Will the Chevrolet Volt be a failure or a success?

Yes but that's not what he said. He said he got about 5 mi/kWh from the battery this month and last, which it totally doable, especially in a Leaf that doesn't see much highway time.

I agree but it's interesting to look at the numbers. The Leaf city MPGe rating is 11.5% better than the Volt, almost exactly their weight difference. Hwy, it's only 2% better, close enough that the kWh/100mi highway rating is the same for both cars.

 

That's not how it works at all. The Volt draws 1450 watts constantly, just like a space heater. It's pulling 12 amps on the 15 amp circuit, which is the maximum continuous current you should draw.

 

GM Volt Supply Poised to Surge in Race With Nissan’s Leaf: Cars
Bloomberg July 27, 2011, 2:15 AM EDT

Should be a very interesting 2012!
GM Volt Supply Poised to Surge in Race With Nissan’s Leaf: Cars - Businessweek

 

I got that. The lifetime average is more important. I am sure it'll change as it doesn't have a full year of data accumulated yet.

 

Grid user typically do have waste heat -- at the central power plant. And it is quite uncommon for it to be used.

 

You are wrong here, it works in bursts.

How do you think you get 110volts AC into a couple hundred volts DC? A SWITCHED mode power supply. When it is switching it draws a lot of current. When it is not switching, it draws very little current.

This is very fast, a few hundred kilohertz probably, but it is still pulsed current.

 

Ah, completely not at the scale I thought you meant. I see your point.

 

That 3.7 m/kwh is from the wall - as I said my 5 m/kwh is from the battery in the last 2 months.

When talking about m/kwh of an EV (w.r.t. battery capacity) one talks about battery to wheel. Not plug to wheel. While plug-to-wheel matters when we talk about emissions etc, when talking about EV range, we need to consider battery to wheel.

For eg. when GM was talking about using 8 kwh of the battery to get 40 miles, they were talking about battery to wheel.

 

Hmmm ... the point was ?

 

How did you come up with that? EPA use kWh from the wall to give the rating on the label.

 

Does that mean if I run in Mountain Mode for 15 minutes prior to plugging in so I need less kwh's from the wall that my electric system efficiency will go up? Seems counter intuitive.

 

It seems pretty straight forward right. I don't think GM ever said 8kwh, I do remember speculation of 8.8 kwh usable state of charger and 40 mile range. That the volt can use 9.6 kwh in normal mode, and has power in reserve is an improvement over the whispered volt. Coming in at 35 mile epa instead of the 40 is an over promise. The epa does deflate milage by 30% though, and many owners get 40 miles on this bigger charge. Evnow does get this efficiency from his leaf. I'm not sure why anyone would think gm was only going to deliver only 8kwh recharge capacity, that would be a quite small usable state of charge. As gwmort comments a driver can decide to give the volt a lower useable state of charge, but that doesn't make much sense. evnow is absolutely correct. Then again, i'm not sure how any of this will make the volt a failure or success.

 

Plug-to-wheel matters to the wallet, same as tank-to-wheel.

 

In mountain mode ICE is on, right? so I fail to see how your 'electric system efficiency' will go up using this mode.

 

Do you always challenge EPA rating or only when convenient?

 

The comment I was responding to said the electrical efficiency is measured plug to wheel not battery to wheel.

If the battery is fully depleted, putting the car in MM will cause the car to raise the state of charge to a preset level (idea being to build some extra power reserve in case you need it climbing a mountain soon). I don't know the exact numbers but I usually use for demo purposes: think of full as 86%, "empty" as 35%, and "empty" in MM as 45% State of Charge (when the battery is empty the system generally only makes enough power to maintain that state of charge.

So with a depleted battery if I used MM to raise the state of charge to the higher point before plugging in, any measure of power consumed from the plug would show less energy going into the system so the same miles traveled the next day would show a higher electrical efficiency per mile, of course tracking gas consumption over the same period would show lower gas efficiency.

 

They seem to do pretty well with gasoline numbers these days (ironically by reducing straight test results by as much as 30% through some inscrutable formula I did not have the patience to understand) although engine stop systems should show more improvement than they do. The EV range methodology still needs work IMHO. Personally, I'd like to see results for no HVAC, heat usage, and AC usage too, although I have to acknowledge the window sticker is pretty cluttered already.

It's still nice to have an unbiased source for comparisons though.

 

Well no and yes. I didn't mean to say that the epa number is low, just explaining how its calculated and give an explanation on evnow soundly beating it.

I do wish they added better tests for evs and hybrids and split them out.

I totally agree with you and the epa, that it power consumption should be measured from the wall. The thread had taken a turn to compare efficiency claims with actual efficiency. Those exagerating were comparing claims from the battery to epa efficiency from the wall. You should not do that.

 

Only when they do not fit his EV apologist agenda.

 

You "think" wrong.

Google '8 kwh 40 miles site:gm.com'
Since GM kept up the BS for years, there are dozens if hundreds of links to refresh your memory.