Today, I had a teleconference with my rep at SolarCity regarding the PowerWall. He gave me disappointing news. Earlier in the week I was told that they would only be installing the PowerWall for new customers. I would be considered a new customer if I added more panels to my existing SolarCity solar system. We set a call for today to discuss that option. During the call the rep explained that with the exception of the state of Hawaii, the PowerWall can only be used as a backup battery system during a blackout. Current regulations will not allow you to use the PowerWall to supply energy when the sun is down. "Going off the grid" is not an option unless you live in Hawaii. Even if it were an option, the 10k system can not power your entire home. For that you would need to link several of them together. The $3,500 price that Elon quoted does not include the inverter or installation. The actual price quoted from SolarCity is $7,000 but you are eligible for a $2,000 tax credit bringing it down to $5,000. Even though my solar system has an inverter, I would need another one for the battery system.