"Tom" on the engineering forum has created some excellent calculations and graphs reflecting various scenarios. I used some of them to write this article. It appears to me that many Volt enthusiasts don't understand well the real every-day realities of EV range, and how easily it can be affected by various externalities (headwind, grade, speed, etc.)

It's avery different reality than with gas-engined cars. This is my attempt to shed some light on it.

http://www.thetruthaboutcars.com/chevrolet-volt-home-home-on-the-range/

Paul

They don't no diddle;)

Pure gussing on their part.

Have they witness a test? No

Seen the specs of the test? No

With all your and Tom's respect, anyone who create simalution knows those are difficult to reproduce reality even when you have all the data in hand. To create a simulation when you are missing key element is inviting others to chalange your findings. Good or bad.

I didn't reply on Tom's post as this was an exercice, but for you to actually use this and create an article with it... you are streching the truth my friend.

GM is working with Kryptonite, so engineering calculations are meaningless. Seriously, Tom's calcs may be off a couple of miles, but I've done enough research on this issue to know that they're in the ballpark. How do you think engineers came up with the relevant fundamnetals of the Volt in the first place: battery size, aerodynamics, efficiency targets for the components, range? Look, the prototype they showed barely runs (with a DC motor). It's eye candy. The specs for the real Volt were on engineer's computer calculations a year ago or more, and now they're being turned into reality. That's how it works.

And Tom's calculations confirm the basic specs of the Volt: its 0-60 time, and range, under favorable conditions.

I would love to have a GM Volt engineer challenge Tom's calcs. I contacted the Volt PR folks askeing them for some of this info (range at 70mph; 80mph; 3% grade). They didn't respond.

Keep in mind that the testing cycles (EPA city and highway) are at moderate speeds. Run the Volt at a steady 70, 75 or 80, and range WILL melt away quickly, even more so with a wind, grade, or A/C on. Bring on the evidence to show otherwise! Otherwise, don't talk about "real world" conditions. Cars, airplanes, etc. are all designed in the computer. Boeing doesn't use prototypes; the first plane of a new type to fly is a production plane. Welcome to the modern age.

"Keep in mind that the testing cycles (EPA city and highway) are at moderate speeds. Run the Volt at a steady 70, 75 or 80, and range WILL melt away quickly, even more so with a wind, grade, or A/C on." - pnieder

And it doesn't help when GM obfuscates things by saying, for example, that range might be compromised on the highway because you can't take advantage of regenerative braking at a steady speed on the highway. I'm sure you remember that bit of nonsense. It was reported here on GM-Volt some time ago.

"Keep in mind that the testing cycles (EPA city and highway) are at moderate speeds. Run the Volt at a steady 70, 75 or 80, and range WILL melt away quickly, even more so with a wind, grade, or A/C on." - pnieder

And it doesn't help when GM obfuscates things by saying, for example, that range might be compromised on the highway because you can't take advantage of regenerative braking at a steady speed on the highway. I'm sure you remember that bit of nonsense. It was reported here on GM-Volt some time ago.

Isn't it a bit counterintuitive (more like disingenuous) for you to accuse GM of obfuscation on a site that is DEVOTED to preproduction information and discussion on a level unrivaled by any other car company? If you can point to another MFG that has done better, please post their website.
I suspect that you didn't attend the New York get together.
Thanks

Tagamet: If you can point to another MFG that has done better, please post their website.

www.teslamotors.com

The folks that actually work at Tesla have blogs to directly interface with their fan club. It's not all filtered through the gate-keeper Lyle.

Tagamet: If you can point to another MFG that has done better, please post their website.

www.teslamotors.com

The folks that actually work at Tesla have blogs to directly interface with their fan club. It's not all filtered through the gate-keeper Lyle.

And yet you still hang out here.... No "gate keepers" were at the NYC meeting.
Isn't Tesla still working on car #2?

Looks like car #2 is still missing, but #3 and #4 are being worked on. Gee, and only $109K bare bones. Might as well shell out the $120K and get the options. If, of course, they ramp up that output and find a tranny that works.....

Tagamet, this isn't high school anymore, or the old Ford(Tesla)-guy vs. Chevy-guy thing. I'm a journalist; I'm interested in anything new in the automotive field. You asked me a question about web sites, and you got an honest (and accurate) answer. No need to be defensive.

Tagamet, this isn't high school anymore, or the old Ford(Tesla)-guy vs. Chevy-guy thing. I'm a journalist; I'm interested in anything new in the automotive field. You asked me a question about web sites, and you got an honest (and accurate) answer. No need to be defensive.

Sorry, I guess I still remember your article and the reaction it got hereabouts.

This is a very negative post about a vehicle that hasn't even been built yet.

Do you know what ASSUME stands for?

Robert.V,

An objective one sentence summary of the article is that it quantifies the well know limitations of EV’s at highway speeds and on road grades. It cautions a potential buyer to assess his particular driving route relative to that of the EPA pattern.

The simulation for the Volt is a value neutral, engineering estimate. It is dictated by the laws of physics and not philosophical orientation. The methodology for this analysis, when applied to the EV-1 and Tesla, gives results that agree with their published performance numbers. The battery energy for the Tesla, EV-1 (NMH), and Volt are 53, 29, and 16 kWhr, respectively. Their curb weights are 1350, 2250, and 3140 lbs, respectively. The Volt’s single charge range is obviously dictated by the choice of design parameters and users driving profile.

I share your enthusiasm for the Volt. You have no idea of how desperately I want the Volt, and GM, to be a successful. The relevant issues go far beyond the Volt and GM. They go to the moral imperative of not gorging ourselves on cheap fossil fuels at the expense of generations to come and enriching terrorist nations. But, I fear the success of a disruptive technology like the Volt has less to do with the brilliance and hard work of GM's engineers and more with marketing decisions, existing product mix, and legacy manufacturing operations. We're in this together buddy.

OH Crap! This totally sucks. I am out. I have desperately waiting for the Volt to hit the dealers and now I read that the range will VARY depending on the speed.... :eek:
and whether the lights and ac or on.... :eek:

Screw the Volt you won't catch me posting on this site again. I feel so betrayed by GM keeping this information under wraps.

I guess GM should just quit this Volt exercise because its hard??

I am not suprised Dagwood and pnieder feel this way. They are not interested in a GM success based on previous comments.

Tom, I think marketing decisions will be important for the Volt program. How they promote this car to the masses will decide if the Volt will be niche or mainstream. The technology is only limiting if your expectations are too high. I think GM is keeping expectations reasonable. We are aching for solutions to the oil problems. We all need to be careful not to assume too much, either way.

There is way more we don't know about the Volt than we do know. And I am sure GM wants it that way. :)

I think GM knows exactly what their doing.

"It is not certain that everything is uncertain." - Pascal

OH Crap! This totally sucks. I am out. I have desperately waiting for the Volt to hit the dealers and now I read that the range will VARY depending on the speed.... :eek:
and whether the lights and ac or on.... :eek:

Screw the Volt you won't catch me posting on this site again. I feel so betrayed by GM keeping this information under wraps.

You sound like a 16 years old :rolleyes: And you are over reacting.

After over 30 post here and you haven't read anything about this here?

[QUOTE=frankyB;4547]You sound like a 16 years old :rolleyes: And you are over reacting.
QUOTE]

Omegaman66 was abviously being sarcastic.

"I am not suprised Dagwood and pnieder feel this way. They are not interested in a GM success based on previous comments." - MetrologyFirst

I can't speak for pnieder but you are certainly incorrect about me. I am skeptical of GM's chances for success but still interested, just the same.

Thought provoking article. Not sure why it received such a visceral reaction, physics are physics.

Tom, I do have a technical question though. Have you run your Model of the Volt against the US06 driving cycle? I would guess this is what GM is using to base a 40 mile range on. I would be very curious to see what your model predicts. If it is not slightly more than 40 miles, then I would suspect you might need to tweak a few parameters.

Cheers!

US06 Cycle (http://www.dieselnet.com/standards/cycles/ftp_us06.html)

I seriously doubt if anyone's drive to work and back consists of a US06 driving cycle. My interest is in determining what AER would be under typical and worst case highway driving conditions that correspond to my real life. I will take a look at what would be involved in calculating an approximation for USO6. It would involve more than a "tweak." This reminds me of saying we had in R&D - No job is impossible as long as somebody else has to do it.

[QUOTE=Rooster;4716]Thought provoking article. Not sure why it received such a visceral reaction, physics are physics.

Tom, I do have a technical question though. Have you run your Model of the Volt against the US06 driving cycle? I would guess this is what GM is using to base a 40 mile range on. I would be very curious to see what your model predicts. If it is not slightly more than 40 miles, then I would suspect you might need to tweak a few parameters.

Cheers!


Rooster,

I ran the GM Volt against these two 1 Hz profiles: EPA75 and US06. I used a Regen efficiency of 80%.

The Federal Test Procedure(FTP) is composed of the UDDS followed by the first 505 seconds of the UDDS. It is often called the EPA75.

The AERs for the EPA75 and US06 were 42 and 28 miles, respectively. I suspect GM is using the EPA75 for their AER evaluation. If I'm wrong, then I really do need to do some "tweaking." I'll run some 10 Hz profiles to see if there is much difference. The results for these profiles are consistent with my single speed cruise estimates which predict an AER of 40 miles for a cruise speed of 50 mph.

So far, with this vehicle, GM has under-promised and over-proformed. I've got my fingers and toes crossed that it continues right through the early release date.
Be well,
Tag

So far, with this vehicle, GM has under-promised and over-proformed. I've got my fingers and toes crossed that it continues right through the early release date.
Be well,
Tag

The implication is that their AER "promise" is with regard to an EPA75-like driving profile - 40 miles. An "aggressive" driver will get 28 miles. I'm just calculating numbers here. I share the same hopes you do. But if you were GM and you had two numbers with two different profiles, which number would you "promise?"

For more details on AER for three different driving profiles see post http://gm-volt.com/forum/showthread.php?t=581.

The implication is that their AER "promise" is with regard to an EPA75-like driving profile - 40 miles. An "aggressive" driver will get 28 miles. I'm just calculating numbers here. I share the same hopes you do. But if you were GM and you had two numbers with two different profiles, which number would you "promise?"

28 miles is still more then I need for my dealy commute ;)