I've had many people ask, "how much does it cost to run your car" . So far, I've been unable to answer very accurately. I have a decent understanding of the Wh/mile performance - but that does not account for charging loss, running the fans, etc. So, I picked up this little device over at ekmmetering.com:
I then made a 24-inch long extension cord with this inline to see how well it works. Seems to be working well so far. If I continue to be happy with it, I'll get it mounted in the wall next to the 240V outlet (this extension cord thing is just a temporary kludge). I'll update this post later with the actual *measured* wall-to-road Wh/mile performance of my car.
June 3 2008 edit: I used 6.70 kWh to charge last night - roughly 50 cents worth of electricity. I drove 13.1 miles, which gives 489 wH/m - twice the cost I calculated from watts used while driving. This is likely because of the "finish" / "balancing" stage of charge, and also likely because I bet my tires need filling and my batteries need watering. I'll chart out this over the summer, and include significant maintenance events on the chart.