Batteries for Hearing Aids
The most commonly used batteries for hearing aids are called zinc-air batteries. Small silver discs, zinc-air batteries are not rechargeable, and must be discarded after use.
Hearing aid batteries come in five sizes. The right one for you depends on the style and size of your hearing aids. The hearing aid industry has color-and-number-coded the packaging of batteries to make buying replacements easy-choose 5-red, 10-yellow, 13-orange, 312-brown, or 675-blue. The sticky tab on the back of the battery is also color-coded.
Batteries can be purchased from your hearing care office, most drug stores, and online. Some health insurance plans cover the cost of hearing aid batteries, either partially or in full.
How do zinc-air hearing aid batteries work?
Unlike common household batteries such as AA, AAA and 9-volt, zinc-air batteries are activated by the oxygen in the air. Without oxygen, zinc-air batteries can’t power hearing aids.
Before a hearing aid battery is inserted, a sticker must be removed from the back. This sticky tab keeps the battery fresh, and protects the zinc inside the battery from being activated. Once the tab is removed, tiny holes in the battery casing allow molecules of oxygen to enter. The holes are big enough to let oxygen in, but small enough to prevent battery fluid from seeping out. A filter behind the holes also helps thwart leakage. Remember, once you remove the tab, there’s no turning back! Resealing the battery will not stop the activation process and save it. So, be sure to keep the tab intact until you’re ready to use the battery.
Because oxygen must pass through fine holes and a filter, it’s absorbed slowly. That’s why it’s important to wait a full minute before you insert the battery and close the battery door after you’ve removed the tab. If you don’t wait, the battery may not absorb enough oxygen to properly power your hearing aids.
How long do hearing aid batteries last?
Battery life varies with hearing aid styles. Some hearing instruments require more power to function at optimum levels. Digital hearing aids contain sophisticated circuitry to deliver near-to-natural hearing in a variety of environments, and this requires more power than analog hearing aids need. Typically, wearers of digital hearing aids can expect a battery to last from 5 to 7 days. If you experience shorter battery life, your hearing care professional can check the battery contacts in your hearing aids, as well as, test for battery drain. Most batteries have a “shelf-life” of about three years.
Get the best performance from hearing aid batteries
To enjoy maximum battery life, store batteries at room temperature. Heat exposure can shorten the life of hearing aid batteries, as can a humid environment, such as a bathroom or refrigerator. It is not recommended to carry batteries in a pocket or handbag where they can mingle with metal items like loose change or keys-doing so can short-circuit your hearing aid batteries.
For optimum performance, open the battery compartments in your hearing aids whenever you’re not wearing them. This limits battery drain and helps alleviate moisture build-up. Turning your hearing aids off when not in use can also help extend battery life.
Mercury-free zinc-air hearing aid batteries
Traditionally, a trace amount of mercury was used in hearing aid batteries to assist with conductivity and to stabilize internal materials. Mercury is also found in other button cell batteries such as watch batteries.
There is a perception among the public that the mercury used in hearing aid batteries may be harmful to hearing aid wearers and the environment. Some states have enacted a ban on the sale of hearing aid batteries containing mercury. However, most hearing aid battery manufacturers have voluntarily introduced “zero-mercury” hearing aid batteries that perform comparably to hearing aid batteries that contain mercury.
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