The JBL Charge 3 Bluetooth speaker comes with a power adapter, described in this piece. This adapter can fully charge the speaker’s built in power bank battery in less than five hours. This then allows the speaker to then play play for up to twenty hours per full recharge.
So here, we give the JBL Charge 3 BT speaker power adapter specs. We also show how to use it to charge this portable speaker.
Firstly, this power adapter is bright orange in color, as we see next. Furthermore, it has one USB A female power output port, and retractable AC input prongs.

JBL Charge 3 Power Adapter Specs
Firstly, the model number: 5V-2.3C-1U. Next, the input power specs are: 100-240 volts, 50-60 Hertz, 0.5 Amps Max. Then the output specs are: 5 volts, 2.3 amps Max. Made in China. I.T.E. Power Adapter. LPS Group Intellect Power Technologies Limited.

Energy performance verified. Intertek EP4007837. Safety Mark 130024-17. Conforms to UL. STO 60950-1. Certified to CSA STD. C22.2 No. 50590-1-07. ETL 4007852.
They also include a USB A to micro USB cable, also orange colored. Additionally, this connects the speaker and the power adapter for speaker charging.

Moreover, you connect the AC adapter and speaker to recharge the speaker batteries as we see next. Use the micro USB input on the speaker to recharge the JBL Charge 3.

Finally, this adapter should work well for recharging many of the other JBL Bluetooth speakers. These include the JBL Flip 2, Flip 3, and Flip 4. It can also fully charge the JBL Clip series. Then these include the JBL Clip 2 and JBL Clip 3 models.