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Originally Posted by Clev
Which ones would those be? I believe the EV1 has the lowest consumption of a production EV at 179Wh/mi. The Tesla gets 240Wh/mi, and even Gary Graunke's Insight EV, which uses an AC drive system with regen, gets 185Wh/mi at 50 mph. The one that claimed 120Wh/mi, Aptera, released a press release on April 14 that revised the estimated consumption up to 200Wh/mi.
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Reverend Gadget's GT6 bodied Spitfire uses 100 Wh/mile(from phone conversation with him). It is a very light conversion with the best LRR tires available, but nowhere near as aerodynamic as Dave Cloud's car. It's aerodynamics are definately much better than the average conversion, mind you, due to a very small frontal area(14.9 sq ft for GT6 body, 15.2 sq ft for spitfire MkIV body); it's drag coefficient isn't bad either, and is bound to be lower than the convertible Spitfire Mk I(streamlining and Car Aerodynamics by Jan P. Norbye quotes the MkI as 0.39, and various sites quote the MkIV Spitfire as 0.42). This car gets 24 miles range to 80% DoD on 15 Exide Orbitals at 60 mph; these batteries were measured by Rich Rudman as delivering ~270Wh each at the 1 hr rate, and Gadget was discharging them at about twice the rate!
John Bryan's VW Karmen Ghia needed ~100 Wh/mile highway. IIRC, it got 45-50 miles to 80% DoD on a pack of 16 Optima D750s, or a pack around 6 kWh at the 1 hr rate to 100% DoD.
James Worden's Solectria Sunrise, with extremely lightweight construction and similar, if not worse aerodynamics than Dave Cloud's Metro, could do 200 miles at 60+ mph on only a 27 kWh pack, which is 135 wh/mile. With hypermiling techniques, it set a world record of 373 miles on a charge, putting it well under 100 Wh/mile if driven carefully in city conditions.
Alan Cocconi's electric CRX, with some aerodynamic modification(Cd 0.25), got 135 miles per charge @ 55 mph on a pack of 28 Optima Yellowtops. I don't remember what his pack size was, but the car had a rediculously good efficiency(somewhere around 120 Wh/mile).
Other less efficient cars for comparison:
AC Propulsion's TZero, weighing in at 1900 lbs, and with aerodynamics nowhere near as good as an EV1(and probably worse than Gadget's Spitfire), consumed 160 Wh/mile at 60 mph, going 302 miles on that run before needing a recharge. Its tires have a Crr of 0.0085.
In the past, John Wayland's Datsun 1200, Blue Meanie consumed < 150 Wh/mile at 60 mph. Wayland quoted it many years ago that it used 55A with the pack sagging to 162V at 60 mph on level ground. It has brick-like aerodynamics(compared to say, a Honda Insight) and at the time weighed in at 2,340 lbs, although it made use of some very good LRR tires. This figure is also outdated; he has since upgraded the car.
John Wayland's other Datsun 1200, White Zombie, has thick, sticky drag tires, has the aerodynamics of a brick, and weighs around 2,300 lbs. It consumes an estimated 200 Wh/mile at 60 mph.
With regard to your above comments:
The EV1 achieved 179 Wh/mile on the EPA combined cycle; steady state cruising would yield different figures. At a steady 60 mph, the lead acid version used 164 Wh/mile and NiMH 168 Wh/mile. The EV1 was quite heavy, and probably has worse aerodynamics than Dave Cloud's car, even though the EV1's aerodynamics were exceptionally good and set a world record for a "production" car.
With regard to the Tesla Roadster, if you look at the Wh/mile versus mph chart on their blog, it consumes 250 Wh/mile at a steady 60 mph, with ~110 Wh/mile lost to aerodynamic drag, 80 Wh/mile lost to 'drivetrain'(including BMS, battery cooling, ect.), and 55 Wh/mile lost to rolling resistance. The Tesla has massive losses imposed due to keeping its battery at the proper temperature. The Tesla has mediocre aerodynamics and weighs in at 2,700 lbs, and has thick, sticky non-LRR tires. It is *not* an efficient EV, although it makes even a Honda Insight hybrid look like an energy hog by comparison. The Roadster's energy needs are about the same as Toyota's RAV4 EV!
Do you have links to Gary Graunke's project? I was extremely interested in it back in 2003, but pretty much dropped off the EV list around 2006. I haven't checked up on what became of that project and I am very pleased to hear that it is on the road! If its consumption is that high at 60 mph, I'd be extremely surprised. Then again, some conversions get far better or far worse efficiency than you'd expect...
The Aptera at 120 Wh/mile sounds about right, if not a bit high; initially I remember them quoting 120 miles range on a 10 kWh pack(87 Wh/mile), but their design has changed many times since then. 200 Wh/mile would probably be applicable for the "new" EPA highway cycle where cars are driven harshly to reflect those Americans who drive WOT all the time.
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190Wh/mi is still very good.
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Agreed; given that stock Metro conversions(stock with regard to aerodynamics) can achieve ~200-240 Wh/mile ~55-60 mph, the 190 Wh/mile figure seems a bit high, if measured from the pack; if measured from the outlet, or measured from the pack at 70 mph, it would make more sense.
Even some small lightweight trucks with poor aerodynamics are in the 250-300 Wh/mile at 60 mph efficiency range... even the 5,260 lb "Red Beastie" got around 300 Wh/mile at 60 mph. Surely, Dave Cloud's car has less than half its drag, and with about 2/3 its weight and LRR tires that "Red Beastie" didn't have, it should consume somewhere less than half of "Red Beastie" at the same speed.
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