This is a bug with the firmware where the battery seems to get locked in low power mode if it runs down too far. I had this problem and tried every suggestion found online with no success. After much back and forth with BOSE support, the following finally worked: 1. Plug your speaker into a computer using the USB cable. 2. Go to btu.bose.com in a browser window. Download the software if you don’t have it and launch it. 3. The webpage should change to show it has launched. If it says there are updates available then choose to install them. This should fix it. 4. If it says the software is already up to date, then press the following keys in order: A,D,V,Up arrow, Down arrow. That should now give you the option to downgrade the software. Choose a downgrade and then Apply Changes. That is what brought mine back to life. You can upgrade the software again after that.