Lucid Air over 500 miles on a charge!

[electruck]

Here is yet another reference to range approaching 450 miles from Oct 2018:

Scaringe said they will last 425 to 450 miles on a single charge—a key part of its “adventure” EV brand.

Interesting progression of how the range has been communicated. In May 2018 it was "around 450 miles." Then in October 2018 it was "425 to 450 miles". Then by the November 2018 reveal, it was simply 410+ (or 400+ for the T).

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[electruck]

That comment from the South American trip is the reason why I'm still hoping for 350miles
I'm guessing some of the 315miles include off roading.

350 might be a little bit of a stretch. I prefer to keep my expectations low and be pleasantly surprised when they are exceeded but I get where you're coming from.

 

[ajdelange]

The Tesla ran for 355 miles.

The Lucid ran for 456 miles.

From which we conclude, ceteris paribus, assuming that the Tesla has a 100 kWh battery, that the Lucid has a 100*456/355 = 128.451 kWh battery. Seems, knowing full well that things aren't ceteris paribus, about right. Since motors, inverters etc are well into the 90's in efficiencies we can't give them more than a couple of percent for new discoveries there. Giving them an, IMO, generous 5% there that would imply a battery pack size of 122 kWh which, were I hyping my new entry into this market, I would have no qualms in calling "considerably less".

Rawlinson thinks the official EPA range rating might come in slightly above 550 miles.

No he doesn't. If he did he wouldn't be advertising 400 on his web site. There must be some confusion here with one of the EPA sub ratings. While we may wind up seeing something over 400 on the Monroney sticker it isn't going to be 550.

The key advances to which Rawlinson attributes this efficiency are:

- Lucid has developed a technique for reducing the cogging torque in permanent magnet motors by about two-thirds.

Again I think you may be misinterpreting something. You don't want to eliminate torque. What you want to do is change your design such that a majority of the torque is magnetic torque as opposed to reluctance torque as this reduces torque ripple. Perhaps he said they have reduced torque ripple by 2/3. That has advantages, of course not the least of which is that mostly PM motors are quieter than mostly reluctance motors. They may well have discovered some new technique for reducing ripple but then so does someone else every day. At this point in the state of the art it is pretty much under control via magnet skewing, increased number of poles and increased number of stator teeth. There is very little left to eke out of motor efficiency but every bit helps.

This allows them to use the more efficient PMSM on both axles, whereas Tesla puts its PMSM only on the front axle, where it is the sole drive motor under light loads, leaving the non-cogging induction motor to idle.

Some Tesla vehicles have IPMSM motors in the back and IM in the front and some have IPMSM in front and IM in back and some have IPMSM in both places. No Tesla vehicle has PMASR motors and thus no motors that "cog" are found on Tesla vehicles (note that I am not saying that no Tesla motor has torque ripple - all these motors do). I am delighted that this comment, while incorrect, was made because now I know why I hear the motors more in my Raven X (IPMSM motor up front) than I did in my older X (two IM).

- The >900-volt electrical system reduces internal resistance and cooling requirements in the powertrain, saving weight and allowing smaller air intakes, thus improving aerodynamics.

The big gain comes from going to IPMSM as it removes the copper and reduces the hysteresis losses in the rotor. It also reduces I^2R losses in the stator if you stay with the same size wire but there is a temptation to go to smaller wire which, while it saves some $ and weight brings the I^2R losses back up. There are trades and perhaps Lucid has come up with some. But again, we are talking fractions of a percent.

- Silicon carbide MOSFET inverters.

Obviously with higher voltage architechture you are going to need higher PIV tolerant devices but SiC has some other advantages too such as faster switching times which translate to lower losses. I'm not sure of course but I think almost everyone uses SiC today.

In short SiC, improved torque ripple and 900V architecture aren't going to get a manufacturer 25% extra range. Maybe a couple of percent. Clearly the impressive range is real it is attributable to more battery.

Lucid has abandoned plans to offer a 130-kWh pack, as efficiency advances over the past three years have made range in excess of 400 miles achievable with a smaller battery pack which is lighter, cheaper, and easier to cool. They haven't said what the capacity will be of the new large pack.

If they have indeed picked up a couple of percent efficiency through motors, inverters, 900 V architecture and drag they may well want to reduce the battery size as this only gains them even more given that in all driving regimes except highway the inertial load is the greatest and thus some of the range lost by giving up stored energy is recouped through reduced inertial load. Were I they I would put in enough battery, if forced to guess I'd say 110 kWh, for 425 mi EPA range which will please customers by coming considerably higher than what they are advertising and trump the S by 25 miles. For now that is. Sept 22 is not that far off.


Bottom line is that lurid headlines aside this article raises more questions than it answers. Those of us with long experience in engineering know that if something seems too good to be true, it generally isn't.

The BEV industry seems to be settling in at about 400 mi EPA range, certainly for sedans, SUV and crossover. Even if something really exciting is announced on Sept 22 I don't think the manufacturers are going to be making that many cars with range much greater than this. Trucks are a different matter - the extra energy is needed to maintain reasonable range when towing. I don't really put the R1T in that class. It is an Adventure Vehicle, not a working truck. Needless to say this is just an opinion. I don't have a crystal ball.

 

[Hmp10]

No he doesn't. If he did he wouldn't be advertising 400 on his web site. There must be some confusion here with one of the EPA sub ratings. While we may wind up seeing something over 400 on the Monroney sticker it isn't going to be 550.

I certainly do not understand a lot of the technical analysis you post, although I appreciate it and do my best. However, I'm pretty good at understanding English.

This is from an August 11 "TechCrunch" article reporting an earlier interview with Rawlinson:

"It’s also possible that official EPA estimate could end up landing north of 550 miles, Rawlinson said in a recent interview with TechCrunch.

The 517-mile figure was determined after applying the EPA’s Multicycle Test Procedure, which uses a standard adjustment factor. The initial testing showed an unadjusted estimate of 738 miles on a single charge. Like other electric vehicles, that figure is then adjusted using a standard correction of 0.7. (738 multiplied by 0.7 equals 516.6 miles)

Tesla vehicles have a standard adjustment factor of 0.75, which recognizes the automaker’s advanced aerodynamics and heating, ventilation and air conditioning system. Rawlinson believes that once the EPA receives data on its HVAC system and its aerodynamics data, it too will receive the higher standard adjustment factor. If the EPA validates Lucid’s testing and applies the 0.75 adjustment factor, the Air could end up with a range as high as 553.5 miles."


As for battery size, we may never know the answer, as both Tesla and Lucid are adopting the practice of not disclosing battery pack capacities. We know the current Model S and X have ~ 100-kWh packs from earlier pronouncements and model names (P100D, etc.). But Tesla has never confirmed the pack capacities of the 3 and Y, although other sources indicate they may be around 72-75 kWh.

Tom Moloughney, who frequently works with Sandy Munro, made an interesting observation the other day. Assuming that Lucid is using a 130-kWh pack and getting a proportional range equal to Tesla with a 100-kWh pack, the fact that the 130-kWh pack would weigh considerably more would still indicate the Lucid is operating at a higher total efficiency.

 

[Jehorton]

I certainly do not understand a lot of the technical analysis you post, although I appreciate it and do my best. However, I'm pretty good at understanding English

Haha this is great

 

[Hmp10]

Lucid just posted a release about its charging rate:

https://lucidmotors.com/stories/lucid-air-fastest-charging-ev

 

[Jehorton]

That’s amazing. 20 miles a min. Awesome!

 

[DucRider]

That’s amazing. 20 miles a min. Awesome!

That must be at peak charge rate?
300 miles in 20 minutes = 15 miles/minute which is still respectable and indicates a taper that starts much later than the Model 3. Probably much more like the Taycan with it's 800V architecture.

 

[Hmp10]

The press release mentions "custom" lithium-ion battery cells but, unfortunately, says no more. In earlier interviews and releases Lucid said it was working with Samsung and later with LG Chem on proprietary cell chemistry that would reduce degradation at high charging rates, but this release was mum on that. I wonder if it's a strategic silence or whether it didn't amount to much in the final analysis.

 

[ajdelange]

I certainly do not understand a lot of the technical analysis you post, although I appreciate it and do my best. However, I'm pretty good at understanding English.

This is from an August 11 "TechCrunch" article reporting an earlier interview with Rawlinson:

"It’s also possible that official EPA estimate could end up landing north of 550 miles, Rawlinson said in a recent interview with TechCrunch.

It is possible. It just isn't very likely.

The 517-mile figure was determined after applying the EPA’s Multicycle Test Procedure, which uses a standard adjustment factor...

There are several "factors" that go into an EPA test because the vehicle is not actually moving during the test. Thus neither drag nor inertial nor potential loads can be measured but rather must be simulated by applying these factors. The manufacturer can put in any test coefficients he wants to but the resulting numbers aren't accepted as EPA ratings until the EPA approves the test. Thus to assume an EPA range based on the fact that Lucid might get to use the same number for one of those factors that another manufacturer did with no knowledge of the other factors is naive in the extreme in the opinion of this engineer.

As for battery size, we may never know the answer, as both Tesla and Lucid are adopting the practice of not disclosing battery pack capacities.

I don't know if Occam's Razor is known outside the scientific community (I think it probably is). In a nutshell it says that the simplest explanation for something is often the best explanation. It does not prove anything but scientists and engineers often turn to it in deciding which of several hypotheses to check out first. The obvious explanation given that remarkably long range is encountered is that the vehicle exhibiting it has a bigger battery than a vehicle to which it is being compared while still recognizing that there may be other factors at play. Clearly where actual battery data is obscured Occams razor is appealing.

We know the current Model S and X have ~ 100-kWh packs from earlier pronouncements and model names (P100D, etc.).

I don't know that. I do know that I've had 2 X100 and that both exhibit a charging capacity of about 98 kWh and a discharge capacity of about 92.

But Tesla has never confirmed the pack capacities of the 3 and Y, although other sources indicate they may be around 72-75 kWh.

Tom Moloughney, who frequently ...still indicate the Lucid is operating at a higher total efficiency.

And it may be but I'm not trying to prove anything. I am just trying to point out that the evidence presented is not likely to convince someone with technical background that the Lucid is 25% more efficient than any similar Tesla model based on 900 V architecture, silicon carbide transistors and reduced ripple in its motors. As much as you may want to believe that this is true, it very probably isn't. Over the course of many years looking at technical systems I've developed a pretty good nose for the aroma of snake oil. A bit here and there isn't a bad thing - everybody is entitled to present his product in the most favorable light. But I do get a little troubled when the CEO of one company claims he invented the electric truck and gave the design to Elon Musk and I do get a little troubled when the CEO of another claims that reducing IPMSM ripple by 2/3 represents a major breakthough in BEV techology.

 

[jjwolf120]

I think that the Lucid Air getting a 517 mile range on an EPA like test is that the Lucid no longer has to work on getting a larger capacity battery pack, at least for the Lucid Air. This means that all advances in battery technology can now be steered toward lowering the cost and weight of the battery pack. This is a very positive for affordability of electric vehicles going forward.

 

[ajdelange]

That’s amazing. 20 miles a min. Awesome!

There is information hidden in that. Twenty miles in a minute means 1200 miles per hour. The largest CCS chargers in the US are 350 kW units capable of delivering 350 kWh in an hour. The rated consumption of the car must thus be 350/1200 = 0.292 or 292 Wh/mi. That is a perfectly reasonable number for a vehicle of this size. Now if we assume that the mix of driving in which 456 miles was achieved on a complete battery charge is representative of EPA’s conditions we can calculate that the battery size is 456*.296 = 134.976 kWh. We keep coming back to that same number (i.e. around 130 kWh). This is just further reinforcement of the notion that Occam's Razor applies here. Let me emphasize again that it does not prove that.

 

[Hmp10]

Thus to assume an EPA range based on the fact that Lucid might get to use the same number for one of those factors that another manufacturer did with no knowledge of the other factors is naive in the extreme in the opinion of this engineer.

If you're suggesting that Lucid is not aware of the design or specs of the key Tesla components, I'm not sure that is true. There's a lot of very specific knowledge at Lucid of key Tesla components.

Peter Rawlinson was the Chief Engineer of the original Model S. Although he left in 2013, he certainly knew the car and its components intimately up to that point. Less certain, but quite likely, is that he stayed abreast of at least some subsequent Tesla developments in some detail.

Eric Bach, the head of Hardware Engineering at Lucid held that same post at Tesla until 2015.

Peter Hasenkamp, the head of Supply Chain Management at Lucid came from the same role at Tesla in 2018.

Peter Hochholdinger, the head of Manufacturing at Lucid held that same post at Tesla until 2019.

Unless Tesla was unusually chimneyed in its operations, all of these guys -- including Hochholdinger as recently as just over a year ago -- would have been privy at considerable depth to the technology across all the functions at Tesla.

I've dealt with a lot of non-compete battles in my career as an HR lawyer, and certainly these guys from Tesla could not use what they knew to duplicate Tesla products or technology at Lucid. However, they were certainly free to use that knowledge to set benchmarks to meet or exceed using their own approaches.

My guess is that if Rawlinson thinks he can convince the EPA to give his components as much credit for efficiency as it gives Tesla, he has good reason for thinking so.

 

[duff]

There is information hidden in that. Twenty miles in a minute means 1200 miles per hour. The largest CCS chargers in the US are 350 kW units capable of delivering 350 kWh in an hour. The rated consumption of the car must thus be 350/1200 = 0.292 or 292 Wh/mi.

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.

 

[ajdelange]

If you're suggesting that Lucid is not aware of the design or specs of the key Tesla components, I'm not sure that is true.

No, no. I'm not suggesting that at all. You, nor I, have any idea what drag and mass coefficients were loaded into the dynamometer nor do we have any idea as to how the test was conducted nor do we have any idea as to what derating factors (there are at least two tests each with its own derating factor) might or might not be acceptable to EPA. We have no reason whatsoever to suppose that it would be the same as for any other car. Thus, were I to suggest based on the presented data, to a group of fellow engineers, that the Lucid is going to have 517 miles on its Morony sticker I'd be laughed out of the room or there would be mutterings to the effect that 'ol A.J. has finally lost it.

You as a layperson are expected to be naive about such things. In fact stunts like this one and, for that matter, all advertising, is specifically designed to exploit this naivete. 517 EPA rated miles on a 110 kW discharge capacity battery is 213 Wh/mi. The S's 403 mi on A 100 Kwh battery is 248. That's a 16% improvement. There isn't 16% more improvement to be attained from motors and inverters. To get that kind of improvement you need a bigger battery and that's what Lucid has evidently done and will do.

I've tried to explain what is going on in terms of the fundamentals of physics and the state of the art. This is very hard to do when in the first place no one is in posession of the facts and in the second the audience does not speak the language necessary to understand the principles. 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.

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