Lucid's Charging Curve, can it be improved via OTA update?

[BS8899]

Read my earlier posting on this tread. I explicitly said that part of the Lucid charging problem might be EA chargers. I charge on Rivian on Rivian Adventure Chargers. The Rivian chargers are 300 kW...and they deliver reliably to mid to high 200 kW range at low SoC and mostly sustain to >150kW up to ~80% SoC. I have never come across an EA charger (where I charge my Lucid) that delivers this level of power consistently.

I drove the Quartzsite AZ to Barstow CA route a few times in my R1S. I took the I-10/I-215/I-15 route, approx. 265 miles. I travel this route because there are Rivian Adventure charging stations at both Quartzsite and at Barstow. The travelled distance is ~265 miles between these two locations. Elevation change is ~1.300 ft. I cover this route using ~85% of my SoC (135kWh large pack). This is ~2.4m/kWh with the 1,300 ft elevation change. Yes, I wasn't going @85mph.

 

[coma24]

I think it would be nice to have a 'max rate' charging option, similar to that choice on our A/C panel. The standard then being the more conservative (longer battery life) curve, with the option to flatten the curve when you feel the need to do so. Perhaps implementing this would be more technologically demanding than I'm imagining. If I had only one option, I would prefer the current trade-off between charging time and battery life, but I could see where others would prefer the exact opposite.

I raised this with Zach at the NY owners rally and he laughed (I can see why), and said that it would be a first to go to the software group to ask for an option to deliberately slow down the fast charging. He knew what I was getting at, but it still drew a smile (which was nice since he generally gets pelted with CarPlay, AA and key fob questions). Realistically, slow-playing the charging has etiquette issues at public fast charging locations so even if it could be achieved with a clean User Interface modification, there's still the concern over people now tying up chargers even longer (we struggle seeing people charging very slow to 100% now....imagine if the car was artificially slowing the charging even before reaching 80%, for example).

 

[coma24]

Read my earlier posting on this tread. I explicitly said that part of the Lucid charging problem might be EA chargers. I charge on Rivian on Rivian Adventure Chargers. The Rivian chargers are 300 kW...and they deliver reliably to mid to high 200 kW range at low SoC and mostly sustain to >150kW up to ~80% SoC. I have never come across an EA charger (where I charge my Lucid) that delivers this level of power consistently.

That is not an EA charging deficiency. Due to charging curve decisions, your Lucid isn't asking for 150kw up to 80% SoC. Beyond 50%, my recollection is that is' already < 150kw, and decreases in a more or less linear fashion, then even steeper after 80%.

 

[Buffalo Bob]

I raised this with Zach at the NY owners rally and he laughed (I can see why), and said that it would be a first to go to the software group to ask for an option to deliberately slow down the fast charging. He knew what I was getting at, but it still drew a smile (which was nice since he generally gets pelted with CarPlay, AA and key fob questions). Realistically, slow-playing the charging has etiquette issues at public fast charging locations so even if it could be achieved with a clean User Interface modification, there's still the concern over people now tying up chargers even longer (we struggle seeing people charging very slow to 100% now....imagine if the car was artificially slowing the charging even before reaching 80%, for example).

In the scenario I specified, the 'standard' I mentioned would be the way it works today. The max option would go faster than the status quo, albeit at a greater risk to battery longevity. The part of the equation I had not considered was people who would hit the max button all the time, and then put in a warranty claim years later because they prematurely degraded their battery below the warranty limit.

 

[sri]

I find Lucid charging curves are not better compared to Porsche, Hyundai and Kia. Charging curve drops sharply immediately after 5 to 10min. I saw my friends cars holding up the rate better until they reach 80%. Hope Lucid find a way to hold the speed until 80% like others.

I am not much concerned from above since i can still travel further compared to my Friend’s even with no better charging curve

 

[Adnillien]

Agree with your explanation RE: the battery self-heating during charging is the same, as long as the charge rate is the same. Thus, it calls into question:
> If the self-heating of the battery and other degradations that affect battery life (e.g., cell electrode erosion/dendrites) are mostly determined by charging/discharging processes, why a 900V architecture make sense since it mostly benefits the bus bars and wiring harness but not the batteries, correct?
> by the same argument, why can other EVs maintain a flatter charging curve than Lucid?

The 900V architecture is much more beneficial on the inverter motor drive side than on the battery charging side. The lower current on the drive side does result in less IR loss so the 900V systems have real efficiency advantages.

 

[coma24]

I find Lucid charging curves are not better compared to Porsche, Hyundai and Kia. Charging curve drops sharply immediately after 5 to 10min. I saw my friends cars holding up the rate better until they reach 80%. Hope Lucid find a way to hold the speed until 80% like others.

I am not much concerned from above since i can still travel further compared to my Friend’s even with no better charging curve

if it helps, Lucid's view on this is to focus on "how many miles per minute can I add," and "how long will I need to charge so that I can reach my destination?" It's not always about the 20-80% number.

Also, I'm sure they COULD adjust the curve to have much more aggressive charging rates up to 80%.....at the expensive of battery longevity. I would trust their take on this much more than I would ICE manufacturers who are coming in without Lucid's level of experience in this field.

Consider that every trait of the driving/charging experience represents SOME level of compromise. Consider that cars which are charging to 80% with 'miracle' charging curves are doing so at the expense of long term battery health.

 

[rfc805]

Exactly, it's not "I hope they can figure it out". They can set it to anything they want - they could tell it to just rip 300kW all the way to 100%. It'll just rapidly degrade the battery.

Given Lucid's general approach to "make the car generally a better thing for people", including somewhat against customer's demands, my guess is they're being very conservative with battery longevity in their charging curve.

There is no magic "figure it out" that the other manufacturers have done - they have simply chosen a shorter battery lifespan/higher degradation profile. Long term, we'll have to see how they do. There simply isn't enough data at this point as the vehicles are all too young, and the manufacturers don't release their simulation data.

 

[RM-S8]

My GT-P charges at 145-155kW up to 72%. I believe only the GT-P and DE do this. However, 2025 models should have similar charging curves.

Same here.

 

[chinesejpl]

My agt charges at times up to 310kw but that only lasts for 1 sec. Then it drops quickly to about 270kw within 10 sec and is below 200kw with soc about 25-30%. It then sits around 165kw until about 50% and in the low to mid 100 kw until about 65-70% and from 70-80% it is at 65kw. It takes me 42-45min to go from 10-80%. This is on electrify Canada which is the most reliable here in BC. Petro Canada is even slower

I too wish it could have a flatter curve.

One way to look at lucid's decision to curb their charging is whether they are losing potential customers for the sake of presumed battery Longevity as maybe more people would buy an air if it was the longest range and fastest overall charging car? Also, I mention presumed because I'm not sure anybody definitively knows whether a flatter charging curve reduces battery Longevity. I remember when there were concerns out there that suoercharging teslas would reduce battery life which recently has been suggested is not actually the case

 

[rfc805]

It is actually well known that higher rate of charge at higher SoC reduces battery longevity, it isn't an unknown. The question is just exactly how much the result is over time. See video I linked above, he explains it well and provides references.

I think it's also well known for Teslas that especially in the early models, people were reluctant to buy used models because they were frequently having significant battery pack failures in <= 10 years.

Long term - which reputation is worse? Costing you another 5 minutes when fast charging, or nobody wanting to buy your cars 2nd hand due to pack reliability concerns?

This is exactly why there isn't "better" - it's a compromise. Presumably Lucid have data that back up the curve they've chosen, leading to a % of longevity that they're happy with. We don't know what that actually is, and we also don't know what it looks like when they manipulate the curve up - but I'm sure they have done the simulations and have chosen this.

I'm sure they'll revise it over time if they see less degradation in reality than their simulations show, but this is a process that will happen over years, because we're talking 10 years of battery life at least that they're concerned with. It wouldn't shock me if Lucid is looking more to 15-20 year life, while Porsche and Rivian are looking at 10.

 

[pjdcorp]

Wow. Had to read it twice, not because of your writing, but because of my comprehension. There’s a reason I never became a lawyer. Very informative. Thank you.

Or an engineer

 

[coma24]

I was still seeing ~160kW at 75% in the Lucid. I think it did drop to ~120kW around 80%.

What the.... what manner of witchcraft is this? What sorta goat, chicken or unsuspecting Tesla owner would I need to sacrifice to make this happen?

 

[rfc805]

What the.... what manner of witchcraft is this? What sorta goat, chicken or unsuspecting Tesla owner would I need to sacrifice to make this happen?

Don't know, the car is only a month old yesterday, and I've done 5 fast charging sessions total. The first isn't very good because it was a balanced charger that was being shared, and I did it at like 50% SoC just to test plug and charge/fast charging.

The other 4 (all EA 350kW stations)
49.6 kWh / 20 minutes (148.8 kW average)
53.6 kWh / 23 minutes (139.8 kW average)
63.9 kWh / 26 minutes (147.4 kW average)
51.2 kWh / 19 minutes (161.6 kW average)

Correct me if I'm getting my math wrong here. I charged to between 80-85% each time.

 

[BS8899]

It is actually well known that higher rate of charge at higher SoC reduces battery longevity, it isn't an unknown. The question is just exactly how much the result is over time. See video I linked above, he explains it well and provides references.

I think it's also well known for Teslas that especially in the early models, people were reluctant to buy used models because they were frequently having significant battery pack failures in <= 10 years.

Long term - which reputation is worse? Costing you another 5 minutes when fast charging, or nobody wanting to buy your cars 2nd hand due to pack reliability concerns?

This is exactly why there isn't "better" - it's a compromise. Presumably Lucid have data that back up the curve they've chosen, leading to a % of longevity that they're happy with. We don't know what that actually is, and we also don't know what it looks like when they manipulate the curve up - but I'm sure they have done the simulations and have chosen this.

I'm sure they'll revise it over time if they see less degradation in reality than their simulations show, but this is a process that will happen over years, because we're talking 10 years of battery life at least that they're concerned with. It wouldn't shock me if Lucid is looking more to 15-20 year life, while Porsche and Rivian are looking at 10.

I don't think anyone is advocating charging or fast charging beyond a certain SoC. Typically, this "threshold" is around 80% for Li batteries. I am no expert on the subject but there is plenty of literature and research on this issue. It is a well-known electrochemistry phenomenon. Broadly speaking, my recollection is, charging to and HOLDING at 100 percent for an extended time results in "corrosion" of the electrodes (plating, dendrites etc.) which compromises the battery's lifetime. Thus, it is general good practice to not charge to and hold at100% SoC for an extended time. Others who are far more expert than I can chime in and correct any misconceptions.

The issue discussed in this thread is not about charging ang holding at 100% SoC. The issue we are trying to elucidate and optimize is about how best to replenish charge forroadtrips.

 

[BS8899]

Don't know, the car is only a month old yesterday, and I've done 5 fast charging sessions total. The first isn't very good because it was a balanced charger that was being shared, and I did it at like 50% SoC just to test plug and charge/fast charging.

The other 4 (all EA 350kW stations)
49.6 kWh / 20 minutes (148.8 kW average)
53.6 kWh / 23 minutes (139.8 kW average)
63.9 kWh / 26 minutes (147.4 kW average)
51.2 kWh / 19 minutes (161.6 kW average)

Correct me if I'm getting my math wrong here. I charged to between 80-85% each time.

If you are hitting 150+/- kW AVERAGE for your charging session all the way to 80-85%, these are respectable numbers.

 

[Rogue]

If you are hitting 150+/- kW AVERAGE for your charging session all the way to 80-85%, these are respectable numbers.

That is likely a 2025 GT? Again, for those on the thread, Lucid does average 150kw today through to 80% in a flattish curve for the following trims: GT-P, DE, and 25' GT.

If you have a Pure, Touring, or pre-25' GT, then your charging curve is completely different. Maybe they will swap Pure and Touring trims with the new chemistry. Maybe they will do a Porsche move with greater cooling capacity.

Either way, Lucid has likely hit the limits on the charging curve with current hardware.

 

[BS8899]

I don't think anyone is advocating charging or fast charging beyond a certain SoC. Typically, this "threshold" is around 80% for Li batteries. I am no expert on the subject but there is plenty of literature and research on this issue. It is a well-known electrochemistry phenomenon. Broadly speaking, my recollection is, charging to and HOLDING at 100 percent for an extended time results in "corrosion" of the electrodes (plating, dendrites etc.) which compromises the battery's lifetime. Thus, it is general good practice to not charge to and hold at100% SoC for an extended time. Others who are far more expert than I can chime in and correct any misconceptions.

The issue discussed in this thread is not about charging ang holding at 100% SoC. The issue we are trying to elucidate and optimize is about how best to replenish charge forroadtrips.

Also, I think there are (at least) two mechanisms at play here. DCFC (and discharging) generates heat because of the high current. Going to a higher voltage alleviates some of the thermal concerns (and reduce the bulk in wiring/bussing). The electrode corrosion/plating problem is a separate mechanism driven by the electrochemistry in the battery. However, prolonged exposure to higher temperature and holding at high SoC exacerbate the problem.

Typically, I charge to 80% SoC for everyday use. I DO charge to 100% SoC for the first leg of my long road trips. It is only @ 100% SoC for "a few hours". For storage (say 3 months), I charge and maintain to 60-70% SoC.

Welcome perspectives from experts on the subject.

 

[rfc805]

Check out the Engineering Explained video I linked regarding the lithium ion plating. The tl;dr is it happens at all SoC, and it's just a question of the probability/rate which it happens at different SoC based on a different charging rate. At both higher SoC and higher charging rates and higher temperatures it happens more and more, but each is a factor. So even charging too fast at a low SoC can be damaging, but doing it at higher SoCs, even at say 80%, you get into "guaranteed degradation" parts of the curve. That's what they're trying to avoid.

He put links to the source material in the description, but charts on SoC vs rate of charge and plating are from https://iopscience.iop.org/article/10.1149/1945-7111/abace9

 

[BS8899]

Check out the Engineering Explained video I linked regarding the lithium ion plating. The tl;dr is it happens at all SoC, and it's just a question of the probability/rate which it happens at different SoC based on a different charging rate. At both higher SoC and higher charging rates and higher temperatures it happens more and more, but each is a factor. So even charging too fast at a low SoC can be damaging, but doing it at higher SoCs, even at say 80%, you get into "guaranteed degradation" parts of the curve. That's what they're trying to avoid.

I understand the mechanistic aspect of the "plating" process is always there. The question herein is the rate. As an example, if you have piece of iron sitting in the open, it will rust. It is destiny. If you keep it cool and dry, it might last a "lifetime". Add moisture, temperature, and voltage, it can turn into a pile of rust overnight. Like all thermodynamic processes, it is driven by temperature and voltage (overvoltage) gradients. Entropy at work!