# Electric cars are a pipe dream

Discussion in 'General Science & Technology' started by Syzygys, May 20, 2010.

1. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
I guess not. Well, the bulkiness of the car might bring down the airresistance ratio. And it adds weight, but yes they could put bigger batteries in smaller cars too.

I agree with everything you said and yes, 10 years seems to be doable. Which brings it to my original point, that not RIGHT now...

EVs are like Linux, every year is going to be theirs.

3. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
You don't mind solving this for me?

"Students will be given the following math question:
One boat can carry cargo equivalent to 5-6 trains, or 500-600 train cars. Each train car
holds the equivalent to 3 semi truckloads. 1800 semis = 1 boat. Boats get 45-50 gallons per
mile.
1. Determine the miles per gallon of a ship.
2. If a truck could get 10 mpg, how does the gas mileage compare between semis and
ships?
3. Which is more economically feasible?"

---------------------------------------

Furthermore:

Transportation Modes: An Overview

Maritime transportation (Concept 4). Because of the physical properties of water conferring buoyancy and limited friction, maritime transportation is the most effective mode to move large quantities of cargo over long distances.

http://people.hofstra.edu/geotrans/eng/ch3en/conc3en/ch3c1en.html

Are we good now?

Last edited: May 25, 2010

5. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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19,248
At what speed?
Bearing in mind your call for 70 mph...
At what fuel consumption?
How often do we pack that many people into one vehicle on land?
Specious question.
How about: why can we get 70 mph from a moped of 50 cc engine capacity yet for a water-borne vehicle (jet ski) to approach that speed it requires 400+ cc?
How about a sport jetski that requires a 1500 cc 255 HP engine and does ~ 70 mph yet a Suzuki GSX-R 1000 with 160 HP will do ~200 mph?

Do try to keep your contentions straight: you first claimed that water travel requires less energy and now you're comparing slow-speed efficiency.
Apples and oranges.

7. ### John99BannedBanned

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22,046
Dywyddyr, what do you think of post 49 and using the rotation of the drive shaft or rims?

8. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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19,248
This bit?
Nice idea but taking power off the rotating components causes friction and would slow down the shaft/ wheels, and the whole point is get them rotating as efficiently as possible.
Regenerative power recovery may well cost more than it's worth in losses and increased heating, not mention the extra weight of equipment required to convert that rotation into energy and then store it.

9. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
Seriously dude, you are offtopic and incorrect. I thought it was common sense and public knowledge that water transportation was the most cost effective...

Exactly. That's why it was stupid for Quadro to bring up submarines...

Now if you can't focus on the topic, I will be just ignoring you as I do with Quadro...

10. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Changing the goal posts again.
Is that because you can't refute the point that water transport requires more power than land transport?
You originally claimed it used less energy.

Go ahead, but as long you make stupid comments I'll correct them.

11. ### SyzygysAs a mother, I am telling youValued Senior Member

Messages:
12,671
Last edited: May 25, 2010
12. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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19,248
Funny you should give that link:
So Concorde and the QE2 are both ~ 17 passenger miles per gallon.
So train is ~28 times better.
And a bus is ~ 14 times better.

13. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
Just to make you happy and get back on track, I will buy a personal electric train when they are on sale for my transportation.
Can you make the same math for CARGO instead of per person? I thought in your homework the cargo was 10000 T not passengers...

Damn, I can put moderators on Ignore, what a pity!

Last edited: May 25, 2010
14. ### SyzygysAs a mother, I am telling youValued Senior Member

Messages:
12,671
Now let me tell you about transporting/traveling on water compared to dry land:

http://people.hofstra.edu/geotrans/eng/ch8en/conc8en/ch8c2en.html

"Freight transportation is dominated by rail and shipping, the two most energy efficient modes. Coastal and inland waterways provide an energy efficient method of transporting passengers and cargoes. A tow boat moving a typical 15-barges tow holds the equivalent of 225 rail car loads or 870 truck loads. The grounds for favoring coastal and inland navigation are also based on lower energy consumption rates of shipping and the general overall smaller externalities of water transportation. The United States Marine Transportation System National Advisory Council has measured the distance that one ton of cargo can be moved with 3.785 liters of fuel. A tow boat operating on the inland waterways can move one ton of barge cargo 857 kilometers. The same amount of fuel will move one ton of rail cargo 337 kilometers or one ton of highway cargo 98 kilometers."

Are we really good now? A boat is 120% more efficient/economical than train and 8.5 times than trucks....

So my statement that water transportation is way more efficient and economical than on dry land still stands as correct...

P.S.: Further obvious, irrelevant and offtopic discussions of water and train transportations will be ignored.

Last edited: May 25, 2010
15. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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19,248
I see you didn't look at the chart at the bottom of the page on the link you posted...
Well done.

16. ### quadraphonicsBloodthirsty BarbarianValued Senior Member

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9,391
You promise?

Alternatively, you could just stop debating like an insecure high school underclassman, and you wouldn't be subjected to inputs that cause such dissonance in you.

17. ### ElectricFetusSanity going, going, goneValued Senior Member

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18,523
Water provides more friction then air+rails, no doubt about it, plus a propeller is not as efficient as a drive shaft to a wheel. airplanes loose efficiency despite the lack of ground friction because so much energy is "wasted" keeping the plane in the air, a 250 ton 747 must move the equivalent of 250 tons of straight air down in order to fly ever second.

18. ### iceauraValued Senior Member

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30,994
Electric power is ideal for most of them - low mileage, lots of idle time, starting and stopping frequently - that's where the regenerative braking and lack of power consumption while stopped are most advantageous.

You seemed to be under the misapprehension that battery power was incapable of powering heavy vehicles. That was a significant counterexample. The battery powered switch engines in your local rail yard provide another.

Water resistance is much greater, and increases much more rapidly with speed, than rolling and air resistance, so the speed comparison is irrelevant. The 400k range would be much longer, not shorter, on dry land.
The argument was that performance suffered from switching to electric power. The Tesla counters that.
You are now ignoring the factor you found most important in the initial post on this issue - the speed.

Trucks allowed to travel 10 mph steadily without starting and stopping and idling would be quite a bit more efficient than current trucking - quite possibly getting into ship territory or even better. A train would certainly be far more efficient than a ship, under such parameters of operation.

The point is that anything capable of moving 3000 tons 400k through water is more than capable of handling ordinary weight or size of cargo on land.

19. ### SkepticalRegistered Senior Member

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1,449
Re water versus land transport.

I support syzygys here.

It is not a simple equation. Resistance to movement through water varies enormously depending on various factors. However, a large ship travelling at or below displacement speed will expend less energy per tonne kilometre for its cargo than any land vehicle.

If the vessel is a small planing boat, such as a jet ski, the equations are very different.

Strangely, the most efficient in terms of energy per tonne kilometre is a submarine. This is because the drag at the air/water interface for a floating vessel is greater than the drag of a fully submerged vessel. Some submarines are capable of amazing feats, though finding out exactly what is almost impossible, since these are military secrets. Certainly military submarines are capable of more than 70 knots, while expending relatively little energy for their size and speed.

20. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
People, keep focus and stop the stupidity specially if it was already answered:

For a taxi? The average NYC cab traveled 141 miles per shift in 1990:

http://www.schallerconsult.com/taxi/taxifb.pdf

So today's EVs wouldn't make through one shift, since that miles increased since 1990..

My hairy ass. On dry land. Haven't I just proved that it is way more energy efficient to move heavy shit in water, thus it is easier to do so for batteries too??? Bringing up submarines is stupid...

Where is my electric truck when I need it? oh wait, there is no such a thing...

So where is my electric TRUCK??? Did you steal it???

21. ### SyzygysAs a mother, I am telling youValued Senior Member

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Well, thanks but I think simple logic, facts and knowing 6th grade physics should be fine for my support.

Anyhow, I kind of moved on so unless we can get back to electric cars (for by the way I provided better support than the advocates), I am not interested in passenger average, speed factors and such...

The real question is how low the Li-ion battery's price can come down, before another oil company buys the patent rights...

With the NiMH batteries there hasn't been any improvement in the last 8 years....(and they were actually quite decent back then)

22. ### SyzygysAs a mother, I am telling youValued Senior Member

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12,671
Hey, I did find an electric truck! It isn't an 18 wheeler and has several limitations (price 3 times of diesel truck, 100 miles range,speed) but it is a truck:

http://blogs.forbes.com/energysource/2010/05/13/special-delivery-via-electric-truck/

And also proves my point of batteries not carrying heavy shit on dry land for very far....

"Navistar's new electric truck, called eStar, which is being unveiled today. When Navistar surveyed customers like utilities and package and snack delivery companies it found that 82% had daily routes less than 100 miles. Enter eStar, which can go 100 miles on a charge. Its battery is an 80 kilowatt-hour lithium ion battery made by A123 Systems that powers a 70-kilowatt motor (that translates to a pretty puny 93 horsepower). A full recharge takes eight hours. Top speed: 50 mph.

The thing isn't cheap, at least for now. It will cost $150,000, compared with$50,000 or so for a similar sized truck. "

23. ### kororotiRegistered Senior Member

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252

Really, if oil companies are buying up the rights, it can only be motivated by some kind of collusion. Otherwise, why would any one oil company bear the full financial brunt alone for keeping a tech off the market, when all the oil companies stand to lose together? At the very least, it's a predatory business tactic. But, nobody in the government is going to take action unless the public is sufficiently outraged to force their hand.

So, the problem starts and ends with public support.

True, but the Tesla has to have a successful run, or the 10 year thing will never happen.

Lol. I think that got thirty straight seconds of laughter out of me. Poor Linux.