Electric Cars

[Solomwi]

Oops. My bad. The 70 amp 240v charger is the 3.5 hour charger. I guess you would need much higher amperage even than that for the 1 hour charger.

Unfortunately, I don't know the electrical math here.

P = V*I

E = P*t = V*I*t

P: power, V: voltage, I: current, t: time, E: energy

Hold E and V constant, and the time required is inversely proportional to the amperage, so if 70 amps charges in 3.5 hours, you'll need 245 amps to charge in an hour. At least, I'm pretty sure that's how it works. It's been over ten years now since I had my last physics class, and it doesn't come up often in the practice of law.

[-Jrabbit]

I could easily make due with an electric car for commuting now on the ranges they have, what I don't have is 50K plus to aquire one. Price is really the only hurdle.

Agreed. Obama should offer incentives (tax credits) to accelerate the adoption process.

[Patroklos]

Thats not really a solution, just like any other technology as it is further developed and refined it will become cheaper naturally. At that point, and no sooner, we will start to see electric cars in the numbers Mobius mentioned.

[DanS]

P = V*I

E = P*t = V*I*t

P: power, V: voltage, I: current, t: time, E: energy

Hold E and V constant, and the time required is inversely proportional to the amperage, so if 70 amps charges in 3.5 hours, you'll need 245 amps to charge in an hour. At least, I'm pretty sure that's how it works. It's been over ten years now since I had my last physics class, and it doesn't come up often in the practice of law.

Cool. Thanks. I guess that may take special provisioning by the electric company. Much more than typical residential needs.

[DanS]

Mostly, I disagree with the subsidies. The limiting factor here is batteries. Battery technology progress is increasing cell capacity by about 8% per annum -- without additional subsidies. This rate of improvement is quite acceptable to make electric cars attractive from a range perspective in reasonably short order.

[rah]

P = V*I
It's been over ten years now since I had my last physics class, and it doesn't come up often in the practice of law.

It doesn't come up often in most professions.

[Solomwi]

Cool. Thanks. I guess that may take special provisioning by the electric company. Much more than typical residential needs.

Well, note that I held the voltage constant, for comparison's sake. That wouldn't necessarily be a real-world constraint. I suspect the quick-charging would be reserved (at least in the near term) for commercial stations with 480 V (or higher) power, already common in industrial settings. That would cut the amperage in half right off the bat. Of course, some of the energy flowing from the line to the car is inevitably lost, an amount which could conceivably be reduced to deliver the same amount of energy to the car with less coming from the line. I don't know how much efficiency gain there is to be had by improving technology, but I'd be surprised if there weren't some.

[DanS]

Yes, as you say, 480v is common in industrial settings. From what I've seen, in residential settings 480v isn't provisioned. You would be able to get 480v if you're right next to a 480v pole, I guess. Maybe a basic residential subdivision is different.

This leaves aside whether the Roadster could handle the 480v, of course. I don't know that it can.

[MOBIUS]

What if in the future gas stations turned into battery stations? Let's say your driving from California to New York. At about 300 miles your batteries are running low, so you pull into a battery station, remove your batteries and replace them with charged batteries, then speed on towards your destination, stopping every 300 miles to change out batteries. You belong to a service, you "rent" your batteries, paying some sort of base fee, then paying for energy every time you change out a depleted battery for a charged one.

This is my idea, I came up with it first.

Sorry, some Israeli dude already came up with this idea...

However it is most likely a non-starter due to having to take a massive gamble on investing in a huge infrastructure of 'filling' stations whilst all the time battery capacities go up and charge rates come down.

More likely would be car pools of longer range vehicles for use for those infrequent journeys you go over 200 miles in a day (something I could count on the fingers of one hand last year). So already electric cars could easily handle virtually 100% of all daily car usage as it is.

I think recharge rates will come down massively in the next few years especially now that the big 3 have 'charged' into the fray. Get it down below an hour and that can be a rest stop on the motorway, easy.

[Patroklos]

I am not too worried about the recharge rate if the range is good, I can just charge it overnight. As you said for long distance travel gasoline will still rule for a long time. Which isn't really a big deal, everyday commuter traffic is the source for most resource demand and enviromental damage.

[Solomwi]

Yes, as you say, 480v is common in industrial settings. From what I've seen, in residential settings 480v isn't provisioned. You would be able to get 480v if you're right next to a 480v pole, I guess. Maybe a basic residential subdivision is different.

This leaves aside whether the Roadster could handle the 480v, of course. I don't know that it can.

True, I was divorcing my answer from the particular circumstances and just speculating about how it may happen down the road. 112.5 amps is still a ****load of electrons running through the line.

[Elok]

Sorry, some Israeli dude already came up with this idea...

You mentioned an Israeli without damning his race and/or country. Are you slipping, or are you a doppelganger or impostor of some sort?

[DanS]

112.5 amps is still a ****load of electrons running through the line.

Aye aye

As the battery capacity increases (as stated above, an 8% per annum increase has been observed), they'll be running more than 112.5 amps. It will be impressive for a 1-hour charge, 500 mile range, f.e. You come to expect that these things will be tough to do or will require lots of additional infrastructure spending. But it's not the case here -- well, it's not the case with the distribution infrastructure at least.

I'm guessing that Tesla will cut some deals with restaurant chains just off the freeways for these charging stations. They already have a deal with Hilton Hotels, IIRC.

[Zkribbler]

Then there's the One Cat, which runs on compressed air.

Range ~ 850 miles

It has an onboard compressor, which will recharge the tanks overnight. Or if there's a service station nearby which has a compressor, the tanks can be recharged in ~ 4 minutes.

Due out in 2010.

[snoopy369]

Kuci - yes, you could increase the amperage by using multiple sockets, though I don't think you can get 240V easily. But that's only if the sockets come from separate circuits - each circuit is usually good for 20A or so from what I remember - and often nearby sockets would be off the same circuit (or two). I think you'd have to specifically run cabling and install a special socket realistically to get a lot of current at home - and anyway the point is not home charging (where you can afford hours) but on-the-road charging...and good luck getting 300-400A in one circuit without paying a lot, I'm guessing.