4 ms·

We should use Wh/mi (or km) instead of mpge

by starbase 4y ago

bryanlarsen 4y ago
kWh/100km is the standard for some locations. Most reviews tend to use miles / kWh.
- rektide 4y ago
  I've been told about kWh/100km. Seems OK enough. I do really like that MPGe makes it incredibly easy to compare across gas/electric/hybrid; itvs an already known figure people already understand.
  - starbase 4y ago
    My issue with mpge is twofold. 1. The amount of energy in a gallon of fuel is not constant. Where I live you can buy E85 (24kWh/gal) E15 (31kWh) E10 (32kWh) E0 (34kWh) biodiesel (37kWh) or petroleum diesel (38kWh). These numbers shift a few percent depending on temperature, altitude blend, brand, and season (summer vs winter blend) 2. The fraction is upside down! This is no big deal if you can flip it in your head to get fuel consumption, but many people cannot do this. The difference in fuel consumption between 13mpg and 15mpg is twice as large as the difference between 40mpg and 50mpg. It's just not intuitive.
    - rektide 4y ago
      #1 doesn't wash with me at all. You've picked a variety of niche non-gasoline fuels to compare again, but that's far from the point. The point is we generally have a very strongly calibrated sense of what the MPG of a car has, and this number is for gasoline, not gasoline + X nor gasoline + Y, nor diesel, nor lng, nor jet fuel. These are different. What people actually know to compare their vehicles against is gasoline, and that's what we use. https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent With systems like diesel, it's also very apparent at the pump that the fuel costs a lot more. That diesel has 15% more energy-density is more than made up for in terms of price at the pump. And it's also a bit obvious based on the just-higher mpg that diesel vehicles have. You're not wrong about #2, but I'm only going to give you the point if you can convince the EPA & every car manufacturer on the planet to also flip the fraction for gas vehicles too. Otherwise the advantage of speaking the common language makes it clear, and the advantage of dumbing-it-down-for-folk doesn't have enough benefit. There's also a ton of similar problems, but we don't rewrite all our nomenclature to accomodate stupid: we let people live with the basic facts and figure it out. The difference between going 25mph and 35mph versus between 55 mph and 65 mph is far more pronounced in terms of time saved, but we still use mph or kph and haven't flipped that. Trying to attack this problem in only electric car space, only for range, while leaving everything else (like velocity) flipped: it hides & conceals to more detriment than whatever gains we make by trying to flip the fraction. Also I think the standard kWh/100km unit is just bizarre & cruel use of metric. Way to take a sensible straightforward metric system & contort bizarrely to make even numbers. Screw this. 180kWh/1MM would be fine. Or .18kWh/km. Or 180Wh/km. But 18kWh/100km? Its such a weird contortion, mal-adjusting standard prefixes to get a useful number; it's just so ugly to me. I acknowledge that it has practical value, but it feels like such a betrayal of metric to pick "100 kWh" as your unit value.
      - starbase 4y ago
        With you on #2, there's no easy solution. Love to read a comment that disagrees like this. Re: #1, I have to defend half of those blends as normal. E10 is the standard in US, and E15 was given the green light around the time oil prices got high a year or two ago. Full petroleum or B10 biodiesel blend is also, I think, the normal pump fuel but I've never owned a diesel so I can't say for sure. The last gas car I owned, I'd fuel with E0 at the beginning of a road trip and get 650+ miles on a tank. Hybrid Toyota, I still miss that car. Driving electric I'm looking at half that range in a model S Plaid, unless I'm in a high elevation state where wind resistance is lower. 500+ mile range would be a major selling point for any EV. I guess Lucid makes one but there are no chargers in rural areas (yet) so it's a moot point. Hell, if chargers were as common as gas stations 300 miles would be enough.

We should use Wh/mi (or km) instead of mpge

bryanlarsen 4y ago

kWh/100km is the standard for some locations. Most reviews tend to use miles / kWh.

rektide 4y ago
I've been told about kWh/100km. Seems OK enough. I do really like that MPGe makes it incredibly easy to compare across gas/electric/hybrid; itvs an already known figure people already understand.
- starbase 4y ago
  My issue with mpge is twofold. 1. The amount of energy in a gallon of fuel is not constant. Where I live you can buy E85 (24kWh/gal) E15 (31kWh) E10 (32kWh) E0 (34kWh) biodiesel (37kWh) or petroleum diesel (38kWh). These numbers shift a few percent depending on temperature, altitude blend, brand, and season (summer vs winter blend) 2. The fraction is upside down! This is no big deal if you can flip it in your head to get fuel consumption, but many people cannot do this. The difference in fuel consumption between 13mpg and 15mpg is twice as large as the difference between 40mpg and 50mpg. It's just not intuitive.
  - rektide 4y ago
    #1 doesn't wash with me at all. You've picked a variety of niche non-gasoline fuels to compare again, but that's far from the point. The point is we generally have a very strongly calibrated sense of what the MPG of a car has, and this number is for gasoline, not gasoline + X nor gasoline + Y, nor diesel, nor lng, nor jet fuel. These are different. What people actually know to compare their vehicles against is gasoline, and that's what we use. https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent With systems like diesel, it's also very apparent at the pump that the fuel costs a lot more. That diesel has 15% more energy-density is more than made up for in terms of price at the pump. And it's also a bit obvious based on the just-higher mpg that diesel vehicles have. You're not wrong about #2, but I'm only going to give you the point if you can convince the EPA & every car manufacturer on the planet to also flip the fraction for gas vehicles too. Otherwise the advantage of speaking the common language makes it clear, and the advantage of dumbing-it-down-for-folk doesn't have enough benefit. There's also a ton of similar problems, but we don't rewrite all our nomenclature to accomodate stupid: we let people live with the basic facts and figure it out. The difference between going 25mph and 35mph versus between 55 mph and 65 mph is far more pronounced in terms of time saved, but we still use mph or kph and haven't flipped that. Trying to attack this problem in only electric car space, only for range, while leaving everything else (like velocity) flipped: it hides & conceals to more detriment than whatever gains we make by trying to flip the fraction. Also I think the standard kWh/100km unit is just bizarre & cruel use of metric. Way to take a sensible straightforward metric system & contort bizarrely to make even numbers. Screw this. 180kWh/1MM would be fine. Or .18kWh/km. Or 180Wh/km. But 18kWh/100km? Its such a weird contortion, mal-adjusting standard prefixes to get a useful number; it's just so ugly to me. I acknowledge that it has practical value, but it feels like such a betrayal of metric to pick "100 kWh" as your unit value.
    - starbase 4y ago
      With you on #2, there's no easy solution. Love to read a comment that disagrees like this. Re: #1, I have to defend half of those blends as normal. E10 is the standard in US, and E15 was given the green light around the time oil prices got high a year or two ago. Full petroleum or B10 biodiesel blend is also, I think, the normal pump fuel but I've never owned a diesel so I can't say for sure. The last gas car I owned, I'd fuel with E0 at the beginning of a road trip and get 650+ miles on a tank. Hybrid Toyota, I still miss that car. Driving electric I'm looking at half that range in a model S Plaid, unless I'm in a high elevation state where wind resistance is lower. 500+ mile range would be a major selling point for any EV. I guess Lucid makes one but there are no chargers in rural areas (yet) so it's a moot point. Hell, if chargers were as common as gas stations 300 miles would be enough.