A cochlear implant is a medical device that bypasses damaged parts of the inner ear, converting acoustic information into electrical impulses that the brain interprets as sound. Providing this continuous electrical stimulation requires a consistent external power source. The longevity of this power source is a major concern for users, as it dictates the duration of hearing access throughout the day.
Disposable Battery Lifespan
The most common power source for many cochlear implant sound processors is the disposable zinc-air battery, typically in size 675 or occasionally size 13. These batteries offer a high energy density, providing a reliable power supply. The average lifespan of a set of these batteries ranges widely, from about 48 hours up to five days, depending heavily on the processor model and usage.
Zinc-air batteries are activated by oxygen in the air, which starts the electrochemical reaction. A protective tab covers the air holes to keep the battery dormant until use. Once the tab is removed, the battery begins to discharge continuously, even if it is not placed into the sound processor. This dictates that the battery’s operational life is finite once activated, often requiring users to change batteries every two to three days.
Rechargeable Battery Systems
Rechargeable lithium-ion battery packs offer an alternative power solution, providing predictable daily performance and reducing the need for frequent changes. Runtime varies based on size and capacity; smaller packs typically last 10 to 19 hours, while larger modules can provide up to 40 hours of continuous use.
These systems can be fully recharged, usually taking around four hours when depleted. This allows users to establish a routine of charging overnight, ensuring a full day of power. Unlike disposable batteries, the rechargeable pack has an overall lifespan measured in charge cycles.
A typical lithium-ion battery pack is designed to last between 365 and 500 charge cycles before its runtime significantly decreases. For a user who charges nightly, this generally translates to an overall lifespan of 12 to 36 months for the battery pack itself.
Factors Affecting Daily Battery Drain
Performance estimates provided by manufacturers represent ideal conditions, but several factors contribute to actual battery drain. One of the most power-intensive activities is continuous audio streaming, such as connecting the processor to a phone via Bluetooth or using other wireless accessories. This constant data transmission significantly increases the power demand.
The specific program settings also influence power consumption. Programs set for high-noise environments utilize advanced signal processing features, which require more computational power. Operating the processor at higher volume or sensitivity levels similarly requires greater electrical output, increasing the rate of battery depletion.
Environmental conditions also play a role in battery performance. Exposure to extreme cold or excessive heat can negatively impact battery efficiency, causing a temporary reduction in runtime or accelerating the long-term degradation of the battery cell.