I don't know LMCH, but I think it's something else.|
As I understand it, according to photos that Motobot pointed out a while back and my subsequent downloading and reading of the spec sheets, the internal battery pack protection is on that little circuit board at the top of the battery pack. The two ICs there shut off the incoming charging path when a certain voltage is reached on each individual battery and allow them to charge no higher than that, they also open another circuit from each battery pack individually to the battery leads coming out of the pack if either battery is discharged below a certain level. This is purely a safety function as I understand it.
Now, that being said, it also seems apparent there are other circuits in the system having to do with shutdown, charging, etc. because even when working correctly Win 10 controls charging and my Hi12 varies between 95-99% charge, and Win 10 displays: Not Charging, which has been explained by others as a Win 10 thing when it is unable to identify the battery pack. Sounds reasonable, not positive it's completely accurate, but fair enough as I see no connections other than battery leads coming out of the battery, i.e., no obvious communications pathway. I have no real problem with this, just wish the high and low cutoffs were adjustable as a lot of data seems to indicate charging no higher than 80% may be better for battery life long term, especially if you're not going to need full battery capacity and mostly run while charging as I do, but the Hi12 doesn't seem to charge at a very high rate anyway while running the machine so I'm not going to stress out over it and everything is probably working as intended. I am a little puzzled that if the adapter provides enough power to run the Hi12 while not charging just how the battery level manages to drop to 95% during that period... so perhaps there is an issue there.
The weird thing is when you encounter a situation like the one you're in and the one I experienced... Similar symptoms on the LED -no indication at all despite being plugged into a known and tested good charger, but I didn't think to check USB voltage as I really thought I'd somehow gotten the Teclast BIOS brick despite preparations taken to stave that update off and just spent about 45 minutes trying power button sequences while watching some TV as a last resort while putting off ordering the equipment to flash the bios to the chip externally... and just got LUCKY that it started up before I ordered the programmer and voltage converter.
Now, whether these little bugs have anything to do with the other situation reported in the early days by some owners that charging while running their tablets burnt up the BIOS chip and required replacement I cannot say, but go back and read the threads and do some Googling, etc. From what I read, it seems likely that spate of incidents lead to the infamous "You can't use the tablet while charging" statement by Emily. Pardon the quotes if those were not in fact her exact words, but something to that same meaning. I assumed(could be dangerous) that early problem had been corrected and have used my Hi12 while charging as I have EVERY OTHER TABLET/LAPTOP/CELLPHONE I'VE EVER OWNED... and this goes back to the late 80s early 1990s.
Whether your issues and mine are in fact the same I cannot say, but it might be worth 45 minutes of button twiddling while it's charging to see what happens... Best of Luck.
If that BIOS chip was damaged it's going to require replacement/reprogramming and if there was an issue with earlier boards you'd be better off returning the entire unit and having them replace the Mobo with the updated version.