Range predictions

[Johnny5]

It looks like Tesla Cybercab is going to hit 6 miles/kWh EPA rating. Obviously that’s way more aero than Slate. Perhaps they will come out with a version with no hatch and a tailgate instead. The could call it Cyberute.

There could totally be aero bodies for slate hypermiling! Nerd life! We live it!

 

[Revenant89]

1: vibes

😂

 

[Kopsis]

The "public 3D model" is nowhere near the fidelity needed for a credible Cd estimate. The linkedin post identifies missing detail that could result in better Cd but there are just as many (if not more) missing details that can cause a worse Cd.

Slate obviously has much higher fidelity internal models. If those models show such impressive aerodynamic efficiency (for a pickup), what value would their be in low-balling the range estimates by a large amount? Especially given that they're trying to get consumers (and more importantly, investors) to embrace the design.

 

[E90400K]

The EPA range test should include winter and summer driving cycles. And the Monroney window data sheet should include charge time for winter DC fast charging. Those are the truly important metrics for EV ownership.

 

[TPL]

It's dumb that the range is just one number. In ICE and hybrid vehicles you have different MPG for highway and city since all vehicles have different efficiency ratings depending on the driving speed.

Further, EVs just have MPGe which is a useless metric. Who cares about comparing battery size with the energy density of gasoline? You can't fill an EV up with gas, and you can't fill up a gas car with kwh. In addition, the MPGe is made further useless by including charging losses.

The EPA cycle produces the same highway and city measurements regardless of drivetrain, which is one reason why MPGe exists. It's the same flawed "highway" cycle of course.

A more useful "highway" measure would be range at 70 mph. Better yet, a 2-d graph showing range at constant speed in 5 mph increments.

 

[Revenant89]

The "public 3D model" is nowhere near the fidelity needed for a credible Cd estimate. The linkedin post identifies missing detail that could result in better Cd but there are just as many (if not more) missing details that can cause a worse Cd.

Slate obviously has much higher fidelity internal models. If those models show such impressive aerodynamic efficiency (for a pickup), what value would their be in low-balling the range estimates by a large amount? Especially given that they're trying to get consumers (and more importantly, investors) to embrace the design.

You do know pickups aren't inherently bad, right? It's the massive lifted monstrosities of conventional pickups that are bad.

Rivian R1T 0.30
Chevy Silverado EV 0.33
Tesla Cybertruck 0.34
Which, by the way the same guy got 0.43 on a digital concept cybertruck model.

As to why Slate is low balling.. maybe to under promise and over deliver. Maybe there was a flaw in their testing. But there's no possible way the Slate is going to get only 3.0 mi/kWh in the EPA test cycle. Which is what the website is stating currently.

 

[GaRailroader]

And the Monroney window data sheet should include charge time for winter DC fast charging. Those are the truly important metrics for EV ownership.

Should be a moot point provided the Slate has battery preconditioning. I wonder if it will? With a Tesla if you are navigating to a Supercharger it will automatically precondition the battery for peak charging speed regardless of season. Hopefully there is some way to toggle battery conditioning 20-30 minutes before you get to a DC fast charger.

 

[E90400K]

Should be a moot point provided the Slate has battery preconditioning. I wonder if it will? With a Tesla if you are navigating to a Supercharger it will automatically precondition the battery for peak charging speed regardless of season. Hopefully there is some way to toggle battery conditioning 20-30 minutes before you get to a DC fast charger.

En route preconditioning to warm or cool the battery affects range.

 

[cadblu]

I recall there was a bit of confusion on the stated range with the larger battery. While the specs list the range as 240, some folks at Slate reported it as 230 miles. Perhaps not a big deal, but it’s going in the wrong direction. There was also some speculation that the standard battery chemistry would be Lithium Ion chargeable to 100%. Will need to wait another month to get some clarification.

 

[Revenant89]

I recall there was a bit of confusion on the stated range with the larger battery. While the specs list the range as 240, some folks at Slate reported it as 230 miles. Perhaps not a big deal, but it’s going in the wrong direction. There was also some speculation that the standard battery chemistry would be Lithium Ion chargeable to 100%. Will need to wait another month to get some clarification.

I definitely hope they change to LFP batteries.. it would make so much more sense. NMC only made sense to get the incentive. But if the highway range is much less than what they projected that will be upsetting.

 

[beatle]

LFP is truly terrible in the cold, and with such a flat voltage curve, it can make for further unpredictable range estimates. Definitely not a good look for a new automaker. Ask any of the Rivian LFP owners. Not to mention LFP's lower energy density from NMC. With such a small platform, you really need a dense battery chemistry to get any kind of meaningful range.

 

[GaRailroader]

En route preconditioning to warm or cool the battery affects range.

Agreed. My point was there is no need to show different seasonal charging times if you have the ability to pre-condition the battery. Most of the EV makers are advertising 10-80% charge times and that would be a great thing to have on the Monroney sticker.

 

[beatle]

Charging times can also vary based on the DCFC itself. Many (all?) manufacturers have adjusted charge curves via OTA updates. Sometimes they actually make the charging curve worse. My P85D started supercharging a lot slower in late 2019. Starting from the "actual" 10% SoC can be more difficult than it seems, especially on cars with LFP batteries that have very flat voltage curves.

The 10-80% charge time is useful marketing info, but I don't think it can be standardized enough to go on the Monroney sticker.

 

[E90400K]

Agreed. My point was there is no need to show different seasonal charging times if you have the ability to pre-condition the battery. Most of the EV makers are advertising 10-80% charge times and that would be a great thing to have on the Monroney sticker.

Though my point was the Monroney sticker should include (more importantly) winter range losses, which is a factor of battery preconditioning. Even though preconditioning (warming) does help improve charge times it doesn't fully recover charge speeds to ideal ambient temp conditions around 70 deg. F.

 

[Revenant89]

LFP is truly terrible in the cold, and with such a flat voltage curve, it can make for further unpredictable range estimates. Definitely not a good look for a new automaker. Ask any of the Rivian LFP owners. Not to mention LFP's lower energy density from NMC. With such a small platform, you really need a dense battery chemistry to get any kind of meaningful range.

I guess I'm biased being in the south.. but LFP would be thousands cheaper. And I don't want to worry about charging it carefully over the long term.