View Full Version : What is the Tesla Roadsters charge time on a super charging station?
06-28-2007, 04:21 PM
I was talking to someone today and he told me about super charging stations that he thinks can charge the roadster in a matter of minutes.
Does the Roadster's batteries allow for this?
I still am trying to learn more about the technical side of electric cars so please bear with me.
06-28-2007, 05:00 PM
This issue has been hashed out at length on various entries in the Tesla Motors blog. A synopsis would going something like this:
1) Batteries exist that can be recharged quickly.
2) Tesla Motors is not using those batteries, mainly because they're expensive.
3) If TM switched to these batteries, however, there's a huge question whether the existing electrical infrastructure would be able to support the high current required to charge a 50kWh pack in 10 minutes. (Remember that 50kWh is about two days usage in an average U.S. home -- delivering that kind of electricity in 10 minutes would require some doing.)
4) If the infrastructure were upgraded (somehow), several safety issues may make fast charging less convenient than ordinary gasoline refueling. Some people have mentioned having shielded car stalls and remote switching to avoid killing customers.
5) It's not clear whether there's any money to be made in such stations, as the current thinking has most people charging their cars at home.
06-28-2007, 05:04 PM
A place where this would be useful is at the track however.
That's really what I am thinking about.
Brent did a nice job summarizing.
There really is no way around this for the roadster. The whole pack ESS is very involved to change, so even if you had a fully charged ESS ready to go it would be impractical to swap them. You would basically need to have multiple roadsters at the track so you could drive a backup while the first one was charging.
In terms of the grid power required... Another alternative suggested would be to have a secondary pack that trickle charges all the time, and then can dump the stored power rapidly to some quick-charge capable vehicle when needed. That way you wouldn't ever need to burst-draw an unreasonable amount of grid power from your neighborhood. The costs of a back-up pack would be rather high now. Maybe if EEstor ultracaps turn out to be real and cheap we can think of things like this. Another idea would be a large flywheel shed. You slowly spin up the massive flywheel using grid power, then when your fast-charge EV hooks up it does a burst-regen (to stop the flywheel) from the grid motor to charge up your car pack. I don't know how big & heavy & fast such a flywheel would need to be to hold 56kWh but it would likely be very substantial!
Most people would be fine with the 3.5hour charge since they park at home most nights anyways.
I read an article that said fleet vehicles may need quick charge capability. Vehicles likes Taxis & Police Cars may rotate through multiple shifts of drivers and not have downtime to recharge slowly. Aside from an endurance race, I doubt there are many scenarios with the Roadster like that. Whitestar, on the other hand could be an eco-Taxi or eco-Police car if it weren't for the slow recharge issue (and overall price).
06-29-2007, 03:20 AM
The more I follow this, the more I have the feeling that until a BEV can have sufficient range for a full days travel (thus allowing for overnight recharge), a BEV will never be able to be the only vehicle that a family will have. It will be limited to commuting and short distance driving with an ICE/PHEV vehicle picking up the slack. For those individuals/families that can only afford a single vehicle, it seems that they will have to go with a PHEV (at best) until the range problem is resolved.
The average vehicle has an average range of 300 miles, and there must be few people that need to visit a gas station every day with the tank on "reserve". From my understanding an electric car needs to have the batteries "topped up" every day (night).
In North America there are more vehicles than licensed drivers, most households usually have 2 vehicles as a starting point, and it goes up from there. In most metro centres who wants to drive more than they have to, the daily commute is already a test of "endurance". A 50 mile in one direction for a total of 100 miles a day is a "long commute", and 75 mile one way is "spend your life in the car" experience.
Any vehicle with a 200 mile range will more than suffice for a days normal driving before topping up the battery. Climatic conditions will have an effect on the range, especially when its cold. Its also a good excuse not to get an electric car "I drive a gazillion miles a day, this wont work".
The ideal application for an electric vehicle is a "commuter appication", vehicles with an ICE are extremely wasteful in congested traffic situations. For the vacation, road trip, call it a "travel application" an electric vehicle is not in its element. Then you resort to a vehicle with an ICE.
In the past few months(escalating price of gas), many households are keeping the monster SUV in the driveway for week end use, and have purchased a Yaris or Fit for the daily commute, got get the milk application.
The household than can only afford 1 vehicle, chances are its going to be a used vehicle with an ICE. Electric vehicles have a price premium that folks on a "budget" will not consider.
An electric vehicle is a form of socially responsible LUXURY and ELITISM at this stage. Its a reason why all the weird looking electric stuff that has been sporadically offered never made headways.