On 06 Jan 2006 11:52:35 GMT, Adrian wrote:


Yes. A modified Colt. And a modified Evo.

So where's this "ground-up" EV, then?

About 1-2 years away I'd say.

On Fri, 06 Jan 2006 19:02:40 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On Wed, 04 Jan 2006 15:35:15 +0000, Steve Firth wrote:

Dave Plowman (News) wrote:
In article ,
Steve Firth wrote:
All of Drivel's theories are blown away by the poor thermal
characteristics of current battery technology. The high charge density
lightweight batteries have much lower thermal efficiencies than
lead-acid batteries.
I find it interesting that many car makers are going to expensive lengths
to save weight - extensive use of aluminium etc. But still fit lead acid
batteries - where cost really isn't a consideration.

It's because lead acid batteries don't need complex charge controllers,
work across a wide range of environmental temperatures and provide huge
cranking currents time after time. They are big, rough and tough and
also extremely efficient compared to any of the alternatives around.
Where they fail is on charge per kg which is where Lithium based
batterys win. Where Lithium batteries fail is on charge/discharge
cycles, efficiency and the need for complex charge cycles and careful
management of discharge.

Actually, most of that is utter tosh.

Sadly, not so.

Lithium bateries have almost excatly te same charge characteists as Lead
Acid - constant current with a contsant voltage limit.

200-1000 cycles or about 3 years, whichvere is first, is teh cycle time.

A 70Ah LIPO battery will, on current technolgy, provide about 2KA without
exploding for maybe 5-10 seconds. It will certainly provide 1KA
continuously.

And can be charged at up to 70A..more than most alternators can deliver.

This is not theoretical knowledge: This is how we fly these *******s.

Sure and by doing so you get a relatively poor round trip efficiency
from the battery.

We get about 90% like this. I guess whether that poor, is down to your
definition.

At more modest rates, say 1 hour discharge - its beyond my capacity to
measure the difference between whats gone in and what comes out.


If you want to get the best out of Lithium batteries,
i.e. to get a round trip efficiency of 90% then both charge and
discharge need to be controlled as described, otherwise more of the
energy is going into waste heat. It's possible to get Lithium batteries
down to 50% efficiency if you trea them like lead acid batteries.


Its not. They will destroy themslves first :-)

It is almost IMPOSSIBLE to fly LIPOS at less than 90% efficiency round
trip.

The internal resistance is way lower thanlead acid, and very comparable
with nickel cadmium thses days.

To run them at 50% efficiency implies currents high enough to melt the
electrodes and to instantly explode the battery.


You can treat a battery rough if you're not bothered about efficiency.

The downside is the cost - $1000 currently, though in volume they should
be no more expensive than lead acid ultimately - and safety. The high
discharge rates are achieved by using a fairly aggressive and inflammable
organic polymer, and it can and does, ocasionally go pop under adverse
contitins (over temeperatire, shorting, over charging) and cause a seriosu
fire hazard.

So can a lead acid if course.

Ther are other, heavier and lower charge/discharge rate batteries coming
along that are less flammable. These should be suitable for car usage.

"coming along", "should be".

Yes inded. Look at te new range of batteries descroibed in te URL someone
posted as another thread. OK its pure advertsing, BUT these cells are going
into poro pwqower tools this year. We can see how good they are.

Nick Finnigan ) gurgled happily, sounding much like they
were saying :

The electric motors are instead of a GEARBOX. Not instead of a DIESEL
ENGINE.

There are in addition to a gearbox.

What does the gearbox output drive?

On Fri, 06 Jan 2006 19:12:15 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On 04 Jan 2006 14:36:40 GMT, Adrian wrote:
s.
Indeed. And, when you add in the 70% charging losses estimated elsewhere,

Drivel. That IS drivel. About 5% charging and about 2% discharging.
Real world figures. Not wavy hand magic estimates.
Why not buy yourself some an test them?

Those are best possible figures for LiIon and you're ignoring the losses
in the charger as well. Overcharge the battery and all the energy is
wasted, discharge it too rapidly and more energy is wasted. Real world
estimates of round trip efficiency for LiIon range between 55% and 95%.

You arer as bad as Drivel. You have simply read something somewhere and are
waving your hand...I KNOW what these cells do. I use em regularly.

Chargers can easily top 90% if properly designed.

The cells are WAY over 90% efficient round trip.

Wherever you got for 'facts' from is just plaine out of date.

On Fri, 06 Jan 2006 19:22:03 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On Wed, 04 Jan 2006 01:54:56 +0000, Steve Firth wrote:

Adrian wrote:

Indeed. If you're not 500 miles from the spare battery pack. Or do you just
carry half a ton of spare battery in the boot?
All of Drivel's theories are blown away by the poor thermal
characteristics of current battery technology. The high charge density
lightweight batteries have much lower thermal efficiencies than
lead-acid batteries.

As you wil notice if you try charging any LiIon, NiCd or NiMH battery.
See how toasty and warm it gets while charging? And feel how warm if
gets while discharging as well. It's a lose/lose technology.

You are talking as much drivel as drivel.

Ah good, proof by assertion

Then of course there's the high internal discharge of Lithium Ion
batteries to consider. If I filled the car with petrol, left it at the
airport while I went on holiday and came back to find it empty, I would
suspect theft or a leak. With a Lithium Ion powered car I can expect to
have to charge it when I get back.

Not so energy efficient.

Again, utter drivel.

NiMh bateries discharge in days. LIPO cells I use are generally at 90%
ofcharge after 6 months..

Everything you have said about batteries - low cycle efficiency, hot when
charging, flat in weeks - is totally true on NiMh batteries, none of it
applies to LiPo.

On 06 Jan 2006 10:46:27 GMT, Adrian wrote:

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

Batteries will be even cheaper and better. Technology has moved
vastly prompted by mobile phones.

But mobile phones don't have ****ing electric motors in which is
where it all turns to ****.

You made that up.

Which bit? That mobiles don't have electric motors? Or that electric motors
aren't as efficient as pure electronics?

TBF, I'm not sure whether the vibrating "ring" is a motor whirling a weight
about or a solenoid or what.

Its a motor actually. 'pager motors' are sometimes used to fly sub 4 ounce
models indoors..

On 06 Jan 2006 12:28:26 GMT, Adrian wrote:

The Natural Philosopher ) gurgled happily, sounding much like they
were saying :

Why am I defending Drivel?

Well I am not, I am defending his data.

He hasn't provided any.

well his general thesis then ;-)

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

And the electricity comes from...?

A generator. Wow, boy are you dumb.

And the generator is powered by...?

Some sort of engine.

Yep, 3,650bhp of Diesel.

So, my electric toothbrush is powered a by gas turbine.

Blimey, that's a big toothbrush if it has a gas turbine fitted into it.
Does it get very warm in use? How much fuel does it hold?

I never knew that as I always through it was the lecky
coming of the socket that did it.

So how long an extension lead do these trucks have?

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

They are diesel/electric.

Electric motors propel them.

Indeed. In exactly the same way as they do in diesel/electric trains.

Doctor Drivel ) gurgled happily, sounding much like they
were saying :

Yes, but the energy stored must be brought to the battery - fine
for a few, much new infrastructure to generate and distribute the
energy we use today.

Cables are everywhere.

Thin ones running close to 100% already.

Which will need replacing then and then bigger thicker cables installed.

*DING*

On Fri, 6 Jan 2006 13:06:08 +0000, Clive wrote:

In message , The Natural
Philosopher writes
We are seeng the first entry of serious LIPO pwer into power tools.
That market will allow of significantly larger cells to be mass
prioduced. Enough topower e.g. electric scooters. Japan will probably
be awash with them shortly.
20 years ago we had the Sinclair C5.

20 years ago we didn;t have mass produced LIPO batteries, and anyway,
Clive's ideas about what the world would be using 20 years after he failed
to actually make it work, have always been close to the mark.

- the digital watch.
- the pocket calculators
- the micro TV
- personal computers

And the C5...

I supect that something very like a C5 will in fact be on sale in due
course. The difference will be, this one will actually work...better than a
disability scooter :-)

The Natural Philosopher ) gurgled happily, sounding much like they
were saying :

As an adaptation of an existing IC car, it doesn';t really do the
technology justice though...we found in the toy plane areana, that we
could modify strutcures and shapes to acheive lighter overall
weight..you didn't need to carry a big vibrating lump of IC engine..in
the car, the strength around the engine mounting area is no longer
needed to take the weight torque and vibration of 2200bhp of petrol
engine,..

2,200bhp? I WANT

But you WILL still need the strength and space there, for impact
protection.

but the suspension itself will be taking ALL the torque from
the wheesl, rather than e.g. the differential..

Yep.

On Fri, 06 Jan 2006 16:30:30 +0000 (GMT), Dave Plowman (News) wrote:

In article ,
The Natural Philosopher wrote:
However, no one says that is how it has to be. We are seeng the first
entry of serious LIPO pwer into power tools. That market will allow of
significantly larger cells to be mass prioduced. Enough topower e.g.
electric scooters. Japan will probably be awash with them shortly.

Its only a small step up to urban 'Smart' cars..

I remember the same being said when Ni-Cads became common. Still waiting...

NIcads didn't have the right energt desnity or the right cost performance
criteria, and te price of fuel was a lot lower then, and the environmental
issues were barely dicussed outside of the 'new scientist'...

People tried powerd flight using steam using balloons, and so on, with
remarkably little success...we were stull waiting in 1905 when a
lightweight IC engine finally go the power t weight up enough for it to
become a reality.

We were stuck at top speeds of about 500mph until jet engines came along...

Everything required for electric vehicles existed, except the power source.
Now it exists. Its not totally right, but its very very close. Far closer
than fusion is. Its within development reach. It does not require some
whacky design breakthrough.

On Fri, 6 Jan 2006 15:00:09 -0000, Conor wrote:

In article ews.net,
Doctor Drivel says...

"The Natural Philosopher" wrote in message
...
On 04 Jan 2006 14:41:11 GMT, Adrian wrote:

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

As 90% plus of us live in towns and cities our lungs matter.

Doesn't "North London" count as a "town or city", then?

Because you've already claimed that pollution from an industrial accident
arising from the generation/transmission/storage of energy for
transportation will drift over North London.

The fact that Buncefield's fire was primarily aviation fuel seems to have
slipped you by, too.

Or will your utopia have electric planes, too?

I already fly them :-)

However no, energy density is not and will never be enough for commercial
planes...those will lilely be repalced by high speed trains for overland
routes, and by biofuel or hydrogen for intercontinental flight.

I'd say you COULD get a lightplane up on batteries, with about a hundred
miles or so range - maybe a bit more.


How about the trucks that the food is delivered to these towns and cities
in? Will they be electric? I wonder what the average daily mileage for an
HGV is...?

Nope. Biodiesel. But te short haul delivery vans WOULD be electric.

No one is saying its the answer to all problems - except drivel -

The largest trucks in the world use electric motors.

Really? Proof? Used in general haulage are they? Austrailia has some of
the heaviest road going trucks there are. They're all diesel.

He is probably thinking of electric locomotives.

On Fri, 06 Jan 2006 19:36:26 +0000, Phil Bradshaw wrote:

Doctor Drivel wrote:


"Steve Firth" wrote in message
...
Doctor Drivel wrote:

"Adrian" wrote in message
. 244.170...
Conor ) gurgled happily, sounding much like they
were saying :

The largest trucks in the world use electric motors.

Really? Proof? Used in general haulage are they? Austrailia has some
of the heaviest road going trucks there are. They're all diesel.

And they're *TINY* compared to some of the really big stuff out there.

Think of quarries and mines.

The largest trucks in the world tend to be hydraulically driven,

No, electric motors propel them.

yawn

They are diesel/electric.

Electric motors propel them.

How much of a battery pack will be needed to replace 10.5 ton of 3650bhp
Detroit diesel?

Mm. Depends for how long... I am seeing 5 watt hours per ounce..on a very
small (2Ah) cell

So lets say we go for an hour of running..I make that 15 tons of battery.

AT FULL CONTINUOUS POWER.

I doubt they run full power all the time.




How do sizeable AC motors run off batteries without significant losses?

You use a 3 phase switching invertors,and pulse width modulate the phases
to achieve throttling. The motor inductance itself smooths these out to
limit peak currents to reasonable levels Typical efficiencies are over
95%.at full throttle, but lower at part throttle due to extra switching
losses in the throttling process. Use of extra indictors in the winding
phases to further limit peak currents adds some weight, but improves part
throttle efficiency, as does use of large banks of capacitors to supply
peak current demands on the source. Also use of bigger power stages reduces
on resistance and can improve overall efficiency. These add weight and
cost, but in principle ou can get as high an efficiency as you are prepared
to spend money on.

"The Natural Philosopher" our resident snotty uni man wrote in
message ...
On Fri, 06 Jan 2006 19:12:15 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On 04 Jan 2006 14:36:40 GMT, Adrian wrote:
s.
Indeed. And, when you add in the 70% charging losses estimated
elsewhere,

Drivel. That IS drivel. About 5% charging and about 2% discharging.
Real world figures. Not wavy hand magic estimates.
Why not buy yourself some an test them?

Those are best possible figures for LiIon and you're ignoring the losses
in the charger as well. Overcharge the battery and all the energy is
wasted, discharge it too rapidly and more energy is wasted. Real world
estimates of round trip efficiency for LiIon range between 55% and 95%.

You arer as bad as Drivel.

How dare you. This man is a lunatic.

"The Natural Philosopher" wrote in message
...
On Fri, 06 Jan 2006 19:22:03 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On Wed, 04 Jan 2006 01:54:56 +0000, Steve Firth wrote:

Adrian wrote:

Indeed. If you're not 500 miles from the spare battery pack. Or do you
just
carry half a ton of spare battery in the boot?
All of Drivel's theories are blown away by the poor thermal
characteristics of current battery technology. The high charge density
lightweight batteries have much lower thermal efficiencies than
lead-acid batteries.

As you wil notice if you try charging any LiIon, NiCd or NiMH battery.
See how toasty and warm it gets while charging? And feel how warm if
gets while discharging as well. It's a lose/lose technology.

You are talking as much drivel as drivel.

Ah good, proof by assertion

Then of course there's the high internal discharge of Lithium Ion
batteries to consider. If I filled the car with petrol, left it at the
airport while I went on holiday and came back to find it empty, I would
suspect theft or a leak. With a Lithium Ion powered car I can expect to
have to charge it when I get back.

Not so energy efficient.

Again, utter drivel.

I agree.

"The Natural Philosopher" wrote in message
.. .
On 06 Jan 2006 12:28:26 GMT, Adrian wrote:

The Natural Philosopher ) gurgled happily, sounding much like they
were saying :

Why am I defending Drivel?

Well I am not, I am defending his data.

He hasn't provided any.

well his general thesis then ;-)

I am a brilliant general thesiserist.

"Adrian" wrote in message
44.170...
Doctor Drivel ) gurgled happily, sounding much like
they were saying :

And the electricity comes from...?

A generator. Wow, boy are you dumb.

And the generator is powered by...?

Some sort of engine.

Yep, 3,650bhp of Diesel.

So, my electric toothbrush is powered a by gas turbine.

Blimey, that's a big toothbrush if it has a gas turbine fitted into it.

Boilers make steam which turn steam turbines to turn the genny to send down
the lecky down the line to my house and use the toothbrush.
A coal fired steam boiler runs my toothbrush. Boy you are dumb.

"Adrian" wrote in message
. 244.170...
Doctor Drivel ) gurgled happily, sounding much like
they were saying :

They are diesel/electric.

Electric motors propel them.

Indeed. In exactly the same way as they do in diesel/electric trains.

Yep. Electric motors propel trains weighing 1000s of tons at over 100mph.

On Fri, 06 Jan 2006 19:05:11 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On 04 Jan 2006 14:41:11 GMT, Adrian wrote:

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

As 90% plus of us live in towns and cities our lungs matter.
Doesn't "North London" count as a "town or city", then?

Because you've already claimed that pollution from an industrial accident
arising from the generation/transmission/storage of energy for
transportation will drift over North London.

The fact that Buncefield's fire was primarily aviation fuel seems to have
slipped you by, too.

Or will your utopia have electric planes, too?

I already fly them :-)

However no, energy density is not and will never be enough for commercial
planes...those will lilely be repalced by high speed trains for overland
routes, and by biofuel or hydrogen for intercontinental flight.
[snip]

If hydrogen were to be used for commercial flight, the body of the jet
would have to be the fuel tank and the number of passengers carried
would be the limited to whoever could crowd into the back of the cockpit
and the lavatory.

http://xtronics.com/reference/energy_density.htm

Looks like liquid hydrogen is about one third the weight of equivalent
kerosene...guess thats why they power raockets with hydrogen, and not
diesel..

...as far as volume goes, at 150 bar liquid hydrogen is bulky. 20 times as
bulky as kerosene.

However weight is ultimately what limits flight performance, not bulk. Sure
the plane would be different, but it wouldn't be impossible. There are
planes on drawimng boards of a lifting body/flying wing shape that by
integrateting body and wing achieve a very good lift to drag ratio and
hugely increased internal volumes.

Planes to date have not actually been particularly optimised for fuel
efficiency alone: Other factors like serviceability, and overall cost of
running - of which maintenance and capital depreciation are very large
components - are dominant. Hence the hugely aerodynamically poor design of
engine pods slung under the wings. They are there, because its easy to
replace them in a matter of hours.

The Natural Philosopher wrote:
[snip]
Its not. They will destroy themslves first :-)

It is almost IMPOSSIBLE to fly LIPOS at less than 90% efficiency round
trip.

The internal resistance is way lower thanlead acid, and very comparable
with nickel cadmium thses days.

To run them at 50% efficiency implies currents high enough to melt the
electrodes and to instantly explode the battery.
[snip]

You seem to be basing your comment based on experience with model planes
(only). My experience with LiIon has been with submarine batteries and
with an interest in their use as traction batteries. Firstly let me say
that they are very, very good batteries. However their is much that you
seem to be unaware of.

Lithium ion batteries do not perform well at either end of the ambient
temperature range and in traction use some sort of temperature
conditioning is required, both while charging and discharging. This is
not an issue for model planes, the batteries are small and the surface
area to volume ration permits the battery to remain relatively cool
provided that you don't do anything stupid. Stack those cells into a
traction pack and you need temperature control, which means making a
decision whether to cool actively (liquid cooling preferred) or to
design a passive system, which is better in terms of energy loss but
problematic in terms of adequate cooling in all environments.

The same applies to charge cycles, what is trivial for a few cells
becomes a major problem for large packs. IIRC Toyota try to get around
this problem by never charging to more than 70% capacity and not
discharging below a figure I can't recall, possibly 15%. Fine in a
hybrid, sort of, although it is effectively reducing the capacity of the
battery pack to about half of what you paid for.

There's an American group that assesses technology for EVs, I forget
their name, but they are thorough in their assessments. I can recall a
few papers appearing from them that highlighted exactly these problems
as well as the self discharge characteristics of Lithium cells. Again,
not much of a problem for an aero modeller since I presume you don't
charge the cells then leave them for a fortnight before flying the
plane, but I would be ****ed off to charge a car then have to charge it
again simply because the cells self-discharged while it was in the garage.

IMO EVs may well be forced upon us, but they don't make much of a
rational choice and they are only devices for moving pollution from one
place to another.

The Natural Philosopher wrote:
On 06 Jan 2006 11:52:35 GMT, Adrian wrote:


Yes. A modified Colt. And a modified Evo.

So where's this "ground-up" EV, then?

About 1-2 years away I'd say.

Ah, should just about arrive at the same time as nuclear fusion then,
that's always a couple of years away from a significant milestone.

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

You arer as bad as Drivel.

How dare you. This man is a lunatic.

shrug So are you.

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

And the electricity comes from...?

A generator. Wow, boy are you dumb.

And the generator is powered by...?

Some sort of engine.

Yep, 3,650bhp of Diesel.

So, my electric toothbrush is powered a by gas turbine.

Blimey, that's a big toothbrush if it has a gas turbine fitted into
it.

Boilers make steam which turn steam turbines to turn the genny to send
down the lecky down the line to my house and use the toothbrush.
A coal fired steam boiler runs my toothbrush. Boy you are dumb.

Ah, so your toothbrush doesn't actually have a gas turbine fitted? But
these big trucks DO have a diesel lump fitted. No external electrickery
supply involved, just filling the tank with diesel.

Just the same as diesel/electric trains. Which you happily accept ARE
diesel.

On 07 Jan 2006 13:04:23 GMT, Adrian wrote:


So how long an extension lead do these trucks have?

Actually, that is not totally impossible with earth moving equipment
working over a limited area for a great length of time.

Slap in a substation and have a leccy truck in a cable!

Diesle is great because it is highly portable, but its not the ONLY way to
do things.

Doctor Drivel ) gurgled happily, sounding much like they
were saying :

They are diesel/electric.

Electric motors propel them.

Indeed. In exactly the same way as they do in diesel/electric trains.

Yep. Electric motors propel trains weighing 1000s of tons at over 100mph.

Indeed. Some get their electrickery from trackside cables.

Some get their electrickery from diesel engines powering generators, like
these trucks.

None are battery-powered.

The Natural Philosopher wrote:

[snip]
You arer as bad as Drivel. You have simply read something somewhere and are
waving your hand...I KNOW what these cells do. I use em regularly.

Chargers can easily top 90% if properly designed.

The cells are WAY over 90% efficient round trip.

Wherever you got for 'facts' from is just plaine out of date.

Ah yes, just the same as the person who told me I knew nothing about
fuel cells, then announced that fuel cells would be installed in every
laptop by Christmas. That was Christmas 2004 by the way.

So errm I wonder where they are.

You are taking the experience you have of using very small cells where
TBH you don't measure charging efficiency or have issues of cell cooling
or, I suspect, even have much of an issue with self discharge or even
cell longevity because your use is for an amusing hobby, and assuming
that your experience will scale to traction use.

It won't.

The Natural Philosopher ) gurgled happily, sounding much like they
were saying :

Looks like liquid hydrogen is about one third the weight of
equivalent kerosene...guess thats why they power raockets with
hydrogen, and not diesel..

I think that's got more to do with the fact that diesels require air to
burn with, and that's fairly scarce outside the earth's atmosphere...

Adrian wrote:
Clive ) gurgled happily, sounding much like they
were saying :

No engine, exhaust, cooling system, fuel tank, 4wd transmission... Just
batteries and lightweight hub motors.

This is rubbish, it'll be lighter to have a smaller motor running faster
and geared down. A hub motor would have very low starting torque
extremely high currents and need to be force ventilated at town speeds.

http://www.japanesecarfans.com/news....id/2050824.001

is the best article I've found on the MIEV.


Talk about glossing over problems:

"restrains the increase of unsprung weight."

An odd way of referring to the inevitable massive increase in unsprung
weight.

The Natural Philosopher wrote:

Everything you have said about batteries - low cycle efficiency, hot when
charging, flat in weeks - is totally true on NiMh batteries, none of it
applies to LiPo.

********. You are referring to your experience of playing with toys, no
more.

The Natural Philosopher wrote:
On Fri, 06 Jan 2006 19:05:11 +0000, Steve Firth wrote:

The Natural Philosopher wrote:
On 04 Jan 2006 14:41:11 GMT, Adrian wrote:

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

As 90% plus of us live in towns and cities our lungs matter.
Doesn't "North London" count as a "town or city", then?

Because you've already claimed that pollution from an industrial accident
arising from the generation/transmission/storage of energy for
transportation will drift over North London.

The fact that Buncefield's fire was primarily aviation fuel seems to have
slipped you by, too.

Or will your utopia have electric planes, too?
I already fly them :-)

However no, energy density is not and will never be enough for commercial
planes...those will lilely be repalced by high speed trains for overland
routes, and by biofuel or hydrogen for intercontinental flight.
[snip]

If hydrogen were to be used for commercial flight, the body of the jet
would have to be the fuel tank and the number of passengers carried
would be the limited to whoever could crowd into the back of the cockpit
and the lavatory.

http://xtronics.com/reference/energy_density.htm

Looks like liquid hydrogen is about one third the weight of equivalent
kerosene...

Correct, it's also incredibly leaky and boils off from the tank very
quickly. Even the best insulation available will not stop it from
boiling off. This is why they fuel at the last possible moment.

guess thats why they power raockets with hydrogen, and not
diesel..

Bzzt, wrong: http://www.astronautix.com/props/loxosene.htm

....as far as volume goes, at 150 bar liquid hydrogen is bulky.

Umm you cannot liquefy hydrogen by pressurising to as little as 150bar,
think again. If you could liquefy hydrogen that easily then storage
wouldn't be the problem that it currently is.

20 times as bulky as kerosene.

Which means that storage is going to be one **** of a problem, as I
pointed out previously. To store that much hydrogen is going to take a
tank about the size of a current

However weight is ultimately what limits flight performance, not bulk. Sure
the plane would be different, but it wouldn't be impossible. There are
planes on drawimng boards of a lifting body/flying wing shape that by
integrateting body and wing achieve a very good lift to drag ratio and
hugely increased internal volumes.

yawn

Yes, at this point I should perhaps highlight that my address was once
c/o RAE Farnborough. Flying wings have been on the drawing board for
decades, and that's mostly where they tend to stay. The last time I
saw/heard mention of one, it was beign considered by an aircraft
designer I have considerable respect for (Hi McP if you're reading this,
or if PC Paul contacts you). He discarded the idea as well, because it
all falls apart once you get into embarking and disembarking passengers,
housing landing gear and engines and designing control surfaces. Also
the "huge internal volume" tends to be in a form that's largely
unusable. Unless you are going to insist that the passengers are
strapped horizontal all the way to the USA.

Planes to date have not actually been particularly optimised for fuel
efficiency alone: Other factors like serviceability, and overall cost of
running - of which maintenance and capital depreciation are very large
components - are dominant. Hence the hugely aerodynamically poor design of
engine pods slung under the wings.

Umm it's not "hugely aerodynamically poor design", HTH.

They are there, because its easy to
replace them in a matter of hours.

And because the alternatives were tried and were no better.

Adrian wrote:
The Natural Philosopher ) gurgled happily, sounding much like they
were saying :

Looks like liquid hydrogen is about one third the weight of
equivalent kerosene...guess thats why they power raockets with
hydrogen, and not diesel..

I think that's got more to do with the fact that diesels require air to
burn with, and that's fairly scarce outside the earth's atmosphere...

It's not true anyway, kerosene (diesel) is a fairly common rocket
propellant and was used by both Tsiolkovsky and Goddard, so it's not
like it's a new use of diesel as rocket fuel.

The Natural Philosopher wrote:
On Wed, 04 Jan 2006 15:35:15 +0000, Steve Firth wrote:
[snip]
It's because lead acid batteries don't need complex charge controllers,
work across a wide range of environmental temperatures and provide huge
cranking currents time after time. They are big, rough and tough and
also extremely efficient compared to any of the alternatives around.
Where they fail is on charge per kg which is where Lithium based
batterys win. Where Lithium batteries fail is on charge/discharge
cycles, efficiency and the need for complex charge cycles and careful
management of discharge.

Actually, most of that is utter tosh.
[snip]

Tosh and piffle yourself:

------------
Battery Thermal Management in EVs and HEVs:
Issues and Solutions
Ahmad A. Pesaran
National Renewable Energy Laboratory
Advanced Automotive Battery Conference
Las Vegas, Nevada
February 6-8, 2001

"The need for battery thermal management for ambient temperature
batteries such as valve regulated lead acid (VRLA), nickel metal hydride
(NiMH), and lithium ion (Li-Ion) was not obvious initially, however, EV
and HEV battery and vehicle manufacturers have come to realize such a need."

"Since Li Ion batteries can deliver much more power and thus more heat
for the same volume than either VRLA or NiMH, heat removal needs to be
efficient. Thermal management also depends on the type of vehicle and
where the pack will be located. For EV and series HEV, the pack is
generally large and its thermal management system may need to be more
elaborate, possibly incorporating liquid cooling"

"Li Ion batteries also need a good thermal management system because of
safety and low temperature performance concerns."

"Li-Ion generates more heat in a smaller volume and is more sensitive to
extreme cold and hot, so also need (sic) a complete battery management
system"

The paper notes that an 80-50% discharge of a test Li Ion traction
battery cell produced 2W of heat per AH of cell capacity compared to
1W/AH for Lead Acid, also that the heat evolved by Li Ion batteries on
discharge increases as ambient temperature is reduced.

------------
http://www.powerstream.com/li.htm

... a charge timer should be included for safety.

The charge cannot be terminated on a voltage. The capacity reached at
4.2 Volts per cell is only 40 to 70% of full capacity. For this reason
you need to continue to charge until the current drops, and to terminate
on the low current.

It is important to note that trickle charging is not acceptable for
lithium batteries. The Li-ion chemistry cannot accept an overcharge
without causing damage to the cell, possibly plating out lithium metal
and becoming hazardous.

------------
http://www.batteryuniversity.com/partone-5.htm

The lithium-ion battery

...

Despite its overall advantages, lithium-ion has its drawbacks. It is
fragile and requires a protection circuit to maintain safe operation.
Built into each pack, the protection circuit limits the peak voltage of
each cell during charge and prevents the cell voltage from dropping too
low on discharge. In addition, the cell temperature is monitored to
prevent temperature extremes. The maximum charge and discharge current
on most packs are is limited to between 1C and 2C. With these
precautions in place, the possibility of metallic lithium plating
occurring due to overcharge is virtually eliminated.

Aging is a concern with most lithium-ion batteries and many
manufacturers remain silent about this issue. Some capacity
deterioration is noticeable after one year, whether the battery is in
use or not. The battery frequently fails after two or three years.

The lithium Polymer battery

Lower energy density and decreased cycle count compared to lithium-ion.
Expensive to manufacture.
No standard sizes. Most cells are produced for high volume consumer markets.
Higher cost-to-energy ratio than lithium-ion

------------
http://www.tmcnet.com/usubmit/2004/Oct/1080857.htm

Charging Lithium-based batteries requires different technologies from
those used for other cell chemistries. Attempting to charge
Lithium-based batteries beyond 4.2 Volts per cell permanently damages
the battery and may result in the battery exploding. Over discharging
Lithium-based batteries also results in irreversible changes to the
batteries. For this reason, manufacturers incorporate
semiconductor-based protection circuitry in the Lithium battery pack to
prevent this from happening. In addition, Lithium-based batteries must
be limited in the amount of current they supply; significant
over-current discharge can cause this type of battery to explode.
...

This relatively long charging cycle compared to that of other battery
chemistries is one of the less desirable characteristics of
Lithium-based batteries. Another undesirable characteristic is “capacity
fade”. Each time a Lithium-based battery is charged it loses a little of
its storage capacity. All battery chemistries exhibit some capacity
fade, however, Lithium-based batteries fade more rapidly than Ni-Cd or
Ni-MH batteries. The battery loses a little capacity each time it is
charged. Cell resistance increases with each charge cycle until the
battery is no longer usable. It appears as if the act of charging the
battery damages it, almost as if the size of the battery plates
decreases with each charging cycle.

------------
http://www.batteryuniversity.com/parttwo-34.htm

You will see that LiIon batteries only hold a charge over a long period
if charged to 40% capacity. Charge to 100% and the loss of charge is
rapid, especially at the temperatures to be experienced inside a car.

In message , The Natural
Philosopher writes
Electric trains are probably built to exacting specs for top
performance, and have very little suspension needs.
Then I suggest you try ridding on the steps of a locomotive bogie, which
already has primary springing before it hits your feet. Within ten
minutes you won't be able to walk.
--
Clive

Adrian wrote:
Nick Finnigan ) gurgled happily, sounding much like they
were saying :


The electric motors are instead of a GEARBOX. Not instead of a DIESEL
ENGINE.


There are in addition to a gearbox.


What does the gearbox output drive?

"The (Siemens electric) motors drive an L+ S two-stage planetary gear
set, resulting in a reduction ratio of 37.3:1 to 43.7:1, depending on
application requirements."

http://findarticles.com/p/articles/m...11811#continue

John Wright wrote:
On Fri, 6 Jan 2006 14:55:39 -0000, Conor
wrote:
In article ews.net,
Doctor Drivel says...
"Conor" wrote in message
t...
In article ws.net,
Doctor Drivel says...

But your petrol car is an antiquate piece of junk that pollutes and
wastes
like mad.
And I suppose the UK powerstations are perfectly harmless?
They are not cars. They pollute less than vehicles and don't pollute in
front of people's lungs ruining them

Really? The coal powered powerstation at Ferybridge is right on the
edge of the town and within a mile of 3 towns.

Point taken but the last time I saw that it was in an advanced stage
of demolition.

That great big plume of smoke and steam I can see on the horizon from
the office I work in at Wakefield must be an illusion then.

In article ,
John Wright wrote:
That's all been thought of - the 2004 onwards Prius (and other related
hybrids like the Ford Escape, Lexus Rx400h etc) have electric power
steering and air conditioning as well as the normal services. These
two are special since they aren't normally electric.

Electric power steering has been common on smaller cars for years. Less
wasteful since you don't have a hydraulic pump running all the time.
However, it doesn't give as good a 'feel' as hydraulic - although I'm sure
this will improve.

Prior to 2004 the
air conditioning didn't work when the petrol engine was stopped.

It is said that using the air conditioning in cold weather in a Prius
really hammers the fuel consumption though.

That's the trouble with the Prius - most just quote the wonderful fuel
consumption it can achieve under some conditions - and think it therefore
does this all the time. When Autocar did a full road test including
maximum speed runs and acceleration and brake testing - as they do with
all cars - the overall consumption of that roughly 1000 mile test came out
at 23 mpg. So a planet saver it's not. ;-)

Cars tend to be poorly insulated heat wise, as anyone knows when parked up
in this weather - the car will soon become too cold inside. Or similarly
too hot in the summer. The HVAC system on a conventional vehicle will soon
remedy this - but on a battery vehicle will make a big difference to the
range. Of course better insulation will help, but this adds weight which
is death to a battery vehicle already saddled with a heavy battery pack.

--
*Why is it that to stop Windows 95, you have to click on "Start"?

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 6 Jan 2006 14:55:39 -0000, Conor
wrote:

In article ews.net,
Doctor Drivel says...

"Conor" wrote in message
t...
In article ws.net,
Doctor Drivel says...

But your petrol car is an antiquate piece of junk that pollutes and
wastes
like mad.

And I suppose the UK powerstations are perfectly harmless?

They are not cars. They pollute less than vehicles and don't pollute in
front of people's lungs ruining them

Really? The coal powered powerstation at Ferybridge is right on the
edge of the town and within a mile of 3 towns.

Long chimneys and hot exhaust effluent meant the pollution used to,
(before desulphurisation) come to earth as acid rain in Norway.

And they didn't like it up 'em.

DG

"The Natural Philosopher" wrote in message
...
On Fri, 6 Jan 2006 15:00:09 -0000, Conor wrote:

In article ews.net,
Doctor Drivel says...

"The Natural Philosopher" wrote in message
...
On 04 Jan 2006 14:41:11 GMT, Adrian wrote:

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

As 90% plus of us live in towns and cities our lungs matter.

Doesn't "North London" count as a "town or city", then?

Because you've already claimed that pollution from an industrial
accident
arising from the generation/transmission/storage of energy for
transportation will drift over North London.

The fact that Buncefield's fire was primarily aviation fuel seems to
have
slipped you by, too.

Or will your utopia have electric planes, too?

I already fly them :-)

However no, energy density is not and will never be enough for
commercial
planes...those will lilely be repalced by high speed trains for
overland
routes, and by biofuel or hydrogen for intercontinental flight.

I'd say you COULD get a lightplane up on batteries, with about a
hundred
miles or so range - maybe a bit more.


How about the trucks that the food is delivered to these towns and
cities
in? Will they be electric? I wonder what the average daily mileage for
an
HGV is...?

Nope. Biodiesel. But te short haul delivery vans WOULD be electric.

No one is saying its the answer to all problems - except drivel -

The largest trucks in the world use electric motors.

Really? Proof? Used in general haulage are they? Austrailia has some of
the heaviest road going trucks there are. They're all diesel.

He is probably thinking of electric locomotives.

No. Trucks. Follow the thread.