My Biggest, Baddest Rant - triple digit mileage

[tjr]

OK, just one more

So if a Tesla uses about 200 watt-hours per mile, and the better AA NIMH rechargeables hold about 3ish watt-hours, if I charged up all the ones I have around the house and put them in an electric car, I could drive about half a mile. Hmmm.

Or, the batteries in my solar landscape lights hold about .8 watt hours each. With 2 per light, after a really sunny day I could take all the batteries out of my 18 light set and go a quarter mile. Double hmmm.

Or for those of you with really nice 18V power tools with like 4 amp hour batteries, you could go a third of a mile on one battery. Triple hmmm.

A serious question: is the 200-250 watt hours the amount of energy drawn from the battery or the amount of energy used to charge the battery sufficient to go 1 mile? I would think there's got to be at least some energy lost in the charging process.

[Kristofor]

It would make a lot more sense to me to show miles per KWH. In the example shown that would be roughly 3.

That would be better. Better yet would be KWH/mile rather than the other way around. This would also be more helpful with gasoline powered cars.

Which is a bigger improvement? A 30% improvement going from a 10MPG truck to a 13MPG truck or a 50% improvement going from a 20MPG sedan to a 30MPG sedan? You reduce consumption by 35% more going from a 10MPG truck to a 13MPG truck.

It's much more transparent for the math-challenged in our society (call it 90% of the folks) when you say which will save more going from 0.100GPM to 0.077GPM or going from 0.050GPM to 0.033GPM?

[Alex Franke]

Working out the cost per mile, which is the correct metric, requires dealing with sometimes sizable variations in local electricity and gasoline prices.

I'm not sure that is the correct metric. It seems like the type of fuel consumed (and where it comes from) is increasingly important to consumers - especially the younger ones. Come to think of it, probably even more so to their target demographic. If you're thinking about buying a hybrid or electric car, then you're probably not just thinking about cost per mile. . . .but that's just a guess. I'm not thinking about buying one, so I don't know.

[Kristofor]

I'm not sure that is the correct metric. It seems like the type of fuel consumed (and where it comes from) is increasingly important to consumers - especially the younger ones.

Then the problem is one of accounting for the various fuel sources. Under a proper rate structure the cost should be the metric of value, and the cost should include all of the costs associated with that energy...

If solar costs 20 cents per KWH to produce and coal fired electricity can be made for 4 cents plus 14 cents of remediation cost then we should still be burning coal not making solar panels. Our problem is that we don't have a good way to determine specifically or with certainty what those external costs actually work out to be.

[TB Roye]

I heard on the Newa this evening that the Volt will cost about 40k for a small car. My question is can it go from Sacramento to Winnemucca Nevada at 75 mph (the speed limit) in 4 and a half hours, right at 320 miles? How long whould I have to stay there to charge it. Could it climb up hwy 80 over the Sierras or the passes in Colorado? Good try GM but it is not for me. If the vehicle cant' go 400 miles at Freeway/highway speeds then I don't need it. Tomorrow morning I leave for Meridian Idaho (550 miles) It will take about 8.5 hrs driving time but I will only get 17.5 mpg. I could almost make it on one tank but whould run out of gas in the middle of nowhere Nevada. If I had a 35 gallon tank I could make no sweat. Once on the return trip I made it to Reno Nevada before filling up had 2 gallons left and a 130 miles to go had LOML screaming the last 100 miles. I beleive we are still a long way aways before we get the Green car the will work, as a comuter car or short distance car they are fine but in the west a 4 hour drive is no big deal, for some that is a normal comute.
I also think they are going to have to come up with a better mileage rating system for these new vehicles so people can understand the mileage.

Tom

[mpc]

From what I understand, that 230 MPG rating is based on "most folks commute under 40 miles per day" so that was used in the "city" rating: the Volt can go most, if not all, of that distance on an electric charge and won't run the gas engine much. Okay... so if you drive 80 miles instead, it'll use the gas engine for MUCH more time... and you'll achieve typical mid-size car MPG ratings.

This particular example of "city MPG" computations is very misleading. And how similar is it to the "regular" city MPG used on all others up to now? The Prius might get a triple-digit MPG rating too if it were computed/estimated based on a short & slow drive.

As everybody else has pointed out, this 230 MPG rating neglects the other source of energy used to power the vehicle. Okay, what about non-gas cars today? Using the EPA's new "logic" my folks should say their big RV get's "infinite gasoline MPG" since it's diesel powered.

mpc

[jussi]

Well you're not the only ones confused on how to measure the energy-cost usage of these vehicles. The EPA isn't very certain as well. The way the Volt works is that the wheels are connected directly to the an electric motor. It can run about 40 miles on the battery alone on (what GM calls) average. If you have a lead foot and drain the battery faster the gas serves to recharge the battery. Now based on the EPA's current standards, the Volt can finish most of the mpg test using battery power alone. Thereby giving it a large mpg value. But I think they want to redesign the test so that the battery has to be fully charged throughout the test which will dramatically lower it's mpg rating.


Btw I hear Nissan is coming out with the Leaf (I think that's what it will be called) which claims 300+ mpg. And the kicker is it runs completely on battery power. They used some sort of electrical to gas usage to get that number.

[crokett]

This is yet another example of the law not keeping up with the technology, but you'd think they would have seen it coming. As for all electric cars keeping up with tradtional ones, I am not sure they will ever be able to. A car with a combustion engine that burns something like hydrogen might.

[cabinetman]

Loring you gotta get more current (pun). The newest fad will be perpetual motion. Better yet will be the phartmobile, which will be powered by methane gas, indigenous to the driver. Also under consideration is wind power. Of course on calm days you can't drive anywhere.
.

[tseavoy]

You hit my hot button on this one.
I am also an engineer, an electrical engineer. When quoting the efficiency of a system, the whole system must be considered, not just the part the moves the people and goods. That plug used to connect the car battery to the charger has energy coming from either a hydrocarbon plant burning anything from natural gas up to the heaviest variety of oil or coal, a nuclear plant, a hydro power plant, a windmill, or whatever. The majority of electrical energy in the US is made from hydrocarbon fueled steam plants. The last time I looked the efficiency of these plants was about 35 percent using 1000 psi steam at 1000 degrees Fahrenheit, about the same efficiency as a modern diesel engine. This is without transmission losses.
It is interesting that with hydro power being the cleanest form of energy, there are people in this neck of the woods trying to get dams torn down.

Tom on Marrowstone

[Garasaki]

I'm not really sure what the proper way to quote energy requirements for a adaptable mixed-energy input vehicle is. Perhaps its a range of cents per mile at so-many dollars per gallon for gasoline and so many cents per KW-hour.

I'm sorry, I have to say I didn't read the whole thread.

But what you point to here is exactly the heart of the problem. You can have huge MPG numbers but still use the same or more "source" energy.

What comes to mind for me is converting everything from "miles per gallon (of gasoline)" to "mile per universal unit of energy". For instance, you could easily convert both kWh and gasoline to BTU's. Of course that's an antiquated english measure of energy...but then again so is miles AND gallon so it would fit right in.

Anyway that would be a way to compare apples to apples going from conventional full gas cars all the way to complete electric cars.

[jking]

I'm not sure that is the correct metric. It seems like the type of fuel consumed (and where it comes from) is increasingly important to consumers - especially the younger ones. Come to think of it, probably even more so to their target demographic. If you're thinking about buying a hybrid or electric car, then you're probably not just thinking about cost per mile. . . .but that's just a guess. I'm not thinking about buying one, so I don't know.

While I understand & agree with your point that the type of fuel used is important to consumers, Loring is dead on here. Claiming 230mpg for what is primarily an electric car is misleading at best, some might call it fraudulent. Mpg's are easily related to because it is what everyone has been conditioned to understand. But using mpg's for the Volt simply perpetuates the ignorance most people has went it comes to where electricity comes from & the resulting pollution. Most people don't think about the plant that generates the electricity because it isn't something they see directly. They just know it comes into the house on a line & they get a bill. Similar to how many with no rural background think all food just comes from the grocery store.

What they probably should be giving is a Kwh/mile and then give some kind of an average cost/mile to go with it. They really need to be more proactive in educating the public because there is potential for large backlash if large segments of the population start buying into the concept of electric cars & then complain when they see the large increase in their electric bills that result.

[tjr]

Another shocker for a lot of consumers is gonna be when they buy one of these and find out it needs something like a 220V 50A connector in their garage to charge it. Can't imagine that would be less than $500 plus a permit to have an electrician install. And what about those who live at rentals?

On the other hand, that would be one way to sneak 220 service into the garage to run the power tools without the Mrs. squawking at the price...

[LCHIEN]

... Similar to how many with no rural background think all food just comes from the grocery store.

....

of course it does. Do you think groceries grow on trees and plants?

...

On the other hand, that would be one way to sneak 220 service into the garage to run the power tools without the Mrs. squawking at the price...

I love you guys... always thinking about woodworking.

[Russianwolf]

Okay, I've attached our current EPA label for reference. I don't think much needs to be changed on the label, but the testing would need to be altered.

1) Give the vehicle a set amount of charge and gas. Say 1 kwh and 1 gallon (or whatever so they are fairly equivalent in energy content).
2) Drive vehicle on a CITY test course. (Have 10 drivers do the course with various styles to get averages.
3) Continue running the test course until the vehicle runs out of fuel.
4) take total mileage and divide by 2 (since we have 1 kwh and 1 gallon) to get it's consumption rate.

Repeat for a Highway test course.

Now, Fill out the EPA form as is , but you need to add a kwh price to it also. And change MPG to Mileage.

As long as you use the same measure for all vehicles, and you don't change the estimated price for the energy sources, then the label will keep the playing field fairly even.