There is a little latch on the bottom of your goTenna that gives you access to the micro-USB charging port. If you hold the device vertically and with the goTenna logo facing you, there will be a small lip on the lower-right corner where you open the latch. Opening the latch can be a little stiff at first — this protects goTenna’s electronics from the elements! — so don’t be afraid to use a coin or small flathead screwdriver ’til you get the hang of it. It takes about 1-2 hours to fully charge depending on the amount of power supplied by the power source. The red charging light next to the USB port will turn off when the unit is fully charged.