How to tell if JBL Boombox is charging? Well, this BT speaker, with its GIANT power bank, has a lone row of small LED lights across its pedestal, on the bottom front of the unit, as shown in the pictures following. These lamps tell battery level status. To see if this speaker is charging, look at these these to see Boombox charging going on and how to know that the speaker is indeed accepting charge.
How to Tell if JBL Boombox is Charging
Connect your Boombox to Wall Power
Of course, you can be certain that this speaker is NOT charging with no cord connected to it.
Check the Battery Gauge Lamps
There are five LED lamps that light in one after the other, as the Boombox battery recharging advances. You can tell if the JBL Boombox is charging if you see one of these lamps flashing white. When the battery inside is “undeniably dead,” the light on the far left blinks white while charging. Then as the battery fills up, that lamp changes to a steady white glow. Then, the next lamp to the right starts blinking white.
Also, the speaker may warm slightly during charging as does its charger adapter. This warmth is a quick way how to tell if the JBL Boombox is charging.
When All Lamps Light Solid, Charging is Close to Finished
As speaker charging moves on, more and more of the LEDs light solid, and the flashing moves further to the right, until it reaches the last of these five battery level lamps. This progressive lighting of the LEDs is another indication that the Boombox is indeed charging.
This next picture shows the JBL Boombox just before wrapping up a charging cycle. Note that all the lamps in the battery status meter glow. But the last one goes on blinking for several minutes.

The battery charge cycle is done when all battery gauge LEDs go dark, as shown next. Thus, the battery is no longer recharging when all lamps are OFF. Even with the charger cord still plugged in, no lamp glows when battery is full. The Boombox no longer charges when the battery reaches full state.

Finally, Unplug the Boombox and Turn it On
If the battery LEDs read full (all lights lit), this your Boombox did indeed charge when connected to AC power.
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References for How to Tell if JBL Xtreme is Charging
Change History
- 2021-07-26: First released.