EPA Ratings - when?

[Freyar]

It comes from the fact that there is 33.7kw of chemical energy in one gallon of gasoline. In a ICE less than a third of that energy is converted into usable mechanical energy. Most of it is lost as waste heat.

Good to know about that. Helps reframe the argument, though if I'm understanding it right, I imagine this law behind waste heat is not really something that comes to customer's minds (as it didn't occur to me either.)

 

[AZFox]

EPA figures need to be on the Monroney sticker, so they'll be available before you can order your Slate FN.

Are we there Close To Production yet?

 

[AZFox]

I'm thinking just a M/kWh would be a better metric and keep it separate from gas.

Better yet, a more intuitive KWh per mile if it's going to change.

TL;DR: Miles-per-unit can be deceptive. Units-per-mile is inherently more intuitive.

Units-per-mile is more informative for comparison than -per-unit because it measures the amount of energy or resource used per mile, which provides a direct measure of efficiency. This allows for easier comparison between different vehicles or systems, as it shows how much energy is consumed over a specific distance. For example, miles-per-gallon (MPG) measures how far a vehicle can go on a gallon of fuel, while gallons-per-mile measures how much fuel is used to travel a mile. The latter provides a clearer picture of fuel efficiency and resource consumption.​

 

[EVfun]

MPGe is such a weird metric..
To trust it, I'd have to understand how they came to 1 gallon = 33.7kWh, and I have a suspicion it hasn't been adjusted for improvements to the technology.

I'm thinking just a M/kWh would be a better metric and keep it separate from gas.

I agree that using miles per kilowatt hour makes the most sense. We buy electricity by the kWh, we buy gasoline by the gallon (US). So using M/kWh is looking at it the same way as MPG, just with a different "fuel." If the Slate goes 205 miles on a 63kWh pack then it works out to 3.25 M/kWh.

Since there are about 33.7 kWh of energy in a gallon of gasoline, the energy efficiency is equivalent to a gasoline car getting 109.6 MPG (MPGe). We don't really need that, but it may help people mentally transition.

 

[Shay]

Most of the time ratings aren’t posted until at or near the first delivery of the vehicle. The manufacturer most often tests the vehicles themselves under a prescriptive program. They then submit the results of their testing for certification. The EPA itself rarely actually tests vehicles themselves unless there’s a reason to double check what a manufacturer has been saying.

 

[MAUICUDA]

MPGe is such a weird metric..
To trust it, I'd have to understand how they came to 1 gallon = 33.7kWh, and I have a suspicion it hasn't been adjusted for improvements to the technology.


I'm thinking just a M/kWh would be a better metric and keep it separate from gas.

I agree. My 2020 Leaf dashboard shows 4.3 m/kwh. Easiest for me to understand and comprehend.

 

[Kopsis]

The whole MPG-e thing was meant as a tool for computing manufacturer CAFE regulatory compliance, not as a meaningful tool for EV owners. Up until 2010 the Monroney showed efficiency in kWh/100mi. But EPA focus groups found people were too dumb to understand kWh, so they switched to something even more difficult to understand because it had the comforting effect of making people think they wouldn't have to actually learn anything.

 

[ADFX01A]

The whole MPG-e thing was meant as a tool for computing manufacturer CAFE regulatory compliance, not as a meaningful tool for EV owners. Up until 2010 the Monroney showed efficiency in kWh/100mi. But EPA focus groups found people were too dumb to understand kWh, so they switched to something even more difficult to understand because it had the comforting effect of making people think they wouldn't have to actually learn anything.

"Why don't you do what the government does best, find something simple and complicate it!"
Burt Gummer - Tremors 3: Back to Perfection

 

[Johnologue]

I recall hearing one Slate Rep saying they expect the all numbers may be higher in the final version of the truck.

It appears Slate has followed a policy of under-promising, or at least not promising more than they can deliver ("under 20K after -$7500" and "mid-twenties" were vague and safe).
I think they've expressed that as a "value" in some places, so I'm hoping we'll get a few small boosts by the time people are taking deliveries, rather than a few small losses.

The whole MPG-e thing was meant as a tool for computing manufacturer CAFE regulatory compliance, not as a meaningful tool for EV owners. Up until 2010 the Monroney showed efficiency in kWh/100mi. But EPA focus groups found people were too dumb to understand kWh, so they switched to something even more difficult to understand because it had the comforting effect of making people think they wouldn't have to actually learn anything.

Infuriating, especially since we don't measure EV battery capacity in gallons.
"I've got 10 kWh left, how far should that take me?"
"Well, you get 100 miles per gallon!"
"What?!"

 

[Gladstone]

Does having the epa/mpge rating actually matter? I'd rather have real world testing.

I guess the question will be is Slate going to follow Rivian with the R2 and have massively inflated MPGe because they gamed the testing procedure, or will they be closer to Tesla with their new refreshes and exceed rated MPGe in the real world?

Realistically Highway range is going to be very weak, city should be fine/close to what they are projecting.

 

[KevinRS]

I think the reason for the MPGe ratings is probably that people were confused. With gas powered cars, you want a higher number on the MPG.
With electric, showing kWh per 100 miles you actually want a lower number, not a higher number.

Early EV shoppers were also comparing a number like 26 kWh per 100 miles to a gas car at 32 MPG, and thinking the EV must not be that efficient at all.

So to compare actual energy use, the weird MPGe was come up with, and EVs have higher numbers the more efficient they are, and you can compare to gas cars in a way that makes some sense.

 

[AZFox]

The important (but hard to declare on a window sticker) statistic is dollars-per-mile.

 

[Moe]

We don’t use gallons/100 miles so the US shouldn’t use kWh/100 miles. But the EPA persists in publishing it. I guess they want to be continental like liters/100km. So they came up with an even more US meangless measure instead of using the miles/kWh Americans could relate to. IMO But that made a gallon of gas look much better than electricity.

 

[ADFX01A]

We don’t use gallons/100 miles so the US shouldn’t use kWh/100 miles. But the EPA persists in publishing it. I guess they want to be continental like liters/100km. So they came up with an even more US meangless measure instead of using the miles/kWh Americans could relate to. IMO But that made a gallon of gas look much better than electricity.

 

[Rocks]

But that made a gallon of gas look much better than electricity.

The purpose of a system is what it does. And it's doing what the legacy OEMs want, making gas look better.