In order to check whether batteries are charged or not, you do not have to insert them into a device or even buy a battery tester. There is a simple trick for this.
If you want to know whether a battery is full or empty, you should drop it on a table. Because they behave differently when they hit the tabletop depending on the charge level. TECHBOOK explains why this is so and what the drop test reveals in detail.
Internal gel of dead batteries solidifies
The test works for all cylindrical, non-rechargeable alkaline batteries – above all the common types AA and AAA. You simply drop them from a height of ten to twenty centimeters onto a table top, work surface or similar and observe what happens then. If the battery jumps up a little from the ground, it is empty. If it simply tips over after landing, it is full.
The reason for this reaction is a jelly-like mass of zinc that is inside. This cushions the impact of the battery when fully charged. However, as the battery discharges, the gel-like paste solidifies and can no longer cushion the fall. The battery jumps up. The higher a battery flies in this test, the lower its charge. If the battery jumps about as high as it is long, it’s probably dead. If you want to be absolutely sure, you can also carry out a comparison test with a guaranteed full battery and compare the jump heights.
Also read: 11 batteries in the test – cheap ones are often better than branded products
Another battery trick
That’s not the only trick about batteries. If you don’t have the right battery size at hand, the following trick can help. Did you know that you can turn a small AAA battery into a larger AA battery with very little effort? You can see how this works in our TECH-HACK video or in the instructions on TECHBOOK. All you need is a piece of aluminum foil.
Here are more TECH HACKS
If you like our TECH-HACK on the subject of batteries, please take a look our YouTube channel over. There are more hacks and many tests.