Updated on December 7, 2023


Created on August 17, 2016

Solar Ear Hearing Aid HD-48

Upcoming Update

The Solar Ear Hearing Aid HD-48 is a Behind-The-Ear (BTE) hearing instrument that is suitable for mild to severe hearing loss.

Developed By
  1. Solar Ear
Tested By
  • Department of Audiology, Bispebjerg Hospital
  • Stanford University
Content Partners


Product Description

The Solar Ear Hearing Aid HD-48 is a Behind-The-Ear (BTE) hearing instrument that is suitable for mild to severe hearing loss. The hearing aid uses rechargeable batteries that are charged with a solar powered battery charger. The solar battery charger was selected for inclusion in WHO’s 2012 Compendium of Innovative Technologies for Low-Resource Settings.

Target SDGs

SDG 3: Good Health and Well-Being

Market Suggested Retail Price


Target Users (Target Impact Group)


Distributors / Implementing Organizations

Solar Ear, Auto Alternative Nig LTD, INOVA Centro Auditivo, ONG Instituto de Rehabilitación de Valparaíso, Rejoice Hearing Systems

Competitive Landscape

Direct competitors include ALIMCO Behind the Ear Hearing Aid.

Manufacturing/Building Method

Hearing Aid HD-48 is manufactured by Solar Ear, formerly Deaftronics, in Botswana and in Brazil and China. The manufacturing sites are independently run, owned, and operated.Interview with representative Young deaf people are hired by Solar Ear and taught how to manufacture and assemble the hearing aids.

Intellectural Property Type


User Provision Model

Solar Ear has national distributors in Botswana, Nigeria, Egypt, Brazil, Pakistan, Chile, China, Canada, U.S, and Mexico that can be contacted to purchase the HD-48 Hearing Aid. hearing aids. Customers residing in countries without a national distributor can fill out an online contact form to request a quote.

Distributions to Date Status

50,000 Solar Ear hearing aids, 100,000 solar chargers, and 250,000 rechargeable hearing aid batteries have been sold as of July 2017 interview with representative

Peak OSLP 90 (dB SPL)

130 dB SPL

High frequency average (HFA) OSLP 90 (dB SPL)

122 dB SPL

HFA full-on gain (dB)

48 dB

Total harmonic distortion for 500Hz (%), 800Hz (%) and 1600Hz (%)

5%, 3%, 3%

Equivalent input noise (dB)

30 dB

Number of frequency channels


Battery type


Battery current (mA)

1 mA

Memory switch (Y/N)


T-coil feature (Y/N)


Design Specifications

The Solar Ear HD-48 is an optimized DSP hearing aid equipped with a volume control potentiometer, low battery warning, 12 bands frequency shaping, and feedback cancellation. The hearing aid includes a P trimmer to control for output sound level and a H trimmer to adjust the amount of background noise reduction.The HD-48 can store up to four listening programs that can be accessed with the memory switch. The HD-48 can be powered with Solar Ear's rechargeable #13 Ni-Mh hearing aid batteries or traditional zinc air batteries. The rechargeable batteries are recharged with the Solar Ear Hearing Aid Battery Charger. The Solar Ear Haring Aid Battery Charger can be charged via the sun, household light, or a Nokia cell phone charger. The rechargeable batteries and solar battery charger can also be used with 95% of all Behind-The-Ear hearing aids on the market today.Interview with representative Transportation/Storage Temperature Range: –20-60° Celsius, 85% RH; Pressure Range: 500-1100 hPa Cleaning method: Soft, dry cloth and a small brush Battery charging time: 14-16 hours

Product Schematics

Technical Support

The listening programs must be set by a hearing healthcare professional or the manufacturer. Troubleshooting guidance is available in the user manual. All Solar Ear hearing aids and accessories come with a 2 year warranty.Interview with representative

Replacement Components

Solar Ear will repair or fix any hearing aids or accessories during or beyond the warranty period for no additional charge. Solar Ear will also provide two rechargeable batteries for free upon request Interview with representative


The rechargeable battery can withstand at least 500 cycles. The lifetime of the hearing aid is approximately five years.Interview with representative

Manufacturer Specified Performance Parameters

Affordable hearing (below ~70 USD) , rechargeable hearing aid. interview with representative

Vetted Performance Status

Results from a clinical trial of a Solar Ear BTE hearing aid with 21 participants revealed that the hearing aid offers substantial benefit to the hearing impaired with a severe predominantly sensorineural hearing impairment (i.e >60 dB at 2 kHz) and gives amplification in the desired frequency range that is aligned with National Acoustic Laboratories (NAL) recommendations.


Patients with middle ear infection should not wear the hearing aid until cured unless otherwise instructed.

Complementary Technical Systems

Audiometer exam

Academic Research and References

Parving, A., Christensen, B. Clinical trial of a low-cost, solar-powered hearing aid. Acta Otolaryngol. 2004 May; 124(4):416-20.

Compliance with regulations

FDA, ANVISA (Brazil), CE, ISO marked.

Evaluation methods

The IOI-HA form includes 7 questions with responses according to a graded scale 1-5, where 5 is the maximum score. A previous factor analysis has shown that questions 1+2+4+7 relate to “satisfaction”, while questions 3+5+6 relate to limitations in activities. At the end of the session, the subject should make a preference for the test-HA or the previously fitted HA named HA-AA [interview with representative]

Other Information

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