This was an expensive set of four rechargeable Maxell ML2032 cells and a charger for them, but I'm not convinced the charger is actually suitable for the cells. The Japanese seller also included a set of metal tweezers for removing the cell from the charger, suggesting they are not that technically inclined. (Yeah, I totally used the tweezers with a dead CR2032 cell as a clickbait thumbnail.)
I subsequently received a vague warning from eBay that the listing had been taken down and to stop using the product immediately, but unlike Temu they made absolutely no effort to explain the issue or refund the buyers, and it's not even possible to initiate a return even though it goes through all the motions!
I contacted the seller and they insisted the cells are genuine Maxell ML2032's and that the charger is suitable for them....
Ongoing tests show they do take a charge, but it doesn't appear to be compliant with a charging specification I found, which is a charge current of 2mA (very slow trickle charge) at a maximum of 3.1V - this charger puts out about 30 times that current at 4.2V!
The extremely low charge current is probably why the voltage shot straight up to 4.19V on the standard LTH7 style charge chip. If these are real then I may have to improvise a simple charger. Maybe a simple current limited supply and a TL431 as a programmed voltage cap?
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators