Electric cars

[Jim Yanik]

I want FAST and SAFE, which usually implies BIG ;-)

...Jim Thompson

several Porsches and Mercedes are small,fast,yet safe.
No car should be required to withstand fast collisions or off-road
"shunts".
IMO,people SHOULD be at risk;it will make them pay more attention to their
driving,or thin out the gene pool.

IMO,good handling,braking and most importantly,the DRIVER,make a car
"safe".BTW,"safety" also includes the damage your vehicle can do to other
vehicles.
IMO,having more SUVs and "light trucks" being commonly used as
daily-driver passenger vehicles has DECREASED safety for everyone.

 

[Jim Yanik]

There is special dispensation for rich Democrats ;-)

...Jim Thompson

DemocRATs are "do as I say,not as I do", "And don't question what I say or
do.","Go along with our policies,because we won."

"give us your full support,even though we didn't do that when your guy won
election".

And last;"don't listen to Rush Limbaugh".

 

[Jim Yanik]

Ok, maybe I didn't make my point clearly, or everyone is saying forget
that point, I think it works like this...

Lets say that you have a modular pack composed of 80 differernt
modules. Each module has builtin control and SMPS style outputs so
that even a single module could run the system, if only for a short
time. the on-board electronics, both in each module and in the pack,
monitors each pack for its health and status. If a module's
performance drops to a certain point, it is flagged for replacement.

Now, maybe John is correct, and the individual cells all have close to
identical lifetimes, so that they will all fail within a short period.
If that is the case, then perhaps the single, monolithic pack makes
sense. However, if there is much variablility in the lifetime of
cells, then the individual modules make sense. You only need to
replace the few non-performing units (which should then be easy to
recycle/refurbish) and keep the entire pack up to standard.

So, the remaining packs may have a relatively short time to failure
once units begin to fail, but there may still be months/years on them.
There shouldn't be a single, massive failure of all the packs, which
is a possibility in a mononlifhic pack...

Charlie

no,there would be sequential failures,in an undetermiined time frame.
Who wants to gamble on that?

 

[Jim Yanik]

Who knows what the battery chemistry might be for this kind of
"module". But my experience with LiIon charging controls suggests
that the multi-module approach might be best.

...Jim Thompson

of course,you also add extra expense with all those separate monitoring and
"SMPS outputs",and the extra circuitry and complexity makes for more
failures. Also violates the KISS principle.

 

[Charlie E.]

of course,you also add extra expense with all those separate monitoring and
"SMPS outputs",and the extra circuitry and complexity makes for more
failures. Also violates the KISS principle.

Yes, there is probably a trade-off, but it also means that your
'power' electronics on each pack is a lot smaller, so you get a
distributed system instead of just a few 'large' switching components.
Also, you get an element of redundancy so that any single failure
means you still have a working vehicle.

Charlie

 

[Greegor]

Batteries are lots of trouble in traditional gas
powered cars in cold weather.

Wouldn't batteries as primary power source
be a bad idea in colder northern states?

How economical would all electric cabin heat be?

 

[Jeroen Belleman]

Yes, which is why it's disappointing that nobody seems to be
discussing damping mechanisms, or anything else that will improve the
markets or the economy in the long term.

John

Indeed. Current efforts seem to be bent on restoring economic growth.
Preferably double-digit growth, as the world was so proud of only
months ago. Continuous exponential growth in a world with finite
resources is clearly impossible. I'd argue that the only way to get
a stable economy is to moderate -and ultimately stop- overall growth.

Jeroen Belleman

 

[Martin Brown]

The problem is that greed has a slower time constant than fear, and
nobody has sufficient long-term memory. So, every generation, more or
less, we get a slow greed-driven ramp up to unrealistic valuations,
and an inevitable fast ramp down when the smart money figures they've
got all they can, or some other event trips the crash. It's a
relaxation oscillator.

This is one cause of boom and bust cycles. UK Labour government declared
boom bust to be a Tory thing that they had eliminated. How wrong they were.

The other big one is a chain of highly improbable events that have been
misestimated by otherwise very clever people.

Famour examples include:
Betting that a hole in one will occur at a given top class golf match
(which for a long time was given 10x longer odds than the actuality).

The Irish Lottery where a syndicate betting on a large range of numbers
could never lose money and might win the jackpot. The smallest prizes
were slightly too large and far too numerous.

LTCM - their pockets were not deep enough to keep playing the game.

Controlling the UK economic computer model is surprisingly difficult.
There may even be one of the simpler ones online. You don't get to see
the effects of interest rate changes for nearly 12 months so depending
what hand you are dealt it is very easy for things to go pear shaped.

It is generally when greed and stupidity are combined in roughly equal
measure that you get exceptionally bad things happening. Telecoms
companies are still recovering from their irrational exhuberance in the
Sept 1997 buying 3G UK bandwidth at beyond top dollar in a very
cunningly designed auction. There is also a lot of game theory involved
- see what happened in the Turkish telecom licence. A paper about it is
still online:

http://www.nuff.ox.ac.uk/users/klemperer/biggestsept.pdf

Tax policy could help here. Or control theory, even. Find me a
politician who understands control theory.

Margaret Thatcher did. And to be fair most economists *do* understand
control theory and statistical decision making. As for name a
politiician I don't have to look very far. A constituency Labour MP 30
miles away has an MSc in Control Theory and a PhD in Fluid Dynamics and
worked industrially for British Steel for a while too.

http://www.ashokkumar.org.uk/biography

What cannot be modelled accurately is the herd instinct of traders and
market sentiment. Rumours can be very destructive. You don't really
believe the recent share price movements of UK banks represents anything
real about their business do you? It is just spivs and speculators
whacking the position up and down by shorting. Finally the bank made a
reassurring statement and the price went back to something plausible.

http://finance.google.co.uk/finance?client=ob&q=LON:BARC

There is huge hysterisis in the market valuation of the same position
depending on whether market sentiment is bullish, bearish or as it is
now in total panic. When trust is destroyed the markets are wildly
unpredictable since no-one knows who has what skeletons in their cupboard.

Even so the really smart guys with deep pockets can still make money by
selling large blocks or shorting on already weakened prey to drive the
share price of otherwise sound institutions into the ground with
catastrophic consequences for volatility and jobs. UK govt is permitting
shorting of financial institutions again - I cannot for the life of me
see why. The effect is obvious so I guess they want to nationalise the
banks by stealth.

Same sort of thing happened with the rising oil price in the summer
speculators piled in to drive it through the roof. They make money but
everyone else loses big time (notably the suckers who pile in at the top).

Regards,
Martin Brown

 

[Jasen Betts]

This is what has been bugging me.
Imagine a family with two electric cars. 100HP (75kW) engine each -
not too big, is it? On an average workday each driver commutes for on
hour (lucky guys, aren't they?).
It makes 150KWh energy needed to recharge the cars.

no it doesn't after 1 minute with the foot hard on the "go" pedal
the driver crashes at 100Mph.

Sensible answer: a 75Kw elecric car motor will not be consuming 75Kw of
power all the time that the vehicle is in motion.

 

[Jasen Betts]

[...]
Imagine a family with two electric cars. 100HP (75kW) engine each -
not too big, is it? On an average workday each driver commutes for on
hour [...]
Do we have an infrastructure to support it?

On average, a car needs nowhere near 75kW. Some 10 to 15kW
should do fine. Even so, you are right to believe that the
current infrastructure wouldn't suffice if everyone used
electric cars.

Jeroen Belleman

There might be a hidden benefit to having large numbers of electric
cars. Nuclear plants run best @100% and storage of energy is a
potentially huge cost. Other generation methods have similar
limitations (eg. solar is only available when the sun is shining)
unless they involve burning of fossil fuels.

Thermal plants aren't much better. it takes several hours (half a day?)
to ramp a boiler up or down. hydro can be turned on or off rapidly.
but diesel can too.

 

[TheM]

The stimulus is just more borrowing with funny money, said act being
the cure for too much borrowing with funny money.

John

It is funny money, and much of it will nicely line the pockets of selected few.
Which is not that funny.

First time I heard of these bailouts I asked myself how they plan to control
where the money goes. What's a couple millions out of say 50 billions?

M

 

[amdx]

no it doesn't after 1 minute with the foot hard on the "go" pedal
the driver crashes at 100Mph.

Sensible answer: a 75Kw elecric car motor will not be consuming 75Kw of
power all the time that the vehicle is in motion.

I see this thread generated quite an interest.
To see what DIYers are doing, check these forums.
This one has the most traffic,
http://www.diyelectriccar.com/forums/
They may appreciate input on designing a motor speed control,
something simple, 160v, 1000amps, current limited.
These two have less traffic,
http://www.evforum.net/forums/index.php?s=14c8f1be72295282d527a3bc7b4592b4
http://visforvoltage.org/
And here is a photo album of hundreds of DIY EVs with specifications.
http://www.evalbum.com/
Mike

 

[krw]

Presumably the vast majority of the occupants of those 600 private jets
weren't asking for billions of dollars in bailouts?

No, they were asking for government largess or ROI, depending on
your POV.

 

[Spehro Pefhany]

of course,you also add extra expense with all those separate monitoring and
"SMPS outputs",and the extra circuitry and complexity makes for more
failures. Also violates the KISS principle.

It more than likely can NOT be made to work reliably without a modular
electronic approach involving distributed cell monitoring and
balancing. Whether the individual modules are made replacable by the
user, by service personnel, or not at all, is another thing. There
also could well be some safety requirement that demands internal
barriers in the battery pack so it can't self destruct from relatively
minor damage.


Best regards,
Spehro Pefhany

 

[Raveninghorde]

That is a somewhat racist perception. When white kids riot, it gets
written off as football hooligans on the loose, and nobody write
pretentious editorials about it. The Afro-Carribean riots certainly
weren't muslim in any event.

Football hooliganism is different. If 2 bunches of lads want to beat
the hell out of each other let them. Just prevent colateral damage.
It's OK providing it's between consenting adults. It's usually
prearranged "fun".

You may not think so. It certainly wasn't a direct response to
economic disadvantage, any more than the Irish bombings used to be,
but economic disadvantage played a significant part in generating
community suppoirt for the terorists in both cases.

These people are mainly economic migrants. They come to the west
because even a floor sweeper over here is better of than those that
stay behind. This is also indicated by the flow of funds back to their
homelands to help support their extended families.

They are significantly better off economically over here and they can
return to their homelands if they are not. There is no way you can
call them economically disadvantaged.

SNIP

You can have the last word. You have more spare time than me.

 

[[email protected]]

Shooting all the Democrats does away with all the pols (snicker ;-)

Karl Rove was a Democrat?

 

[krw]

If they really wanted to stimulate the economy, they'd get rid of the
withholding tax.

If they wanted to stimulate the economy they'd get rid of the
capital gains tax and all corporate taxes, permanently.

 

[Jim Yanik]

Yes, there is probably a trade-off, but it also means that your
'power' electronics on each pack is a lot smaller, so you get a
distributed system instead of just a few 'large' switching components.

Also, you get an element of redundancy so that any single failure
means you still have a working vehicle.

Charlie

doubtful on the last part of your post,because it's likely the motor
controller will shut down if the pack voltage drops beyond some set
point,to prevent further pack damage,or undervoltage damage to the motor
itself. I believe most of the power systems on electrc cars today are the
DC-AC type,the controller converting the DC power pack's output to AC to
run an AC motor.

there might not be any way to shunt the "good" cells around the bad
ones,either.

 

[James Arthur]

I want FAST and SAFE, which usually implies BIG ;-)

...Jim Thompson

Lovins says big is safer too--more crumple zone. Weight kills
(but probably the other guy).

Lecture 3, here:
http://www.rmi.org/sitepages/pid231.php

Cheers,
James Arthur

 

[James Arthur]

Eeyore wrote:
Jeroen Belleman wrote:

Michael wrote:
[...]
Imagine a family with two electric cars. 100HP (75kW) engine each -
not too big, is it? On an average workday each driver commutes for on
hour [...]
Do we have an infrastructure to support it?
On average, a car needs nowhere near 75kW. Some 10 to 15kW
should do fine.
That's as idiotic as 200hp ! 0 - 60 in one minute maybe ?
ON AVERAGE, dear Sir. On average. I've said nothing about peak power.
Now that we're at it, to get a 1000kg car to, say, 100km/h in 10
seconds would require about 45kW, neglecting friction losses.
Round that up to 50kW. But it would still consume some 10
to 15kW _on average_.

Jeroen Belleman

Right. I measured my car, and found it uses 11 kW cruising at 112 km/h.

Cheers,
James Arthur

Yeah,and now you gotta accellerate to get around that semi before
xxwhateverxx happens....

ever been in an underpowered car,particularly a econobox?
Or had to wait behind one while they waited for an opening they could move
out into?

Your point makes perfect sense.

Carmakers fit internal combustion engines (ICE) that
are ~8-10x oversized to ensure good acceleration.

The goal here is to make a car that has good acceleration,
but still not waste gas by being grossly overpowered on the
highway (because ICEs aren't efficient at 10% load).
Optimally loading an ICE roughly doubles its efficiency.

So as a first step toward fuel economy, just making the car
lighter--with no improvement in the drivetrain technology--
saves gas. If the car weighs a third less, you can accelerate
it with 2/3rds the motive force/energy/torque/motor. And
that's a lighter, cheaper motor.

That still leaves the ICE oversized on the highway by the
almost same factor, but uses less gas with no need for
drivetrain improvement--if the current system is 15% tank-
to-wheels efficient, that same 15% of a smaller demand is
still a smaller number overall.

And the highway load factor is, actually, improved, since
the 15 or 20 h.p. of fixed wind and friction loading is then
a bigger portion of the engine's total capacity, improving
the ICEs power conversion efficiency.

Next, you streamline the thing and save even more. Zero
technology risk.


Next step: if you have a hybrid or electric car, a small
electric motor can easily put out big chunks of peak power,
which is ideal. The motor can then be small and light,
sized for the continuous load, yet able to handle the peaks.

For example, my car puts out about 130 peak ft-lbs of torque
at optimum (4,500) rpm. PML Flightlink's 14.4 kW (=19 h.p.)
electric motor weighs 40 lbs. It puts out 470 ft-lbs
intermittently, 118 ft-lbs continuous.

At lowest r.p.m. ICEs' torque falls off and the electric
motor's torque advantage is even greater. This puny 19 h.p.
electric motor could kick my car's internally combusting a$$.

Plus, electric motors are much more efficient than ICEs, and
over a much wider load range. I could get an eighty--or even
a forty--h.p. electric motor and really make some smoke.

So, we're not talking about underpowered econoboxes.
We're talking fully-powered equally-performing econoboxes.


Cheers,
James Arthur