I have no solar panels on my roof yet, but am hoping to add some to offset a portion of my electricity use. About half of the electricity I buy each month is consumed by my Model S, so I don't care whether the solar generated power goes into my appliances or my car. It seems to me that it would be a great idea for Tesla to build PowerWalls with charge cables on them (or a component that can be easily connected to a series of PowerWalls) so that a Model S/X/3 owner can avoid the entire concept of power inversion by taking DC from the solar panels, storing it in the PowerWall, then transferring it to the car in the evening as direct current, the same way a supercharger does. The downside would be that the PowerWall wouldn't be able to provide AC power to the house during a power outage, but the upsides are huge: no expensive DC-AC inverter is needed, no complex house/panel/transfer switch wiring is necessary, no DC-AC conversion inefficiencies are introduced. Sure, the 6.4 kWh capacity of one PowerWall is not enough for my daily commute, but 25.6 kWh is (4 PowerWalls). Given the option, I'd rather spend my money on panels and PowerWalls to use this simple setup rather than panels, PowerWalls, an inverter, a transfer switch and more electrical wiring/labor. Has this been discussed before? Charging a car directly from a series of PowerWalls seems like a pretty obvious idea.