Buying used Rechargeable hearing aids? - Be careful

[Markismus]

@pvc

Maybe planned obsolescence to kill the market for their used hearing aids??

Seems a little far fetched. If you rephrase it to “design didn’t have reuseability as one of its targets”, than yes.

Still, the batteries for PowerOne are 25€ in Holland, the paste is under 10€ on AliExpress. So I can change the batteries without a major hassle and costs. This is good thread! See next post!

I also don’t worry much about the nano coating and IP rating. I had to open my Audeo M90’s, because I had pushed the plastic holding the receiver plug too far. I have opened my B90’s and afterwards dived into the pool whilst wearing them and the damage was wholly to my mood.

[Markismus]

@Vigilo

Power One Li-on accu -120

Your link is wrong. It points to NiMh batteries. This one points to Li-ion. Can’t find a place to buy them, though.

(PowerOne’s) NiMh generates 1.2V
(Zpower’s) SilverZinc generates 1.55V
(PowerOne’s) Li-ion generates ~3.2 to 3.7V.

So if @Vigilo is correct, we’re not there yet.

[pvc]

Yep, I was able to google-search many sources for “PowerOne ACCU plus p13 Ni-MH”. Maybe first-gen Signia rechargeable HAs used these Ni-MH rechargeable batteries because I found many references for Signia. Note the warning about compatibility below;

But I can’t find any PowerOne ACCU plus p13 Li-Ion batteries and I don’t think that we will be able to find these. The battery manufacturer/PowerOne from Germany says-in-this-link “The power one lithium ion batteries are built into the hearing aids. It is therefore important for manufacturers that the service life of the cell is just as long as the hearing aid’s lifetime. The power one Li-Ion accus have demonstrated a service life of 4 to 5 years, which means they last just as long as a hearing aid. No more battery changing is needed.”

Is it too soon to say that some manufacturers may be intentionally “Bricking” their hearing aids/HAs after warranty expiration? Correct me if I am wrong. But I don’t know what else to call this? What else can it mean if the batteries are soldered in place and we are unable to find replacement batteries?

fwiw> In the past, our supply-chain friends in China tend to provide solutions for unavailable parts. But I suspect that it won’t be the same for the German supply chains.

btw> Please don’t try applying heat to Lithium Ion battery which might cause an explosion. This is what happens inside a battery right before it explodes

[sterei]

@pvc

It appears that the battery is encased inside that black container with a cover that screws on. I doubt that it has a wire soldered directly to the battery. At least now we have clues as to what it looks like

I think the video shows not all parts, the connection to the battery is missing.
Some time ago I made a 3D CT-XRay-scan of my P90R:

It seems to me that there are wires welded (not soldered) to the battery. Soldering is a no go in this case. Welding can be done in a real short time preventing the part to heat up. .
Note: There are only metal parts visible.

@Markismus

Seems a little far fetched. If you rephrase it to “design didn’t have reuseability as one of its targets”, than yes.

I think also the goal was to achieve more reliabilty. Replaceable batteries have disadvantages, contacts may corrode, sealing of the battery door etc.

Probably the rechargeable batteries Phonak uses are custom made. Therefore it will not be possible to buy them anywhere.

EDIT:
It might be possible to solder the wires on the PCB. If we get the replacement-battery with the wires attached.

[Markismus]

@sterei

It might be possible to solder the wires on the PCB. If we get the replacement-battery with the wires attached.

Or we just tape them using metallic tape (very thin). If the contact is lost, we’ll open it up again and re-apply tape.

Problem remains of how to get our hand on batteries before they die on us.

Does anyone know the diameter and thickness? Searching on Rechargable Li-ion battery button gave a lot of hits.

If they are regular orange 13 batteries, than according to this data sheet they are 7.9mm x 5.4mm and known as either A13 or PR48 (380mAh).

So if the A13 takes about a week to deplete and the Li-ion about a day, we would be looking for a battery that has about 55mAh.

Smallest one I found up to now is the LIR1254 (12mm x 5.4mm, 62mAH). LIR621 (6mm x 2.1mm, 5.5mAV).

If the estimate of 55mAh is in the right ballpark, than the LIR1254 or ML1254 has a comparable amount of energy with a width of 150%!! So that would mean that the lads at PowerOne really did some innovative engineering.

[tenkan]

Now this post is really starting to get fascinating, I’m following with interest.

[sterei]

@Markismus

Does anyone know the diameter and thickness?

I measure a diameter of 7.9 and thickness of 5.3.

[Vigilo]

Images of a B70-R

[pvc]

Wow!! Thanks!! I am wondering if these two features pointed out are Phillips head screws?

[Vigilo]

There is a single screw (the obviously visible one) - looks like it holds the PCB to the pink plastic battery casing

The other arrow (pointing nearer the silver external casing) is black resin that covers the components sealed onto the PCB

Sadly I don’t have a screwdriver that small to even attempt it - looks like its 1mm or less across the head

[pvc]

Oh okay, one screw. The miniaturization makes it difficult to visualize. Also, maybe it’s a Torx screw head or some other screw head requiring a tool that is not so common as a miniature phillips screwdriver.

ETA: This makes me wish that I could have a look at the workstations used by Phonak Repair. They must use some sort of magnification. But every time I look at workstations sold on EBay it is mostly junk, and you could end up spending a large amount of money for magnification. This linked video shows several magnifiers. Some are very clumsy. I don’t think I am ready to try magnifiers yet??

[pvc]

If, the act of removing that phillips screw will release the battery and allow the battery to slide out from its enclosure then we have only solved part of the problem.

• It looks like there is a wire soldered to the battery?
• It looks like the case would still block the path for sliding out the battery?

Does anyone know if/how the remaining top part of the case could be pried off of the hearing aid electronics? These was some discussion here, How to replace hearing aid housing.

[tenkan]

In most disposable battery types the circuit board just clips into place, so this is probably the same,but I don’t think you would need to remove the circuit to replace the battery, I don’t think the wire connecting the battery is going to be the end all, finding a way to remove without to much damage is the key, the battery size could be hard to find tho.
As for working with things this small, jewellers tools, anti-static mat and a USB microscope like these
https://www.amazon.com/USB-Microscopes/b?ie=UTF8&node=2742273011

[pvc]

Thanks for the tip about Digital Microscopes. I was unaware of that technology.

I don’t follow your vision about battery removal with the case blocking the path for removal? The battery would need to slide out of the battery enclosure in the direction indicated by the arrow, right? It seems clear to me that the case is blocking that particular battery removal path?

Also; from @sterei 's pictures there will be two wires;

[tenkan]

Yes, actually looking at that again does seem you may need to do that, yeah 2 wires for positive and negative, I’m interested enough to try it with the Unitron models I have (Marvel equivalent) as I’m quite sure they’ll be the same under the skin.

[Vigilo]

Have been using a jewlers loop to view the screw, even took an imprint using bluetac and its a 4 pointed (Philips) screw

Wires are connected to the battery directly (most likely welded as previously discussed on this thread) so not an easy way of removing and replacing (needs the right equipment)

[DaveL]

@pvc

I am so grateful to find your post. Thanks.

I have Phonak Audeo Paradise P90R’s which are rechargeable. Every bit of knowledge helps.

[pvc]

I found other naked pictures of a Phonak Audeo Paradise P90-R hearing aid. It seems that Phonak’s technique for attaching the wire to the battery has changed/evolved. So I replaced the pictures in the DIY School PDF file named (05 Buying Rechargeable Hearing Aids). Meanwhile, thanks to @Vigilo for the temporary use of your pictures.

[Markismus]

Varta has a new line of Li-ion rechargeable button cells!

Their contact form even allows you to specify hearing aids as application. They also ask the number of cells required annually, though, so it is not meant for consumers.

Looking at the documents on the linked page, I constructed the Varta coinpower A4 code to be CP7954. However, Google generated no hits. Close to it is the CP1254 on Conrad. However, that one is 12mm wide with 74mAh.

Back to the data sheets there is a CP7840 F1 with 12.2 mAh. The previous generation button cell, the Varta CP7840 A3, has only 16mAh. So that road seems a dead end.

Looks like that either Varta won’t be helping us with this generation or that the mAh needed for a HA is much lower than the 55mAh, that I estimated (rather roughly) in a previous post. Looking at the rechargeable PowerOne 13 cells that capacity is 28mAh, so both CP7840 seem to weak.

[pvc]

Maybe these new Varta button cells are too weak. But they surely have a pretty picture! Congrats to the professional photographer who produced that picture! btw> I would like to link to the other thread where there is ongoing attempts to replace these built-in batteries. Here’s a link;
Insight into the inside of the hearing aid