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How do you Estimate Hearing Aid Battery Life from the Datasheet?

Denis Carpenter

May 18, 2015



Is the battery current drain on the hearing aid datasheet a good estimate to give my patient?  What if my patient is using wireless streaming or other advanced features?


Today’s hearing aids are essentially mini computers.  They require significantly more power than the old analog hearing aids of years past. These computers analyze sound and make decisions and the processing is very sophisticated.  Processing is measured in MIPS or million instructions per second.  The more instructions that occur in that timeframe, the more power that is required to run the hearing aid.

The measurement for battery drain in hearing aids hasn't changed; it’s based on how much current is required to amplify a pure tone sound. So on the product data sheets you're seeing the same type of current draws today, even though real life current needs are very different. For example, take a hearing aid where the product data sheet says that the current drain is 1.5 milliamps.  When the patient wears that hearing aid in background noise situations, the signal processing is going to kick in to high gear to utilize noise reduction, directional microphones, multichannel compression, feedback management and other features.  In these situations, the current draw will increase substantially.  And if you add in wireless audio streaming on top of that, you might see the current drain double or even triple what’s on the spec sheet.

So if you estimate battery life by looking at what’s on the data sheet you will be overestimating by quite a bit.  For example, if the battery is rated at 150 milliamps, you divide by 1.5 and you’ll estimate 100 hours.  However, in dynamic, real-life contexts much more current is required and the battery life will be less.

This Ask the Expert was taken from an AudiologyOnline interview with Rayovac - read the full interview here. For more information, visit or the Rayovac Expo Page on AudiologyOnline.

denis carpenter

Denis Carpenter

Rayovac Zinc Air Technical Manager and OEM Liaison

Denis Carpenter is Director of Zinc Air Technology and OEM Liaison at Rayovac.  He has been with Rayovac for more than 30 years and was on the original zinc air development team. Denis has held a position on the International Electro-technical Commission (IEC) committee since 1999 and is also a member of the American National Standards Institute (ANSI) committee.  In 2008 Denis was recognized by the IEC, celebrating his career-long contribution to improvements in hearing aid battery technology and his ‘exceptional’ work towards international standardization in electro-technology.  He earned his BS in Chemistry at the University of Wisconsin – La Crosse.

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