How does the discharge function work on my Fenix battery charger?
The charge/discharge function on Fenix chargers has two uses. First, you can use it to charge 18650 batteries by plugging the cable in. You will plug the micro USB end of the cable into the appropriate port on the charger. The other end goes into a USB port, like on a computer. That charges the battery.
Second, you can use your Fenix charger to charge other USB devices, such as a camera or flashlight, while the 18650 battery is inside the charger.