Official 2011 Chevrolet Volt EPA Fuel Economy Released

[Lyle]

Its official. 35 miles EV range. 35/40 mpg (37 mpg combined) in charge-sustaining mode:

http://gm-volt.com/2010/11/24/offici...nomy-released/

[Rusty]

And, just for grins, it appears to have the same discrepancy in the MPGe that the Leaf has.

(15000/100)*36*.12 = $648 (miles/100 * MPGe / cost, sticker says $601)

For CS mode, same equation is:

(15000/37)*3.2 = 1297.3 (close enough to $1302)

Leaf, using same equations, is:

(15000/100)*34*.12 = $612 (EPA says $561).

So they're both off from what I'd expect by around 8% low. What am I not understanding? Has EPA documented its EV rating method? At least they were kinds enough to not try and do a combined CS/CD rating!

[Raymondjram]

The EPA did the right step again, posting an average annual cost for gas and electric modes. As I posted before, most car buyers want to know how much would it cost and save to drive a Volt, and this EPA label gives them the information they want. Most Volt buyers are better educated and technically prepared to understand how the Volt works, but GM needs more buyers in all levels.

Congratulation to Lyle, now that the EPA label is out, GM can deliver the first Volts to buyers. And what would Lyle do now, having his own Volt delivered while still driving the CAB loaner? I recommend giving the purchased Volt to his wife while staying with the CAB loaner until the trial period is over next year.

[rhodomel]

IS THE 36 KWH/100 MILES rating based on the energy stored on the battery or on the amount of electricity used to recharge the battery? It is better to have the outlet kWH per 100 mile rating posted in the EPA sticker than the battery's kWH per 100 mile.

[ChuckR]

Rusty,

The EPA sticker says they used 11 cents per KWH not 12. That doesn't get $601, but it's closer at $594. Maybe the 36 KWH/100 miles is a rounded number.

[Rusty]

Rusty,

The EPA sticker says they used 11 cents per KWH not 12.

You're right, it does. I'd look at the Leaf's (and just did again), and it says $.12. That mostly makes up the difference (probably enough to get to rounding error).

Is it just a typo on the Leaf's label? I'll re-run the numbers after lunch...

[ChrisC]

I'm so glad to see that they included a value for kWh per 100 miles. Maybe this will be the beginning of the end of the MPG illusion. I know, dream on

Good to see that that table in the lower right corner made it onto the sticker, although I'm not sure I like the cents per mile metric.

As Lyle noted at the very end of his article, it seems that the usable battery capacity has now bumped up to 12.9 kWh. THAT is a pretty big step up from 10.4 kWh. However I suspect that this table is showing power consumed at the wall outlet, not what's getting drained out of the battery. The difference is the efficiency of the charger. This makes sense because the context of that table is to provide information on how much it really costs to operate the car.

This probably applies to the other kWh numbers too, like the 36 kWh per 100 miles figure.

[Rusty]

Good to see that that table in the lower right corner made it onto the sticker, although I'm not sure I like the cents per mile metric.

I read that and thought "metric miles? What's he *talking* about??" :-)

As Lyle noted at the very end of his article, it seems that the usable battery capacity has now bumped up to 12.9 kWh.

Rerunning the calculations using $.11/kWh (thanks Chuck!) my table now shows:

Leaf: kWh/100 = 34.00 (EPA 34), MPGe = 99.118 (EPA 99). If I calc battery by range*kWh/100, I get 24.82 kWh.
Volt: kWh/100 = 36.42 (EPA 36), MPGe = 92.521 (EPA 93). If I calc battery by range*kWh/100, I get 12.75 kWh.

Those numbers I can live with, in terms of consistency of data. Note that battery margin of error is 1.4% for Volt, .68% for Leaf.
Using the same miles/(cost/gas-cost) method gives 36.866 MPG (EPA 37). Using the 12.9 kWh/charge figure yields a range around 35.4 miles.

[Rusty]

In the blog, you say

6. 60 MPG is the official overall combined number (MPGe + MPG) of fuel economy behavior over lifetime of the vehicle. [snip] This is the highest, of course, in the segment.

Are you saying highest in the EREV segment, or highest in the compact car segment?

The ranges are pretty large here, from 14 MPG to 60 MPGe. Likewise the Leaf's comparison range is for midsize cars, range 9 MPG (senseless, if they're talking EV) to 99 MPGe.

I think that 60 is compared to ALL compact cars, not EREVs. I believe the Prius is a midsize car. At 50 MPG it would now be second in its class, and third overall...

[Lyle]

In the blog, you say


Are you saying highest in the EREV segment, or highest in the compact car segment?

Compact car. That was GMs statement.