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For an electric car, here is my summary: For a car, a 20 gallon tank of gasoline is tough to compete with. E.g., the US is dotted with high density with gas s

For an electric car, here is my summary: For a car, a 20 gallon tank of gasoline is tough to compete with. E.g., the US is dotted with high density with gas stations, can fill a 20 gallon tank in just a few minutes, and at 20 MPG that tank will fuel the car for 400 miles. For a battery, apparently so far the range is about 200 mile; for the readily available charging sources the charging time is much longer, maybe hours; and from a really powerful charging source the battery will get hot and need cooling (e.g., see the Jay Leno piece on the new, all electric Mercedes which does cool the battery while charging). The weather is a significant issue: In hot weather, the battery needs more cooling. In cold weather, the battery loses lots of its power. So I agree with the OP: For a good electric car, need a better battery. IIRC long ago a Ford executive stated "You build me a good battery, and I'll build you a good electric car." Actually, all electric cars are not new but old and go way back to the first days of cars, e.g., before Ford's Model T. And as Leno mentioned, for all or nearly all the time since then, battery technology hasn't made much progress. Right: Battery technology is still based on basic chemistry, and that chemistry was understood well enough in 1900. Of course, people saw all this 100+ years ago and for one solution tried hybrids where a gasoline engine charged a battery. Apparently, net, that meant that the car had two sources of power, gasoline and a battery, and could get by with just one, the gasoline, which is just what has been done since then. Still there is some hope for hybrids. Yes, there are some uses for electric vehicles. Still: Yup, a 20 gallon tank of gasoline is tough to compete with.

frogpelt 8y ago
This page (https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density) has a chart on energy density shows that gasoline contains roughyl 36 MegaJoules per Liter and 46 MJ per kg of energy density while a lithium-ion battery has less than 3 by both measures.
- graycat 8y ago
  WOW. Good way to put it. Also, as I've done a few times, can take your 36 megaJoules per liter and ...: Let's see, a Watt is a Joule per second. So the energy in 36 megaJoules would be a million Watts for 36 seconds. A liter is ballpark a quart, and a gallon is 4 quarts, so 20 gallons is 80 quarts or ballpark 80 liters, and even with a megaWatt power source we're talking charging time 36 times 80 seconds, a bit over 40 minutes. So, drive up to a gas station, convenience store, plug in the mega Watt power source, get some lunch, check the air in the tires, clean the floor mats, put in a DVD for a movie, .... Before you connect that megaWatt cable, let me step back about 50 feet and look in a different direction. Let's see: My house has 100 A at 240 V, that is 24,000 Watts. So a mega Watt is ballpark 40 times that much. If use only half that power to charge the car battery, a mega Watt is 80 times that much. So the 40 minutes becomes 3200 minutes, something over 50 hours, two days. "Sorry, Boss, I'll be charging my battery on Monday and Tuesday and will be in on Wednesday. Since my commute is 100 miles a day, I'll need to do this two day charge once for each four working days. Or, I'll be okay Wednesday through Friday, drive another 100 miles on the weekend, and will charge again Monday and Tuesday of next week, too." Right, he could charge at work. Each day at work will need about six hours of charging at the full 100 A at 240 V. Uh, at 10 cents per KWh, the 40 minutes at one megaWatt would cost: A megaWatt hour would be 1000 times a KWh and cost 1000 times 10 cents or $100. The 40 minutes would be 2/3rds of that or $66 or the same as gas at $3.30 a gallon. Not a bargain. And that $3.30 per gallon applies wherever have to pay 10 per KWh, at a charging station, at home, at work, at a restaurant, etc. People don't give away gasoline and won't give away electric power for charging. In particular, a full charge like 20 gallons of gas at home, at 10 cents per KWh, will still cost the $66. Right, the gasoline burns with maybe only 30% efficiency, but there are efficiency losses from heat when charging the battery and again when driving the car. Yup, for powering a private car used as they commonly are, a 20 gallon tank of gasoline is tough to compete with. For an electric, range is too short and charging time is too long. With electric power at 10 cents per KWh and gas at $2.75 a gallon, the cost will be ballpark much the same, no big savings either way. Ah, maybe it's just me: I want a Corvette or Dodge with 700 HP! :-)

frogpelt 8y ago

This page (https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density) has a chart on energy density shows that gasoline contains roughyl 36 MegaJoules per Liter and 46 MJ per kg of energy density while a lithium-ion battery has less than 3 by both measures.

graycat 8y ago
WOW. Good way to put it. Also, as I've done a few times, can take your 36 megaJoules per liter and ...: Let's see, a Watt is a Joule per second. So the energy in 36 megaJoules would be a million Watts for 36 seconds. A liter is ballpark a quart, and a gallon is 4 quarts, so 20 gallons is 80 quarts or ballpark 80 liters, and even with a megaWatt power source we're talking charging time 36 times 80 seconds, a bit over 40 minutes. So, drive up to a gas station, convenience store, plug in the mega Watt power source, get some lunch, check the air in the tires, clean the floor mats, put in a DVD for a movie, .... Before you connect that megaWatt cable, let me step back about 50 feet and look in a different direction. Let's see: My house has 100 A at 240 V, that is 24,000 Watts. So a mega Watt is ballpark 40 times that much. If use only half that power to charge the car battery, a mega Watt is 80 times that much. So the 40 minutes becomes 3200 minutes, something over 50 hours, two days. "Sorry, Boss, I'll be charging my battery on Monday and Tuesday and will be in on Wednesday. Since my commute is 100 miles a day, I'll need to do this two day charge once for each four working days. Or, I'll be okay Wednesday through Friday, drive another 100 miles on the weekend, and will charge again Monday and Tuesday of next week, too." Right, he could charge at work. Each day at work will need about six hours of charging at the full 100 A at 240 V. Uh, at 10 cents per KWh, the 40 minutes at one megaWatt would cost: A megaWatt hour would be 1000 times a KWh and cost 1000 times 10 cents or $100. The 40 minutes would be 2/3rds of that or $66 or the same as gas at $3.30 a gallon. Not a bargain. And that $3.30 per gallon applies wherever have to pay 10 per KWh, at a charging station, at home, at work, at a restaurant, etc. People don't give away gasoline and won't give away electric power for charging. In particular, a full charge like 20 gallons of gas at home, at 10 cents per KWh, will still cost the $66. Right, the gasoline burns with maybe only 30% efficiency, but there are efficiency losses from heat when charging the battery and again when driving the car. Yup, for powering a private car used as they commonly are, a 20 gallon tank of gasoline is tough to compete with. For an electric, range is too short and charging time is too long. With electric power at 10 cents per KWh and gas at $2.75 a gallon, the cost will be ballpark much the same, no big savings either way. Ah, maybe it's just me: I want a Corvette or Dodge with 700 HP! :-)