I am an electrical engineer who works at a large electronics manufacturing company. I am also an electric vehicle enthusiast and owner of a 2013 Chevy Volt.
A few of my co-workers and I developed an electric vehicle charging system that uses two L2 EV chargers to service four or more vehicles for as little as a quarter of the cost of a one-charger-to-vehicle system. Our design does not require modification of the L2 EV chargers and can be constructed by someone with a modest amount of electrical knowledge. We installed this system at our facility and it has been in operation for over 5 months.
We got permission from our company to share the idea and presented it at a conference recently (IEEE Transportation Electrification Conference 2014). Our company is not planning on selling this system as a product so we are trying to spread the word so that others can adopt this system for their own business / place of employment. I thought this forum would be a good place to start.
Here is a link to the paper we wrote about our idea:
https://docs.google.com/file/d/0BwECF1OOiUNsSDQ0bmNnUGp1akk/edit?usp=docslist_api
Please contact me if you would like to know more about the system and how you can implement one yourself. I would be very happy to answer any questions.