5 ms·

What got me is a charge rate of "150 miles of drive time in an hour" - so it takes an hour to charge for every 2.5 hours of driving?

by BruceIV 14y ago

maxmcd 14y ago
Yes, that is one of the EV issues. Primarily why, I assume, hybrids and electric cars like the Volt have seen more widespread use because they have a gasoline fallback. The popular counter argument is that the vast majority of daily driving amounts to less than 40 miles.
- BruceIV 14y ago
  Fair enough - but you'd need a charging station at your destination to make the OP's argument work, because if you charge your car at home every night like your phone, you're on the hook for the electricity (which probably costs more per mile than gasoline - I don't know, but I know it's cheaper to heat with diesel then electricity, so I assume auto fuel is similar)
  - bosie 14y ago
    > which probably costs more per mile than gasoline Though electric cars are much more efficient [1] [1] https://en.wikipedia.org/wiki/Electric_car#Energy_efficiency https://en.wikipedia.org/wiki/Electric_car#Energy_efficiency
  - rtkwe 14y ago
    Very incorrect. A short back of the napkin calculation: 286mi/85kwh / .12 (dollar per kilowatt hour) = 28 miles per dollar or .03 per mile. Gasoline on the other hand is: 30 mpg / 3.50 (dollar per gallon) = 8.5 miles per dollar or .11 per mile Electricity comes out far better. Cars are much less efficient than heaters at capturing the stored energy from it's fuel. With a heater you have the benefit of insulation and none of the losses associated with moving a hunk of metal through air.
    - BruceIV 14y ago
      Thanks.
    - greenyoda 14y ago
      In NYC, I pay a total of 41 cents per kilowatt hour (including supply charges, delivery charges, fees and taxes) for my electricity. (Source: my latest electric bill. Total of $56.36 for 137 kWh.) Using that cost in your calculation would yield 8.2 miles per dollar, or .12 dollars per mile. -
      - BruceIV 14y ago
        In southern Ontario, I pay 6.5 cents/kWh (off-peak, say the "charge at night" scenario I mentioned as a hypothetical.) and $4.50/gallon for gas. (the exchange rate between Canadian and American dollars is even right now). -- That's 0.15 $/mile for gas and 0.02 $/mile for electric. ... huh, so I'd be saving nearly about $850 $/yr with an electric car, even though I only drive about 6500 mi/yr (though half of that is the cross country trip to visit my folks). That said, my car only cost $5500, so it would take longer than the life of the car to pay off the difference to a Tesla.
      - rtkwe 14y ago
        What's your gasoline cost like though? Similarly expensive I'd wager? These number have to be compared together to be worth a damn. Though yes the numbers make more sense in areas with lower per KWh costs. Cars barely make sense in NYC to begin with it seems though, who's that much of a masochist.
        greenyoda 14y ago
        A gallon of gas costs around $4.00 here right now, not much different from the $3.50 assumption in the original calculation. Lots of people in NYC have cars. NYC isn't just Manhattan, and much of the area in the outer boroughs is more suburban than urban and not accessible via subway.
        14y ago
dman 14y ago
Would be neat if the battery itself was something that was like a module. You could drive up to the driving station and some kind of robotic arm would just hook up - swap out your battery module and replace it with a charged version. In essence companies owning the charging stations would own a pool of batteries that they would charge and swap in and out of drivers cars.
- indiecore 14y ago
  Why does it need a robot? Just put a handle on the battery.
- _mulder_ 14y ago
  Agreed. This seems a much better business model. You avoid the cost/liability of owning and replacing the batteries too. On the downside, you're back to paying out money to an energy supplier like we do today for gas.
- droithomme 14y ago
  The Tesla battery contains over 6800 3100mA 3.7V Panasonic 18650 Li-ion battery cells. It costs $40,000 to replace. This battery has a life expectancy of 500 charge cycles. That means the battery cost per 240 mile charge is $80, and the company would have to charge that to recover just their battery costs. Add another $20 to handle tax, labor and the cost of maintaining the equipment and the recharging, so $100 per swap, assuming this is run as a non-profit endeavor. Do you feel there is a large market for people willing to pay $100 for every 240 miles they travel? Such a network of replacement stations assumes that the market will pay these costs.
  - dman 14y ago
    a) http://green.autoblog.com/2012/11/30/tesla-adds-replacement-battery-pack-costs-to-price-increase-deta/ http://green.autoblog.com/2012/11/30/tesla-adds-replacement-... suggests that the battery replacement costs are much lower ( < 12000 in the worst case for the 85-kWh pack and as low as 8000 for the 40kwh pack). I dont know if this price assumes that you will be turning your old batter in - otherwise I would imagine you would be able to recoup some money for that via selling it to recyclers. b) Also http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries http://batteryuniversity.com/learn/article/how_to_prolong_li... suggests that the 500 charge cycle number is only valid if every cycle depletes the charge to 0. Assuming that each cycle discharges to 25% - the number of cycles goes upto 2000 - 2500. Assuming a price of 10000 (Using a medium capacity battery as well as assuming whole sale prices) and a depth of discharge of 25% per cycle and hence assuming battery life of 2250 cyles - you get the battery cost per charge to be 12000 / 2500 = 4.8 . Assuming a 10% tax rate thats about 5.28 dollars per cycle. This number does not seem bad at all.
droithomme 14y ago
These times are only assuming you stop at a 440V Supercharger, of which there are eight total nationally, and only on three road routes, six stations on two California routes, and two stations on a single route between DC and Boston. The 440V high amperage charge also lessens the life of the battery - Lithium Ion cells don't like high amperage or temperatures. Fortunately battery replacements are only $40,000. A 240V 24A charger which is much more common, and which is not paid for by Tesla so has its own terms, can recharge 18 miles of range per hour of charge, so 13 hours are needed for a full recharge. A 240V 40A charger can recharge 31 miles of range per hour of charge, so 8 hours are needed for a full recharge. Tesla also notably recommended that people drive low speeds on long trips to increase the chances they will see ranges of 240 miles as opposed to the 170 or so that seems to be under more typical driving conditions. When one is off of the Tesla routes on the west and east coast, and driving a steady 60mph without climate control, one can travel 240 miles per 12 hour period if they have access to the higher capacity 240V/40A charger exactly every 240 miles (20 mph average speed), or 240 miles per 17 hours with the 240V/20A station (14.1 mph average speed). This is assuming there is no cold weather. If there is cold weather or faster driving, that reduces to a 170 mile range per 12 or 17 hour period (10-14mph average). Tesla plans to address this with a nationwide network of Supercharger stations which will reduce the full recharge time dramatically, at the cost of shorter battery life. Tesla claims that all energy for the network, which requires the ability to deliver to 4 cars simultaneously in 1 hour about 100kWh total of power per 85kWh capacity charge, will run exclusively on a small 30 kW max rated capacity installation of solar powered panels at each 4 car charge station and that customers will not only "Drive for Free. Forever. On Sunlight.”, but stations will produce a surplus of energy that will be sold at a profit. source for recharge times: http://www.teslamotors.com/charging#/outlet http://www.teslamotors.com/charging#/outlet source for solar powered car claims: http://www.visualnews.com/2012/09/26/tesla-electric-cars-drive-for-free-forever-on-sunlight/ http://www.visualnews.com/2012/09/26/tesla-electric-cars-dri...
- ryandvm 14y ago
  What I never get is why doesn't anyone ever propose battery exchanges instead of charging stations. It would make a lot more sense to pull in and exchange your dead battery for a charged one (just like buying propane).

What got me is a charge rate of "150 miles of drive time in an hour" - so it takes an hour to charge for every 2.5 hours of driving?

by BruceIV 14y ago

What got me is a charge rate of "150 miles of drive time in an hour" - so it takes an hour to charge for every 2.5 hours of driving?

maxmcd 14y ago

Yes, that is one of the EV issues. Primarily why, I assume, hybrids and electric cars like the Volt have seen more widespread use because they have a gasoline fallback. The popular counter argument is that the vast majority of daily driving amounts to less than 40 miles.

BruceIV 14y ago
Fair enough - but you'd need a charging station at your destination to make the OP's argument work, because if you charge your car at home every night like your phone, you're on the hook for the electricity (which probably costs more per mile than gasoline - I don't know, but I know it's cheaper to heat with diesel then electricity, so I assume auto fuel is similar)
- bosie 14y ago
  > which probably costs more per mile than gasoline Though electric cars are much more efficient [1] [1] https://en.wikipedia.org/wiki/Electric_car#Energy_efficiency https://en.wikipedia.org/wiki/Electric_car#Energy_efficiency
- rtkwe 14y ago
  Very incorrect. A short back of the napkin calculation: 286mi/85kwh / .12 (dollar per kilowatt hour) = 28 miles per dollar or .03 per mile. Gasoline on the other hand is: 30 mpg / 3.50 (dollar per gallon) = 8.5 miles per dollar or .11 per mile Electricity comes out far better. Cars are much less efficient than heaters at capturing the stored energy from it's fuel. With a heater you have the benefit of insulation and none of the losses associated with moving a hunk of metal through air.
  - BruceIV 14y ago
    Thanks.
  - greenyoda 14y ago
    In NYC, I pay a total of 41 cents per kilowatt hour (including supply charges, delivery charges, fees and taxes) for my electricity. (Source: my latest electric bill. Total of $56.36 for 137 kWh.) Using that cost in your calculation would yield 8.2 miles per dollar, or .12 dollars per mile. -
    - BruceIV 14y ago
      In southern Ontario, I pay 6.5 cents/kWh (off-peak, say the "charge at night" scenario I mentioned as a hypothetical.) and $4.50/gallon for gas. (the exchange rate between Canadian and American dollars is even right now). -- That's 0.15 $/mile for gas and 0.02 $/mile for electric. ... huh, so I'd be saving nearly about $850 $/yr with an electric car, even though I only drive about 6500 mi/yr (though half of that is the cross country trip to visit my folks). That said, my car only cost $5500, so it would take longer than the life of the car to pay off the difference to a Tesla.
    - rtkwe 14y ago
      What's your gasoline cost like though? Similarly expensive I'd wager? These number have to be compared together to be worth a damn. Though yes the numbers make more sense in areas with lower per KWh costs. Cars barely make sense in NYC to begin with it seems though, who's that much of a masochist.
      - greenyoda 14y ago
        A gallon of gas costs around $4.00 here right now, not much different from the $3.50 assumption in the original calculation. Lots of people in NYC have cars. NYC isn't just Manhattan, and much of the area in the outer boroughs is more suburban than urban and not accessible via subway.
        14y ago

dman 14y ago

Would be neat if the battery itself was something that was like a module. You could drive up to the driving station and some kind of robotic arm would just hook up - swap out your battery module and replace it with a charged version. In essence companies owning the charging stations would own a pool of batteries that they would charge and swap in and out of drivers cars.

indiecore 14y ago
Why does it need a robot? Just put a handle on the battery.
_mulder_ 14y ago
Agreed. This seems a much better business model. You avoid the cost/liability of owning and replacing the batteries too. On the downside, you're back to paying out money to an energy supplier like we do today for gas.
droithomme 14y ago
The Tesla battery contains over 6800 3100mA 3.7V Panasonic 18650 Li-ion battery cells. It costs $40,000 to replace. This battery has a life expectancy of 500 charge cycles. That means the battery cost per 240 mile charge is $80, and the company would have to charge that to recover just their battery costs. Add another $20 to handle tax, labor and the cost of maintaining the equipment and the recharging, so $100 per swap, assuming this is run as a non-profit endeavor. Do you feel there is a large market for people willing to pay $100 for every 240 miles they travel? Such a network of replacement stations assumes that the market will pay these costs.
- dman 14y ago
  a) http://green.autoblog.com/2012/11/30/tesla-adds-replacement-battery-pack-costs-to-price-increase-deta/ http://green.autoblog.com/2012/11/30/tesla-adds-replacement-... suggests that the battery replacement costs are much lower ( < 12000 in the worst case for the 85-kWh pack and as low as 8000 for the 40kwh pack). I dont know if this price assumes that you will be turning your old batter in - otherwise I would imagine you would be able to recoup some money for that via selling it to recyclers. b) Also http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries http://batteryuniversity.com/learn/article/how_to_prolong_li... suggests that the 500 charge cycle number is only valid if every cycle depletes the charge to 0. Assuming that each cycle discharges to 25% - the number of cycles goes upto 2000 - 2500. Assuming a price of 10000 (Using a medium capacity battery as well as assuming whole sale prices) and a depth of discharge of 25% per cycle and hence assuming battery life of 2250 cyles - you get the battery cost per charge to be 12000 / 2500 = 4.8 . Assuming a 10% tax rate thats about 5.28 dollars per cycle. This number does not seem bad at all.

droithomme 14y ago

These times are only assuming you stop at a 440V Supercharger, of which there are eight total nationally, and only on three road routes, six stations on two California routes, and two stations on a single route between DC and Boston. The 440V high amperage charge also lessens the life of the battery - Lithium Ion cells don't like high amperage or temperatures. Fortunately battery replacements are only $40,000. A 240V 24A charger which is much more common, and which is not paid for by Tesla so has its own terms, can recharge 18 miles of range per hour of charge, so 13 hours are needed for a full recharge. A 240V 40A charger can recharge 31 miles of range per hour of charge, so 8 hours are needed for a full recharge. Tesla also notably recommended that people drive low speeds on long trips to increase the chances they will see ranges of 240 miles as opposed to the 170 or so that seems to be under more typical driving conditions. When one is off of the Tesla routes on the west and east coast, and driving a steady 60mph without climate control, one can travel 240 miles per 12 hour period if they have access to the higher capacity 240V/40A charger exactly every 240 miles (20 mph average speed), or 240 miles per 17 hours with the 240V/20A station (14.1 mph average speed). This is assuming there is no cold weather. If there is cold weather or faster driving, that reduces to a 170 mile range per 12 or 17 hour period (10-14mph average). Tesla plans to address this with a nationwide network of Supercharger stations which will reduce the full recharge time dramatically, at the cost of shorter battery life. Tesla claims that all energy for the network, which requires the ability to deliver to 4 cars simultaneously in 1 hour about 100kWh total of power per 85kWh capacity charge, will run exclusively on a small 30 kW max rated capacity installation of solar powered panels at each 4 car charge station and that customers will not only "Drive for Free. Forever. On Sunlight.”, but stations will produce a surplus of energy that will be sold at a profit. source for recharge times: http://www.teslamotors.com/charging#/outlet http://www.teslamotors.com/charging#/outlet source for solar powered car claims: http://www.visualnews.com/2012/09/26/tesla-electric-cars-drive-for-free-forever-on-sunlight/ http://www.visualnews.com/2012/09/26/tesla-electric-cars-dri...

ryandvm 14y ago
What I never get is why doesn't anyone ever propose battery exchanges instead of charging stations. It would make a lot more sense to pull in and exchange your dead battery for a charged one (just like buying propane).