# [EVDL] Upper theoretical limits of A123 cells



## EVDL List (Jul 27, 2007)

vehicle performance would be asymtotic to having 100% batteries with no 
weight in body, motor, or anything else. It is a calculable number. But 
from a practical standpoint, you must add incrementally to frame weight and 
motor size in order to carry extra battery weight. You can do a simple 
computer program to optomize vehicle performance if you can make some 
assumptions about these various factors. Then you can do "what if" 
calculations.

I love the 100% battery number. When someone tells me they are shooting for 
300 miles range or some other wishful performance specification with lead 
batteries, I can tell them that even if they had 100% batteries, they 
couldn't do it.








On Wed, 12 Dec 2007 23:17:05 -0600, Ryan Stotts wrote
> "4500+ A123 battery cells so this thing's gonna fly like a Batt(ery)
> out of hell!"
> 
> That got me thinking about these batteries. Say for example these
> cells cost nine cents each. If we piled on for instance, 86,000 
> cells on this vehicle. At what point are we going to reach the 
> point of diminishing returns?
> 
> Would it get to the point where the weight is being piled on at a 
> rate faster then the power that is being provided? Or something 
> else all together?
> 
> 176,000 cells on wheels.
> 
> It just seems like there is some unknown upper limit to all this. 
> And where do we go from there or how do we get past it? Thinking about
> that is like thinking about the limits of lead. I'm sure lithium has
> a limit but it's currently so far(it would appear) away that it's not
> yet on our minds.
> 
> But if it was; what could we do about it?
> 
> Power and power density..
> 
> Either incremental increases in the amount of batteries to go faster,
> or larger steps of double or tripling the amount.
> 
> I guess it's just the nature of batteries and it takes more to do
> more. The same goes for motors?
> 
> http://www.seasideaffair.com/images/Verslagen/Arnhem%202007/MC1F6991.jpg
> 
> It will be interesting to see the results and where it goes from
> there(Top Fuel numbers?).
> 
> Dennis; you still in the race?
> 
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## EVDL List (Jul 27, 2007)

> Ryan Stotts wrote:
> > "4500+ A123 battery cells so this thing's gonna fly like a Batt(ery)
> > out of hell!"
> >
> ...


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## EVDL List (Jul 27, 2007)

> George Swartz <[email protected]> wrote:
> >
> > vehicle performance would be asymtotic to having 100% batteries with no
> > weight in body, motor, or anything else. It is a calculable number. But
> ...


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## EVDL List (Jul 27, 2007)

"Juiced Up"'s batteries should be capable of over 2 MW. I don't think
their motors, controllers, or especially traction will be able to
handle that.

I'd say the really interesting limit is capacity/range. It will be
nice when we can do "real" races with EV's, multi-lap, multi-mile
races that really stress the vehicles for an extended time.

-Morgan LaMoore

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## EVDL List (Jul 27, 2007)

> Morgan LaMoore <[email protected]> wrote:
> > "Juiced Up"'s batteries should be capable of over 2 MW...
> 
> Oops, my bad. Using the datasheet ESR of 10 mOhm, the max power is
> ...


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## EVDL List (Jul 27, 2007)

Hi Morgan,


> I'd say the really interesting limit is capacity/range. It will be
> nice when we can do "real" races with EV's, multi-lap, multi-mile
> races that really stress the vehicles for an extended time.
>
> -Morgan LaMoore

It is nice doing "real" races with an EV, multi-lap, multi-mile races that 
really stress the vehicles for an extended time.<G>
http://www.proev.com/P1RaceH.htm

It is not up on the website yet but the Kokam powered Electric Imp was the 
fastest SPU (Super Production Under 2.5 liters) qualifier at the Nov 17-18 
SCCA Palm Beach Classic. A problem with our generator took out two chargers 
and kept us from chasing that elusive first win.

<I still think that circuit racing is more interesting and challenging
than drag racing, though.>

Don't under estimate the challenges the drag racers face. There is some 
amazing ground breaking work being done on the drag strips!


Cliff
www.ProEV.com




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## EVDL List (Jul 27, 2007)

> George Swartz wrote:
> > I love the 100% battery number. When someone tells me they are
> > shooting for 300 miles range or some other wishful performance
> > specification with lead batteries, I can tell them that even if they
> ...


----------



## EVDL List (Jul 27, 2007)

I hope you are speaking rhetorically here. This is the kind of silly idea
that keeps people's minds willing to accept the idea of perpetual motion.
The only way there is no limit is if you found a hill you could coast down
forever.

-----Original Message-----
There *is* no theoretical upper limit to how far you can go!

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## EVDL List (Jul 27, 2007)

Lee is correct, there is no *theoretical* upper limit to how far you can go.

Or can you prove such a theoretical limit? What is it? 




> <[email protected]> wrote:
> > I hope you are speaking rhetorically here. This is the kind of silly idea
> > that keeps people's minds willing to accept the idea of perpetual motion.
> > The only way there is no limit is if you found a hill you could coast down
> ...


----------



## EVDL List (Jul 27, 2007)

I made an error when I said halving the resistance would give 40% more 
power. it will double it, thermal issues aside.
as for power electronics I think that's quite easy to make enough power. 
the zilla for instance is not huge and can be made even lighter in a 
larger configuration.
and putting the power into the road, we have the funny cars as example. 
aren't those in the 6000 pony range?
if there's a problem it can be made into tank tracks 

Dan


Morgan LaMoore wrote:
>


> Morgan LaMoore <[email protected]> wrote:
> >
> >> "Juiced Up"'s batteries should be capable of over 2 MW...
> >>
> ...


----------



## EVDL List (Jul 27, 2007)

> We used to think that a solar powered car could barely move in direct
> sunlight. But teams have built solar cars that go over 70 mph on pure
> sunlight.

Have they done this without storage cells? I thought they were only
getting those kinds of speeds by letting it sit in the sun for several
hours charging up the batteries.


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## EVDL List (Jul 27, 2007)

> Peter VanDerWal <[email protected]> wrote:
> >
> > > We used to think that a solar powered car could barely move in direct
> > > sunlight. But teams have built solar cars that go over 70 mph on pure
> ...


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## EVDL List (Jul 27, 2007)

> Peter VanDerWal wrote:
> >> Have they done this [70 mph] without storage cells? I thought they
> >> were only getting those kinds of speeds by letting it sit in the
> >> sun for several hours charging up the batteries.
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >> There *is* no theoretical upper limit to how far you can go!
> 
> [email protected] wrote:
> ...


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## EVDL List (Jul 27, 2007)

The "cars" that are doing this are one-off increadibly light, special efforts for things like the Trans-Australia Solar Race.? They DO hit those speeds but are NOT "real world cars".? Even a converted 1970's era car would have more safety features and crash-worthyness.
Matt Parkhouse
Colorado Springs, CO
Welding up battery boxes and getting ready to wire up the '72 VW Van. Advanced motor is in place!




> Have they done this without storage cells? I thought they were only
> getting those kinds of speeds by letting it sit in the sun for several
> hours charging up the batteries.

Alot of them do have storage cells (often two lead acid batteries)
that they can charge for cloudy or nighttime use, but IIRC, they are
achieving 70mph with just solar direct during the day.





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## EVDL List (Jul 27, 2007)

Well, there are limits based on how little drag you can get with say a
5-passenger sedan. The cross sectional area requirement is there. The
front and rear could be made an optimal shape but there's kind of an
optimum there and we're not likely to rewrite the book on that.

Hey there are concepts to make a high speed vacuum subway, where the
entire system is pumped down to a vacuum and the trains are pressured
like aircraft. It allows for speed and efficiency that would not
otherwise be possible. Zero aero drag, even on a flat-front train. I
wonder how you even keep it cool? Radiators don't work in a vacuum,
neither do air conditioners. I guess you could let some water boil off
in the vacuum which gets fairly cool (but does not freeze except over a
long, long time). How they pump out this much air I have no idea. How
do you get passengers on and off without losing the whole system's
vacuum? I gotta admit the whole lateral-thinking of this intrigues me.

Danny

----- Original Message -----
From: Lee Hart <[email protected]>
Date: Thursday, December 13, 2007 5:18 pm
Subject: Re: [EVDL] Upper theoretical limits of A123 cells
To: Electric Vehicle Discussion List <[email protected]>



> > Lee Hart wrote:
> > >> There *is* no theoretical upper limit to how far you can go!
> >
> > [email protected] wrote:
> ...


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## EVDL List (Jul 27, 2007)

Actually, I agree with Lee Hart in spirit (seems like a safe position
to take in general ;-) But... there IS a theoretical result on how much 
longer before the Sun blows up into a red giant star and completely
swallows the Earth, also there's a theoretical maximum on speed 
(in fact, the speed of light has been shown to be a practical as well
as theoretical limit). Just multiply these quantities to get a theoretical
limit on how far you can go!

Also -- just to be completely pedantic -- a satellite in
LEO (low earth orbit: about 200 miles altitude) goes around about every
90 minutes which amounts to about 150 million miles a year. Such a
satellite
typically has a lifespan of under 10 years before its orbit decays. So it's
only
a bit over 1 billion miles.

Seriously though, when one says that something is true *in theory* it's
important
to be specific about which "theory" this statement is in reference to. 
There are 
theoretical treatments of rolling resistance and there are theoretical
frameworks
where "frictionless surfaces" don't exist -- in fact that's the sort of
theory where
perpetual motion is disallowed. 

To bring it back to EVs, of which I haven't yet built *one* and Mr. Hart has
clearly
produced *many*, the statement that "there are no theoretical limits to how
far you can go" is basically true, even if it's false in a nerdy, math
professorly,
sort of way. The state of the art is so far from the theoretical limits
that you
may as well forget about them!

Cheers,
Joe




> Lee Hart wrote:
> >
> >
> 
> ...


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## EVDL List (Jul 27, 2007)

Actually, the rules of the race say you aren't allowed to break the
speed limit. The rules also limit the total area of your solar array
(the max size is slowly decreasing as the cars get better).

As such, the winner of the WSC 2007 race averaged 56 mph over a 3000
km race length. This means that when it was sunny, they were doing the
speed limit while charging the battery, and when it was cloudy, they
were still going fast enough (with battery help) to keep the average
speed up.



> <[email protected]> wrote:
> > The "cars" that are doing this are one-off increadibly light, special efforts for things like the Trans-Australia Solar Race.? They DO hit those speeds but are NOT "real world cars".? Even a converted 1970's era car would have more safety features and crash-worthyness.
> 
> Yes, they aren't "real world cars". However, they are pretty safe.
> ...


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## EVDL List (Jul 27, 2007)

Do you know of one of these cars in the so.cal area?

Sent from my iPhone



> "Morgan LaMoore" <[email protected]> wrote:
> 
> Actually, the rules of the race say you aren't allowed to break the
> speed limit. The rules also limit the total area of your solar array
> ...


----------



## EVDL List (Jul 27, 2007)

From: [email protected]
> The "cars" that are doing this are one-off incredibly light, special
> efforts for things like the Trans-Australia Solar Race. They DO hit
> those speeds but are NOT "real world cars". Even a converted 1970's
> era car would have more safety features and crash-worthiness.

Yes, of course. The safety and crashworthiness criteria for these cars are different than for your family sedan. But they prove that it is *possble* to do drastically better than most cars.

OK, so let's ask the question this way: What would it take to go 300 miles on a charge with ordinary lead-acid batteries in a "normal" car? I used my EV performance calculator to give it a try:

Batteries: 12 T-105 6v golf cart batteries (as ordinary as you can get)
Motor: Lemco 90% efficient PM DC motor
Tires: 0.006 rolling resistance (same as used on GM EV1)
Vehicle weight: 1000 lbs (achievable with aircraft grade composites,
while still maintaining safety and crashworthiness
Drag Coefficient: 0.18 (what Aerovironment achieved on the Impact,
before the GM stylists modified it to make it prettier)
Frontal area: 12 sq.ft. (the size of a small 2-seat sports car, like
Bob McKee's Sundancer EV)
Loss coefficient: 0.0001 (best ball bearings, dry sump gearboxes, etc.)

This gives us a 2-seat sports car, a bit smaller than an GM EV1, with about 50% of its weight in batteries, using technology that has actually been used to date. My calculator predicts:

344 miles at 25 mph
294 miles at 30 mph
249 miles at 35 mph
212 miles at 40 mph
180 miles at 45 mph
153 miles at 50 mph
131 miles at 55 mph
112 miles at 60 mph

None of this requires technology that hasn't been around for at least 10 years. Certainly if someone had the time and money, and used the knowledge learned from the solar cars and other state of the art vehicles, we can do even better.

Suppose we seat driver and passenger inline, like the Tango, to cut frontal area. Use an ultra-streamlined teardrop body. Cut the weight with aerospace materials. Install the best brushless AC drive system, and the best lead-acids available. Now we get:

Batteries: Hawker 12v 38ah AGMs
Motor: UQM brushless DC, 93% efficient
Tires: special 0.005 rolling resistance
Vehicle weight: 500 lbs less batteries
Drag Coefficient: 0.15 (a "bullet car")
Frontal area: 8 sq.ft.
Loss coefficient: 0.0001 (best ball bearings, dry sump gearboxes, etc.)

604 miles at 25 mph
553 miles at 30 mph
501 miles at 35 mph
450 miles at 40 mph
404 miles at 45 mph
362 miles at 50 mph
325 miles at 55 mph
292 miles at 60 mph

Definitely getting 'way out there', but you still have a 2-seat car that is fully enclosed and a lot safer than a motorcycle. And, it has more range than many ICE vehicles!

Imagine what it could do with lithium ions! 

--
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--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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## EVDL List (Jul 27, 2007)

-----Original Message-----
OK, so let's ask the question this way: What would it take to go 300 miles
on a charge with ordinary lead-acid batteries in a "normal" car? I used my
EV performance calculator to give it a try:
----

For people who demand quick-charging, extending the EV range out to 100 or
200 miles is not going to win them over because eventually they will have to
stop and wait around for the car to recharge. Pure Evs are going to be
attractive to people who can do their daily commutes and errands in them
with a little cushion to spare. They need no more range than they drive in
a given day. That does not require 300 mile range. If you had to fill your
gas tank every day it would be pretty annoying, but it's no great
inconvenience to plug your car in at night. So there is no reason for Evs
to have equivalent range on a charge as a tank of gas. People just float
that 300 mile figure like some kind of holy grail but logically it makes no
sense.



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## EVDL List (Jul 27, 2007)

These sorts of contests have been going on for ages now and I think they've
reached a point of diminishing returns as far as producing any tangible
benefit to the greater auto industry. I think everyone knows what it takes
to get maximum efficiency. There really is little new to discover in that
arena. It all comes down to what kinds of tradeoffs the consumer will
accept. Lots of people are turned off by the Aptera, for instance. So
what's good for efficiency is not necessarily attractive to the consumer.
You have to find a sweet spot.

-----Original Message-----
So the cars are safe, but they are definitely not practical. The three main
barriers to practicality are the lack of a way to get in/out by yourself,
the fragility of the solar panels, and the crazy expensive costs.

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## EVDL List (Jul 27, 2007)

Right, but how will they make it lighter? Make it like a stock car where
the entire interior is gutted? Rip out half of the roofline like that Geo
Metro? Make it like an enclosed luge? At some point, radical weight and
aero mods mean nothing outside of the small clique of people who care about
records. It's not going to advance the adoption of electric vehicles. If
GM were to produce Apteras side by side with Chevy Volts that had no range
extender, I would bet you they would sell more Chevy Volts. They would be
willing to give up some range for a more conventional driving experience.

-----Original Message-----
To make it more real: No matter how light you make your car, someone 
else can make one lighter.

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## EVDL List (Jul 27, 2007)

From: [email protected]
> Right, but how will they make it lighter?

Materials science has advanced a *long* ways past the stamped steel bodies used for essentially all production cars. Aircraft and other high performance applications routinely use materials and methods with many times higher strength-to-weight ratios. As Amory Lovins has often pointed out, we could build cars that weighed half as much with no loss of strength or styling at all.

> At some point, radical weight and aero mods mean nothing outside of
> the small clique of people who care about records. It's not going
> to advance the adoption of electric vehicles. If GM were to produce
> Apteras side by side with Chevy Volts that had no range extender,
> I would bet you they would sell more Chevy Volts.

There are at least two ways to approach this: On a performance level, and on the fashion level.

Performance sells. If the "new" car is extremely fast, or gets extreme fuel economy, or has some other best-in-class feature, then you *will* find customers. There are people who always buy the fastest car, no matter what it looks like. Likewise, there are customers for the car that gets the best gas mileage, no matter what. Many people think the Prius is ugly; yet Toyota has sold a million of them.

Fashion is fickle. Most people rely on others to tell them what is fashionable. It oculd be their peer group, or movie stars, or just the incessant advertising. Carmakers really can get people to buy some pretty outlandish things. Just look at some of the popular cars of the past!


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## EVDL List (Jul 27, 2007)

-----Original Message-----
Materials science has advanced a *long* ways past the stamped steel bodies
used for essentially all production cars. Aircraft and other high
performance applications routinely use materials and methods with many times
higher strength-to-weight ratios. As Amory Lovins has often pointed out, we
could build cars that weighed half as much with no loss of strength or
styling at all.
--------------------------

I knew you'd go here, and I'll concede you that point. But according to
your original line of reasoning, there is ALWAYS this magic leap of
technology waiting around the corner, something that will net equally huge
gains. Assuming all automakers switch to composite frames (kind of
following the Boeing 787 model) then what? Antigravity? You can make a
case that automakers aren't doing everything they could be doing today, but
it's another matter to say that you can infinitely increase range (let alone
with lead acid batteries). It just borders on science fiction at that
point, and is not something you can accurately predict. The physical limit
is however far an electric chassis would go on remote control without any
body sitting on top at all. No matter how much you reduce weight, that
limit will persist to infinity.



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## EVDL List (Jul 27, 2007)

Hey. Science fiction.. antigravity.. wow.. It's getting interesting..
Don't forget inertia dampeners..

About the EV range. The dilemma is that people cannot comprehend that 
such operation as filling up the tank is not required anymore. Plugging 
in the vehicle is just so darn convinient.

http://uk.youtube.com/watch?v=9eSvSec6QRU

Again.. how can ANYONE claim that to be an pain in ass ?

Instead of this...

http://uk.youtube.com/watch?v=PqJnT0Zjj0Q

We need to put up more HQ video stuff to tube. rEVolution is here !

-Jukka

Driving under influence of Lithium.. EVery day...

[email protected] kirjoitti:
> -----Original Message-----
> Materials science has advanced a *long* ways past the stamped steel bodies
> used for essentially all production cars. Aircraft and other high
> performance applications routinely use materials and methods with many times
> higher strength-to-weight ratios. As Amory Lovins has often pointed out, we
> could build cars that weighed half as much with no loss of strength or
> styling at all.
> --------------------------
> 
> I knew you'd go here, and I'll concede you that point. But according to
> your original line of reasoning, there is ALWAYS this magic leap of
> technology waiting around the corner, something that will net equally huge
> gains. Assuming all automakers switch to composite frames (kind of
> following the Boeing 787 model) then what? Antigravity? You can make a
> case that automakers aren't doing everything they could be doing today, but
> it's another matter to say that you can infinitely increase range (let alone
> with lead acid batteries). It just borders on science fiction at that
> point, and is not something you can accurately predict. The physical limit
> is however far an electric chassis would go on remote control without any
> body sitting on top at all. No matter how much you reduce weight, that
> limit will persist to infinity.
> 
> 
> 
> _______________________________________________
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> http://lists.sjsu.edu/mailman/listinfo/ev

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## EVDL List (Jul 27, 2007)

> <[email protected]> wrote:
> > otherwise be possible. Zero aero drag, even on a flat-front train. I
> > wonder how you even keep it cool? Radiators don't work in a vacuum,
> > neither do air conditioners. I guess you could let some water boil off
> ...


----------



## EVDL List (Jul 27, 2007)

> Actually, the rules of the race say you aren't allowed to break the
> speed limit. The rules also limit the total area of your solar array
> (the max size is slowly decreasing as the cars get better).
>
> As such, the winner of the WSC 2007 race averaged 56 mph over a 3000
> km race length. This means that when it was sunny, they were doing the
> speed limit while charging the battery, and when it was cloudy, they
> were still going fast enough (with battery help) to keep the average
> speed up.
>

I'll admit it's been a couple years since I last read up on solar raycers.
Back then they would spend several hours a day SITTING STILL and charging
the batteries from the solar array, then they would rayce under a combined
solar and battery power. This was the only way they could achieve 60+
mph. None of them were doing highway speeds and charging the batteries at
the same time (quite the opposite).

If this has changed recently, that's awsome. Can someone point me to a
link discribing this?

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## EVDL List (Jul 27, 2007)

> Peter VanDerWal <[email protected]> wrote:
> >
> > > Actually, the rules of the race say you aren't allowed to break the
> > > speed limit. The rules also limit the total area of your solar array
> ...


----------



## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > But according to your original line of reasoning, there is ALWAYS
> > this magic leap of technology waiting around the corner, something
> > that will net equally huge gains.
> ...


----------



## EVDL List (Jul 27, 2007)

---- Original Message ----
Perhaps you are using different meanings for the words that I am. An 
"infinite increase" means no matter how big the range is, you can
always 
do something to improve it a little more. It does *NOT* mean you can
get 
infinite range.
---------------------

Law of diminishing returns. It's like dedicating a massive supercomputer to calculating PI. Beyond a certain point, the improvements become so miniscule to not be worth continuing. It just becomes a frivolous stunt devoid of practical value.





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## EVDL List (Jul 27, 2007)

> Glenn Saunders wrote:
> > Law of diminishing returns. It's like dedicating a massive
> > supercomputer to calculating PI. Beyond a certain point, the
> > improvements become so miniscule to not be worth continuing.
> ...


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