wait for the green light to indicate that the battery is completely charged.

Remove the battery from the charger and put it in the electronic item.

Note the time. Turn the electronic item on.

Leave it on undisturbed until the battery dies completely. Note the time it took for the battery to die.

Compare the actual run time of the electronic device compared to the expected battery charge life expectancy. Shorter actual times mean the battery is losing its ability to hold a complete charge and is dying.


Batteries maintain a charge longer in warmer conditions. Don't let a battery overcharge. This may overcook the battery and shorten its charge time and life expectancy.

Things You'll Need

  • Battery charger
  • Watch
  • Calculator
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About the Author

With more than 15 years of professional writing experience, Kimberlee finds it fun to take technical mumbo-jumbo and make it fun! Her first career was in financial services and insurance.