I love my portable Bluetooth speaker, Bose Soundlink Mini 2: https://www.amazon.com/Bose-SoundLink-Bluetooth-Speaker-Carbon/dp/B00WK47VEW
It has a very good sound for its small size and I have been perfectly happy with it, usually it is used by my kids when they watch Youtube videos on a tablet. It was more expensive than other "similar" portable BT speakers, but seemed to have considerably better sound when I tested it upon purchase (I think I paid like 200€ or more for it some years ago).
However, lately it doesn't seem to charge much at all, and basically works only if it is connected to the charger all the time. I figured maybe its battery is now just dead (I've had it for a few years) and needs a replacement, and you can buy replacement batteries for that speaker for like 40€, and they can be easily replaced yourself (open the unit with four screws and you can take the old battery out etc.).
However, while searching for information on this, I also learned online that many people have this charging problem even if their battery seems to be ok. There were lots of instructions, e.g. resetting the speaker to factory settings etc. to clear that problem, and also updating its firmware.
I installed and ran the firmware update utility, and yeah I have quite an old firmware... but the utility refuses to update the firmware because my battery is low. Well, it doesn't charge either, so I can't update the firmware without replacing the battery, right?
ANYWAY, then I read some more discussions about this problem on the Bose forums, and many have this issue even with the latest firmware. Also, some reported that when they upgraded to the latest firmware, it was as if e.g. the bass levels of the device became weaker, ie. worse sound.
Some even suggested there might be a bug in the latest firmware where it reads the device identification wrong, and that is the reason for not charging. And as Bose has discontinued this product already with newer BT speakers, maybe they are not keen to try to fix the firmware anymore.
- Now I don't dare to buy a replacement battery, as I am unsure if my current battery really is dead or the device just refuses to charge it, and I might still have this problem with a new battery as well, at least after awhile.
- Even if I could, I don't dare to upgrade the speaker firmware, if it possibly makes the bass lose its oomph.
So I guess I just keep using it connected to the charger all the time, at least it still works that way. At least for now...