[samclem]

Quote:

Originally Posted by Walt34 I remain skeptical. While I'm not an engineer and can't do the math involved, it seems on the face of it to be impossible to replace in 5 minutes, via household electrical outlet, (which at best is 30 amps) the energy required to move a car with occupants 80 miles. Or even with a 220 volt outlet as used by an electric clothes dryer or electric oven. Further, it apparently assumes a capacitor with almost no leakage over long periods of time and wiring with no resistance. For anyone who buys into that, I can whip up some snake oil converted from water to power the next generation car. Any real live engineers care to comment?

I certainly don't qualify as an engineer, but:
- I didn't see that the claim was that the car could be recharged in 5 mins from a household plug. It's possible that they are envisioning higher wattage "fueling" stations, like a gas station, that you could use for cross-country trips. 5 minutes would be an entirely acceptable wait time, well in line with the time we spend at the pump now. One problem with conventional chemical batteries is that they simply cannot accept a charge at very high rates, but a capacitor can. Yes, it would be one heck of a current flow.

Back of the envelope math: 1 HP = 745 watts. So, if we assume this vehicle uses 30 HP to go 60 MPH, then it takes 4 hours to cover it's approx 240 mile max range, and takes 90 kilowatt hours of electricity. A 50 amp/220V plug (like one on most home electric stoves) provides 11 kilowatts of juice, so could recharge the car in a little over 8 hours.

And, the fill-up would cost about ten bucks (at a $.12 kw/h electric rate).

I don't know if/how they've solved the leakage problem. I also think a huge capacitor like this would give emergency workers something to think about when attempting to cut someone out of a car (even moreso than the batteries in hybrids now). On the plus side, it would be darn easy to gin up a very effective antitheft/anti-carjacking device by putting this capacitor to use.