EV Digest 4765
Topics covered in this issue include:
1) Another NEDRA rule question
by Tim Humphrey <[EMAIL PROTECTED]>
2) RE: World Solar Challenge
by "Peter VanDerWal" <[EMAIL PROTECTED]>
3) Re: Another NEDRA rule question
by "Roderick Wilde" <[EMAIL PROTECTED]>
4) Re: Which Nedra class? Last posting .......Comments
by "Bob Rice" <[EMAIL PROTECTED]>
5) RE: World Solar Challenge
by "David Roden" <[EMAIL PROTECTED]>
6) RE: World Solar Challenge
by David Dymaxion <[EMAIL PROTECTED]>
7) Re: We got the Sunrise !!!
by "Paul G." <[EMAIL PROTECTED]>
8) RE: battery explosion
by TiM M <[EMAIL PROTECTED]>
9) Re: Advice on getting motocycle glider for an EV
by [EMAIL PROTECTED]
10) Re: Wife's EV questions?
by David Dymaxion <[EMAIL PROTECTED]>
11) Unibody (was RE: We got the Sunrise !!!)
by "Don Cameron" <[EMAIL PROTECTED]>
12) Capacitor Drag Racing Idea
by David Dymaxion <[EMAIL PROTECTED]>
13) Solar Trailer?
by Mark Hastings <[EMAIL PROTECTED]>
14) Re: White Zombie Electrifies PIR ...12.424 @ 103.57 mph!
by "Rich Rudman" <[EMAIL PROTECTED]>
15) Re: Asking for witnesses (was: Which Nedra class? )
by "Rich Rudman" <[EMAIL PROTECTED]>
16) EV Donor car available
by Tom Hudson <[EMAIL PROTECTED]>
17) Re: Advice on getting motocycle glider for an EV
by "damon henry" <[EMAIL PROTECTED]>
18) Re: Siemens EV Motors
by Lee Hart <[EMAIL PROTECTED]>
19) Re: ThunderSky Self-Discharge
by Lee Hart <[EMAIL PROTECTED]>
20) Re: World Solar Challenge
by Lee Hart <[EMAIL PROTECTED]>
21) Re: World Solar Challenge
by Danny Miller <[EMAIL PROTECTED]>
22) Re: PIR 100 mph Club
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
23) Re: ThunderSky Self-Discharge
by Victor Tikhonov <[EMAIL PROTECTED]>
--- Begin Message ---
Is John's Siamese 8 one motor or two?
I say it's one motor.
Why do I ask? Because Electric Jr Dragsters are limited to one motor. Not that
I'm thinking of needing more than one, but it's nice to know.
Stay Charged!
Hump
--- End Message ---
--- Begin Message ---
> Probably not, but I ask this: why are so few EVers at all interested in
> integrating solar arrays into the bodies, or at least the roof, of their
> car conversions?
That's easy. Relative to a solar car, conversions require a lot of energy
to move. THey don't have a lot of flat area and what they do have is
generally not optimally positioned for solar charging. Net result is that
if you covered the useable area on a conversion with solar cells, you'd
collect enough energy in a day for one, /maybe/ two miles. It's simply
not worth the time and effort.
> And do it for the free solar recharging and free EV advertising while at
> work: 500watts*5 solar hours: 2.5kwh/day----that's good for 10 miles of
> driving at 250wh/mile.
Just out of curiousity, have you actually experimented with solar cells?
You can get maybe 150 whrs per square meter, at high noon, in Arizona,
during the middle of summer, with cool cells. And that is with the panel
pointing directly at the sun.
Sure high efficiency cells will give you a bit more, at geometrically
higher price.
Once the cells heat up, aren't pointing directly at the sun, the sun moves
from directly overhead, etc. etc. etc. the power drops off.
How are you going to keep the cells pointing directly at the sun? Park on
a hill and move the car every 1/2 hour? Or make all the panels lift off
the roof and rotate? Neither solution is all that practical for a daily
driver.
I'm sure it's solveable, but I can't think of any solution that doesn't
cost a fortune, and/or add a significant amount of weight & drag.
In real life, getting 2.5 kwh per day is going to require a lot more area
than is available on most conversions. THe ones that DO have enough area,
are going to require more than 250 W/mile.
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wish with the message. By posting the message you agree that your long
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--- End Message ---
--- Begin Message ---
Hi Hump,
This is only my opinion, the final decision would come from our tech
director but I would feel that since it is on a single armature shaft and
there is no coupling I would personally call it a single custom made motor
with two commutators.
Roderick Wilde
----- Original Message -----
From: "Tim Humphrey" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, September 27, 2005 8:36 AM
Subject: Another NEDRA rule question
Is John's Siamese 8 one motor or two?
I say it's one motor.
Why do I ask? Because Electric Jr Dragsters are limited to one motor. Not
that I'm thinking of needing more than one, but it's nice to know.
Stay Charged!
Hump
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--- Begin Message ---
Hi Rod;
Thanks for the kind words. I thought I'd throw out those comments as I
met most, to all, all youse guyz in my travels. I do my trip West to
recharge my brain cells with you all. You are all great guys Love ya all!
That wedding musta been awesome. Amps were covered after the ceremony,
for sure. I didn't want to stur up a flame war, on the List. I don't think I
did?
BTW I SUPPORT NEDRA and wanna join again, putting my money where my mouth
is. Forgot, how much, do we have lifetime membership. I know you put your
heart and soul into it, and to be Dissed hurts me as well as the Org. in
general. Wish I had come on board early enough to have met Ed Rannburg,
sigh!
Seeya
Bob
----- Original Message -----
From: "Roderick Wilde" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, September 27, 2005 11:34 AM
Subject: Re: Which Nedra class? Last posting .......Comments
> Hey Bob, Thanks for your thoughtful comments. As anyone who has met me in
> person knows, I am very easy to get along with. Heck, Dennis was even a
> guest of honor at my last wedding along with Ed Rannberg. Two top ampheads
> in one place. It was awesome! The marriage was good also :-)
>
> Roderick
>
> ----- Original Message -----
> From: "Bob Rice" <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Sent: Tuesday, September 27, 2005 8:00 AM
> Subject: Re: Which Nedra class? Last posting .......Comments
>
>
> >
> > ----- Original Message -----
> > From: "Roderick Wilde" <[EMAIL PROTECTED]>
> > To: <ev@listproc.sjsu.edu>
> > Sent: Tuesday, September 27, 2005 8:56 AM
> > Subject: Re: Which Nedra class? Last posting
> >
> >
> >> I will make the following post as politely as possible so as to not
> > offend
> >> some of the more sensitive readers.
> >
> > Hi All;
> >
> > Me too. as Rodney King sez" Can't we all get along" I think, that
NEDRA
> > got us ON the NHRA track, allowing Electrics their rightful place to get
> > out
> > there and kick ass with the gassers"What He doesn't have any Stinking
> > Pistons!" comes to mind. I feel that all the parties involved here Rod,
> > Dennis Bill, Dave could settle any differances over a good Mexican
dinner
> > at
> > the place JW takes us to in PDX. I would pay it to try to smooth things
> > over
> > AND the drinks<g>Can't offer Airfare, though. Sigh!Sunrise is
> > rising<g>!$$$$$$$
> >
> > We can't be bickering among ourselves here, we hafta have a united
> > front. hash out tech differances, I can't get into that because I don't
> > know
> > what I'm talking about. I plead guilty here.
> >
> > I go to EVents, hear the little kids say" Heres that Awesome Electric,
> > again" as Zombie blows the Vette away. <Maybe my tapes and cheapo
> > 'camcorder
> > picked that up? Ahh! The wonder of it all! My thanks to NEDRA for making
> > it
> > happen, Yeah? I think my membership ran out? But I'll be happy to
> > resubscribe. We have brough EV racing before Joe Sixpack's kids too and
> > they
> > love it. Gees! Kids are our only hope as a nation, anyhow.
> >
> > OK down from my soapbox, but I wanted to throw a relevent comment or
too
> > out there.
> >
> > Seeya
> >
> > Bob
> >
> >
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Anti-Virus.
> > Version: 7.0.344 / Virus Database: 267.11.7/112 - Release Date:
9/26/2005
> >
> >
>
>
>
> --
> No virus found in this outgoing message.
> Checked by AVG Anti-Virus.
> Version: 7.0.344 / Virus Database: 267.11.7/112 - Release Date: 9/26/2005
>
--- End Message ---
--- Begin Message ---
IMO, the easiest way to have a solar conversion EV is to mount a large
quantity of PV panels on your home's roof, and buy a grid intertie inverter.
Assemble a system capable of producing in a day at least as much energy as
your EV uses in the same period. While your car is sitting in the parking
lot at work, your PV system is storing electricity in a huge battery - the
power grid. When you come home, you plug in the car and it consumes the
energy your PV panels made during the day.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- Begin Message ---
Solar cells don't add much range, and indeed the extra weight and
aero drag of solar panels could reduce the range.
Where solar panels would probably be most valuable would be propping
up the lowest battery in the pack.
--- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> > Probably not, but I ask this: why are so few EVers at all
> interested in
> > integrating solar arrays into the bodies, or at least the roof,
> of their
> > car conversions?
>
> That's easy. Relative to a solar car, conversions require a lot of
> energy
> to move. THey don't have a lot of flat area and what they do have
> is
> generally not optimally positioned for solar charging. Net result
> is that
> if you covered the useable area on a conversion with solar cells,
> you'd
> collect enough energy in a day for one, /maybe/ two miles. It's
> simply
> not worth the time and effort.
>
> > And do it for the free solar recharging and free EV advertising
> while at
> > work: 500watts*5 solar hours: 2.5kwh/day----that's good for 10
> miles of
> > driving at 250wh/mile.
>
> Just out of curiousity, have you actually experimented with solar
> cells?
>
> You can get maybe 150 whrs per square meter, at high noon, in
> Arizona,
> during the middle of summer, with cool cells. And that is with the
> panel
> pointing directly at the sun.
>
> Sure high efficiency cells will give you a bit more, at
> geometrically
> higher price.
>
> Once the cells heat up, aren't pointing directly at the sun, the
> sun moves
> from directly overhead, etc. etc. etc. the power drops off.
>
> How are you going to keep the cells pointing directly at the sun?
> Park on
> a hill and move the car every 1/2 hour? Or make all the panels
> lift off
> the roof and rotate? Neither solution is all that practical for a
> daily
> driver.
> I'm sure it's solveable, but I can't think of any solution that
> doesn't
> cost a fortune, and/or add a significant amount of weight & drag.
>
> In real life, getting 2.5 kwh per day is going to require a lot
> more area
> than is available on most conversions. THe ones that DO have
> enough area,
> are going to require more than 250 W/mile.
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
On Sep 27, 2005, at 7:31 AM, Dave wrote:
Thanks for the info. I wasn't aware it was a uni-body (Pioneered by
Lincoln Zephyr in 1939, by the way). As I said, it was just a random
thought.
Unibody construction was used before 1939. The Chrysler Airflow was a
unibody vehicle and was introduced in 1934. I doubt they invented the
concept either.
Paul
--- End Message ---
--- Begin Message ---
Hey Joe,
Did the battery actually explode, or did you blow
a terminal off the top of the battery? This happened
to me on my truck. The batteries were old and hadn't
been properly cared for, they had "universal"
terminals on them and the interconnects weren't the
best. I knew all this when I bought it and was
planning on addressing all these problems. Well the
truck decided I was taking too long. I was pulling
about 300 amps from a stop when I heard a bang and
lost power. I coasted to a conveniently located
parking spot and took a look. One battery in the
middle of the pack had almost no post left. There was
a scorch mark on the top of the battery box and little
trails across the top of the rest of he batteries from
the little balls of molten lead bouncing around.
A dirty connection leads to resistance which
causes heating, which causes higher resistance, which
causes more heating... if it goes on long enough,
bang!
I found out the hard way, you need to keep your
battery connections clean and tight.
TiM
__________________________________
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--- End Message ---
--- Begin Message ---
Where to find a motorcycle glider for conversion to EV? In my area there are
probably 7 motorcycle specific parts junkyards within a 50 mile radius. Be
careful as some of these chassis will have critical parts stripped and sold.
Also in my area is a local salvage yard that specializes in auctioning off
auto and truck vehicles. They also have a number of motorcycles. This is an
excellent source for a glider. Keep in mind that these vehicles will fall into
the following categories:
1) wrecks - forget these
2) abandoned vehicles - yes
3) theft recoveries - yes if not totally stripped (the insurance company has
already paid the owner off).
In my estimation the single biggest issue is to find a straight (not
wrecked) chassis in good shape with plastic intact that has a good or salvage
title.
I would not advise you to buy on a bill of sale if your goal is to get to an
on road EV motorcycle. This will make the DMV hoops you need to jump through
easier.
My advice. Find out the bidding criteria, look at the cycle inventory to be
sold (my salvage yards is available online with pictures and damage details)
and attend an auction at a salvage yard. My 1994 Ninja began its new EV life
as a theft recovery with less than 2,500 miles on the odometer and a salvage
title.
Mike Bachand
Denver Electric Vehicle Council (DEVC)
Board Member, Web Administration and Newsletter Editor
Kawasaki Ninja EV
_http://www.devc.org_ (http://www.devc.org/)
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
I'd be sure to get a sample and test before assuming you could drive
a vehicle 5 or 10 miles. BYU's capacitor driven EV1 (a light and
aerodynamic vehicle) only does 1/4 mile. They push it to the starting
line to conserve energy. Admittedly that's drag racing, but it
probably could only do 2 or 3 freeway onramps before it ran out of
power in real-life driving.
The esma cap specs typically show xx kw and yy joules. yy/xx ranges
from about 1 to 10 seconds of operation at max power (in practice
that's less, as the power drops as it gets discharged). You would
have to draw power out at 1% or less of the max power to get even 5
or so miles.
--- Roland Wiench <[EMAIL PROTECTED]> wrote:
> Hello Stefano,
>
> 10,000 lb trucks and 20,000 lb buses can used asymmetric super
> capacitors instead of batteries. The capacitor cells are gain
> together in a battery like cases from 6 to 42 volts units.
>
> Unlike batteries, they can be charge in 10 to 15 minutes.
>
> They have over 500,000 charger/discharger cycles unlike some
> batteries that can only get from 500 to 1000 cycles.
>
> They are normally used for low speed truck delivery and bus runs of
> 10 to 20 miles.
>
> I have contacted this company some time ago, and I may used these
> in my new EV which will be a very large pickup so I can carry more
> cargo. My daily runs are from 5 to 10 miles with many one hour
> stops.
>
> For more info. see:
>
> www.esma-cap.com<http://www.esma-cap.com/>
__________________________________________________
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--- End Message ---
--- Begin Message ---
How about this:
"The first automotive application of the monocoque technique was 1923's
Lancia Lambda. Citroën built the first mass-produced monocoque vehicle in
1934, the innovative Traction Avant. The popular Volkswagen Beetle also used
a semi-monocoque body (its frame required the body for support) in 1938.
In the post-war period the technique became more widely used. The Ford
Consul introduced an evolution called unit body or unibody. In this system,
separate body panels are still used but are bolted to a monocoque
body-shell. Spot welded unibody construction is now the dominant technique
in automobiles, though some vehicles (particularly trucks) still use the
older body-on-frame technique.
In automobiles, it is common to see true monocoque frames, where the
structural members around the window and door frames are built by folding
the skin material several times. In these situations the main concerns are
spreading the load evenly, having no holes for corrosion to start, and
reducing the overall workload. Compared to older techniques, in which a body
is bolted to a frame, monocoque cars are less expensive and stronger.
Monocoque design is so sophisticated that windshield and rear window glass
now often make an important contribution to the designed structural strength
of automobiles"
BTW - it was used extensively in aircraft before being applied to
automobiles.
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Paul G.
Sent: September 27, 2005 9:07 AM
To: ev@listproc.sjsu.edu
Subject: Re: We got the Sunrise !!!
On Sep 27, 2005, at 7:31 AM, Dave wrote:
> Thanks for the info. I wasn't aware it was a uni-body (Pioneered by
> Lincoln Zephyr in 1939, by the way). As I said, it was just a random
> thought.
Unibody construction was used before 1939. The Chrysler Airflow was a
unibody vehicle and was introduced in 1934. I doubt they invented the
concept either.
Paul
--- End Message ---
--- Begin Message ---
Use a PFC charger to charge a supercapacitor to as high a voltage as
possible, and power the field with it. Power the armature with a
Godzilla controller. This would only work for a single gear vehicle.
The capacitor gives the field more than series current at first,
giving the motor more than series torque. Since current
multiplication would not be needed now, the motor would run more
efficiently. It would automatically field weaken as the car went down
the track, keeping the motor near its sweet spot the whole run.
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
I was thinking about solar on my house myself but where I really need power is
at work. What if I left a little trailer with solar panels and some batteries
at work and plugged in during the day? No they won't give me a plug at work I
tried that. But 1/2 of the 300 spots are empty and no one wants to park in the
sun in Texas anyways.
It would be for my semi streamlined motorcycle conversion to give me a little
bit extra range so I don't push it too far. Currently I go 13 miles each way at
about 40-45 in my truck. It would have sun all day but I don't think it would
have to be that big. Does that seem like it might help if security will let me
do it?
David Roden <[EMAIL PROTECTED]> wrote:
IMO, the easiest way to have a solar conversion EV is to mount a large
quantity of PV panels on your home's roof, and buy a grid intertie inverter.
Assemble a system capable of producing in a day at least as much energy as
your EV uses in the same period. While your car is sitting in the parking
lot at work, your PV system is storing electricity in a huge battery - the
power grid. When you come home, you plug in the car and it consumes the
energy your PV panels made during the day.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
Ken... you certainly can do series parallel on the field coils of a 4 pole
Series wound motor. One of the larger Warp motors has just this kind of
setup.
The draw back is the step change is too much for most Street uses.
FT has played with this kind of setup. Works... but takes some practice.
When you weaken the fields by less than 1/2 it's just called field
weakening.
Doing this under a really heavy load can really mess up the brush timing
since the timing retard is a function of field strength, Dropping the Bfield
by 1/2 sure is going to move the instant Zero point.
Rich Rudman
Manzanita Micro
----- Original Message -----
From: "Ken Trough" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, September 26, 2005 9:31 AM
Subject: Re: White Zombie Electrifies PIR ...12.424 @ 103.57 mph!
> > Can a S/P setup be done with 1 Motor ?
>
> How can a single motor be wired in series or parallel with itself? It
> can't. You could limit the voltage at the take off point, then give full
> voltage down the track a ways, but that is it.
>
> You could also have some contactors or something that changes your
> battery configuration from parallel banks to series banks or something,
> but this is a totally different approach essentially.
>
> The whole point is that having two motors gives you this series/parallel
> possibility in motor control.
>
> -Ken Trough
> Admin - V is for Voltage Magazine
> http://visforvoltage.com
> AIM - ktrough
> FAX/voice message - 206-339-VOLT (8658)
>
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, September 26, 2005 8:40 AM
Subject: Asking for witnesses (was: Which Nedra class? )
>
>
> I don't race much anymore, mostly because of Dennis. He took all
> the fun out of it for me.
>
> Bill Dube'
>
The most effective solution Bill is to Get back to twisting wrenches on the
bike...take the new motor performance data we have, and clean Dennis's clock
with his own "tricks"
John Wayland is now going faster than he ever has... with low tech
batteries... and a Racer's work ethic of, You have to try ,...to go faster.
And keep from antagonizing him ...if you don't have to.
You clearly didn't have to this time, You chose to. And in a public forum.
And this is what I have a problem with.
Rich Rudman
--- End Message ---
--- Begin Message ---
I have been contacted by a man who has a red 1994 Saturn SL2 that he is
willing to donate to someone from Illinois or Wisconsin (or possibly
outside that area) for use as an EV. The car is presently an ICE and
will probably have to be towed wherever it's going. There is some body
rust, from what I can see mainly below the doors.
Anyone interested please contact me off-list and I'll send you photos
and contact information.
-Tom
--
Thomas Hudson
http://portdistrict5.org -- 5th District Aldermanic Website
http://portev.org -- Electric Vehicles, Solar Power & More
http://portgardenclub.org -- Port Washington Garden Club
http://portlightstation.org -- Light Station Restoration
http://klanky.com -- Animation Projects
--- End Message ---
--- Begin Message ---
I would not advise you to buy on a bill of sale if your goal is to get to
an
on road EV motorcycle. This will make the DMV hoops you need to jump
through
easier.
Actually since I live in the same state as the originator of this post I can
comment on the hoops involved in WA as I did buy my motorcycle on Bill of
Sale from a seller in Oregon.
It really was not bad, I had to have it inspected by the WA State Patrol.
This was strictly a VIN inspection as they were checking for the possibility
of stolen parts. In my case I already had the Electric Motor in the chasis
which caused nothing more than a "Did you change out the motor in this
thing" comment from the State trooper.
After the State Patrol inspection the Department of Licensing allowed me to
register it, and will grant me a new title after I have had it registered
for 3 years. That was about 2 1/2 years ago, so I will know how well that
works out soon enough.
As long as you are sure that you are not dealing with something stolen then
I wouldn't worry about buying on Bill of Sale in the state of Washington.
damon
--- End Message ---
--- Begin Message ---
Shawn Rutledge wrote:
>> A motor designed for an EV has to operate at a pretty wide range
>> of speeds, and that is achieved by varying the frequency a lot,
>> right?
Correct. Except for exceptional cases like starting, frequency
determines speed. If the nameplate speed is 3500 rpm at 60 hz, then you
get 350 rpm at 6 hz, 7000 rpm at 120 hz, etc.
>> So I would guess these motors are much more tolerant of different
>> frequencies than typical stationary motors. How would they achieve
>> that?
All AC motors work at different frequencies, and so can run at different
speeds without any changes in the motor itself. If they know it will run
at one frequency, they can optimize things for it; but the optimizations
are extremely mild -- a normal 60hz motor will work from 30-120hz with
essentially no loss of performance or efficiency.
If you want the same torque, you need the same current. To make the
current stay the same as you change frequency, you must change the
voltage proportionately. A 120vac 60hz motor produces the same torque
and draws the same current (and has the same efficiency and same
temperature rise) at:
60vac at 30hz
120vac at 60hz
240vac at 120hz
Note that when the torque is the same and the speed changes, the
horsepower changes. Now you can see why people want to run AC motors at
high frequencies and higher rpms. If you can double the frequency and
voltage, you get double the horsepower out of the same motor with no
loss of efficiency!
That's why manufacturers will redesign a 60hz motor with better bearings
and better balancing; they can run a 120vac 60hz 3500rpm 10hp motor at
360vac 180hz 10,500rpm and get 30hp out of it!
Victor Tikhonov wrote:
> Mainly by altering magnetic characteristics (other than mechanical
> design of course). The motors have to have low enough inductance
> to get decent current to flow at high frequencies (where inductive
> resistance rise)...
This is correct, but confusing. Let me see if I can explain it more
clearly. Let's start with a standard AC induction motor:
Surplus Center <www.surpluscenter.com> item# 10-1937, $259.99
- 10hp at 3500rpm, continuous duty, 90.2% efficiency
- 12" long x 9" diameter, 110 lbs.
- 230/460vac, 25/12.5amps, 3-phase
We want to use it in an EV. The bearings and balancing are probably good
enough as-is for 7000 rpm. And we can get 20hp continuous, and probably
30hp for 1 hour out of it at 7000rpm.
But to reach 7000rpm, we need to apply twice the voltage and frequency;
460 or 920vac at 120hz. That's one heck of a battery pack! Let's say the
highest pack voltage we can get is only 160vdc. The peak of a sinewave
is 1.4 times its RMS value, so a 160vdc pack can only produce a 160/1.4
= 115vac sinewave. We have to reduce the motor's basic voltage by 2:1.
"230/460vac" means this motor has pairs of windings that you can connect
in parallel (for 230vac operation) or series (460vac). Neither of them
gets us to 115vac. (If it had been a 4-pole motor, we could have
connected its four windings all in parallel to get 115vac. Now you see
why 4-pole motors are preffered for EVs.)
Ah well. We have to take it to a shop and have it rewound for 115vac.
This means using half the turns of twice the wire size. This is a
straightforward operation; motor shops do this sort of thing all the
time, so it won't be all that expensive.
What we have done is to reduce the turns, and so lowered the motor's
inductance. The lower inductance lets the motor draw full current even
at 120hz. This is what Victor was talking about. Custom EV motors are
rewound for lower voltages. He goes on to say...
> yet have lamination material properties to prevent saturation at
> near zero RPM.
The lamination thickness and the grade of steel used determine a motor's
magnetic losses. Normal production motors use the thickest laminations
and cheapest steel they can get away with. At higher frequencies, core
losses go up, so the motor gets hotter and efficiency drops.
But, how *much* does it drop? This motor is 90% efficient at 60hz. Core
losses are generally 1/3rd of the total loss (with another 1/3rd being
resistive losses in the windings, and the other 1/3rd in mechanical
losses). So this motor has about 3% core loss at 60hz.
Core loss doubles when you double the frequency; so at 120hz they go up
to 6%; our 90% efficient motor is now 87% efficient. That's not a
killer; the fan is also running twice as fast, so the motor is likely to
be cooler (not hotter) at the higher speed.
A purpose-built EV motor that they know will run at 120hz will have much
thinner laminations and use a better grade of steel to get the core loss
at 120hz back down to 3%. But this adds significant cost. It's not
practical to make such a change to an existing motor.
> Of course balancing at 12k RPM is quite different from that for
> 3,550 RPM, and so is the bearing construction, associated shaft
> material with predictable temp expansion (requiring floating
> bearings) and other tricks.
Correct. They don't want just 2x the speed; they want 3x or more! Speeds
over 10,000 rpm are getting into "exotic" territory, where the cost goes
up fast. Normal transmissions can't handle these speeds either; you'll
also need a special high-priced gearbox. But it does let them squeeze a
little more horsepower out of the same size motor.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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Bill Dennis wrote:
> When ThunderSky cells have been self-discharging for a few months
> and are at different voltages, can you tell which cells are the
> strongest and weakest based on which have discharged the most?
Caveat: The following is based on my experience with four Thundersky
LP-90 cells, purchased as part of what appears to be substandard batch.
It may or may not reflect what others do.
No, you can't tell from voltage alone. Voltage gives you a rough idea of
their state of charge, but no idea at all of their amphour capacity. Two
cells can be at the same voltage, but one has half the capacity of the
other.
Likewise, the self-discharge rates seem to vary drastically between
cells.
Beware: Do not let them discharge too deeply! They will be permanently
damaged if they go below about 2.5v!
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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>> What is the future of the solar cars anyways?
Myles Twete wrote:
> They're asking themselves that question... what does it all mean and
> why is this important.
Well, normal racing is all about spectator sports, selling products, and
making people rich and famous.
Solar racing is more about pushing the state of the art, to see what can
be done. Like going to the moon; it has no direct practical purpose, but
helps you learn things that might be useful elsewhere.
That said, I'm a bit worried that the solar racers focus too much on
"racing" and not enough on "solar". Too much competition and focus on
winning -- no matter what it costs. And too little innovation and
experimentation. The cars are basically the same; same solar cells, same
motors, same controllers, same batteries, same tires. Nearly all the
teams just buy these parts; they didn't design or build them. There
isn't much innovation going on.
The technologies and innovations to "win" have become so specialized and
so expensive that they are impractical for any other "normal" use. No
solar car could be used for a run to the store. Its solar panels can't
be used for routine daily power production, because they mustn't wear
them down at all before the race.
> I ask this: why are so few EVers at all interested in integrating
> solar arrays into the bodies, or at least the roof, of their car
> conversions?
I'd love to do it; but what the solar racers have taught me is that it's
astoundingly expensive and impractical. They're not demonstrating how
"easy" it is -- they're proving how "hard" is is!
> The Solar Rayce teams have shown us the way to do better and get
> the looks from the spectators. And guess what? You all laugh.
Exactly. The solar racers get the WRONG kind of looks. The engineers
appreciate the technology and marvel at the craftsmanship. Joe Average
looks at them like a joke. "A million bucks for that? They must be
nuts!"
> So don't ask: "Will anyone on this list ever drive to work in one?"
> Rather, ask: Will anyone on this list dare to make and adapt a high
> efficiency integrated solar array to an EV?
No; I think the first question is the correct one. "How can I drive to
work on solar power?" The answer is that you don't put the solar panels
on the car. Put them on the roof at home, and use them to charge the
car.
Or, look for ways to build a *practical* solar-powered vehicle that you
really can drive to work. Joel Davidson, a PV pioneer, built a
solar-powered recumbent trike many years ago, and used it for routine
commuting. It was a PV/pedal hybrid -- no batteries! Or maybe you could
build an NEV that was entirely solar powered. Either way, instead of
something you can drive once in a lifetime, you'd have one you could
drive every day!
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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By all means, just make up a company name. Don't write, call. In my
experience companies pay little attention to individuals. In some cases
they are not set up to vend to individuals because they can't charge
sales tax. In this case it is usually no problem to create a business
on paper, it depends on your state.
Look into the liabilities of any technology, particularly "high end"
ones. For example, I recall that solar cells with ridiculously high
efficiencies only did so for a limited number of hours as the cell would
degrade in sunlight. Thus it might make an impressive racer yet its
practical uses were limited. That was a long time ago and I have no
idea what the state of the technology is today, but these are things to
understand.
BTW, don't underestimate the benefits of cooling the cells either. The
power output is reduced significantly as they heat up. While cooling
them is difficult to do well due to their construction, it is something
to think about.
Danny
Meta Bus wrote:
Hi Myles (via sunlight, somedaze)--
I have been inquiring after solar panels for several months, planning
my solar-electric RV. I have a system design plan and allocated funds,
and my design falls into that "very lame" category, using "commercial"
panels mounted to an existing roof. I currently plan on 14 Sanyo HIT
190 (16% efficiency) panels, using every square inch of my REV's roof.
Regarding the challenges you laid out--
1) I've discovered in my research that even the so-called "commercial"
panels are difficult to get. I have written to several online
merchants, and all but one have ignored my mail. I am at the point
where I will probably invent a business entity to gain distributor
access, just so I can get in the queue for panels. With a planned
purchase of about $12K (for four 4-packs, as the Sanyos come), and the
cash available, I am stymied in my efforts. Lead times and waiting
lists make it difficult, and finding stock is an ongoing effort. Until
people can waltz into WalMart and browse the solar aisle, I am afraid
clean & free energy will take dirty and expensive work on the part of
early-adopters.
2) The 23-28% efficiency you cite is a saliva-producer. But I know
those cells are both prohibitively expensive as well as hard-to-get.
University teams with research grants and free post-grad labor make
for very poor trickle-down economics. EVer's already face plenty of
obstacles in obtaining SOTA motors and controllers, because so many of
the mfr's (abbreviation is decoded two ways) won't deal with an
individual.
So, to invert your challenge, can you provide the list with a
practical plan for integrating solar into EV designs-- beginning with
a source of those university-research-level solar cells, or even a
consistent and reliable supplier of those lame commercial panels?
Or, how about implementing your bimini and then coming back and
sharing the details of your accomplishment (including where and how
you got your cells, how long it took, how much you paid, etc)?
Because I agree, to an extent, that the integration of solar into an
EV is a natural mix (like peanut butter and chocolate!), but the grid
is everywhere, and the alternative solar is currently (too many puns)
more expensive and harder to obtain than truffles.
Stocking up on Reese's cups for my future LSD trip,
Jim Davis
Myles Twete wrote:
Ryan Stotts asked:
Will anyone on this list ever drive to work in one?
Probably not, but I ask this: why are so few EVers at all interested in
integrating solar arrays into the bodies, or at least the roof, of
their car
conversions?
I've seen only a few attempts, and these usually consist of 1-4
slapped-on
commercial solar panels---nothing approaching high tech and very
lame. You
put so much into getting your cars converted to make an EV, then on the
road, it just looks like any other car. Then you realize that few
people
notice that you're driving an EV, and then what do ya'all do? You get a
custom license plate or bumper stickers or you hang a charger pigtail
out
the back and to try to emphasize that "hey, this is an electric".
Good for
you.
But why stop there? The Solar Rayce teams have shown us the way to do
better and get the looks from the spectators. And guess what? You all
laugh.
Why not instead of laughing take that boring roofline and make an
integrated
solar array out of it?
Making a custom integrated solar panel is not easy, but it's not total
rocket science either.
But think of the looks your EV will get! And you won't need that
"180V EV"
custom plate to suggest to folks that your car is electric. They'll
get it
in an instant.
And then what?
You won't need to buy one of those solar EVs...you'll have one.
You also won't need so much plug-in power at work either!
But don't do it for performance: you'd be lucky to get 500watts out
of high
efficiency cells on even a large car top. At 15kw, that's only 2minutes
worth of juice.
Do it for the looks.
Do it for the enjoyment and challenge.
And do it for the free solar recharging and free EV advertising while at
work: 500watts*5 solar hours: 2.5kwh/day----that's good for 10 miles of
driving at 250wh/mile.
Sorry, but plugging the car in or having a license plate that says
"EV4ME"
won't get the looks like a professional quality integrated solar roof
will.
So don't ask: "Will anyone on this list ever drive to work in one?"
Rather, ask: Will anyone on this list dare to make and adapt a high
efficiency integrated solar array to an EV?
Or this: With all the egos on this list, why hasn't anyone done this
already? Or is this road-EV community just into high power? [Many
practical E-boats have long gone to solar---I'm slacking with mine]
Today's top solar race teams are integrating 23-28% efficient cells
in their
solar panels.
Their panels generate in the 1kw range.
One such panel would push my boat at 4knots---That gets me pretty
excited.
Go solar-
-Myles Twete, Portland, Or.
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Wilde, Wayland and All,
Bandimere's in Denver not only has a 100 mph club, but they set aside a
date for them, which was the 11th of this month.
BB
>Date: Tue, 27 Sep 2005 07:13:22 -0700
>From: John Wayland <[EMAIL PROTECTED]>
>
>Hello to All,
>
>Roderick Wilde wrote:
>
>> Hi John, Could you please elaborate on this. I was not aware that the
>> gas guys had a 100 mph club. Please tell all you know about this. You
>> said: "The track officials were so pumped, they took pictures of Tim
>> and I in front of the car and handed us a couple more 100 mph club
>> stickers for the car."
<snip>
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Bill,
You can assume that "strongest" (lowest R_int) cells also
have lowest rate of self-discharge, but this is not strictly related.
Also, stiffer battery may have less capacity than softer one next to it,
so despite being stronger during discharge (less voltage sag) will
reach minimum voltage sooner.
Define your question berrer, what do you menan "strong"?:
Lowest R_int?
Highest capacity?
Lowest self-discharge rate?
Bill Dennis wrote:
When ThunderSky cells have been self-discharging for a few months and are at
different voltages, can you tell which cells are the strongest and weakest
based on which have discharged the most? If so, is it the weakest cells
that discharge the fastest, or the strongest ones?
Thanks.
Bill Dennis
--
Victor
'91 ACRX - something different
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