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Lucid Air over 500 miles on a charge!

ajdelange

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Isn't that an assumption that you will get 350 kWh for the full charge hour?
No. Not at all. It assumes that at the time at which the battery is adding charge the fastest, even if that lasts for only 20 seconds, the absorption rate is 350 kW. That is a rate of 350000 joules per second equivalent to a rate of 350 kWh/h which adds mileage at the rate of 20 [Edit: this was incorrectly entered as 30 for about 4 hours] miles per minute equivalent to a rate of 1200 miles per hour. The the rate of consumption is 350 (kW-h/h)/1200 (miles/h) = .292 kWh/mile. This gives us an estimate of the EPA consumption for the car.

BTW 350 kW is not only the maximum size of a CCS charger in the US. It is the maximum the CCS standard supports.
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azbill

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The numbers in that article are inconsistent, unless there is significant taper. They first claim 20 miles per minute, then cite 300 miles in 20 minutes, which is actually 15 miles per minute. I read another article where they claimed a max charge rate of 300KW, not 350KW, I think they are just mentioning 350KW because that is the rating of the chargers that will allow them to charge at 300KW. I think they are playing games with marketing statements here.

Also, if they could charge at 350KW, then in 20 minutes that would be 116KW, so the battery needs to be bigger than that. At 300KW, 20 minutes would be 100KW. In either case the numbers do not jive with the stated range of 500+ miles. Let's assume the range is 500 miles with 100KW battery, as they seem to claim. Then they would need 60KW in 20 minutes to add 300 miles, that is an average charge rate of 180KW.
 
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Hmp10

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If you want to believe 517 EPA range for this vehicle I don't see any real harm done. Who knows. It may even turn out to be true! Anyway this is supposed to be a Rivian forum.
I don't see any reason to doubt the 517 EPA estimate. In both the Car & Driver "convoy" test and in another Motor Trend test where a Model S Long Range Plus followed a Lucid driving the same way, the Lucid outlasted the Tesla by ~100 miles.

The Tesla in those tests got about 88% of its EPA-rated range (355 miles against 402 miles per C&D).

The Lucid in those tests got about 88% of its claimed EPA-like range (456 miles against 517 miles per C&D).

I think the issue is about what battery pack size Lucid was using to get that range, not whether it actually got the range.

I would like to think that Rawlinson's claims about higher efficiency and a smaller battery pack are true, for the sake of advancing EV technology. But frankly, at the end of the day, I don't really care about battery size. What I care about is that the Lucid I'm getting will go considerably further than a current Model S, thereby allowing me to stop a few less times on trips, or to drive the Lucid faster on the interstate, or not to have to charge too close to 100% to leave enough margin for unexpected traffic or weather conditions.

And, yes . . . this is a Rivian forum. However, we are on a thread that is clearly labeled as being about the Lucid Air. People are free to ignore it if the car is of no interest to them.
 

DucRider

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BTW 350 kW is not only the maximum size of a CCS charger in the US. It is the maximum the CCS standard supports.
Nope. You should check your facts on that one (and maybe some of your other assumptions as well)
 

azbill

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Nope. You should check your facts on that one (and maybe some of your other assumptions as well)
The standard theoretically supports 500KW: 1000Volts at 500Amp. The EA chargers support 900V and 500A, but are still limited to 350KW. 700V at 500A, or 900V at 389A.
 
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ajdelange

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Well I admit I was lazy and went to Wikipedia. So I subsequently went back and looked again. I find dozens of references to CCS being capable of up to 350 kW (note: I am not shelling out $80 to SAE). So if this is not correct please let me know where I can find the correct answers.'

I am also more than willing to check on other assumptions so could you please indicate which ones need attention.

Thanks.
 

ajdelange

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I don't see any reason to doubt the 517 EPA estimate.
I know you don't. I have given you some reasons why you should but you choose to ignore them. That is up to you but really that's the discussion in a nutshell.
 

ajdelange

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The numbers in that article are inconsistent, unless there is significant taper.
There is the definite hint of snake oil in the air with that article but I have no problem with their claim that they get a peak charge rate of 20 miles per minute. I am starting to get the feeling that people don't know what a rate is. I guess I shouldn't be surprised. I just learned about the "MPG illusion".

In any case the 20 miles per minute here is only significant as a path to the Wh/miles number which we can obtain assuming that they attain it at a 350 kW charger. But now we are led to believe there are bigger chargers out there and are awaiting feedback on how big they are.
 

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No. Not at all. It assumes that at the time at which the battery is adding charge the fastest, even if that lasts for only 20 seconds, the absorption rate is 350 kW. That is a rate of 350000 joules per second equivalent to a rate of 350 kWh/h which adds mileage at the rate of 30 miles per minute equivalent to a rate of 1200 miles per hour. The the rate of consumption is 350 (kW-h/h)/1200 (miles/h) = .290 kWh/mile. This gives us an estimate of the EPA consumption for the car.

BTW 350 kW is not only the maximum size of a CCS charger in the US. It is the maximum the CCS standard supports.
wait 350/1200 is ~.292 not .290 and substituting units doesn't help explain what your trying to convey in the math i.e. joules/sec to kWh/h just stick with one. The equation you put forward is assuming a constant 350 kWh for an hour i.e. 350(kW-h)/1200(miles/h) hence the hour in the equation. Also where is the 30 miles/min come from? It was is 20 miles/min from a previous post which would equal 1200(miles/h). I'm not say what the battery capacity is, I have no clue but the equations your putting out here are based on assumptions not fact which you readily state as is, I'm just showing with other assumptions other answers are possible. I work with this type of stuff every day and have been burned more than once tying to calculate what I assumed and what reality actually is.
 

azbill

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Well I admit I was lazy and went to Wikipedia. So I subsequently went back and looked again. I find dozens of references to CCS being capable of up to 350 kW (note: I am not shelling out $80 to SAE). So if this is not correct please let me know where I can find the correct answers.'

I am also more than willing to check on other assumptions so could you please indicate which ones need attention.

Thanks.
I have seen specifications on the CCS connector ratings, like this one. That should be the limiting factor, but it is also dependent upon the liquid cooling capability in the cable and charging units, as well as the car wiring.

https://ittcannon.com/core/medialib.../itt-cannon-evc-dc-liquid-cooled-brochure.pdf

The main limiting factor will be the current and that is why these use liquid cooling to keep the wire size reasonable. The voltage rating will be more likely determined by the connector contact spacing, and insulation to prevent arcing.

My comment here is based on what the connector ratings are, so as I stated it is theoretical.
 

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ajdelange

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wait 350/1200 is ~.292 not .290 and
That's a typo. Should not have obscured the meaning, nevertheless, I apologize.

substituting units doesn't help explain what your trying to convey
It should.

The equation you put forward is assuming a constant 350 kWh for an hour i.e. 350(kW-h)/1200(miles/h) hence the hour in the equation.
No, it absolutely is not. 350 kW is a rate. It is the first derivative of energy, which is expressed in kWh, with respect to time. I assumed EE stood for "Electrical Engineer" and that you would understand that. Are engineers not taught calculus these days?


Also where is the 30 miles/min come from? It was is 20 miles/min from a previous post which would equal 1200(miles/h).
I'm sorry to say that was another typo. Again, I apologize.

I'm not say what the battery capacity is, I have no clue but the equations your putting out here are based on assumptions not fact which you readily state as is,
The article states 20 miles per minute charging. It is reasonable to assume that this would be attained when using the fastest chargers available to drivers in the US which deliver, AFAIK, 350 kW. Therefore, I used 350 kW.

What you wrote was
Isn't that an assumption that you will get 350 kWh for the full charge hour? If you "assume" that the charger is actually ~263 kWh or ~219 Wh/mi with the taper and such then you have ~100 kWh battery size.
I couldn't respond to that because chargers can't be described in kWh as that is an energy unit. They can be described in terms of how many kWh they can deliver in given time period. This is called Power. A station that delivers 263 kWh of energy in an hour, even though it delivers 200 kWh in the first half hour and 63 kWh in the second is delivering Power at the average rate of 263 kW.
I work with this type of stuff every day and have been burned more than once tying to calculate what I assumed and what reality actually is.
It will help to get clear on the distinction between power and energy.
 

Hmp10

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I know you don't. I have given you some reasons why you should but you choose to ignore them. That is up to you but really that's the discussion in a nutshell.

Do you doubt that a Lucid Air hit 456 miles in the "convoy" test on public roads (with a good bit of 70 mph driving) with a Car & Driver writer along? And that the Tesla hit 355 in the same convoy?

If you doubt the truth of the Car & Driver article, then I can say nothing more, as we simply disagree on what the facts are.

But if you do accept that the Lucid hit 456 miles in that convey test, why would it be untenable that in the FEV test using EPA protocols the Air was rated at 517 miles?

That is the exactly the same ratio of real-world driving mileage to estimated EPA mileage for the Lucid (456/517) that Tesla realized (355/402).

Why would Tesla be able to achieve 88% of its EPA rating in the convoy test and Lucid not be able to achieve 88% of its FEV rating?

Are you saying that what is possible for Tesla is not possible for Lucid from an electrical engineering standpoint?
 

ajdelange

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You are asking me if I doubt the accuracy of the reporting in popular journalism? That's a joke, right?
 

jjwolf120

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If you doubt the truth of the Car & Driver article, then I can say nothing more, as we simply disagree on what the facts are.
All he is saying is that they are not facts. They are in fact inferences based on incomplete data. There is nothing particularly wrong with 517 estimate or whatever other estimates are in the article, but it is an estimate. That is how I interpret what ajdelange is asserting.
 

ajdelange

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Found the following in an article about Lucid's charging

"Lucid Air owners who take U.S. delivery will receive three years of complimentary* charging at Electrify America’s extensive nationwide network of ultrafast charging stations that currently boasts 2,000+ individual chargers — 150kW through 350kW."

Hint, hint.

Of course the * points us to the catch but it is a small one. You must be enrolled in one of EAs plans which will cost you $4/mo or $1 per charging session.
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