This is absolutely the case, except you don’t need an empty battery to cause a high pitched tweeter sound and shutdown. Just having the charger connected to bat

This is absolutely the case, except you don’t need an empty battery to cause a high pitched tweeter sound and shutdown. Just having the charger connected to battery and charging while playing at any level above 5 will cause a shutdown. The charger connected by itself will cause speaker to shutdown with a high pitch sound always after 5. Also causing the battery to fail afterwards.