Hearing aid batteries are small, specialized power sources fundamental to maintaining consistent hearing assistance. Choosing the correct power source and understanding how to care for it directly impacts the reliability and performance of the hearing aid. This guide provides a clear understanding of the options available and steps to extend their functional life.
Understanding the Types and Chemistry
Modern hearing aids primarily use two types of power sources: disposable zinc-air batteries and integrated rechargeable systems. Zinc-air batteries are single-use cells that rely on a chemical reaction between zinc metal and oxygen drawn from the surrounding air. This mechanism provides high energy density, allowing a significant amount of power to be packed into a small, lightweight casing. These batteries offer a long lifespan, often lasting several days or weeks before replacement.
The primary alternative is the rechargeable system, which typically uses lithium-ion chemistry, similar to smartphone batteries. These systems are permanently sealed within the casing and are charged nightly in a dedicated cradle. Lithium-ion offers convenience and reduces the environmental impact associated with disposing of batteries every few days. While the daily run time is sufficient for a full day, these batteries may need professional replacement after a few years.
Rechargeable hearing aids often have a higher initial purchase price due to the integrated technology. Conversely, disposable zinc-air cells have a lower upfront cost, but the expense of continually purchasing replacements adds up over time. The choice depends on preferring daily convenience and lower long-term waste versus a longer single battery life and lower initial device cost.
The Universal Sizing System
For disposable zinc-air batteries, the industry uses a globally recognized system to ensure users can easily identify the correct size. This standardization relies on a numbered size and a corresponding color code, consistent across all manufacturers. Selecting the wrong size prevents the hearing aid from closing properly or connecting to the terminals.
The four standard sizes are designated by number and color:
- Size 10 (yellow)
- Size 312 (brown)
- Size 13 (orange)
- Size 675 (blue)
Size 10 batteries are the smallest, typically used in discreet, completely-in-canal devices. Size 675, the largest, is reserved for high-power hearing aids or cochlear implants requiring the most energy. This color-coding system helps quickly match the packaging to the device.
Maximizing Performance and Longevity
The performance of a zinc-air battery begins the moment the factory-sealed protective sticker is removed. Once the tab is peeled off, air enters the battery through activation holes, initiating the chemical reaction. It is beneficial to allow the battery to “breathe” for a period, ideally around one to five minutes, before inserting it into the hearing aid. This activation time allows the battery to reach its optimal voltage, potentially extending its life.
Daily habits significantly influence the lifespan of both zinc-air and rechargeable devices. Zinc-air users should open the battery door at night to disconnect the battery, preventing parasitic drain and allowing moisture to evaporate. For rechargeable hearing aids, the best practice is to place them in the charging unit every night. Modern lithium-ion batteries are designed to be charged constantly and will not degrade from overcharging, making the nightly habit simple.
Proper storage is a significant factor in preventing premature power loss. Zinc-air batteries should be kept in their original sealed packaging in a cool, dry place at room temperature. Exposure to high heat, such as leaving them in a car or humid bathroom, can drastically reduce their shelf life. When purchasing, check the expiration date and avoid buying large quantities unless they will be used within a few months, as they slowly lose charge even when sealed.
Environmental conditions can temporarily affect battery performance; for example, cold weather can lead to a drop in voltage. If this occurs, briefly warming the hearing aid or battery, such as by placing it in a pocket, can help restore function. For rechargeable devices, ensure the charging contacts on both the hearing aid and the charger are clean and free of debris, as a poor connection prevents a full charge. Limiting the use of high-drain features like continuous audio streaming can also maximize the daily life of any battery type.