Instantly Tell If A Battery’s Dead With This Simple Test
We have all been there on a Friday night when the TV remote suddenly stops working right in the middle of a good show. You inevitably end up digging through a drawer or container in the kitchen where random batteries go to die. It is so frustrating staring at a handful of loose AA batteries with no idea which ones are fresh and which ones are duds. But there is actually a brilliant little physics trick that can solve this problem and tell you which batteries still have life left in seconds.
Dropping It On The Counter
The test itself is incredibly simple and requires zero special tools. You just pick up the alkaline battery in question and hold it vertically a few inches above a hard surface like your kitchen counter or a tile floor. Then you just let it go and drop it. It sounds almost too easy to be true but the way that battery hits the table tells you everything you need to know about its chemical state. It’s a genius science hack.
Why The Chemistry Changes The Bounce
Inside a brand new alkaline battery there is a layer of zinc that acts like a dense gel or paste. This gel is great at absorbing impact which means a fresh battery lands heavy and stays put. As you use the battery, that zinc turns into zinc oxide which is much harder and stiffer. That stiff structure acts like a spring. So essentially you are testing whether the inside is still soft and full of energy or hard and empty.
Understanding What You See
If you drop the battery and it lands with a solid thud and maybe even stands upright, it is likely fresh and ready to use. That heavy gel inside cushioned the fall. However, if the battery bounces up and skitters away or falls over immediately it is probably dead or on its last legs. A high bounce equals an empty battery. It is a really clear visual indicator once you try it a few times and see the difference for yourself with different batteries.
Knowing The Limits
While this is a fantastic quick fix, it is not a totally perfect science. A battery that is only half used will often bounce just as much as one that is totally dead because the chemical change has already started. So while the bounce test is great for sorting the definitely bad from the definitely new, it won't give you a precise percentage of how much energy is left. If you need to know if you have exactly fifty percent charge left, you are still better off using a real battery tester.
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This is one of those little life hacks that you’ll remember forever once you learn it. It saves you from that annoying dance of swapping batteries in and out of the remote just to see if they work or not. Next time you are faced with a pile of mystery batteries, give them a quick drop test. It is a satisfying way to find the batteries you need and not bother with the ones you don’t.
Bliss Donahue-Power
