After failing to charge/start, I was unable to remove the battery from the Frekvens speaker.

- I opened the case, disconnected the battery controller from the main board, and was able to power on the unit.

- I reattached the battery connector cable, gave the battery some time to charge

- Finally, I removed the power cable and it now functions properly.

This should have been a simple matter of removing / reinserting the battery, but it appears to "lock" into place and cannot be removed easily.