Why rechargeable Hearing Aids aren’t there yet

When I tested hearing aids for my latest purchase late last year (2019), I was specifically curious about hearing aids with rechargeable batteries. Nowadays several manufacturers offer those. I wanted to do my part for the environment, and hence not having to buy new batteries all the time was on my wish list. However, it turns out that the offering of hearing aids with rechargeable batteries on the market does not do it for me yet. Sadly, it seems I have to wait till the next cycle. See my report.

Rechargeable hearing aids of the past

My history with rechargeable hearing aids dates back about 10 years ago when I got my first hearing aids. Those were of the model Siemens Pure. They were rechargeable, although they came with some major drawbacks. First of all, the power of the rechargeable batteries only lasted 8 hours. That is a rather short day even for the 70+ year olds that the hearing aid industry usually targets. But, Siemens was smart enough to make the batteries exchangeable, so that it was possible to get over a day by switching between 2-3 sets of rechargeable batteries. However, the standard charging unit required that you put in the batteries with the hearing aids. That is of course not an option if you want to continue using your hearing ais while that first set of batteries charging. Additionally one could buy a charger that did not require the hearing aids itself and with that I found a setup that was annoying, but usable.

When I was buying my next set of hearing aids about 6 years ago I found out that the offering of rechargeable hearing aids was not much better than 3 years before. All setups did not last an entire normal day. Even more annoying the manufacturers turned to models where the battery was built into the hearing aid and was not exchangeable anymore. I dropped this idea and bought some devices without rechargeable batteries.

Rechargeable hearing aids these days

So, 2019 came along and I was looking for a fresh set of hearing aids. This time I thought the industry had 6 more years to get better and yes, things happened. Many manufacturers now offer rechargeable hearing aids that supposedly cover an entire day and only need to be recharged during the night. For example see Phonak, Resound, Widex, Oticon and Signia.

What most manufacturers understood was that about 20 hours are necessary to cover a normal user’s day. What some of them also got, is that sometimes 20 hours might not be enough and so the solution they offer are charging units with speed charging and power banks. Speed charging means that you can charge your hearing aid for about 30 minutes to get a few more hours of power. If you need to do that on the run, you don’t even need a power socket, because some chargers come with a portable power bank.

Why that is not enough?

20 hours is not a day

I question the assumption that 20 hours of power is enough for a day. It might be enough for a normal day, but life does not only consist of normal days. There are plenty of occasions where non-normal days happen:

  • I travel cross-atlantic and soon my day has 36 hours.
  • After a full working day, I attend a party till 3 o’clock in the morning.
  • I am having a normal day, but I forget to put my hearing aids in the charger and now I have a problem on the next morning.

The hearing aid industry might argue now that at least the first two examples do not apply to their usual target market, which are the 70+ year olds. I challenge that. I certainly believe that it is more common to have more normal days if you are out of the work force and live your life as a pensioner. However, you will still have unnormal days and those are the special days that you do not want to miss.

My parents are approaching 70 and never traveled outside their continent. But all of a sudden my Mom decided that she wants to see something of the world as long as they are fit enough to travel. And boom, a cross-Atlantic flight is booked. And it would be really sad if she cannot understand that officer at immigration, because her hearing aids just gave up the moment she enters the country.

What I think is even more common than trans-Atlantic travel is that old people celebrate parties. I certainly hope I will do so when I am old. Every birthday might be the last, so better party as hard as you can. Also, when we get old, we tend to need less sleep. Think about all the things you can do when you need less sleep! I truly hope that when I am old I can stay long at the few birthday parties of the few friends that did not kick the bucket yet. Same applies for once-in-a-lifetime-parties like weddings.

So, dear hearing aid industry, 20 hours might be normal day, but there are non normal days and those are the special ones where we actually want to be able to communicate and interact socially.

Built-in Batteries rob me of Options

The fact that all rechargeable hearing aids on the market have the batteries built-in and not removable annoys me. That means I have no option of using 2 sets of batteries and charging one while continue using the hearing aids with the other one.

Speed-Charging is a poor Option

The hearing aids industry’s answer to these problems is the speed-charging option. I find that rather annoying for two reasons.

First, I can only use it if I remember to pack the charger in the morning and carry it around all day long. I might not be such an organized person and who likes to carry around unnecessary stuff. Also, life is spontaneous and you simply might not know in the morning that you will only come home at 3 o’clock at night.

I find it naive to think that people have 30 minutes in their late afternoon where they can afford not communicating while their hearing aids are lying in the charging cradle. I often head to social gatherings after a full work day. My work day is full of meetings and social interactions. There are just not 30 minutes where I have the luxury of not having to listen. Also on the way to the gathering I either drive and for the sake of safety should be able to hear, or I use public transport where I also want be able to listen to the announcements. And needless to say, once I enter the place of social gathering, I also need my ears to be ready use. I simply don’t have 30 minutes for charging on those days.

Then comes Bluetooth

A rather appreciated innovation in the hearing aid industry is that hearing aids with Bluetooth streaming capabilities are happening. See my review of the Resound LiNX Quattro and the one of the Phonak Audeo Marvels.

Being able to stream via Bluetooth is huge improvement in usability of hearing aids. Since I bought the Marvels, I don’t want to ever go back to having to wear clunky Bluetooth adapters around my neck.

However, Bluetooth comes with a price. The price is electricity. What all the advertisements of the hearing aid manufacturers mention as a footnote at most is that those 20 hours that they are talking about are computed with none or minimal Bluetooth usage during the day. And from my experience those “minimal Bluetooth usage” is about 15 minutes of phone calls at most.

As an example I tested the Phonak Audeo Marvels in their rechargeable version. The specs are fairly comparable to others on the market, so I hope this was somewhat representative. Phonak claims also 20 hours of power. What they don’t say is that for every hour of Bluetooth streaming, you lose 2 hours of power for the day.

Let me give you an example for a day that actually happened to me: I get up at 7, go to the gym, listen to an audio book for an hour on the treadmill (using Bluetooth streaming with my mobile phone). Then I go to work, have a couple of meetings. 2 hours of them are via video conferences and I join them with my laptop that I connect via Bluetooth. That makes 3 hours of Bluetooth streaming in total, which translates to -6 hours of power. That means, instead of having 20 hours I end up with a 14 hour day. Unfortunately, this was day of my employer’s Xmas party that I attended after work. Sadly I had to go home early, because my hearing aids were out of power.

And that was not even an excessive amount of streaming for one day. It was a very normal day for me. And I think I am rather moderate in my consumption of audio streaming. My (hearing) husband listens to music pretty much from the time he leaves the house till he comes back. And I think that is a not so uncommon behavior either, even for people who aren’t teenagers anymore.

And as emergency situations often bubble up inherent problems, you can also see this here. When Covid-19 came along, I was sent to work from home by my employer. Suddenly, all my meetings are video conferences. That means I spent 4-5 hours connected to my laptop every day – using Bluetooth. One some days I would not be able to work a full day if I had bought the rechargeable hearing aids.

Dear Hearing Aid Industry

To summarize, I love to send these messages to the hearing aid industry.

Stop assuming that your users don’t have a life

I find it offending that you assume that hearing aid users (old or young) have only 20-hour days. The non-normal days are the special ones and our hearing aids should be able to get us through those as well.

And even if you think those people with more-than-20-hour days are the power users: yes we might be, but we are still your users. And often we are tech-savvy and influence others in their purchase decisions. In general it is a good design principle to design for the power users to end up with a product that is excellent for every user.

Stop assuming that smaller is better

My guess is that the hearing aid manufacturers don’t offer more than 20 hours of power, because they would need to make the batteries bigger and with that need to make the hearing aids bigger. And that would conflict with the seemingly never ending race of the industry for smaller smaller smaller hearing aids.

I think it is a questionable assumption that hearing aids still have to become smaller these days. My hunch is that the industry is still traumatized from market research from the 80ies. Let me tell you, hearing aid industry: you made it. The devices are small enough. You can stop now.

Just to make an example: here is a picture of my old hearing aid (Phonak Bolero) next to my new one (Phonak Audeo Marvel).

There is about a (cubic) centimeter that the Audeo Marvel is smaller than the Bolero. That is one (cubic) centimeter of space that could have been filled with a battery. But instead you went for an even smaller size. But the Boleros were already a good size. This space is basically now unused and unseen(!) space behind my ears. (Addendum: one might point out here that the comparison of the hearing aids is a bit sketchy, because the Boleros’ behind-the-ear part is bigger not because they are older, but because they do include the speakers, while with the Audeos the speaker goes into the ear canal. So not only age, but also type of hearing aid is the reason for the size difference. However, my point holds that there is more space available, but it was not used for batteries.)

And if you don’t believe me, there is even recent research on the topic. The research program Hear How You Like To Hear of the Fraunhofer Institute in Oldenburg ran a survey with 600+ participants. Among other things, the researchers asked how important it was to the people that hearing aids are small. You can watch the results in this video (in German) starting at 12:17. Here’s a screenshot:

Note: the caption in the slide is misleading, the question was actually “How important is it for you that the hearing aid is small.” (as was explained in the video).

To summarize the slide: of the 616 participants in the survey 245 are currently wearing hearing aids. Of those, 179 answered that the size of the hearing aid is not important to them. That is 73%. Also for those who do not wear hearing aids yet (366 participants) the majority expressed that they don’t care about the size.


To summarize the situation around rechargeable hearing aids:

  • Most manufacturers offer rechargeable hearing aids with about 20 hours of power per charging cycle. Some offer speed-charging and power banks.
  • 20 hours is not enough, because that only covers normal days. It the special days where we need our hearing the most.
  • Speed charging is a lame option, because affording 30 minutes of not hearing is a luxury busy people (like in the work force) don’t have.
  • Bluetooth reduces the 20 hours significantly to the point where people working in jobs with lots of (virtual) meetings would not get over a normal working day.
  • The industry sacrificed longer power duration for the never ending run for smaller devices.

Too bad the industry still isn’t there yet. I would have loved to do my part for the environment, but I ended up buying hearing aids with regular batteries again.

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