The Fugoo speaker's LED should pulse green when the battery is being charged. The LED may stay off for speakers that have not been updated to newer firmware (ver 1.0.36 or newer).
New firmware for your speaker is available at our Start Guide page. Aside from correcting the LED indication, it also makes the speaker significantly louder than it is with earlier firmware (before ver 1.0.36). The new firmware also adds other features, including a quieter setting for voice prompts.
The battery in the Fugoo Bluetooth Speaker is charged by plugging the included AC adapter into a wall socket, and then connecting the AC adapter to the speaker with the included USB charging cable.
As soon as this connection is made, battery charging starts. If the speaker is turned on, The LED starts to pulse green, and then glows 'solid' green once the battery is fully charged.
If the speaker is off, battery charging also starts as soon as the speaker is connected to a plugged-in AC adapter, though the LED may stay off. If you turn the speaker on, or unplug and re-plug the USB cable, then the LED slowly alternates between on and off. Once the battery is fully charged, the LED pattern changes slightly -- the LED glows solid green, rather than briefly pulses green, as it slowly blinks on and off.
The included AC-to-USB adapter is specifically designed to fast-charge the speaker's high-capacity battery, in about 3-1/2 hours. Most other AC-to-USB adapters, including those rated for 2 amps or more, are capable of charging the battery only very slowly.
The speaker can also be charged (slowly) from the USB port of a PC or Mac (it may be necessary to have the computer turned on).