Hey buddy, i got the same problem last week-end, for a Megaboom that i bought only since 3 month and when i called Them (Logitech) they told me one thing to do and it works for me. You have to press at the same time bluetooth button, volume up, and volume down. The speaker will be shutdown and after that you turn on the speaker and you’ll see, the battery will charge until 100%". But the men told me that i had to do those commands with the charge plugged in the speaker. Let me know!