I inserted the 110V 3-pronged unit (on the left) into the charger head and can't release it. I'm sure it's a simple process, but for the life of me I can't figure it out. Would appreciate any assistance. Thanks in advance. COMMENT | REGRETS: I've had my Model X for 13 days now - really like the vehicle, but perhaps did not think the process through enough. I live in Manhattan and have discovered that there are no free Super Chargers in New York City except JFK Airport. That's at least a 30-45 minute trip with round trip tolls totaling $12. The two Super Chargers suggested by Tesla personnel are in parking lots and costs from $12 to $27. Currently I go at night to the Tesla Service Area in Paramus, NJ, which is also a $12 toll. Not what I expected.