Beware: reduced charging speeds if frequently fast charging

[segbrk]

I think you meant 200kW, not 200kWh. The Pure has a lower ceiling of charging Wattage than the AGT, correct? I thought it is 225 or 250 kW.

That said, according to @Adnillien, all the Airs use the same battery pack. The differences is in the number of packs. With fewer kWh batteries in the Pure/Touring, the charge RATE should be the same (same as the AGT) as long as there is enough voltage to sustain the charge. Isn't that correct? Are there other limiting factors that affect the CHARGE RATE?

All Airs do not use the same cells, though aside from the special ones in the Dream Editions I don’t think it makes much of a difference to charging. More cells does equal higher charge rate. You’re adding more batteries that can charge at the same wattage, so the pack overall can take and distribute more wattage.

 

[BS8899]

All Airs do not use the same cells, though aside from the special ones in the Dream Editions I don’t think it makes much of a difference to charging. More cells does equal higher charge rate. You’re adding more batteries that can charge at the same wattage, so the pack overall can take and distribute more wattage.

Yes, more cells takes on more charge. That's why the AGT and DE can charge at a higher kW. But when normalized to SoC, is there (should there) be a difference in how fast the different trims charge to a given SoC?

 

[nothingemotional]

I think you meant 200kW, not 200kWh. The Pure has a lower ceiling of charging Wattage than the AGT, correct? I thought it is 225 or 250 kW.

That said, according to @Adnillien, all the Airs use the same battery pack. The differences is in the number of packs. With fewer kWh batteries in the Pure/Touring, the charge RATE should be the same (same as the AGT) as long as there is enough voltage to sustain the charge. Isn't that correct? Are there other limiting factors that affect the CHARGE RATE?

Yep, my bad meant to say kW

 

[WhistleKing30]

Lithium batteries are sensitive to heat. And DC fast-charging creates a buttload of heat. Current EV battery packs simply are not designed with the intention of exclusive fast-charging. If Lucid decided on some form of throttling it might not be such a bad thing as it might just save your battery.

Bjørn Nyland made an interesting video discussing a 2021 Tesla Model 3 that was almost exclusively supercharged (link). The battery was charged about 16,000 kWh (about 200 full cycles) and the battery saw a degradation of over 15%. This 15% is massive. But more importantly, supercharging also significantly increases the chance of one individual cell to fail. Often resulting in the battery pack needing to be refurbished or even replaced ($$$).

I think you meant 200kW, not 200kWh. The Pure has a lower ceiling of charging Wattage than the AGT, correct? I thought it is 225 or 250 kW.

That said, according to @Adnillien, all the Airs use the same battery pack. The differences is in the number of packs. With fewer kWh batteries in the Pure/Touring, the charge RATE should be the same (same as the AGT) as long as there is enough voltage to sustain the charge. Isn't that correct? Are there other limiting factors that affect the CHARGE RATE?

I guess what you meant is the difference in the number of modules. One battery pack consists consists of a collection of modules. Then the amount of modules determine the capacity of the battery (in kWh). Typically, a different capacity or different amount of modules is considered to be a different pack. As far as I know, all Airs use the same architecture, but in different collection of modules / configurations..

And indeed, the charge rate should be somewhat similar, with the C-rating being the charge current proportional to the battery capacity.

 

[Adnillien]

I think you meant 200kW, not 200kWh. The Pure has a lower ceiling of charging Wattage than the AGT, correct? I thought it is 225 or 250 kW.

That said, according to @Adnillien, all the Airs use the same battery pack. The differences is in the number of packs. With fewer kWh batteries in the Pure/Touring, the charge RATE should be the same (same as the AGT) as long as there is enough voltage to sustain the charge. Isn't that correct? Are there other limiting factors that affect the CHARGE RATE?

I said that the GT/Touring/Pure charge at the same current. I did NOT say that the GT and Touring and Pure will charge at the same rate. They do use the same battery pack and the Touring and Pure have fewer modules and thus fewer cells in series than the GT. Hence, the Touring and Pure have lower battery voltages than the GT. Since power is voltage * current, having the same current and lower voltages means the Touring/Pure will charge at a lower power in kW.

I also said that the 20% to 80% charging time should be the same since it takes less energy to charge the smaller Touring/Pure batteries. They charge at a lower power but the same current with the same 20% to 80% charging time.

 

[californiaboy935]

From my own experience I DC fast charge the car pretty exclusively; and have not experienced any drop off of the maximum charge output from DC charging on the EA network. I could be an outlier, but the picture I could find shows 154kW charge speed after 14 minutes of charging with EA, (from a 5% SOC) I’d say it probably started at 250kW which is the max I’ve seen from this particular station. I’ve gotten close to 300 on stations further away from downtown LA like the one in Colton, CA which consistently gives me 325kW charge speed starting out but ramps down like all chargers.

Obviously, this is a purely anecdotal experience, but important for many to hear.

My car currently sits at 52,398 miles and counting.

 

[BS8899]

I said that the GT/Touring/Pure charge at the same current. I did NOT say that the GT and Touring and Pure will charge at the same rate. They do use the same battery pack and the Touring and Pure have fewer modules and thus fewer cells in series than the GT. Hence, the Touring and Pure have lower battery voltages than the GT. Since power is voltage * current, having the same current and lower voltages means the Touring/Pure will charge at a lower power in kW.

I also said that the 20% to 80% charging time should be the same since it takes less energy to charge the smaller Touring/Pure batteries. They charge at a lower power but the same current with the same 20% to 80% charging time.

If the GT/Pure/Touring charge at the same current, but the voltages are adjusted accordingly to match the same number of cells, then, the charge rates (using your #s) from 20% to 80% should be similar, correct?

If that's true, then we have the same understanding.

The original post seems to suggest that the Pure/Touring charge at a slower rate (20% to 80%). Since the GT/Pure/Touring all charge at the same current, for the Pure and Touring packs to charge slower (again, 20-80%) they must be voltage limited. Is that the correct interpretation?

 

[BS8899]

From my own experience I DC fast charge the car pretty exclusively; and have not experienced any drop off of the maximum charge output from DC charging on the EA network. I could be an outlier, but the picture I could find shows 154kW charge speed after 14 minutes of charging with EA, (from a 5% SOC) I’d say it probably started at 250kW which is the max I’ve seen from this particular station. I’ve gotten close to 300 on stations further away from downtown LA like the one in Colton, CA which consistently gives me 325kW charge speed starting out but ramps down like all chargers.

Obviously, this is a purely anecdotal experience, but important for many to hear.

My car currently sits at 52,398 miles and counting.

View attachment 26773

I need some education here about charging and DCFC charging.

> DCFC charging involves high current and produces more heat than L2 charging, right?
> Presumably, when batteries are hotter, they are more susceptible to degradation (thermodynamics)?
> Aside from getting hotter, isn't there another mechanism at play vis-a-vis, the battery voltage gets higher when "fully charged" (i.e., 100% SoC)? Isn't this higher voltage a significant factor in promoting battery degradation?

If so,

> one would expect frequent DCFC to 100% SoC would like cause accelerated battery degradation (plating, dendrite growth, etc.).
> But I would think that even frequent DCFC to say 70% SoC (e.g., on road trip stops) without overheating the batteries would have much less adverse effect.


Thoughts?

 

[Adnillien]

If the GT/Pure/Touring charge at the same current, but the voltages are adjusted accordingly to match the same number of cells, then, the charge rates (using your #s) from 20% to 80% should be similar, correct?

If that's true, then we have the same understanding.

The original post seems to suggest that the Pure/Touring charge at a slower rate (20% to 80%). Since the GT/Pure/Touring all charge at the same current, for the Pure and Touring packs to charge slower (again, 20-80%) they must be voltage limited. Is that the correct interpretation?

It all depends on your definition of "rate." Do you mean Current? Power? Time? It would be much better to use the term that you actually mean.

 

[BS8899]

It all depends on your definition of "rate." Do you mean Current? Power? Time? It would be much better to use the term that you actually mean.

My understanding is:
How fast the battery charges is a function of current, voltage and temperature. In our prior discussions, you said that the charging (at least in the initial low SoC) is constant current. If so, the voltage is a resultant number that is dependent on the current and number of cells in the string. Is that correct?

What is not as clear to me is, as the batteries approaches high SoC, the current will decrease, correct? Since the cells are in series, they will all see the same current. At high SoC, is the voltage the controlling variable then?

Also, as we approach 100% SoC, would the battery chain's voltage "peak"? And if left in that state (100% SoC), would it promote adverse phenomena such as dendrites?

 

[momo3605]

+1 been doing a lot of exclusive EA charging while free and never saw any throttling. I typically see peaks of 150+. (I rarely plug in below 10%, so i almost never see 200)

 

[californiaboy935]

I need some education here about charging and DCFC charging.

> DCFC charging involves high current and produces more heat than L2 charging, right?
> Presumably, when batteries are hotter, they are more susceptible to degradation (thermodynamics)?
> Aside from getting hotter, isn't there another mechanism at play vis-a-vis, the battery voltage gets higher when "fully charged" (i.e., 100% SoC)? Isn't this higher voltage a significant factor in promoting battery degradation?

If so,

> one would expect frequent DCFC to 100% SoC would like cause accelerated battery degradation (plating, dendrite growth, etc.).
> But I would think that even frequent DCFC to say 70% SoC (e.g., on road trip stops) without overheating the batteries would have much less adverse effect.


Thoughts?

I think my real world experience has been good towards disproving degradation, battery tech isn’t perfect and my battery will deteriorate.

But I am of the opinion that people are very mislead in thinking the battery (at least Lucid’s architecture) needs to be baby’d. My Tesla model 3, sure over the three years of ownership I lost about 100 miles of range on my battery charging DC to 100% every time, just to be able to crawl into destinations. The lucid isn’t like that, I charge over 80% infrequently, and when I go over 80% I discharge it almost immediately.

I’ve seen maybe a 4-5% degradation that would be in line with the metrics on this forum for any battery to deteriorate over time.

I think a lot of why the used car market for lucid is so bad is because people don’t understand EV’s lasting lifecycle. And the accounting doesn’t make sense to the average person. Almost any vehicle if driven regularly will have problems, my Mercedes was in the shop more often then me driving it. (Slight exaggeration but still).

The battery and drive train in this car is meant to last, they broke the module with part efficiency and management, but the science of battery cells hasn’t changed. At least enough to justify the concerns that many have over the longevity of this vehicle.

 

[BS8899]

I think my real world experience has been good towards disproving degradation, battery tech isn’t perfect and my battery will deteriorate.

But I am of the opinion that people are very mislead in thinking the battery (at least Lucid’s architecture) needs to be baby’d. My Tesla model 3, sure over the three years of ownership I lost about 100 miles of range on my battery charging DC to 100% every time, just to be able to crawl into destinations. The lucid isn’t like that, I charge over 80% infrequently, and when I go over 80% I discharge it almost immediately.

I’ve seen maybe a 4-5% degradation that would be in line with the metrics on this forum for any battery to deteriorate over time.

I think a lot of why the used car market for lucid is so bad is because people don’t understand EV’s lasting lifecycle. And the accounting doesn’t make sense to the average person. Almost any vehicle if driven regularly will have problems, my Mercedes was in the shop more often then me driving it. (Slight exaggeration but still).

The battery and drive train in this car is meant to last, they broke the module with part efficiency and management, but the science of battery cells hasn’t changed. At least enough to justify the concerns that many have over the longevity of this vehicle.

While I believe in thermodynamics and entropy, and that the batteries will develop defects and eventual fail over time, I think the EV industry as a whole should endeavor to better understand the degradation mechanisms and practices to preserve/extend/repair the battery in order to extend their useful life.


I have two relatively new EVs, 2022 AGT w/ 14,500 miles and 2023 Rivian R1S w/ 9,500 miles. And I drive long distances (~780 miles one way, between AZ and CA).

At home (CA and AZ), I mostly use L2 charging to 80%. I usually charge my EV to 100% SoC hours before I leave on my long trips. En-route, I'd charge to between 70-80% SoC at DCFCs.

I don't have enough data to say definitely that my practice is good. I am basing my practice on what I know of batteries and electrochemistry. I am no expert in any of these subjects. Time will tell whether I am right or not.

My believe is that conservative practices such as not charging to and holding batteries at 100% SoC is a good. Practicing such practices does not make you immune to battery failures. It is inevitable that some cells might have defects and could fail. I believe most properly maintained battery packs will last quite long. And failures in properly maintain battery packs are likely caused by defects in a few isolated cells.

I am hoping that the after-market will evolve and provide battery cell replacements and repairs at a reasonable cost to extend the useful lives of the EV battery packs,.

Looking back at hybrid cars, (yes, I know they use a different battery technology), like the Toyota Prius, the battery on the Prius was expected to last 7-10 years. Yet, many older Prius are still on the road with their original batteries. My daughter is driving a 15 year old Prius, with its original battery, and it is working fine.

I am in no way encouraging callous practices in charging your EV. That said, I do believe if you practice conservative charging (e.g., charging to 70-80% SoC, use L2 where available, etc.) the batteries will last longer than you think.