In fact, they’re so important that a lot of people who wear a hearing aid keep a hearing aid battery tester handy. That way they can tell when the battery is beginning to run out of power. Then they can be prepared with spare batteries when it needs to be replaced.

The length of time that hearing aid batteries will last depends on the style of hearing aid being worn. The smaller hearing aids that fit into the ear canal have a shorter battery life. The reason is that these are smaller batteries and don’t have as much of the power producing components.

Older styles of hearing aid batteries used mercury to power the device. But there are newer zinc batteries that are much more effective and therefore more commonly used.

Something called zinc air is the secret behind zinc batteries. This is a mixture of oxygen in the air along with the zinc present inside the battery. This produces a reaction that powers the battery. They have about twice the life of the conventional mercury batteries.

You’ll find that zinc hearing aid batteries have a color coded tab. One of the reasons for this is so you can know the size of the battery. However, it also prevents air from entering the battery until you’re ready to start using it.

As soon as the tab is pulled off, oxygen starts to enter the battery. As the oxygen combines with the zinc, the battery becomes activated. For this reason the tab should not be removed until you’re ready to use it so it doesn’t start losing power.

Most hearing aids today use one of four different sizes of batteries that are readily available. There’s a specific size of battery for every type of hearing aid out there. A number 10 battery with a yellow color code is the smallest you can purchase. The largest size is 675 and is labeled in blue. The small sizes are most commonly used for the smaller digital hearing aids that go into the ear canal. The large sizes are used for the behind the ear hearing aids.

The larger sizes are longer lasting since there is room to hold more zinc inside the battery. However, they are a lot more bulky. Many people would rather change the battery more often and have a less noticeable hearing aid.

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