BEV mass and Regeneration efficiency

[aerohead]

Originally Posted by freebeard

vs


Moving the goal posts closer together?

I'll apologize for #22 just to be gracious, but not #17 nor #19. </sarcasm>

They were never moved in the first place.

[aerohead]

I have no idea what your comment meant.

[aerohead]

I have no idea how to associate your comment in relation to BEV mass and regen.

[redpoint5]

I still have no idea what this thread is on about, and I don't care enough to look at the paper to try to decipher the footnote comments.

[aerohead]

Originally Posted by Vman455

You have argued in the past:



You contradicted oilpan4's (correct) assertion that a lighter Model 3 would be more efficient. This paper does not support that contradiction. It clearly shows that the heavier the car is, the more energy it uses per mile regardless of the effects of regenerative braking:



You seem to be confusing efficiency of the movement of energy from battery to wheels with efficiency of energy per distance traveled. They are two different things.

1) If the Model 3 were already 'optimized' for mass, arbitrarily lightening it would have the potential to lower its overall efficiency in an urban setting, the exact context of the Master's Thesis on page -26. There is no contradiction.
2) The Thesis is discussing overall efficiency. All other mass-related potentialities are encompassed within their use of 'efficiency.' It could not be more clearly spelled out. Net efficiency.
3) It's impossible to contradict an ' assertion' when no one is in possession of the facts which would prove the correctness about how a Tesla Model 3 'might' perform at lower mass. It's pure speculation.

[Isaac Zachary]

Originally Posted by aerohead

1) If the Model 3 were already 'optimized' for mass, arbitrarily lightening it would have the potential to lower its overall efficiency in an urban setting, the exact context of the Master's Thesis on page -26. There is no contradiction.
2) The Thesis is discussing overall efficiency. All other mass-related potentialities are encompassed within their use of 'efficiency.' It could not be more clearly spelled out. Net efficiency.
3) It's impossible to contradict an ' assertion' when no one is in possession of the facts which would prove the correctness about how a Tesla Model 3 'might' perform at lower mass. It's pure speculation.

Of course, and this has already been brought out, more efficiency doesn't mean better total efficiency or better miles per kWh, etc. A lighter Model 3 will get better miles per kWh even if regen efficiency drops.

A Model 3 also ususally hauls only one person and not much more, and has a limit of 5 (or is it 4?) passengers and some 900lbs total weight of cargo and passengers (although I'm sure you could add more than that). But if you could lighten it and replace that mass with even more passengers and/or cargo, then miles per kWh per passenger or lb of cargo would also increase considerably.

This whole thing reminds me of the BSFC efficiency of an ICE being at around 80% load. But if you drive around constantly at 80% load you'd actually get worse fuel mileage.

[Vman455]

Originally Posted by aerohead

1) If the Model 3 were already 'optimized' for mass, arbitrarily lightening it would have the potential to lower its overall efficiency in an urban setting, the exact context of the Master's Thesis on page -26. There is no contradiction.
2) The Thesis is discussing overall efficiency. All other mass-related potentialities are encompassed within their use of 'efficiency.' It could not be more clearly spelled out. Net efficiency.
3) It's impossible to contradict an ' assertion' when no one is in possession of the facts which would prove the correctness about how a Tesla Model 3 'might' perform at lower mass. It's pure speculation.

This, exactly (emphasis added):

Originally Posted by Isaac Zachary

Of course, and this has already been brought out, more efficiency doesn't mean better total efficiency or better miles per kWh, etc. A lighter Model 3 will get better miles per kWh even if regen efficiency drops.

This is exactly what the paper shows, in these two charts which I posted previously:





Even though BTW efficiency is slightly lower for the lighter EV, its overall efficiency measured in Wh/kilometer is better than the heavier EV.

As I pointed out before, you seem to be confusing the definition of "efficiency" in the paper (percentage of stored energy that makes it to the wheels) and "efficiency" meaning the amount of energy required to travel a given distance.

[aerohead]

Originally Posted by Vman455

This, exactly (emphasis added):



This is exactly what the paper shows, in these two charts which I posted previously:





Even though BTW efficiency is slightly lower for the lighter EV, its overall efficiency measured in Wh/kilometer is better than the heavier EV.

As I pointed out before, you seem to be confusing the definition of "efficiency" in the paper (percentage of stored energy that makes it to the wheels) and "efficiency" meaning the amount of energy required to travel a given distance.

1) Not to sound like Bill Clinton, but we need to clarify exactly what you mean 'heavier' EV.
2) I'm only talking about the 2015 Volvo V40, 'small' SUV, at a different weight.
3) Not the Volvo S80, or XC90, both of which have different CdAs as well as higher curb weight.
4) None of the tables presented in the thesis reflects the V40 at a different curb weight.
5) Since last Monday, I located enough data from my archive to scientifically prove that a 'heavier' V40 would be 'totally' more efficient for all considerations. It all hinges upon the ' strange behavior... connected to the regenerative braking which is dependent on available wheel power and mass.'
6) It's a page full of data, including Volvo's own solution for the 2021 model year XC40 P8 AWD Recharge ( R-Design).
7) It's quite damning to your hypothesis.

[redpoint5]

You're messin with my head, it's not Wednesday.

[aerohead]

Yeah, I thought I'd try Mondays and Thursdays for awhile and see how that goes.