Not sure I can buy that. I’d never design it that way without some significant pressure to hold it in place. I’d want something gas-tight.
WH
They are welded, because that’s the only way to get a reliable connection. At larger scale, like in EV battery packs, the size of things makes it practical to spot weld. That process is where a current is run through the battery end cap and wire/cable/nickel strip, and the resistance from the tiny point contact turns that current into sufficient heat to melt things together. Without being enough to damage the battery.
On a smaller scale, which might very well apply here, a very light gauge wire is fed and pressed in contact with the battery while an ultrasonic vibration is induced between the two. The friction creates the heat to form the weld, and again it’s very localized and limited to protect the battery (or other parts involved.)
In any case, the joint is welded, as in the two metals melted together.
I can’t see the spot weld on the KS10 battery. There’s a small exposed section of enameled wire that’s touching the battery. Absolutely no trace of welding or soldering between the wire and battery.
For what it’s worth there are wireless earphones that don’t have welded battery:
2 Likes
DavelL, you are are correct. 70% alcohol and 30% water. Good for disinfecting and cleaning.
Wax are produced by our ears naturally. Lubricating and protecting our ear canals. Some have more and some have less. Those who produced more will have to check their wax guard regularly. Used the brush to brush away the wax everyday before putting them into the charger. The Audi will teach you or watch some of the video in YouTube…
2 Likes
The 2 dimples are made in such a way so there is a contact with the battery. Maybe a special type of adhesive is apply on the nickel plate to attached to the battery.
Many thanks to yoyomin and others for the very interesting info. I opened (very easily) my Phonak audeo M50r. The battery is a Z23L Li-ion. No luck to find anything like that on google. It seems that the wires are glued to the circuit.
7 Likes
Thanks for the picture. On your hearing aid it appears that the wire is soldered to the battery. The battery case looks different from KS10 as well.
Yes the KS10’s are a different housing.
It’s made by this company http://m.zenipower.com/page.html?id=73
They are 7.8mm x 5.3mm and 23mAh according to;
4 Likes
More good detective work there.
So it seems we just need someone brave enough to try the swap out ; )
1 Like
M7854S1 seems to be another version by a different company:
https://www.hearingaidbattery.cn/MC-M7854S1.html
I’m trying to buy the ones available on Alibaba but unfortunately the shipping and taxes are very high.
2 units are about £75 and 10 units are about £110
Instead I’ve locally ordered two 400909 lipos and I’ll see if I can stuff one into a Marvel 90R.
2 Likes
Ohhhh that’s the way, our first “guinea pig” so to say! I’ll be looking forward to hearing your results on this.
1 Like
Would it be possible to make a group buy?
If it is glued, how do we proceed for the swap?
A google search for electrical conductive adhesives:
3 Likes
Website for Zhuhai Zhili Battery - ZeniPower Zinc Air Batteries | Zhuhai Zhi Li Battery Co., Ltd.|珠海市至力电池有限公司
They actually give some options at the bottom of this page, the first option looks like a nickel tab is just attached with tape:
https://www.coincell.cn/Secondary%20Coin.html
I’ve also seen a few like this which look spot welded:
4 Likes
I hear ya Dave! I do prefer the Cerustop matchstick style! Changing waxguards is definitely a challenge…
1 Like
The 400909 lipo cells have shown up, they are tiny but I suspect that they won’t fit as the largest dimension is 9mm and they aren’t particularly squishy.
I’m waiting on some secondhand Marvel 90Rs which are due to be my backup pair but also the guinea pigs for this.
I think that getting hold of some real button cells will be the only proper solution though.
There are a lot of cheap rechargeable hearing aids on Amazon, I have a couple, maybe one of those might yield a suitable battery…
1 Like
this topic is interesting to me 
it gives hope to me who bought the demo hearing aids
By the way, maybe we will see that someone manages to make rechargeable hearing aids that can carry an additional slot for disposable batteries like roger-x. …
I would ask the admin to separate the conversation in which the wax protectors /clean dome are talked about so that the topic would be transparent for new members later.
2 Likes