Recently I was at a friend’s place who heard about this quick method to test your AA alkaline batteries. I found it hard to believe when he described it. However seeing is believing and this does work! Upon returning back home I searched online and realized other people have discovered the same thing.
THE DROP TEST
Take a AA battery, hold it over a hard surface (one that you won’t worry about scratching) about 2″ up, and drop the negative flat side unto the surface. One of two things will happen:
- The battery will “thud” on the surface and might even stay standing up.
- OR the battery will “bounce” and fall over.
The batteries that thud are still good. The ones that bounce are bad.
Do not try this on your lithium ion batteries, only alkaline.
The scientific explanation for this has to do with hydrogen gas that is released as the alkaline batteries are used due to the chemical reaction inside. This creates pressure inside the battery with the trapped gas. It is this gas that causes the battery to bounce and fall over if it is a “dead” battery.
My friend and I ran the test on a number of AA batteries, sorted the solid thud ones from the bouncy ones. We then measured them all afterwards using a digitial multimeter. The test was 100% correct. We were both amazed. I am not sure if this works for other sizes (AAA, C, D) but it definitely does for AA.
I ran a search online and found a short YouTube video demonstrating this.