Now that you’ve got your new hearing aid, you need a battery to power it. High-quality cells are essential for the proper operation of hearing aids. Batteries that are running low on charge can affect user experience and reduce the quality of sound output.

There are many types of hearing aid batteries, each with different size and charge life. In this guide, we’re going to unpack some of the complexities of hearing aid batteries so that you can navigate this somewhat complicated market.

Hearing aid battery technology

Hearing aid batteries depend on a type of battery technology called zinc-air. Unlike many cells, zinc-air batteries rely on the battery being exposed to air to activate. When you first get your hearing aid batteries, they will be covered with a small plastic strip. The purpose of the strip isn’t purely cosmetic: it helps keep the cell inactivated until it is needed. Once you remove the strip, it’ll take a couple of minutes for the battery to activate, ready to provide power for your device.

Old zinc-air batteries used to contain mercury to help the electrolyte (the part of the cell which facilitates the transport of ions from anode to cathode), but advanced zinc-air batteries no longer require the use of this dangerous heavy metal.

Hearing aid battery sizes and colors

Hearing aid manufacturers use four batteries in their devices.

  • 675. The 675 is, like all the other batteries in this list, is a button-shaped cell, about half the size of a quarter coin. It comes with a blue plastic tab covering the negative terminal and is often used to power behind-the-ear hearing aids. It measures 11.6mm by 5.4 mm and will last anywhere from 9 to 20 days.
  • 13. The 13 is a slightly smaller cell than the 675 and is used in both behind-the-ear and in-the-ear devices which require a smaller power source. Because it’s smaller, it has a lower lifespan: anywhere from 6 to 14 days.
  • 312. The 312 measures 7.9 mm by 3.6 mm. It has the same diameter as the 13, but is not as thick, meaning that it has a shorter lifespan, anywhere from three to ten days, depending on usage.
  • 10. The 10 is the smallest battery, used for completely-in-the-ear-canal devices. It lasts between three and seven days before needing to be replaced.

How to extend battery life

Changing the battery on your hearing aid is simple. But if you want to avoid changing batteries regularly, what should you do?

The first thing to do is turn off your device when not in use, especially at night. Turning off the device will inactivate all components inside which drain energy.

The second thing is to make sure that you leave the battery door open. This stops the battery from discharging and prevents the buildup of moisture which could affect charge strength in the future.

Finally, keep your battery stored at room temperature. Cells lose performance when left in cold or warm environments. A hearing healthcare professional can provide additional information.