It is common to store batteries in a drawer in the house, some being used and others still in good working order. The problem is knowing which ones are still loaded. To check whether the batteries are full or not, you don’t need to insert them into any device or even buy a battery tester. There is a simple method to do this.
Holding a stack – Source: spm
If you have found several different batteries and are wondering if it is possible to use them in your device, try the following method. The test works for all non-rechargeable cylindrical alkaline batteries, especially common AA and AAA types. You simply hold the stack ten to twenty centimeters above a table, work surface or the like, then let go and watch what happens next. If the stack only bounces once before folding, it is full. If, on the contrary, it bounces several times, it is empty.
The reason for this reaction is a gelatinous mass of zinc 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, so the battery jumps. The higher the stack jumps in this test, the lower its charge. If you want to be absolutely sure, you can also perform a comparison test with a full stack and compare the jump heights.
Half-full batteries should not be discarded immediately. It is better to continue using them until the end in a device that can work with weak batteries, for example in a clock or in a remote control.
What if you don’t have the right battery size?
Inserting batteries into the remote control – Source: spm
If you don’t have the right stack size handy, the following trick may help. Did you know you can turn a small AAA battery into a larger AA battery with very little effort? Here’s how it works. All you need is a piece of aluminum foil.
Insert the AAA battery into the battery compartment. The trick works best when the positive battery terminal is in contact with the device terminal, leaving only the negative terminal unconnected. Then, bend the aluminum foil and use it as an electrical conductor to complete the gap.
Of course, the smaller AAA battery doesn’t offer as much power. So you need to buy the right batteries in time. But this trick always acts as a temporary solution.
Attention, this trick does not work in the case of rechargeable batteries, because they are based on a different operating principle.
- Use a battery tester: these devices can measure the charge of the battery and know if it is still usable or if it needs to be replaced.
- Use a device that uses the battery: if the battery fails to power the device or if it drains quickly, it may indicate that it is dead and needs to be replaced.
- Charge the battery: if the battery does not charge or does not hold a charge, it may indicate that it is dead and needs to be replaced.
- Using a multimeter: if you have a multimeter, you can measure the battery resistance. If the resistance is less than a few ohms, it may indicate that the battery is dead and needs to be replaced.
Read also How do I know if the batteries are still charged?
Via SPM