Depending on the status of the speaker, the LED indication may not be on when the speaker is being charged. That may give an impression that the speaker is not charging.
if the speaker is off, there will be blinking LED to indicate that it is charging.
if the speaker is on, the speaker beeps once but there is no charging indication on the LEDs.
If the speaker battery is completely empty, it may take some hours to charge before the speaker can give any indication.
To manually check the battery level, briefly press the on/off button in either power-on or power-off mode.
A 5V, 0.5A adaptor is recommended for charging the speaker.
When connecting the supplied USB cable to a power adaptor:
Note that the USB plug has two sides. One side has metal pins and the other side does not. When inserting the USB plug into the jack of the power adaptor, make sure the metal pins on the plug is on the same side as that in the jack. If the USB plug is inserted incorrectly, the speaker cannot be charged.
The information on this page applies to the following models:BT3900A/00 , BT3900B/00 , BT3900P/00 .