SSC’s plug-in supercar would need the mother of all plugs

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With billions in taxpayer moolah floating around to encourage the development of next-generation plug-in hybrids and electric cars, the public needs to be wary of claims of too-good-to-be-true technologies, magic batteries, cars powered by pollen, dandruff, zoo poo, whatever. At a minimum, we should keep a calculator on hand.

Consider, for example, a claim made by Shelby SuperCars, a Washington-based outfit (not affiliated with famed performance-car designer Carroll Shelby) that announced last week that it would build a revolutionary electric vehicle called the Ultimate Aero EV ‘that will set a new standard in the electric car industry –- one of 10-minute recharges, super horsepower and ranges up to 200 miles.’

Thanks to SSC’s ‘Nanotechnology Lithium-Ion’ battery pack (buzzwords, anyone?), the car is ‘rechargeable in 10 minutes on a standard 110-volt outlet and has a 150-200 miles range on a single charge,’ according to the company’s press release.

That sounds amazing, doesn’t it? And more that that, completely freaking impossible.

Consider these fun facts: 110 volts times 20 amps (typical household current) equals 2,200 watts -– that’s about the draw of two good hair dryers. In 10 minutes, that equals 0.36 kilowatt-hours. Now let’s look at the SSC: It’s a super-slick, tube-frame sports car weighing 2,950 pounds. It would also have to be shod with foot-wide high-performance tires to accommodate its purported 208-mph top speed. So add 5% for frictional drag. It has a coefficient of aero drag of 0.348, which is to say, it’s not very slippery. It has two 375 kW three-phase AC induction motors for a total output of more than 1,000 horsepower.

Tally it all up and you’re talking about a car that would require at least 250 watt-hours per mile, estimates electric car guru Tom Gage, whose company, AC Propulsion, supplies core technology to Tesla, BMW and others in the field. In other words, to go 200 miles on a charge, the car would require a 50-kWh battery pack. In itself, that’s plausible; after all, the Tesla pack is 56 kWh. What’s wildly, insanely not plausible, and is in fact a monstrous load of fertilizer, is the claim that you could recharge such a battery in 10 minutes on household current. For that you would need to plug into 300 kilowatts, or 0.3 megawatt, roughly the equivalent of a small neighborhood substation.

‘You’d have to have a pretty big cable,’ Gage says. ‘What they are talking about has absolutely no relation to household current. It’s completely bogus.’ I repeatedly tried to contact SSC, with no luck.

Finally, I called Philippe Harari, chief executive of Sheffield International Finance Corp., a Palm Beach, Fla.-based outfit that is shopping around SSC’s investor prospectus. ‘All I can tell you is that many people have doubted [SSC principal] Jerod Shelby,’ Harari says. ‘And they’ve all been proven wrong.’

Late on Thursday, however, journalists received a cryptic e-mail from the company, with this passage: ‘There was a premature release that was leaked yesterday, if there were posts made based on this release, there is one major change that needs to be made. The 10 minute recharges are possible via a 220v outlet NOT a 110v outlet. In addition, there are a few new items in this official release including an email address to register for our media event. I apologize for any inconvenience this may have caused anyone.’

All well and good. SSC seems to want to walk back its wild claim. However, 220V doesn’t help much. At 220V and -- oh, let’s say 30 amps -- that’s 6,600 watts. You would STILL need nearly eight hours to recharge a 50kWh battery. The 10-minute figure is, let’s say, highly fanciful. And, just as a PS: SSC promises the battery will last 20 years. Do I hear 50? Why not 100?

-- Dan Neil