How About an Electric Car With No Batteries: This sounds like a good deal - an electric car with a supercapacitor, rather than batteries. It would charge in just minutes.

jerryc41 Loc: Catskill Mts of NY

This sounds like a good deal - an electric car with a supercapacitor, rather than batteries. It would charge in just minutes.

http://paultan.org/2014/11/15/battery-free-electric-cars/

tschmath Loc: Los Angeles

What ever happened to the flux capacitor that allowed Marty McFly to time travel? It had up to 1.7 jigabytes (as Doc Brown pronounced it) of energy. That was such a promising technology - it ran on household garbage. I guess it only worked if you owned a DeLorean, though.

jerryc41 Loc: Catskill Mts of NY

tschmath wrote:

What ever happened to the flux capacitor that allowed Marty McFly to time travel? It had up to 1.7 jigabytes (as Doc Brown pronounced it) of energy. That was such a promising technology - it ran on household garbage. I guess it only worked if you owned a DeLorean, though.

We'll have that in the future. :D

Frank T Loc: New York, NY

Don't worry guys. I'm sure the oil companies are busy buying up the patents for the supercapcitor so they can make it disappear.
Got to keep pumping oil. Damn the pollution, full speed ahead.

jerryc41 Loc: Catskill Mts of NY

Frank T wrote:

Don't worry guys. I'm sure the oil companies are busy buying up the patents for the supercapcitor so they can make it disappear.
Got to keep pumping oil. Damn the pollution, full speed ahead.

With profit per barrel down, I'm sure they'd gladly switch to making money from capacitors. It's money they love, not oil.

johnst1001a Loc: West Chester, Ohio

Charge in minutes, but what you have to realize is in order to do this, you have to have an outlet capable of providing a lot of watts in a hurry.

It takes around 10,000 watts to yield the equivalent of 1 gallon of gasoline. If your electric car has a range of 200 miles, and gets the equivalent of 30 miles per gallon if it were a gasoline driven car, you would need 200/30*10,000 or 66,000 watts. For a 220 volt system, the current would be 300 amps to charge it in an hour. For practical purposes, a 30 amp circuit, 200 volts would charge the car in 10 hours. 60 amps in 5 hours. 60 amps is pretty high as most houses only have 100 amp service.

But the good thing if your electric rates are 12 cents/kwh like mine, the cost of electricity for 200 miles would be 66,000/1000*.12 or about $8.50 where as gasoline would be 6 gallons times $3 or $18.

DaveMM Loc: Port Elizabeth, South Africa

johnst1001a wrote:

It takes around 10,000 watts to yield the equivalent of 1 gallon of gasoline.

I agree with your conclusions, although would debate the calculations. According to Wiki, the energy of petrol is 33.3kWh per US gallon (note the watt hours, not watts). In addition you have to take into account the relatively high efficiency of an electric motor compared with petrol. Electricity is probably 70% or maybe 80% efficient for the charging and driving component (although there is a much lower overall efficiency if you allow for the 40% typical efficiency of a modern power station). Petrol engine cars are unlikely to be better than 25% efficient.

This means that to charge a capacitor (or a battery) for 200 miles in 5 minutes for a mid size car would need about 5000 amps at 230 V. It could conceivably be done at a specialised recharging station, but not without enormous investment. It could never be done at home.

I do agree with your cost figures - at the prices for petrol and electricity in my country I would probably save nearly 2/3 of my fuel bill.

pecohen Loc: Central Maine

jerryc41 wrote:

This sounds like a good deal - an electric car with a supercapacitor, rather than batteries. It would charge in just minutes.

http://paultan.org/2014/11/15/battery-free-electric-cars/

Another technology that's been suggested as an alternative to a battery is a fly-wheel. I have to guess that this and the super-capacitor are still experimental ideas that are still pretty distant from production.

jerryc41 Loc: Catskill Mts of NY

pecohen wrote:

Another technology that's been suggested as an alternative to a battery is a fly-wheel. I have to guess that this and the super-capacitor are still experimental ideas that are still pretty distant from production.

I once used a log splitter that was power by a gas engine spinning a flywheel. I really packed a wallop.

I'm not going back to re-read the article, but one of the critical layers in the capacitor would be one atom thick. I'm sure production will not be starting tomorrow.

ecblackiii Loc: Maryland

It would be a great advance! However, we have long had capacitors that store much more power than a battery can and that can be recharged far more quickly than a battery. That's not really the problem. The problem is that capacitors are devices that, by their nature, discharge their power quickly, in a very short burst, rather than slowly, over a long period of time--like batteries do. Until someone finds a way to make capacitors discharge their energy slowly--over a period of hours or days, instead of a fraction of a second-- capacitors will not be useful as a battery replacement.

jerryc41 Loc: Catskill Mts of NY

ecblackiii wrote:

The problem is that capacitors are devices that, by their nature, discharge their power quickly, in a very short burst, rather than slowly, over a long period of time--like batteries do.

Yeah, I wondered about that. I'm sure there's a way to do it, and if I could develop that, I'd be very rich. :D

Bpace Loc: Alabama

I can remember seeing the cover of one of my dads popular mechanics magazine featuring a car powered by a flywheel.
Seems like it was depicted in the trunk and about the size of a spare tire. This was late 60's?

pecohen wrote:

Another technology that's been suggested as an alternative to a battery is a fly-wheel. I have to guess that this and the super-capacitor are still experimental ideas that are still pretty distant from production.

johnst1001a Loc: West Chester, Ohio

The calculation for kilowatts and equivalent miles per gallon is correct, 10,000 watts is equivalent to about 1 gallon on the road, not KW/BTU. This 10kw/gallon does take in to account the ratio of electric motor efficiency to gasoline engine efficiency, that is actual energy consumed turned in to energy at the wheels. The ration you mentioned where an electric motor is about 80% efficient and the gasoline engine somewhere around 30% is correct. That is why it only takes 10 kw of energy instead of 33 kw to get the same yield of power at the wheels. I rounded the number to 10 kw by the way, It actually about 10,400. And this is too varies by the car.

Bpace Loc: Alabama

Capacitors can release energy slowly just like a battery.
It depends on the load. Small load, slow release.

ecblackiii wrote:

It would be a great advance! However, we have lon... (show quote)

johnst1001a Loc: West Chester, Ohio

A flywheel stores energy for sure, but so does a battery in a hybrid. Same concept, different technology. Not sure the efficiency of a fly wheel though. The conversion of using the hybrid motor as a generator during breaking, and then as a motor during acceleration is about 60%. Considering the energy used for acceleration is about 30% of the total energy consumed by the car, the net is you improve your gas mileage by an average of 24%. Wind resistance is about a third, and rolling friction is about a third, making up the rest of the energy consumption. I am sure there is a bit in there for air conditioning.