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Old 04-27-2009, 11:17 AM   #15 (permalink)
Ernie Rogers
Ernie Rogers
 
Join Date: Feb 2008
Location: Pleasant Grove, Utah
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I'm sorry, Ryland,

I see I have hurt your feelings. There is a wild assumption here--the presumption by EV enthusiasts that their cars are naturally superior, and they "prove" that by the rediculus assumption that 34 kWh of electricity is exactly equal to the 116,000 BTU of heat contained in a gallon of gasoline. I am just pointing out that the idea of expessing EV efficiency in "miles per gallon" is absurd and should be abandoned.

Any crappy, poorly-designed EV looks good using bad math, which I confess is the normal practice everywhere, including by the EPA. You do your brotherhood a disservice by continuing this.

Ways to avoid this problem are--

1. Just admit there isn't a fair way to compare EVs and gassers, and provide separate lists of ranking.

2. We can all agree that electric drives are very efficient. We could concentrate on car efficiency from the motor shaft to the wheels, where all cars share roughly the same parts. Then we can compare merits of cars by their common elements of design such as rolling resistance, regen. braking, and aero drag.

3. We can go to the energy source in determining efficiency-- this is called "well-to-wheels" efficiency. (Which just gives us new things to argue about).

I have offered a reasonable compromise, that we simply acknowledge that heat and work (electricity) are fundamentally different, and I suggested that we connect them using the second law principles. This is what normally happens at an electric power plant anyway.

Ernie Rogers

Quote:
Originally Posted by Ryland View Post
So why are making wild assumptions and just tossing out 50% of the energy that is being used? just because we feel like it!
After all, gas cars have to run off a heat engine, so lets use their poor performance to drag down the math on electric cars too, after all I bet no one who owns an electric car has ever charged it using solar or wind and that doesn't work in to our nice simple "lets just toss out 50% of your energy" theory, so we will just ignore it all together.
If you were to pole electric vehicle owners I would bet that a large percentage of them charge with renewable energy.
I thought that the reason for finding a common factor like BTU was so you could make the math more reliable and if reliable math is what we are looking for tossing in randomness then makes total sense.
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