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I'm eagerly looking forward to when I can replace gas tanks with batteries of comparable energy density, and put 400+HP electric motors in unsafe light old driv

I'm eagerly looking forward to when I can replace gas tanks with batteries of comparable energy density, and put 400+HP electric motors in unsafe light old driver's cars.

semi-extrinsic 8y ago
Electric Renault 5 Turbo Maxi
- newnewpdro 8y ago
  There are many great cars with mature and comprehensive performance aftermarkets that would make excellent candidates. I'm deliberately refraining from turning this into a masturbatory gearhead thread where we all enumerate our favorite sports cars from the past however.
- tim333 8y ago
  Had to google that https://rmsothebys.com/en/auctions/LF16/London/lots/r113-1986-renault-5-maxi-turbo/380780 https://rmsothebys.com/en/auctions/LF16/London/lots/r113-198... yeah would be fun
maxerickson 8y ago
You gotta be euphemistic, the software running the site is precious about certain topics. (that is, your grandchild comment here done be killed)
rmah 8y ago
That will be a long long time coming. Gasoline is about 46 MJ/KG or 34 MJ/L. The best lithium-metal batteries are about 2 MJ/KG or 5 MJ/L. The best lithium-ion batteries, about half that. Gasoline is extremely energy dense. For a comparison, TNT is only 5 MJ/KG and 7 MJ/L.
- jdhawk 8y ago
  ICE efficiency brings that down a decent amount, no? 35-40% at best. The fuel is much more dense, but converting it is not as efficient.
  - prolepunk 8y ago
    Back of the napkin calculation Ice is 18% efficient at the wheels. So the energy spent on propelling the car is 46*0.18 = 8.28MJ/Kg Let's say efficiency of electric car is 60%, 8.28/0.6 = 13.8 MJ/kg. In order to have batteries occupying the same amount of space as gas tank they need to be almost 7 times as energy dense. But then it's possible to get rid of a lot of other systems that support ICE engine, like transmission, cooling, lubrication, led acid batteries engine itself is a lot smaller.
  - prolepunk 8y ago
    Even more, electric engines don't use any fuel at idle, so I for city driving batteries can be even less dense.
  - NegativeLatency 8y ago
    Especially in an older car with a less efficient engine.
  - akira2501 8y ago
    > ICE efficiency brings that down a decent amount, no? In terms of power to the wheels, yes. Some of that latent energy can be useful, especially after it's converted into heat.
  - hwillis 8y ago
    Roughly 15-20% during actual driving.
- mecameron 8y ago
  Fortunately, gasoline cars are so inefficient that you only need about 1/3 of the comparable energy in an electric car to move the vehicle. Still a ways to go, but we don't need to get to all the way gasoline energy density for the equivalent range.

I'm eagerly looking forward to when I can replace gas tanks with batteries of comparable energy density, and put 400+HP electric motors in unsafe light old driver's cars.

semi-extrinsic 8y ago

Electric Renault 5 Turbo Maxi

newnewpdro 8y ago
There are many great cars with mature and comprehensive performance aftermarkets that would make excellent candidates. I'm deliberately refraining from turning this into a masturbatory gearhead thread where we all enumerate our favorite sports cars from the past however.
tim333 8y ago
Had to google that https://rmsothebys.com/en/auctions/LF16/London/lots/r113-1986-renault-5-maxi-turbo/380780 https://rmsothebys.com/en/auctions/LF16/London/lots/r113-198... yeah would be fun

maxerickson 8y ago

You gotta be euphemistic, the software running the site is precious about certain topics. (that is, your grandchild comment here done be killed)

rmah 8y ago

That will be a long long time coming. Gasoline is about 46 MJ/KG or 34 MJ/L. The best lithium-metal batteries are about 2 MJ/KG or 5 MJ/L. The best lithium-ion batteries, about half that. Gasoline is extremely energy dense. For a comparison, TNT is only 5 MJ/KG and 7 MJ/L.

jdhawk 8y ago
ICE efficiency brings that down a decent amount, no? 35-40% at best. The fuel is much more dense, but converting it is not as efficient.
- prolepunk 8y ago
  Back of the napkin calculation Ice is 18% efficient at the wheels. So the energy spent on propelling the car is 46*0.18 = 8.28MJ/Kg Let's say efficiency of electric car is 60%, 8.28/0.6 = 13.8 MJ/kg. In order to have batteries occupying the same amount of space as gas tank they need to be almost 7 times as energy dense. But then it's possible to get rid of a lot of other systems that support ICE engine, like transmission, cooling, lubrication, led acid batteries engine itself is a lot smaller.
- prolepunk 8y ago
  Even more, electric engines don't use any fuel at idle, so I for city driving batteries can be even less dense.
- NegativeLatency 8y ago
  Especially in an older car with a less efficient engine.
- akira2501 8y ago
  > ICE efficiency brings that down a decent amount, no? In terms of power to the wheels, yes. Some of that latent energy can be useful, especially after it's converted into heat.
- hwillis 8y ago
  Roughly 15-20% during actual driving.
mecameron 8y ago
Fortunately, gasoline cars are so inefficient that you only need about 1/3 of the comparable energy in an electric car to move the vehicle. Still a ways to go, but we don't need to get to all the way gasoline energy density for the equivalent range.