EPA efficiency rating confusion

[Vette2Lucid]

Hey crew, here's my first question for the forum, and included in it, hopefully some consolation for my fellow owners:

My AT with 19s has a quoted range of 425 miles, and the battery pack is indicated to be 92kWh. 425 mi / 92 kWh = 4.6 mi/kWh, a figure I've seen quoted here, along with disappointment of "why can't I achieve that?"

The EPA also says the AT with 19s is rated at a combined efficiency rating of 140MPGe (141 city, 140 hwy). The conversion factor quoted by the EPA to mi/kWh is 33.705 kWh/gal. 140 / 33.705 = 4.2 mi/kWh. And multiply that by 92kWh, suggests a range of just over 380 miles. Still a very respectable number.

Can someone explain the discrepancy?

I'm averaging 4.3 in my first three weeks, with some driving in mild weather with A/C off but mostly using A/C. I predict that I'll be around 4.2 over the Arizona summer months, but I'm driving like I enjoy spending time in the car. Aside from the A/C, the headlights also appear to be a surprisingly large drain.

 

[hydbob]

Hey crew, here's my first question for the forum, and included in it, hopefully some consolation for my fellow owners:

My AT with 19s has a quoted range of 425 miles, and the battery pack is indicated to be 92kWh. 425 mi / 92 kWh = 4.6 mi/kWh, a figure I've seen quoted here, along with disappointment of "why can't I achieve that?"

The EPA also says the AT with 19s is rated at a combined efficiency rating of 140MPGe (141 city, 140 hwy). The conversion factor quoted by the EPA to mi/kWh is 33.705 kWh/gal. 140 / 33.705 = 4.2 mi/kWh. And multiply that by 92kWh, suggests a range of just over 380 miles. Still a very respectable number.

Can someone explain the discrepancy?

I'm averaging 4.3 in my first three weeks, with some driving in mild weather with A/C off but mostly using A/C. I predict that I'll be around 4.2 over the Arizona summer months, but I'm driving like I enjoy spending time in the car. Aside from the A/C, the headlights also appear to be a surprisingly large drain.

The EPA efficiency of 4.6 is from 100 to 0% and how many miles you can get. The mpgE takes that distance, and how much energy it takes to go from 0-100%. Part of the problem with charging is that it's not 100% efficacy and you lose roughly 10% to charging losses. Hence the difference of 0.4mi/kwh between the two. Hope that is clear enough to understand.

 

[GMan]

The EPA also says the AT with 19s is rated at a combined efficiency rating of 140MPGe (141 city, 140 hwy). The conversion factor quoted by the EPA to mi/kWh is 33.705 kWh/gal. 140 / 33.705 = 4.2 mi/kWh. And multiply that by 92kWh, suggests a range of just over 380 miles. Still a very respectable number.

In my case, it's the following:

Trim: Touring
Wheels: 20"
Total Miles: 2000

Lifetime m/kWh: 3.9

EPA MPGe: 121 (I think the EPA page is inaccurate because 121 MPGe is the same value as the 21" AT)
EPA Calculation: 121 / 33.705 = 3.6
EPA Range Estimate: 3.6 x 92 kWh = 331 miles.

However, I'm getting 359 actual miles lifetime (3.9 x 92 kWh), so I wouldn't put too much faith in the EPA numbers. They are just forecasts.

Based of my Lucid's numbers for AT 20", 406 estimated miles, I'm getting 88% (360/406), which I'm quite happy with.

The key to remember is that no publication can predict your actual mileage, because of the variables that effect mileage such as:

• Temp
• Changes in elevation
• Wind
• Rapid acceleration
• Weight (# passengers, cargo, etc..)
• etc...

 

[kerplunk]

In my case, it's the following:

Trim: Touring
Wheels: 20"
Total Miles: 2000

Lifetime m/kWh: 3.9

EPA MPGe: 121 (I think the EPA page is inaccurate because 121 MPGe is the same value as the 21" AT)
EPA Calculation: 121 / 33.705 = 3.6
EPA Range Estimate: 3.6 x 92 kWh = 331 miles.

However, I'm getting 359 actual miles lifetime (3.9 x 92 kWh), so I wouldn't put too much faith in the EPA numbers. They are just forecasts.

Based of my Lucid's numbers for AT 20", 406 estimated miles, I'm getting 88% (360/406), which I'm quite happy with.

The key to remember is that no publication can predict your actual mileage, because of the variables that effect mileage such as:

• Temp
• Changes in elevation
• Wind
• Rapid acceleration
• Weight (# passengers, cargo, etc..)
• etc...

I only have 300 miles on my AT and all of it has been in rainstorms. But the best I managed was 3.2 in smooth mode on 20" wheels. I forgot where i saw it but I thought the total range was around 384 miles for AT on 20s.

At any rate I'm at about 276 miles in total range. I'd love to get your mileage. Teach me your ways!

 

[Adnillien]

Hey crew, here's my first question for the forum, and included in it, hopefully some consolation for my fellow owners:

My AT with 19s has a quoted range of 425 miles, and the battery pack is indicated to be 92kWh. 425 mi / 92 kWh = 4.6 mi/kWh, a figure I've seen quoted here, along with disappointment of "why can't I achieve that?"

The EPA also says the AT with 19s is rated at a combined efficiency rating of 140MPGe (141 city, 140 hwy). The conversion factor quoted by the EPA to mi/kWh is 33.705 kWh/gal. 140 / 33.705 = 4.2 mi/kWh. And multiply that by 92kWh, suggests a range of just over 380 miles. Still a very respectable number.

Can someone explain the discrepancy?

I'm averaging 4.3 in my first three weeks, with some driving in mild weather with A/C off but mostly using A/C. I predict that I'll be around 4.2 over the Arizona summer months, but I'm driving like I enjoy spending time in the car. Aside from the A/C, the headlights also appear to be a surprisingly large drain.

The EPA number uses the energy to required to charge the battery from 0% to 100% using a level 2 charger. Those numbers include AC to DC conversion and charging losses in the car. For most cars, including Lucid, the charging losses are around 15%. Charging losses do not affect range but you do pay for them on your electric bill.

 

[Vette2Lucid]

Hydbob and Adnillien, thank you so much-- that clarifies a lot. So MPGe is based on the energy coming out of the wall socket, and range is what could be accomplished with a fully charged battery. So if the number I see on my Pilot Panel is 4.6 (which maybe I'll achieve in October/November, when the weather gets milder, and I get some quality window tint to reduce the need for A/C), then I could reasonably expect that range-- if going all the way from 100% to 0%, which of course we won't do if we want to keep our batteries healthy. But still useful from the perspective of knowing what range to expect for a given percentage of battery consumed.

Losses while charging, I presume, would include the following:

• AC-DC conversion losses in the Wunderbox (proportional to the energy going in?)
• EVSE losses (hopefully minimal, but probably some small static component)
• Resistance losses (proportional to the current going in?)
• Battery management system losses (guessing this might be the largest component. Perhaps some static value, plus whatever energy is needed to manage the temperature of the battery, which may increase with power and state of charge?)
• The main computer is awake while the car is charging, which may also be significant but static
• Energy balancing vampire drain

With some of those losses being static, I suspect that means 120V charging is going to be quite inefficient (if it were perfectly efficient, we'd see charge rates of 6mi/hr), but it'd be interesting to know what current is most efficient for charging at 240V and how that balances with battery longevity.

And the efficiency number on the Pilot Panel ignores the time spent charging and includes vampire drain after the charging cycle completes. The impact of that is huge when you first start driving and diminishes as you drive further.

 

[Adnillien]

Hydbob and Adnillien, thank you so much-- that clarifies a lot. So MPGe is based on the energy coming out of the wall socket, and range is what could be accomplished with a fully charged battery. So if the number I see on my Pilot Panel is 4.6 (which maybe I'll achieve in October/November, when the weather gets milder, and I get some quality window tint to reduce the need for A/C), then I could reasonably expect that range-- if going all the way from 100% to 0%, which of course we won't do if we want to keep our batteries healthy. But still useful from the perspective of knowing what range to expect for a given percentage of battery consumed.

Losses while charging, I presume, would include the following:

• AC-DC conversion losses in the Wunderbox (proportional to the energy going in?)
• EVSE losses (hopefully minimal, but probably some small static component)
• Resistance losses (proportional to the current going in?)
• Battery management system losses (guessing this might be the largest component. Perhaps some static value, plus whatever energy is needed to manage the temperature of the battery, which may increase with power and state of charge?)
• The main computer is awake while the car is charging, which may also be significant but static
• Energy balancing vampire drain

With some of those losses being static, I suspect that means 120V charging is going to be quite inefficient (if it were perfectly efficient, we'd see charge rates of 6mi/hr), but it'd be interesting to know what current is most efficient for charging at 240V and how that balances with battery longevity.

And the efficiency number on the Pilot Panel ignores the time spent charging and includes vampire drain after the charging cycle completes. The impact of that is huge when you first start driving and diminishes as you drive further.

Very good list of charging losses. Don't try 120V charging with your Lucid hear in the summer. The battery cooling will take more energy than the 120V outlet can provide.

As far as the efficiency display in the car goes, they do not include charging losses. The since last charge line does include vampire drain, the trip lines do not include vampire drain (they only include energy used while driving).

 

[GMan]

I only have 300 miles on my AT and all of it has been in rainstorms. But the best I managed was 3.2 in smooth mode on 20" wheels. I forgot where i saw it but I thought the total range was around 384 miles for AT on 20s.

At any rate I'm at about 276 miles in total range. I'd love to get your mileage. Teach me your ways!

First thing to do is turn on High Brake Regeneration.

You're already running in Smooth mode which is the other most important thing which you can control.

Minimize A/C. I use seat cooling which works for me.

During the cold, i never turn on heat. Just heated seat and heated steering wheel.

Minimize rapid acceleration.

Lots of factors are outside of your control like elevation change, and weather (temperature most importantly).

Good luck!

 

[GMan]

And the efficiency number on the Pilot Panel ignores the time spent charging and includes vampire drain after the charging cycle completes.

That's only true for "Since last charge". Trip mileage doesn't include vampire drain. That's important because "Since last charge" isn't telling you car mileage performance. It's telling you how many kWh you battery consumption since the last charge whether driving or not.

 

[Vette2Lucid]

Thanks to both Adnillien and GMan. You're right. I noticed today that the trip computer only includes energy consumption when the car is not in Park.
One more related question. I've seen so many images of the Glass Cockpit showing not just the miles driven since last charge, but the energy consumption rate. I even remember seeing that back when I test drove a GT back around October. But my car doesn't show the energy consumption up there, I have to look down to the Pilot Panel. Is there a setting I'm missing, or was that wonderful feature taken away with a more recent software release? (If so, please bring it back!!!)

 

[Adnillien]

Thanks to both Adnillien and GMan. You're right. I noticed today that the trip computer only includes energy consumption when the car is not in Park.
One more related question. I've seen so many images of the Glass Cockpit showing not just the miles driven since last charge, but the energy consumption rate. I even remember seeing that back when I test drove a GT back around October. But my car doesn't show the energy consumption up there, I have to look down to the Pilot Panel. Is there a setting I'm missing, or was that wonderful feature taken away with a more recent software release? (If so, please bring it back!!!)

The cockpit panel efficiency display was removed with an update last fall. I think that most people here, including me, would like to have it back

 

[Daniel2022AT]

Many many years ago, (I'm a former automotive engineer) when the EPA was getting a handle on ICE efficiency ratings in the 1970's, there were many iterations of the EPA test cycle to try to get an accurate estimate of fuel economy. It went from way too high and optimistic, to today when EPA estimates are conservative and it is pretty easy to beat the EPA mileage for many ICE vehicles.

This is deja vu to me. We are in the early phase of EV efficency estimates and most of these range calculations are theoretically best case/perfect case. So they will not be attainable in real life.

Acceleration, grade, and speed are the enemies of efficiency. If you play around with your driving stytle and watch the trip calculator you can get a good feel for it.

My experience, Touring 19 inch: 4.5 if I really baby it, 4.2 with smooth conservative driving, and 3.9 if I drive normally without thinking about it. (Flat midwest roads, 50-60 degree temps.)

The Lucir Air achieves the same efficiency as much smaller EV's due to its "best EV" status in terms of aerodynamics and virtually every other aspect of the design of the vehicle and its driveline components. For example, the next best EV in efficency to the Lucid Air is the Tesla Model 3, which is smaller and about 800-1,000 lbs. lighter.

 

[GMan]

Thanks to both Adnillien and GMan. You're right. I noticed today that the trip computer only includes energy consumption when the car is not in Park.
One more related question. I've seen so many images of the Glass Cockpit showing not just the miles driven since last charge, but the energy consumption rate. I even remember seeing that back when I test drove a GT back around October. But my car doesn't show the energy consumption up there, I have to look down to the Pilot Panel. Is there a setting I'm missing, or was that wonderful feature taken away with a more recent software release? (If so, please bring it back!!!)

They ditched that on the cockpit display, I want to say prior to Dec, 2022. I suspect due to the difference between what owners were actually achieving versus the expectation Lucid set for performance efficiency.

The reality is Lucid is providing optimal numbers and each of us drive in suboptimal reality.

 

[Vette2Lucid]

They ditched that on the cockpit display, I want to say prior to Dec, 2022. I suspect due to the difference between what owners were actually achieving versus the expectation Lucid set for performance efficiency.

The reality is Lucid is providing optimal numbers and each of us drive in suboptimal reality.

That could be just as true in so many other cars too. And so many other cars make that information available to the driver in the instrument cluster so drivers can consider on the fly how their driving behavior is influencing their efficiency. When it's on the Pilot Panel, I basically only get to see it when I'm waiting at a stoplight.
It would also be good to see instantaneous energy efficiency. Again, a useful feature common on other cars.
OTOH, I do think Lucid did very nicely with the swinging energy flow indicator around the speedometer. It would be nice to a subtle tick mark to it, to indicate how far along the charging range you'd have to be to engage the brake lights.

 

[Chandi23]

I am not sure if this is the sub forum for, but I wanted to share my experience recently to get some feedback.

I went on a road trip earlier in the week in my Touring and had issues with the amount of charge in the car and wanted to get some feedback. Here goes:
The distance that I travelled was 250 miles each way.

• When I left home, the car had enough charge to cover 410 miles.
• After travelling about 200 miles, the available charge suddenly dropped to 50 miles (BTW, the weather was fine at about 70 degrees)
• I had to find a found a charging place quickly and found one within the next 20 miles and put in additional charge to cover about 150 miles.
• On my return, I charged the vehicle at the same place to get a range of 360 miles (the distance to travel back was about 170 miles) which should have resulted in approximately 180 miles remaining charge when I reached my destination (that’s what the vehicle display showed at that time)
• After travelling about 100 miles, the range suddenly dropped to 80 miles, and I barely made it home (with 15 miles charge left)
• I had done a similar trip in the past and the display numbers checked out and there was no drop in the estimated charge distance.
• I have the latest version of the software (.33)

I believe that the drop in estimate was too much. Just wondering if anyone knows what is happening.

 

[borski]

I am not sure if this is the sub forum for, but I wanted to share my experience recently to get some feedback.

I went on a road trip earlier in the week in my Touring and had issues with the amount of charge in the car and wanted to get some feedback. Here goes:
The distance that I travelled was 250 miles each way.

• When I left home, the car had enough charge to cover 410 miles.
• After travelling about 200 miles, the available charge suddenly dropped to 50 miles (BTW, the weather was fine at about 70 degrees)
• I had to find a found a charging place quickly and found one within the next 20 miles and put in additional charge to cover about 150 miles.
• On my return, I charged the vehicle at the same place to get a range of 360 miles (the distance to travel back was about 170 miles) which should have resulted in approximately 180 miles remaining charge when I reached my destination (that’s what the vehicle display showed at that time)
• After travelling about 100 miles, the range suddenly dropped to 80 miles, and I barely made it home (with 15 miles charge left)
• I had done a similar trip in the past and the display numbers checked out and there was no drop in the estimated charge distance.
• I have the latest version of the software (.33)

I believe that the drop in estimate was too much. Just wondering if anyone knows what is happening.

When you say “suddenly dropped” do you mean that is was a slow decline in remaining charge or literally a sudden drop?

Also, are you using the lucid Nav? The lucid nav will give you a very accurate “miles remaining on arrival” estimate, but the general “Miles left” for range is often incorrect as it relies on the EPA estimate.

Most people have switched that to percentage instead of miles, and just multiply by the mi/kWh in their “Trips” screen.

I’d be curious to see what happens if you set it to percentage; if there really is a *sudden* drop, you should definitely have service look at it, as that isn’t normal.

 

[Chandi23]

On my trip up, it was more sudden (within a few minutes). On my return trip, the number changed gradually, but the last 70 or 80 miles remained consistent. I was using Lucid Nav. How does speed of the vehicle matter?

 

[Adnillien]

On my trip up, it was more sudden (within a few minutes). On my return trip, the number changed gradually, but the last 70 or 80 miles remained consistent. I was using Lucid Nav. How does speed of the vehicle matter?

Speed is probably the most important factor in efficiency. Anything much over the speed limit will reduce range and reduce the accuracy of miles remaining at destination when using navigation. Also putting the car in Sprint mode will constantly condition the battery which decreases efficiency.

 

[hydbob]

I am not sure if this is the sub forum for, but I wanted to share my experience recently to get some feedback.

I went on a road trip earlier in the week in my Touring and had issues with the amount of charge in the car and wanted to get some feedback. Here goes:
The distance that I travelled was 250 miles each way.

• When I left home, the car had enough charge to cover 410 miles.
• After travelling about 200 miles, the available charge suddenly dropped to 50 miles (BTW, the weather was fine at about 70 degrees)
• I had to find a found a charging place quickly and found one within the next 20 miles and put in additional charge to cover about 150 miles.
• On my return, I charged the vehicle at the same place to get a range of 360 miles (the distance to travel back was about 170 miles) which should have resulted in approximately 180 miles remaining charge when I reached my destination (that’s what the vehicle display showed at that time)
• After travelling about 100 miles, the range suddenly dropped to 80 miles, and I barely made it home (with 15 miles charge left)
• I had done a similar trip in the past and the display numbers checked out and there was no drop in the estimated charge distance.
• I have the latest version of the software (.33)

I believe that the drop in estimate was too much. Just wondering if anyone knows what is happening.

How fast were you driving?

Driving at 70mph will get you roughly 90% of your EPA, not accounting for factors like temp/wine/elevation changes. 80mph will get you closer to 80%.

The miles remaining in nav and also your total miles available in your dash is using EPA efficiency, not your normal usage.

 

[borski]

not accounting for factors like temp/wine/elevation changes

I was gonna correct your typo, but I suppose accounting for wine matters too