Here's the exact quote from the latest DJI Phantom 2 manual:

"It’s recommended to charge and discharge the battery thoroughly once every 20 charge/discharge cycles.
Users should discharge the battery until there is less than 8% power left or until the battery can no longer be turned on. Users should then fully recharge the battery to maximum capacity. This power cycling procedure will ensure the battery is working at its optimal level."
Can somebody tell me what is the most easy way to completely discharche the Phantom batteries?

please check the attachment.