Electric cars

Martyn1981

AdrianC wrote: »

At 2kWh per mile, 400 mile range is 800kWh.
In 30 min, that's 1.6MWh charge rate.

Correct, that's the figure given some time back.

Are truck mega-chargers now a negative to you? Perhaps you'll soon be denying their deployment too.

AdrianC

Basic laws of physics don't get repealed by press releases and optimism, y'know.

Martyn1981

AdrianC wrote: »

Basic laws of physics don't get repealed by press releases and optimism, y'know.

Are you saying that the information is untrue and that Tesla isn't going to build out a mega-charger network? (Similar to your earlier claim that Model 3's weren't being delivered.)

Q.2. Are you claiming that the trucks only have one charge port?

Martyn1981

AdrianC wrote: »

There's a difference between the concept happening (although it's worth remembering that as I write this, we're currently at about 17% wind, on- and off-shore, and that's pretty much peak, with just under 43% CCGT) - and swallowing Elon's kool-aid wholesale.

In case you are interested, your claim that wind was at peak when producing ~7GW is currently being beaten, it's about 12.5GW, that's about 34% of demand.

zeupater

AdrianC wrote: »

At 2kWh per mile, 400 mile range is 800kWh.
In 30 min, that's 1.6MWh charge rate.
At the same 480v that the current Superchargers use, it'd be nearly 3,500A.
Even at 11kV grid voltage, that's 150A.

Without calculating charging losses. Or heat dissipation.

Who's man-handling those cables about...?
How many charging points do you foresee at one services?

Hi

No, the charge rate you need to consider is power, energy is meaningless for what you've attempted to convey !

HTH
Z

Martyn1981

Gloomendoom wrote: »

I actually reckon that the Perth area is ideally suited to EVs. The vast majority of car journeys are well within the range of the cheaper offerings. Overloading the grid would be the biggest issue, as it is virtually everywhere else.

Yep, definitely an ideal place for EV's. Add in some PV and a domestic battery and free fuel!

My, not exactly ideal, E/W system has around 15kWh spare generation on average for the better 6 months, so a (dare I say it?) Tesla battery could store that, eliminate my additional import, and still have 10kWh per day for the car, so 30/40 miles per day, or about twice what we actually drive.

In Perth, the better generation and flatter seasonal curve could well provide 12 months 'fuel'. [Note - obviously if the car is home during the day, then even better for charging. M.]

It shouldn't be long before PV generation + storage is cheaper than the cost of distributing leccy in WA, so even if the companies could generate it for free, you'd still be better off going DIY.

I suspect by 2020 things will have moved on considerably and our direction of travel (teeny pun) will be changing fast.

Martyn1981

Just some fun predictions for EV's in 2018:

2 Dozen Electric Vehicle Predictions For 2018

With 2017 being such a huge breakthrough year in the transition to electric vehicles, it raises the question: “What major news, milestones, and developments related to electric vehicles will occur in 2018?”

In an attempt to answer this question I’ve grabbed my crystal ball and tapped my inner Carnac the Magnificent to bring you my EV predictions for 2018. Some of them will seem rather obvious and logical to EV observers, some likely a stretch, while others may fall into the camp of purely crazy speculation. In some cases I’ve been very specific with the names of companies — not for the purpose of being precise but merely to make the predictions feel a bit more real.

Joe_Horner

zeupater wrote: »

Hi

No, the charge rate you need to consider is power, energy is meaningless for what you've attempted to convey !

HTH
Z

His slip on the units doesn't alter the (correct as an approximation) final result.

Now, for copper cable in free air and assuming 4 metre charging cables, that 1500 amps would require a cross section of 300mm^2, or roughly 1.8cm diameter for a solid conductor - physically bigger for multi-strand. That 300mm^2 x 4m cable is going to weigh around 115kg just for the conductor, plus the insulation and armoured sheathing which will be essential for safety.

Times 2 because you also need a return line as well.

The only way to reduce that is to operate the chargers at higher voltage (needing less conductor but significantly more insulation) , which isn't likely to be acceptable for "flying" leads being dragged round a charging point by consumers!

Martyn1981

Joe_Horner wrote: »

The only way to reduce that is

Are you also claiming that there will only be one charging port for one cable?

Am I the only one that's bothered to watch the videos and pics from the launch?

Isn't it also entirely possible that the charging will be done mechanically?

I love the way people like to explain how things can't be done, as if those that are doing it (what can't be done(?)) aren't aware of this.

Tesla Semi — 8 Charger Holes, 800 kWh Battery? Tesla Megacharger — 1.6 Megawatts?

Joe_Horner

Martyn1981 wrote: »

Are you also claiming that there will only be one charging port for one cable?[/URL]

Not at all, but the same basic physics applies. If there are 8 charging ports then you still the same total cross section to (safely) carry the total current. So that's still nearly a quarter ton of conductor for 4 metre leads, and by splitting into more cables the insulation and sheathing requirements will be even greater. It doesn't matter how clever Mr Musk may be, he's not allowed to re-write basic physics.

As for "mechanical charging", that might conceivably be viable if manufacturers standardise all aspects of the charging ports - size, configuration, position on the vehicle and so on. Even you have to admit that doesn't appear likely. Any time soon. And without that any automated connection is going to be manufacturer, or even vehicle, specific and will have to be duplicated, at least in part, for other marques.