The Truth About EV Range & Towing compared to ICE towing?

Lil'O Annie

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I thought this was an interesting discussion about the differences between EV and ICE towing. It helped me better understand why towing and roof-top cargo impacts an EV more than an ICE.
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EVSport7

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ajdelange

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Both these guys are good. They both leave out drive train losses and slip loss and 2 But has math errors but that doesn't matter. The essential fact is that it takes energy to move a trailer and a diesel with a 40 gal tank has lots of energy on board.

The truth about any vehicle is that you can go r = C/Tu miles where C is the energy on board and Tu is the energy used to go one mile. For example my X has 98.92 kWh on board and requires, on average, .282 kWh to go a mile. I can, on average, go 98.92/.282 = 351. If something happens which increases the amount of energy required per mile, the the miles go down. A wet road increases my consumption to .382 kWh/mile and thus I can only go 98.92/.382 = 259 miles if it rains.

It takes energy to move a trailer just as it takes energy to move a car. If the car required Tc and the trailer Tt Wh.mi then Tu = Tc +Tt and the distance you can drive is r = C/Tu = C/(Tc + Tt). A little algebra recasts this as r = (C/Tc)*(1/(1 + Tt/Tc). C/Tc is the range without any additional load and so it is easy to see that this range is reduced by the factor 1/(1 + Tt/Tc). For example we quickly see that if the trailer energy demand is twice that of the car the range will be reduced to 1/(1 + 2) = 1/3 of the nominal (no trailer attached) range.

This elegantly simple formula suffers from one magor diffucilty: we don't know what Tt is. It is very simple for the car (or truck) to measure Tt by simply incorporating a load cell into the trailer hitch. This opens up the possibility of all sortd of neat information displays. I haven't seen Rivian make any mention of this (nor Tesla) so I assume it will not happen and drivers will have to deduce Tt by taking note of what happens to the values of Tu reported by the truck when the trailer is attached.
 
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LoneStar

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I believe Ford has incorporated a tow load sensing setup
 

Riventures

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Yes, I certainly agree. There are math and conceptual errors in his thesis, but in the end those errors don't change the overall functional result.

We are in the infancy of electric vehicles, there is much room to grow. I don't think in 7-10 years the EVs will operate the same way they do today. I think the battery technology will continue to evolve similar to microchips over the last 35 years, there will be leaps with each iteration/generation.
 

ajdelange

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We are in the infancy of electric vehicles, there is much room to grow. I don't think in 7-10 years the EVs will operate the same way they do today. I think the battery technology will continue to evolve similar to microchips over the last 35 years, there will be leaps with each iteration/generation.
Microchips evolved according to Moore's law which stated that the number of transistors in a given chip area would double every 2 years (and they did). That's an annualized increase of 41%. In batteries the rate of progress has been 13%. This means that it will take 5.65 years for battery capacity to double. I think electrochemistry is well enough evolves that the scientists know that no unobtanium is going to emerge with energy density higher than what the existing metals can provide and therefore I don't expect any revolutionaly "breakthrough" to occur. But I do expect the evolutionary progress to continue.

The only revolutionary change I can even imagine is that the problems with hydrogen storage and transportation get solved such that the power source in these vehicles becomes hydrogen rather than a battery. I'm not holding my breath on that one either.
 

Autolycus

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Microchips evolved according to Moore's law which stated that the number of transistors in a given chip area would double every 2 years (and they did). That's an annualized increase of 41%. In batteries the rate of progress has been 13%. This means that it will take 5.65 years for battery capacity to double. I think electrochemistry is well enough evolves that the scientists know that no unobtanium is going to emerge with energy density higher than what the existing metals can provide and therefore I don't expect any revolutionaly "breakthrough" to occur. But I do expect the evolutionary progress to continue.

The only revolutionary change I can even imagine is that the problems with hydrogen storage and transportation get solved such that the power source in these vehicles becomes hydrogen rather than a battery. I'm not holding my breath on that one either.
The real breakthrough will be when Mr. Fusion finally comes out.

Seriously though, solid state batteries have the potential to more than double energy density and provide significant improvements in charge and discharge capability as well as thermal management and safety. That's a pretty revolutionary breakthrough compared to the current rate of progress, and solid state batteries will likely improve over time as well.

But maybe solid state batteries are exactly like Mr. Fusion and they'll always be 10 years away.
 

ajdelange

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The real breakthrough will be when Mr. Fusion finally comes out.
My X currently runs on fusion. And my R1T will too. But in both cases the energy from the fusion source is stored in batteries as the fusion source is not available to me 24/7/365.

Seriously though, solid state batteries have the potential to more than double energy density and provide significant improvements in charge and discharge capability as well as thermal management and safety. That's a pretty revolutionary breakthrough
Yes, at the current range of advancement battery energy will double in 5.56 years. But that's hardly revolutionary. It's evolutionary.

But maybe solid state batteries are exactly like Mr. Fusion and they'll always be 10 years away.
It seems they are 10 years away (c'mon Pradeep!) but they too represent an evolutionary rather than revolutionary change.
 

Autolycus

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My X currently runs on fusion. And my R1T will too. But in both cases the energy from the fusion source is stored in batteries as the fusion source is not available to me 24/7/365.
Mr. Fusion would definitely be available 24 hours. It also provided at least 1.21 jiggawatts of power. Way more than the radiation receptors you're talking about! :p
 

ajdelange

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I only take what I need.
 
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