Unable to charge the built-in battery
When using the supplied AC adaptor, make sure the AC adaptor is firmly connected to the speaker and AC outlet.
When using a USB AC adaptor (commercially available), make sure the USB cable is firmly connected to the speaker and the USB AC adaptor.
In addition, make sure the USB AC adaptor is firmly connected to an AC outlet.
When using a USB AC adaptor (commercially available), make sure the USB AC adaptor has the ability to output in 1.5 A or more.
Depending on the type and specification of the USB AC adaptor and micro-USB cable, the charging time may take a long time.
Using a USB AC adaptor with an output current of 1.5 A or more and a micro-USB cable conforming to the USB standard is recommended. Charging from the other device is not guaranteed.
The charging time may vary depending on the ambient temperature or conditions of use.