Battery Applications in OTC (Over-the-Counter) Hearing Aids

OTC hearing aids, designed for mild to moderate hearing loss, require batteries that prioritize long runtime, easy replacement, and broad compatibility. Below are common battery types and their applications:

1. Common Battery Types

**(1) Zinc-Air Batteries**

• Standard Sizes:
• Size 675: Largest size, longest runtime (20–30 days), ideal for high-power Behind-the-Ear (BTE) devices.
• Size 13: Universal size, 10–15 days runtime, fits most In-the-Ear (ITE) aids.
• Size 312: Compact size, 7–10 days runtime, used for In-the-Canal (ITC) or low-profile designs.

• Size 10: Smallest size, 5–7 days runtime, for ultra-compact Completely-in-Canal (CIC) aids.

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• Features:
• Air-Activated: Remove adhesive tab to expose air vents for activation.
• Stable Voltage: 1.4V ensures consistent sound quality.

• Low Cost: ~$0.15–0.50 per battery but requires frequent replacement.

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**(2) Rechargeable Lithium Batteries**

• Types:
• Lithium-Ion (Li-ion): USB-C/wireless charging, 16–30 hours per charge (e.g., Jabra Enhance Select).

• Lithium-Polymer (Li-Po): Slim design for micro hearing aids (e.g., Eargo Neo HiFi).

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• Features:
• Eco-Friendly: Reduces disposable waste, supports 500+ charge cycles.
• Fast Charging: 30-minute charge to 80% capacity (e.g., Signia Silk Charge&Go).

• Use Cases: High-frequency users, tech-savvy demographics, or eco-conscious consumers.

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2. Battery Performance Comparison

3. Usage Tips

1. Zinc-Air Battery Tips:

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• Activate Immediately: Install within 1 minute after removing the tab to avoid energy loss.
• Dry Storage: Keep unused batteries sealed in low-humidity environments (<60% RH).
3. Rechargeable Battery Care:
• Avoid Deep Discharge: Charge when battery drops below 20% to extend lifespan.
• Monthly Calibration: Fully drain and recharge once to maintain accurate power indicators.

4. Emergency Backup: Carry 1–2 zinc-air batteries for travel or outdoor activities.

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4. Innovations & Trends

• Solar-Assisted Charging: Micro solar panels for outdoor runtime extension (experimental).
• Low-Energy Bluetooth: Advanced chips (e.g., Qualcomm QCC5100) reduce power consumption.

• Hydrogen Fuel Cells: Compact hydrogen cartridges for 1-month runtime (prototype stage).

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5. Sustainability & Recycling

• Zinc-Air Battery Recycling: Contains zinc/mercury—return to pharmacies or e-waste centers.

• Lithium Battery Recycling: Programs like Call2Recycle offer mail-in or drop-off options.

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Summary

OTC hearing aids primarily use zinc-air batteries for affordability and compatibility, while rechargeable lithium batteries gain traction for convenience and sustainability. User choice depends on:

• High Usage/Portability: Rechargeable Li-ion/Li-Po (e.g., Jabra Enhance Pro 10).

• Budget/Backup Needs: Zinc-air (Size 312/13).
  Future advancements in fast-charging and renewable energy will further enhance battery performance.