People trying to take winter road trips in a Model S have run into some difficulties with range and charging in the frigid Northeast: http://www.teslamotorsclub.com/showthread.php/13639-Worst-Case-Scenario http://www.teslamotorsclub.com/showthread.php/13633-NYT-article-Stalled-on-the-EV-Highway Driving slowly in the 50-55 MPH range, turning off the heat, and freezing in the car was not fun for these drivers. Now there were things that could have been done, esp. w' the NY Times reviewer, that could have mitigated or avoided these problems, but I take it as a given that drivers will inevitably make mistakes and unexpected things (like broken/incompatible charge stations) will occur. My question is, for future Model S, maybe a generation or so down the line, how big a battery is necessary if one wants to drive @ flow of traffic in cold temps without being frozen inside? Here are my parameters: Model S sized vehicle w' 19" wheels, 65-70 MPH cruise, interior cabin temp of 20C, headlights & electronics on, travel of about 250 highway miles. General rule of thumb I've seen is that 67% of EPA rating is reasonable for "worst-case" scenario, or approx. 177 miles for the 85 kWh Model S. To get to 250 miles, a 120 kWh battery therefore seems reasonable. Any thoughts?