After returning to this forum after a 4 year absence, I have been trying to catch up this last week. This forum has quite a collection of knowledgeable EV folks, so is a good place to bounce some ideas. I saw Alan Cocconi's Tzero at the '97 LA Auto Show and was truly impressed with both the performance, and the range he was getting out of a bunch of yellow top Optima AGM lead acid batteries. It used 28 of these batteries which only have 44 ahr and because being lead acid had a much higher Peukert effect than lithium, so under heavy load had less than 44 ahr. Lithium has very little Peukert effect or voltage sag under the same heavy loads. OK, back on topic, this low energy density 14.8 kWhr bank still managed 85 miles with a 5000' elevation change. 18 year old technology, yet 145 whr per mile urban, 171 whr per mile at freeway speeds. Battery energy density 38 whr per kg. This range increased to 200 miles with commodity lithium-ion cells of this time which has 1/2 the energy density of current cells. When Eberhard and Musk approached Cocconi and Tom Gage individually to prod them into taking the next step and produce the vehicle, Gage opted instead to introduce Musk to Eberhard and get back to work on his own projects. I would say that was the start of the Roadster. As Elon has said, the Roadster was a proof of concept minimum production run to validate a fun to drive EV, even though IMO Cocconi had already had that with the Tzero. I understand market demand, so the Model S was needed but I'm still a diehard EV nut with the hopes that sometime down the road a new version Roadster based on the minimalist Tzero would be built. At 171 whr per mile at freeway speeds with the reduced weight of the new 3.9 ahr 18650 cells comprising a 85 kWhr bank, gone is range anxiety. That is almost a 500 mile range and if you hypermile drive it, over 500 miles. When I drive cross country I plan on 800 miles before dinner and a hotel. Only a revamped Roadster built to be light and efficient could pull this off, 450 miles, 1/2 hour lunch while on a Supercharger, then 350 more miles to a hotel that can deliver 10 kW charge for overnight. And when those 400 whr per kg batteries are in production, you can skip the 1/2 hour lunch on the SC, and just drive 80 mph for 10 hours and bag a hotel for the night that recharges you the driver and your Roadster.