InsideEVs Podcast episodes

Will you' all be doing a Friday, December 31, 2021 YouTube?

If so, it would be neat to see their favorite adult beverage for after the broadcast. <GRINS>

Bob Wilson
 
bwilson4web said:
Will you' all be doing a Friday, December 31, 2021 YouTube?

If so, it would be neat to see their favorite adult beverage for after the broadcast. <GRINS>

Bob Wilson
Click to expand...
Yes, we're planning on a live show on Friday morning. I was about to say I only have sake in the house, which I'm not sure is a great morning drink, but then I remembered I have this bottle of coffee Jägermeister someone gave me about a year ago. Hmm. ;)
 
I watched #92, as I was interested to learn more about the Silverado EV. First off, I totally agree with Domenick calling it the Avalanche. That's what they should have called it. I used to own an Avalanche, and have to say it was the most useful and versatile truck I ever owned. I owned a rental home back then, as well as my cabin, and both required periodic maintenance such as deck and dock rebuilds. I had the 2500 model and wow could I haul lumber with that thing. Close up the mid gate and it was like a luxury SUV (I had the top trim). And towed my boat like it wasn't there (8.1L engine). Also liked the fast charging of the EV, 100 miles in 10 minutes,... that's pretty decent. But agree, waiting until 2024 is too long for this vehicle...

I also liked the looks of the Equinox, but need more details. I disagree with the comments that only need 250 miles of range. This will be a car for the masses who will want to use it for trips. 350 miles is the minimum. That's the biggest issue most non-EV owners point to for not buying an EV now. And again waiting 2 years is too long.

I also think both the BMW and Mercedes look downright ugly. Esp that BMW front end, looks even worse than the ICE ones which at least were trending smaller and less obtrusive. These guys still have their heads stuck in the past.

New Chrysler looks half decent, but have no faith in their ability to deliver anything innovative. And by the time it is available in 3 years, will have obsolete tech. Chances are parent company Stellantis will be in deep financial trouble by then.
 
We have a 2014 BMW i3-REx that technically is considered a UFO in Mississippi. It still is better than the 2017 Prius Prime we traded in for a 2019 Tesla Model 3 Std Rng Plus.

The worst thing BMW did was to chase off their I3 design engineers and sell their carbon fiber plant. BMW is trying to fix their four year old mistake but nothing happens instantly. Perhaps not obvious but the new hire engineers likely look at BMW as a way to get a good job with Tesla.

No thinking, young engineer would trust the BMW board of directors ... until more of those fossils go away.

Bob Wilson
 
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I appreciate the ‘Lucid range’ podcast not because of the car but your team discussion of ‘70 mph’ testing.


My +10 years of Prius testing revealed ~63 mph within a Standard Day comes closest to achieving EPA metrics. But I also appreciate using 70 mph for the reasons you discussed.

Perhaps a little too abstract, I like to use the EPA roll down metrics to model the total vehicle drag power required at different speeds. This lets me see the efficiency of the drivetrains. But then I’m a retired (aka unemployable) engineer.

Regardless, I appreciate your work and wish you’all well.

Bob Wilson
 
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bwilson4web said:
I appreciate the ‘Lucid range’ podcast not because of the car but your team discussion of ‘70 mph’ testing.


My +10 years of Prius testing revealed ~63 mph within a Standard Day comes closest to achieving EPA metrics. But I also appreciate using 70 mph for the reasons you discussed.

Perhaps a little too abstract, I like to use the EPA roll down metrics to model the total vehicle drag power required at different speeds. This lets me see the efficiency of the drivetrains. But then I’m a retired (aka unemployable) engineer.

Regardless, I appreciate your work and wish you’all well.

Bob Wilson
Click to expand...

Is this the coastdown data you look at, Bob?
 

Attachments

I’m on iPhone and will check later. Here is the URL where I download the data:
https://www.epa.gov/compliance-and-fuel-economy-data/data-cars-used-testing-fuel-economy

There is a quadriplegic formula to convert to the drag force. Then you can plot the drag power as a function of speed. This is great for comparing vehicles.

As you point out, manufacturers can do the 2 or 5 test and afterwards ‘sandbag’ a worse mileage number. But the roll down coefficients are consistent for all vehicles.

Another approach is to do three, 10 mile benchmarks:
  • 20-30 mph - one constant speed
  • 40-50 mph - another constant speed
  • 60-70 mph - 3d constant speed
Use the three points fitted to a quadratic equation and you can plot consumption as a function of speed. Very useful when customizing a car.

For example my Model 3 has after market light weight rims and Bridgestone ECOPIA tires. Below 45 mph, I’m ahead but higher speeds I’m about 2-3% behind. So I’m working on aero covers.

Bob Wilson
 
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bwilson4web said:
I’m on iPhone and will check later. Here is the URL where I download the data:
https://www.epa.gov/compliance-and-fuel-economy-data/data-cars-used-testing-fuel-economy

There is a quadriplegic formula to convert to the drag force. Then you can plot the drag power as a function of speed. This is great for comparing vehicles.

As you point out, manufacturers can do the 2 or 5 test and afterwards ‘sandbag’ a worse mileage number. But the roll down coefficients are consistent for all vehicles.

Another approach is to do three, 10 mile benchmarks:
  • 20-30 mph - one constant speed
  • 40-50 mph - another constant speed
  • 60-70 mph - 3d constant speed
Use the three points fitted to a quadratic equation and you can plot consumption as a function of speed. Very useful when customizing a car.

For example my Model 3 has after market light weight rims and Bridgestone ECOPIA tires. Below 45 mph, I’m ahead but higher speeds I’m about 2-3% behind. So I’m working on aero covers.

Bob Wilson
Click to expand...
I went to this page and opened up the 2022 spreadsheet. Was interesting to see some models not yet listed on fueleconomy.gov, but couldn't figure out any useful data aside from horsepower numbers.
 
Check columns:
  • BC - Target Coef A (lbf)
  • BD - Target Coef B (lbf/mph)
  • BE - Target Coef C (lbf/mph**2)
The formula for HP:

HP = v * (A + B*v + C*(v*v)) / 375
745 W = 1 hp​

Create a spreadsheet with a column of mph from 10 mph to your desired max mph in whatever increments you want. Then setup a column for each vehicle using separate columns of the coefficients. Load the cells and do a scatter plot where speed is the X-axis and resulting HP or kW is the Y-axis.

ENJOY!

Bob Wilson
 
bwilson4web said:
Check columns:
  • BC - Target Coef A (lbf)
  • BD - Target Coef B (lbf/mph)
  • BE - Target Coef C (lbf/mph**2)
The formula for HP:

HP = v * (A + B*v + C*(v*v)) / 375
745 W = 1 hp​

Create a spreadsheet with a column of mph from 10 mph to your desired max mph in whatever increments you want. Then setup a column for each vehicle using separate columns of the coefficients. Load the cells and do a scatter plot where speed is the X-axis and resulting HP or kW is the Y-axis.

ENJOY!

Bob Wilson
Click to expand...
Thanks, Bob!
 
Just sharing some 'lessons learned':
  • Typically 3-4 vehicle graphs work as any more becomes confusing.
  • Use 3-4 columns on the left to hold on each row: vehicle name, Coef A, Coef B, and Coef C
  • The next MPH column works best starting around 10-15 mph with a 5 mph increment going down the row
  • Each vehicle column uses the "name" and "coefficient" values in a source column
  • Cut-and-paste for vehicle columns makes it trivial to generate the vehicle values
  • Select columns for a 'scatter' graph showing the vehicles
Would you like an OpenOffice, spreadsheet example?
  • 2019 Tesla Model 3, Tesla Plaid, Lucid Air, and Ford Mach-E
Bob Wilson
 
bwilson4web said:
Just sharing some 'lessons learned':
  • Typically 3-4 vehicle graphs work as any more becomes confusing.
  • Use 3-4 columns on the left to hold on each row: vehicle name, Coef A, Coef B, and Coef C
  • The next MPH column works best starting around 10-15 mph with a 5 mph increment going down the row
  • Each vehicle column uses the "name" and "coefficient" values in a source column
  • Cut-and-paste for vehicle columns makes it trivial to generate the vehicle values
  • Select columns for a 'scatter' graph showing the vehicles
Would you like an OpenOffice, spreadsheet example?
  • 2019 Tesla Model 3, Tesla Plaid, Lucid Air, and Ford Mach-E
Bob Wilson
Click to expand...
Just a screenshot would be fine, since my math capabilities are somewhat below engineer level. :)
 
Here is an example chart:
upload_2022-1-27_5-17-40.webp

  • Lucid has excellent low drag at low and high speeds
  • Model 3 has higher drag at lower speeds - tires
  • Model 3 has better drag than Plaid at high speeds
Based on this chart, I would look at lighter weight and narrower tires for the Model 3. Better tires would make the Model 3 more efficient in kWh per mile.

I've embedded the OpenOffice spreadsheet in an attached ZIP file. If you have questions, let me know and we can tweak the chart for other vehicles and details. For example, I would set the X-axis scale to 60-70 mph and the Y-axis scale to expand the HP details. Prius experience has shown EPA metrics can be achieved by holding 63 mph on a benchmark loop.

Bob Wilson
 

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