Fast charging - Page 9

EVnut · 03-27-2009, 03:29 PM

Oops! Sorry - slipped my mind. :)

dpeilow · 04-13-2009, 02:43 AM

Quote:

Is the future of motoring electric? Only if a whole new infrastructure of charging points is put in place. Even state-of-the-art batteries need to be topped up after a hundred or so miles of travel, so unless every journey begins and ends at home, the electric equivalent of a network of filling stations is required. Evoasis, an American company, plans to build exactly that.

Evoasis’s designs feature off-street bays for up to 24 cars to recharge at the same time, with electricity supplied not in the 220-volt form accepted by most current models of electric vehicle, but at up to 440 volts — powerful enough to charge a suitably adapted car in about 20 minutes.

Because of the dangers involved with such high voltages, the recharge would be performed by station staff. Each station would maintain a “tack room” of cables to ensure that every make of electric car could be catered for (to get a glimpse of the potential chaos waiting in the future, just think of the jumble of mobile phone chargers and connectors).

WarpedOne · 04-13-2009, 03:03 AM

I sense a bit of reason in their technical plan but I'm not sure about financial side of it. Would you rather go to them and buy their expensive electricity or drop by a frend and charge from his home outlet and buy him a beer?

Charging facilities only make sense as a part of bigger economic activity like stores, cinemas etc where the point is to do something else and charging is only a nice addition or added value to the whole service. Here charging would be at same price as home electricity as part of the price would be in the cost of main service. I'm not sure a coffy shop is enough for such main service.

dpeilow · 04-13-2009, 03:25 AM

I agree. London may have a large population density, but the centre of a big city is not where I would expect there to be a great demand for this type of station. They are expecting a model where people drive in from surrounding towns and suburbs, do their shopping or whatever and then go to the charging station for the trip back. That has two issues: firstly as you say people can charge at the service they are going to use and secondly people don't tend to drive into central London for this type of service - those that live outside the city will tend to go to an out of town location and those living in the middle will probably have enough range to go there and back and charge at home.

I see more use for this type of station on the motorways/highways when the long-distance EV fleet is large enough, but even then it will have to be offered by or in conjunction with the existing service station operators.

Takumi · 06-13-2009, 10:43 PM

Well, no point in developing quick charging seeing how it'll be obsolete after this.

TEG · 06-13-2009, 11:12 PM

Gives new meaning to the term "power band".

dpeilow · 06-16-2009, 05:26 AM

Arguably the least appropriate post in a Fast Charging topic ever.

Unless Nokia plans to set up terawatt transmitters and give free power to everyone...

LogicWorks · 07-04-2009, 02:29 AM

Moderators note: This and following McDonalds posts moved from the Model S Specs thread.

Quote:

The problem with charging a 70kWh pack at 400V in 45 minutes is that it takes 233Amps! That requires wires (at least two) about half an inch (0.4"; 10mm) thick! And that's from the power company all the way to your home, your garage and into your car. At 90% efficiency you have to "cool away" 10kW for the duration of the charge. I could heat my entire house with that!

In America we run very high voltages to reduce wire size and power losses (100,000's of volts). The 480 volts is from-step down transformers that you probably have seen when you drive on the road where those tall wood poles with round looking cylinders (the transformers) taping in the wires above them. In America the 7,200 volts 3-phase lines coming from the substations that have been step down from 250,000 volts is tapped with 3 transformers that are configured either Wye or Delta configuration 3-phase. Above ground service of 480v 3-phase is available up to 600 amps from the transformers to the building and 480v 3-phase is available up to 3,000 amps below ground service from ground transformers (they are in large green enclosures) to the building. So the claim of 45 minute recharge time seems plausible, the only problem is 3-phase power is very expensive to have ran to a residential area!!!

SByer · 07-04-2009, 10:46 AM

Yeah, but you'll never need the fast charge at home. Just plug-in overnight, and all is good off of 240v service. Fast charge only has to be available at "common long trip maximal overlap points" - i.e., halfway between SF and LA.

vfx · 07-06-2009, 01:24 PM

How about a high powered charging station along every major highway. Put one every two miles would make about 11,000 charge stations by one estimate. Less than a billion could do that.