BS: 230 mpg

Subject: BS: 230 mpg
From: dick greenhaus
Date: 12 Aug 09 - 06:57 PM

Has anyone besides me done the arithmetic on claims for the soon-to-be-new Chevy Volt? It's an electric car with a back up 53KW gasoline-powered charging system--you plug it in to a power line at night and it's supposed to have a range of some 40 miles without recharging. After 40 miles, the engine starts up and recharges the batteries.

Now, the chhrging system is a 53 KW generator. It it were 100% efficient, it would require an eighty or so hp gas engine to run it.
And, once you've passed that initial 40 miles, you're effectively running the car on the gas engine, with a generator and electric motor acting as intermediaries. How in hell does that get the claimed 230 mpg? Or have I made a mistake somewhere?

Subject: RE: BS: 230 mpg
From: catspaw49
Date: 12 Aug 09 - 07:15 PM

I wondered the same thing Dick but I'll assume there is a lot of engineering here I don't understand. That said, I think GM is also full of crap. Yeah.......I'll drive it on gas and charge it and then I'll run on the juice til I need to recharge and then I'll drive it on gas and charge it and then I'll run on the juice til I need to recharge and then I'll drive it on gas and charge it and then I'll run on the juice til I need to recharge and then........yeah, right.......

Like you, it seems this would take a lot more gas engine than they're talking at the moment.

Spaw

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 12 Aug 09 - 07:59 PM

This article tells you how the figure was calculated.

Volt 230

Look at the factors and assumptions and see if you agree with the calculation.

It does not apply to highway driving, or to extended driving in the city.

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 12 Aug 09 - 08:10 PM

A good discussion in the Montreal Gazette.

First Drive

Full production not until 2011.

Subject: RE: BS: 230 mpg
From: Bill D
Date: 12 Aug 09 - 08:33 PM

230 is absolute top possible under ideal circumstances... I'd be happy with 163.837! If it comes anywhere close, we are on the right track.

Subject: RE: BS: 230 mpg
From: dick greenhaus
Date: 12 Aug 09 - 08:44 PM

A bet, if anyone wants to accept it. Five bucks says that, on the road, it won't beat 60 mpg. Which would be pretty damn good for an 80 hp 1 1/4 liter engine engine propelling a whole lot of weight.

Subject: RE: BS: 230 mpg
From: Janie
Date: 12 Aug 09 - 08:46 PM

Bring 'em on, regardless.

Of course many are in the same boat as me....I may be able to afford a hybrid once it is 15 or 20 years old....

Subject: RE: BS: 230 mpg
From: BaldEagle2
Date: 12 Aug 09 - 09:03 PM

The trick is, that for the first 40 miles (on average) of any drive, the petrol consumption will be zero.

If you drive less than 40 miles, and recharge before the next trip, you now get to go 40 miles before the petrol consumption starts to count.

If you only did a 40 mile round trip to work and back each day, after 6 days you would have 240 miles on the odometer, and your petrol tank would be as full as it was first thing Monday morning.

GM has factored in that during this theoretical week you did actually use just over a gallon of petrol - hence the theoretical 230 mpg.

Which is somewhat misleading, for they should be required to give the equivalent petrol usage "consumed" by each of the battery recharges, don't you think?

Regards

BE2

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 12 Aug 09 - 09:14 PM

The first article I linked cannot be raised now.
It had several assumptions, and would have been one of those "maximum-possible" figures.

The second article linked gives access to other articles worth a look.
The battery will have a 10-year life.

The lithium battery, by the way, uses the technology of Exxon-Mobil, one of whose subsidiaries has devised a new membrane that simplifies anode-cathode separation, and other improvements.
Electric car program

Subject: RE: BS: 230 mpg
From: robomatic
Date: 12 Aug 09 - 10:28 PM

I took a look at the link Q posted. The only way that makes sense is if GM is assuming that the cost of electricity is close to free. What they may be overlooking is that you don't charge a battery in an instant, the power is a multiplication of volts times amp which equals watts, and you pay the electric company by the kilowatt hour. A kilowatt is equivalent to about 1.3 horsepower, so a 50 kilowatt electric motor is roughly equal to a 60 horsepower gasoline motor. You shouldn't lean on this too much because electric motors can be made to put out a great deal of low rpm torque, meaning that an electric motor of surprisingly low horsepower can compete with gas motors at low to moderate speeds. So if you are expending 50 horsepower over an hour, you've consumed 50 kilowatt hours of electric 'juice'. A medium price for a kilowatt hour is 20 cents. So you've gone an hour using your 50 kilowatt electric motor , and consumed say 10 bucks of electricity, the cost of replacing that 50 kilowatt hours. If your car will go 60 miles an hour with that motor, you've spent 10 dollars to go 60 miles, How much gasoline will $10. buy? These days in my neck of the woods, you can get 3 gallons. So your equivalent is about 30 miles to gallon, which is good but not great, and far far from the kind of thing GM is talking about.
On the other side, you may be able to go faster on less horsepower, and I think you can shoot for an energy equivalent of 100 miles per gallon, but I'll be very surprised if the Chevy Volt achieves this.

Batteries don't charge for free, they don't charge with perfect efficiency, and they have a major efficiency problem when they are drained too fast. You might be able to drive 40 miles at some stable speed like 40 mph, but if you pass somebody at 60, you might have now reduced your range by HALF.

Anyway, that's the way I look at it. The math is pretty simple.

Subject: RE: BS: 230 mpg
From: Peace
Date: 12 Aug 09 - 10:30 PM

Yeah, easy for YOU to say . . . .

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 12 Aug 09 - 10:50 PM

The problem with all of these vehicles is insufficient power for mountain roads and the fact that over the long distances here in Alberta-British Columbia, gas must be used; important considerations for many westerners.
No problem for the city driver. It may be OK for him.
The cost of the Volt vehicle is est. $30,000 or more.

My old 1995 Jeep Cherokee does about 18mpg on the highway, has plenty of power with its 4litre engine, hauls a lot including dogs and gets me there comfortably. It has been maintained and should be good for another 10 years. Its trade-in value is essentially zilch, so any new vehicle means a large outlay.

Two years ago I got rid of my second car, another Cherokee bought in 1985. If one maintains his vehicles, they are good for a long time.

The new hybrids and electrics are interesting, but not for me.

Subject: RE: BS: 230 mpg
From: Barry Finn
Date: 12 Aug 09 - 11:31 PM

Have they explained that the sails are made of dacron?

Barry

Subject: RE: BS: 230 mpg
From: Peace
Date: 12 Aug 09 - 11:33 PM

I thought Dacron was in Ohio?

Subject: RE: BS: 230 mpg
From: Peace
Date: 12 Aug 09 - 11:36 PM

"General Motors Co. is touting the 230 mpg figure following early tests that used draft guidelines from the Environmental Protection Agency for calculating the mileage of extended-range electric vehicles.

The EPA guidelines, DEVELOPED WITH HELP FROM AUTO MAKERS [emphasis added], figure that cars such as the Volt will travel more on straight electricity in the city than on the highway. If drivers operate the Volt for less than 40 miles, in theory they could do so without using a drop of gasoline.

Subject: RE: BS: 230 mpg
From: Bill D
Date: 13 Aug 09 - 10:46 AM

Well, if *I* had one, it might get 500MPG, averaged over a few years. Who wants to subsidize me for the trial?

Subject: RE: BS: 230 mpg
From: Paco Rabanne
Date: 13 Aug 09 - 11:29 AM

I don't have a car (automobile for our colonial chums) I have a Brompton S2L folding bicycle, and my wife has the same. We find that with the judicious use of England's railway network, and a smattering of Latin based languages, we can go to Seville and back using zero MPG.

Subject: RE: BS: 230 mpg
From: Bobert
Date: 13 Aug 09 - 11:45 AM

Well, I'll let a few other folks fork over 40 grand for these flashlights with wheels...

I reckon, like everything else that is new, if they work then wait a year and the price will be half that... Wait two years and you'll get one for the cost of a BIC lighter...

But seriously, I do hope it works... Not because I like Chevy's, which I don't, but because it will be another step closer toward tellin' the Saudis "No, thank you..."

B~

Subject: RE: BS: 230 mpg
From: Bee-dubya-ell
Date: 13 Aug 09 - 01:05 PM

Stating the efficiency of electric cars in miles per gallon of gasoline when, in fact, no gallons of gasoline may ever be consumed, is a bit of hocus-pocus created by the auto industry because they think we're too dumb to wrap our heads around the idea of miles per kilowatt-hour of electricity. Well, if I were considering buying an electric car, MPK-W/H is precisely the figure I'd want to know. How much is it going to cost me in electricity to fully charge the batteries for 40 miles of driving? My Corolla will go 40 miles for $3.00 at current US gas prices. If it's gonna cost anywhere near that to charge a Volt's batteries, someone's gettin' sold a bill of goods.

Anyway, considering that most electricity in the US is generated by inefficient coal-powered plants, would the environmental impact of operating a grid-fed electric car really be any less than that of a gasoline or diesel powered car with a highly efficient engine?

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 13 Aug 09 - 01:10 PM

South Korea's LG Chem subsidiary, Compact Power of Troy, MI, has been selected to build the batteries for the Volt. A new lithium battery facility, operated by GM, will be built at a yet unannounced site in Michigan.
In conjunction, the University of Michigan is developing a curriculum for battery engineers.

From various news reports yesterday and GM press release.

Subject: RE: BS: 230 mpg
From: open mike
Date: 13 Aug 09 - 02:14 PM

if you ride on a train using diesel fuel to operate
you are using SOME mph to get to your destination.

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 13 Aug 09 - 04:21 PM

The more miles per hour the quicker ...

Subject: RE: BS: 230 mpg
From: catspaw49
Date: 13 Aug 09 - 06:51 PM

Am I the only one who can't help but think about perpetual motion when I read this stuff? I'm sorry but each page has a flashing sign at the top saying, BULLSIT....BULSHIT....BULSHIT.

Conversely, if the thing gets a third of what they advertize it will show promise. But as a commuter car for a lot of Americans, it will need to go a lot farther and a lot longer. And let's not forget this company gave us the Vega, Chevette, and all those 5.7 diesels that were going to save the planet as well.

Spaw

Subject: RE: BS: 230 mpg
From: catspaw49
Date: 13 Aug 09 - 07:06 PM

LMAO....I guess my bull has to sit before he can shit....LOLOL


Spaw

Subject: RE: BS: 230 mpg
From: dick greenhaus
Date: 13 Aug 09 - 08:39 PM

Another point that everyone seems to miss is the the holy measurement--miles per gallon--is a lousy one. Look at some numbers--if you drive, say, 15000 miles each year and your old clunker got 10 mpg, you'd burn 1500 gallons of fuel yearly. Switching to one that got 15 mpg, you'd burn 1000 gallons per year. From a 50% improvement in mpg.

Now consider that if you had a car that got 30 mpg, and switched to one that got 60 mpg--a 200% improvement, and drove the same 15000 miles per year, your yearly consumption would go from 500 gallons per year to 250 gallons per year--a saving of 250 gallons. From a 200% improvement in mpg. In fact, if you started with a 30 mpg car and switched to one that got a million miles to the gallon, your savings would be less than what you got from switching from 10 to 15 mpg.

Gallons per mile--or per 1000 miles--is a much more meaningful statistic.

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 13 Aug 09 - 09:26 PM

The U. S. Government fuel economy comparisons (subject of previous threads) is a good way to compare costs and fuel use. Most vehicles are included in the tables.

Using Chevrolet 2009 as an example:
Malibu 2.4l 4cyl auto- City 22, Hwy 33, cost $1409/15000 mi.
Malibu 3.5l 6cyl auto- City 18, Hwy 29, cost $1665/15000 mi.
Malibu hybrid 2.4l 4cyl auto- City 26, Hwy 34, cost $1263/15000 mi.

A mid-size SUV- Jeep
Cherokee 3.7l 6cyl auto 4wd- City 15, Hwy 20, cost $2152/15000 mi.
Patriot 2.4l 4cyl auto 4wd- City 20, Hwy 22, cost $1742/15000 mi.
'Clunker'
(1985 Jeep Comanche, 2.86l 6cyl auto- City 15, Hwy 17, cost $2288/15000 mi.)

US Fuel economy

Subject: RE: BS: 230 mpg
From: robomatic
Date: 13 Aug 09 - 09:56 PM

If you are interested in seeng how much it costs to charge a vehicle, you have available from your utility the cost of electricity which is usually price per kilowatt hour which can be lower than 10 cents in some states served by hydro (who have paid off the capital costs) and as high as 30 cents or more.

Your car battery will have an energy storage in kilowatt hours as well. Your charger should be at least 80% efficient, so you can pretty easily calculate what a 'tankful' of electricty costs. What you need to find out more practically is how far you can go on a tankful. Once you do this, you can tell what you're paying per mile. In theory your maintenance costs for an electric motor should be way lower than for a standard mechanical engine car, BUT, if you're driving a hybrid, you still have a mechanical engine to deal with. BUT, the mechanical engine should require less maintenance over the years than a regular auto because the car computer will try to run the fuel engine at constant rpms for charging purposes, which causes less wear.

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 13 Aug 09 - 10:59 PM

The Volt battery pack is est. 16kWh capacity, but it is only charged to 85% full and is discharged to 30% SoC approx, before the engine cuts in. When the vehicle is plugged into a charger the battery SoC is restored to 85%. Hence the battery has an effective capacity in use of 8.8 kWh.
This taken from Wikipedia.

I'll let you sharp mathematicians figure out the cost of a charge.

Subject: RE: BS: 230 mpg
From: Peace
Date: 13 Aug 09 - 11:07 PM

"I'll let you sharp mathematicians figure out the cost of a charge."

Robomatic, that's your cue.

Subject: RE: BS: 230 mpg
From: kendall
Date: 14 Aug 09 - 06:25 AM

If this question was covered I didn't see it. ...when the battery is depleted the engine starts... How?

Subject: RE: BS: 230 mpg
From: Q (Frank Staplin)
Date: 14 Aug 09 - 02:55 PM

Kendall, a little mouse starts up on what I once heard a kid call a merry-go-wheel -

Subject: RE: BS: 230 mpg
From: dick greenhaus
Date: 14 Aug 09 - 07:28 PM

Thee 230 mpg claim reminds me of a friend who raced a go-kart at Nassau Speed Week back in the 50s. He claimed an average speed of 350 mph---because most of the trip was by plane.

Subject: RE: BS: 230 mpg
From: robomatic
Date: 15 Aug 09 - 04:05 PM

Okey doke. It's a fair cop to describe the battery the way Q described it. If it was a gasoline tank, there's be a bit at the bottom you're never gonna get to, so when you're told you have an 'X' gallon gas tank, that's a start, but unless you drive to exhaustion and manage to fill up, you're never gonna know for sure. (I know for sure with my car!).

Back to the battery. Accepting the 8.8 kWH (kilowatt - hour) figure, let's talk about that. In basic terms, that means it will put out 8.8 kilowatts of power for an hour. In THEORY it means it will put out 4.4 kilowatts for TWO hours, or 17.6 kilowatts of power for a half hour. Due to the realities of chemistry, the reality is the rate of power use directly affects the capacity of the battery AND it's lifetime. The manufacturer will have standardized on the most likely power draw the battery is expected to provide. For argument's sake, and because it may even be close to reality, let's say the battery will actually put out 8.8 kWH for an hour:

8.8 kilowatts is about 11 horsepower. That may be all that is required to overcome air resistance once you are up to speed. But how do you get up to speed?

By applying more horsepower, hence more kilowatts. If you've got say a 50 kilowatt motor, you can accelerate, as you English say, jolly fast. You will also suck out electric power out of battery real fast, but this will occur over a period of seconds, hence it will not necessarily be a noticeable battery killer, (note of faith, a competent battery designer will have designed the battery to take this kind of use becaust it is absolutely part of the known requirement to drive a car).

So you get up to speed and need about 10 horspower to push the thing against friction and wind resistance. Wind resistance and the car's drag coefficient will determine the speed you can reach. Wind resistance is related to the front of a car's cross sectional area and increases as the square of the car's velocity relative to the air. (Wind resistance is also related to the overall skin area of the car, but the relationship is less critical).

How about going up and down hills? Going up a hill will increase that horsepowe draw in a predictable manner, because you are fighting gravity and that is easy to calculate. You then have to know how long the battery can supply that extra current and you'll get a good idea of how much range you've lost. Going back down a hill may or may not allow you to recover a portion of the potential energy depending on whether or not the car uses regenerative breaking. Toyota Prius is designed that way. It's hard to imagine an electrical engineer who would design (or buy) an electric car without regenerative breaking, but it makes for a more complicated design.

This explains to me why the Chevy Volt has such limited electric range (40 miles) because of its 11 horsepower for an hour availability to do work.

All of the physical constraints on moving around apply to gasoline just the same way as on electricity, but gasoline (and petrochemicals in general) is one of the best ways to store a huge amount of energy in a small amount of space. We sort of live in a fool's paradise of cheap easy abundant energy. Batteries while they CAN be very efficient are only efficient at certain rates/ temperatures/ conditions of use, and they are not able to store energy in a 'dense' way, so that 8.8 kilowatt hour of available energy comes at a high weight.

This is not at all to put down electric vehicles. I'm just attempting to summarize a 'state of the art' snapshot. I've thought of getting a Prius many times to celebrate my crid-life misis!

Subject: RE: BS: 230 mpg
From: Peace
Date: 15 Aug 09 - 04:08 PM

Thank you.