My right ear(a) sounded muffled, and both buds batteries last for 40 minutes only, so I decided to share my notes here on how I replaced the battery and managed to kill a driver.
Use a plastic vice grip with silicone utensils and 70c air heat around the edges, then squeeze it until a seam appears, do not overheat else it will deform permanently.
Use a copper wire from a cable to slice through adhesive, don’t use any prying tools if you want it to looks unopened after repair.
Adhesive reference
When removing the speaker, the positive speaker coil is OUTSIDE the epoxy, I have no idea why, its part of the rubber glues as you can see, meaning that removing the speaker will destroy it unless you remove the glue from the chassis, not from the speaker, even then the risk is very high, these are thinner than human hair and enameled.
You can see the very thin copper wire in the rubber adhesive.
Glue removed and positive wire cut.
I had to remove it because of the grill that has very weak adhesive that happened to fall through, this muted bass, unfortunately this ended up killing the speaker. Ending my battery replacement attempt, I should have left it and shook/drop it a few times as that mostly works…
Here shows how weak jelly like the adhesive is, I never used a brush to clean, only wipes and blow air (mouth).
Hope this helps someone that is out of warranty…
Edit: I noticed the cut off voltage is at 3.4v which is industrial standard, however many 3.85v nominal voltage batteries particularly Panasonic mention that the safe cycle cut off is at 3.55/3.6v due to different chemistry… Chinese makers call these HV Lipo.
If I were to buy any new TWS earbuds these days (all 3.85v) I’d be careful of going under 20 percent battery charge.
My earphones degraded in 600 cycles to 30% of their capacity. ( a 1 year usage)
80% is the average standard for most batteries at 800 cycles, so there is something wrong.
My other advice is to have TWS and wired, use wired on desktop, these aren’t meant to be used all the time, its not just nothing products. For ANC in office, headphones provide wall power (type-c) with ANC. Only use TWS outside and not more than 3 hours… Save your money and avoid more e-waste…
I currently use wired with arm mount smartphone while running, and TWS on commute and cleaning house where wires are a big deal.
I’m eyeing the XM series from Sony, they have number of hours logging for device and battery usage, maybe Nothing could add this as a feature? The battery is harder to replace on the newer models compared to the XM3 though, still no soldering or tools needed…
There is also a half bridge dual diode modification in series on battery that slightly cuts the charging and cutoff voltage, you will lose around 20% capacity and the charging will take a bit longer, however it should technically last thousands of cycles (5+ years) before having any noticeable degradation. This isn’t recommended on high power devices, only low power lithium devices.
