OT: Electric cars; how green are they?

[Roger Chapman]

Any use of electric cars over even relatively short distances is fraught with difficulties. If the battery can't be charged at home over night or at the office during the day then what is the driver to do if the journey is out of battery range? At the very least he will have to sit and wait at a service station while the battery is charged. The service station will have to have a monster electric supply whether it is charging batteries in car or off car.

I have just had a stray thought that I haven't the technical know how to follow up. Would it be possible to recharge batteries just by changing the electrolyte? Or is that me just displaying my ignorance again.

[The Natural Philosopher]

which is £20k.. so I want far out..

Actually replacing a lead acid starter battery with a lithium, would make sense in any car.

[Jeff Gaines]

A car-battery size nuclear power generator would solve a lot of problems.

[The Natural Philosopher]

Thats utter rubbish.

Their is no breakthrough, because the laws of physics haven't changed. Billions have not been spent.

The very best metal to use is lithium. Its theoretical energy per unit weight is the best there is for electrochemical batteries.

WE are somewhere near 50% of that theoretical maximum energy density. No amount of money or time spent will break the laws of physics (as I told Clive Sinclair once, and was never forgiven for it).

Battery development consists in trying to get a bit closer to the maximum, and in making batteries that charge faster, last longer and run cooler and more efficiently.

Lithium batteries have made huge strides in the latter area in the last few years, but they haven't go ant lighter as a result..

[The Natural Philosopher]

about a tonne and about the size of 20 bags of cement.

No worse than every railway line having the equivalent of a substation every 40 miles or so.

Let's say we have 200Kwh batteries, and we want to charge 200 cars in half an hour. That's 200x200,000x2 watts or 80000000 watts - 80MW.

about the same as 5-10 electric trains draw (peak)

I cannot see even the biggest service station on a motorway needing more than that.

I think the reality is that fast charge at service stations will be waht is aimed for: expensive and slightly deleterious to the battery, but not impossible, technology wise.

I know the battery manufacturers are targetting, and getting close in the lab to 5 minute recharge times (I've waited longer than that at a service station) which at 200Kwh is about 2MW peak power flow. At 400V which is probably where you would want to go, that's 5000A.

That's not a 13A plug for sure, but its not impossible.

[The Natural Philosopher]

I think that's true, and therefore battery cars will actually only get taken up by people whose work car parks include charging.

Once upon a time you had to go to the chemist shop to buy petrol and it was a brave motorist who dint set out without a couple of spare tins in the dicky seat.

Before that they said horses would never catch on because you would need stables and ostlers everywhere to house and feed the horse.

Providing on street charging is no more hard or expensive and a lot more profitable than providing on street parking meters.

[The Natural Philosopher]

We do that for tyres anyway, so its no big deal. Kwikfit etc is exactly the sort of place you would get a P/Ex battery fitted in under 15 minutes.

As far as fast swapping in transit goes, um yes possibly.

I have been long of the opinion that Bernie Ecclestone ought to organise an all electric Formula-E series. No holds bared, any technology you like, the name of the game is to cover 200 miles as fast as the technology and pits stops will allow.

That would really develop battery swapping I reckon.

As well as drive all the technology forward a a huge rate.

Ad be utterly fascinating to watch.

[The Natural Philosopher]

You are wrong. 5 minutes is on the cards, BUT the peak power requirements make the actual plug and cable you use a bit interesting.

5 minutes.

[The Natural Philosopher]

Yes.

And titanium is not that hard to get hold of either.

Its the only metal that feels warm to the touch. Weird stuff.

[Alan Braggins]

There are batteries that you can do that with.

you could use a fuel cell in the car, and have "charging" stations that used an electricity supply to regenerate the fuel. if you have oodles of practically free electricity, from a working fusion reactor or magic pixies, whichever is available first, you can synthesise hydrocarbons from water and carbon dioxide, letting you keep internal combustion engines and the existing distribution infrastructure while staying carbon neutral. an option if you are building a vast solar power station in the Sahara and want to use the power all over Europe, as an alternative to cables transmitting electricity between continents.)

[Alan Braggins]

And the cables going to the service station that has a whole row of such charging points being used continuously for hours on end are also going to be interesting, compared to sticking a concrete tank in the ground and emptying a tanker into it.

"no prospect ... ever" might be wrong, but it's not going to happen easily.

[tony sayer]

Apart from such uses and milk floats, and the one around our way is Petrol driven, Electric car's won't really come into their own till such times as either the superconductor battery gets invented .. or they can carry their PRIME power source onboard;!...

[tony sayer]

What might be an idea is to "charge as you go"! thats to say inductive power units in the road that can be "received" as it were in the vehicle.

Perhaps installed on Main roads and use the batteries when "off grid" as it were;?..

[Man at B&Q]

Google Redox battery.

MBQ

[Man at B&Q]

How much power can you get from an RTG? How big?

MBQ

[Tim Streater]

How about Polonium? :-)

[Dave Plowman (News)]

Seems strange even Rolls Royce etc doesn't.

[Dave Plowman (News)]

Horrendously inefficient, IIRC. Doesn't much matter with a toothbrush, though.

[jgharston]

That's why I specifically said /used/ cooking oil. I shake my head every time I see a technology for usefully using waste products (oil, woodchip, paper, etc.) being subverted when somebody discovers the profits to be made in feeding it with raw materials.

Having passed my test, I'm planning on buying a diesel car, I live about 20 miles from

and the round trip (especially if I was going into Aberdeen anyway) would be worth the 20p/l saving and the contribution to preventing a useful waste product from just being dumped.

JGH

[Matty F]

"A new breed of rechargeable zinc-air batteries is soon to be available, and may replace lithium-ion batteries in cell phones, laptops and other consumer items. Lithium-ion batteries store only a third of the energy and cost around twice as much as the new batteries.

ReVolt has also been developing zinc-air batteries for use in electric vehicles. These batteries resemble fuel cells, with a zinc slurry forming a liquid zinc electrode, and a series of tubes forming the air electrode. Electricity is generated by pumping the slurry through the tubes, where it is oxidized and releases electrons. The resultant zinc oxide is stored in another compartment and flows back through the tubes when the battery is recharging. This releases oxygen, and the zinc oxide reverts to zinc."