"No battery power, no charging after replacing battery"に関する回答It seems as the chargers power is routing straight to the main power and you battery is failing you to some degree. What I recommend if you can, try and buy a new receiver for the battery and solder it on the mother board. If you cannot do that then buy a new motherboard and use your old battery.
"Why is my bluetooth speaker randomly turning off? (JBL Xtreme)"に関する回答So with these type of batteries they tend to drain if not used constantly. If you have left this in a box for some months then most likely the battery is depleted. So what i recommend is to open it up replace the battery and if that doesn't work then i dint know what to tell you