EV Digest 4543
Topics covered in this issue include:
1) Re: Cost of using wide tires
by Ryan Stotts <[EMAIL PROTECTED]>
2) Re: Finding Parts
by "John G. Lussmyer" <[EMAIL PROTECTED]>
3) Re: Tubes
by Victor Tikhonov <[EMAIL PROTECTED]>
4) Re: hybrid battery question
by [EMAIL PROTECTED]
5) Re: Racing 3wheels, Re: 3 wheel EV's trike pick up, and CUSHMAN Truck
by "ProEV" <[EMAIL PROTECTED]>
6) RE: Cost of using wide tires
by "Don Cameron" <[EMAIL PROTECTED]>
7) Re: Deka dominato. Now: Are they as good as Optima or Exide?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
8) Re: Cost of using wide tires
by David Dymaxion <[EMAIL PROTECTED]>
9) Re: Tire Recommendations
by =?ISO-8859-1?Q?Jukka_J=E4rvinen?= <[EMAIL PROTECTED]>
10) Re: N-wheel vehicle stability
by David Dymaxion <[EMAIL PROTECTED]>
11) RE: Cost of using wide tires
by "Adams, Lynn" <[EMAIL PROTECTED]>
12) Re: Cost of using wide tires
by "Roland Wiench" <[EMAIL PROTECTED]>
13) RE: N-wheel vehicle stability
by "Stu or Jan" <[EMAIL PROTECTED]>
14) Re: Racing 3wheels, Re: 3 wheel EV's trike pick up, and CUSHMAN
Truck
by David Dymaxion <[EMAIL PROTECTED]>
15) RE: Cost of using wide tires
by "Philip Marino" <[EMAIL PROTECTED]>
16) Re: CalCars Teach Lead Ron Gremban's battery evaluation and production
cost summary
by Danny Miller <[EMAIL PROTECTED]>
17) Re: Segway?
by [EMAIL PROTECTED]
18) RE: Tubes (semiconductor = resistor)
by Jeff Shanab <[EMAIL PROTECTED]>
19) RE: Tubes (semiconductor = resistor)
by "Stu or Jan" <[EMAIL PROTECTED]>
20) Re: Tire Recommendations
by Victor Tikhonov <[EMAIL PROTECTED]>
21) Re: Finding Parts
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Racing 3wheels,
by Victor Tikhonov <[EMAIL PROTECTED]>
23) Re: Segway?
by "Christopher Robison" <[EMAIL PROTECTED]>
24) Re: Tubes
by "Nick 'Sharkey' Moore" <[EMAIL PROTECTED]>
25) Re: G'day ... thinking about Electric Motorcycles
by "Nick 'Sharkey' Moore" <[EMAIL PROTECTED]>
26) Re: tilting, Re: Racing 3wheels,
by jerry dycus <[EMAIL PROTECTED]>
--- Begin Message ---
Dave wrote:
> Does anyone have any hard figures on what the cost would be
> of running a wider lower profile tire compared to a hi pressure
> skinny low resistance tire? Just curious how much it would kill
> the range or speed or anything else as I've not seen any figures
> on this.
I was just thinking about this earlier today. If we had two cars of
the same make and weight, and one had 3" wide tires, and the other had
12" wide tires, and we were to get behind each of them and push them
for a distance from a standing stop: Would the 3" tired one
absolutely roll easier then the 12" one? If so, how much easier?
What about at highway speeds?
--- End Message ---
--- Begin Message ---
At 10:16 PM 7/31/2005, Lee Hart wrote:
I pulled out my AMP catalog for an example. Their nickel and
nickel-plated copper terminals are trademarked "Strato-Therm". They look
just like normal crimpable ring terminals, and come in both uninsulated
and insulated versions (the insulated ones use Teflon).
I just tried the AMP website.
Not only do they have one of the worst search systems I have ever
seen, the Strato-Therm parts don't even come in the size I need, with
the hole I need.
I did find some plain copper terminals that match, but they can't
tell me if any exist, or what they cost.
I did call SMH about their terminals, you can't buy direct from SMH
until you have a credit-checked account setup, which takes about 2
weeks. (They don't care if you will pay first, you still have to
have credit with them.) They also couldn't tell me a local
distributor that carried their parts.
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream....
http://www.CasaDelGato.com
--- End Message ---
--- Begin Message ---
:-)
[EMAIL PROTECTED] wrote:
<<No; that is exactly right. A vacuum tube is a variable resistor. I am
speaking of traditional vacuum tubes, which have a true vacuum inside.>>
What?!?!! You've got to be kidding me! Is this some kind of sick joke? All
a bloody vacuum tube is is a resistor? What the hell is so impressive about
that?
Among other things, impressive is that:
unlike variable resistor the tube is controlled electronically
(by voltage on the grid)
The gain can be very high (it takes *much* lower power on the grid
than the power in the load you're able to control.
BTW, the same goes for transistors.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Thanks a lot for the responses to the battery question. I have forwarded
them to the young lady who was interested and hope she will decide to buy
a hybrid when she is shopping for a new car.
David and Bob, you made me feel terribly guilty about even considering a
gasoline powered car so I will now investigate what is out there in NEV
land. I was wavering over which way to go and I think you guys pushed me
back in the appropriate direction. I do not need to go very far, or very
fast. I just retired and will now be spending my time helping out at the
ice skating studio so wanted a car with the following features:
- brakes always work
- lights allow me to see at night, and come on without having to bang the
dashboard multiple times
- windshield wipers don't fall off at night in the middle of a storm
- contactors all work
For several months I have had functional EVs, thanks to the efforts of
Richard Furniss who replaced a lot of parts and did a lot of work. Now
they are falling apart again because they are old. Richard has a job, is
President of the LVEVA, has a family, etc. so is not sitting around
waiting to work on my cars, but fits them in when he has time and it is
not too hot in his garage. It was pretty easy to ride my electric bike to
my office or take the bus on really rainy days, so it wasn't too big a
deal when the cars were all broken. Getting to the ice studio is more
difficult as I will have my skates in my backpack, the route is uphill
coming home, and none of the bus routes go close. Also, I have an elderly
dog who may need to go in for medical care and although she is small,
hauling her on my bike would not be practical, especially if it happens to
be one of our 117 degree days. So, I think a NEV would serve my purposes
reasonably well. An Insight would be way more luxurious than I need. Any
recommendations as to which NEVs are really cool? Lee Iacocca had one a
few years ago that was very cute but I don't know if it is still being
built.
As a member of the Citizens Advisory Committee for the RTC I have the
opportunity to inquire about the installation of bicycle lockers and
electric vehicle charging whenever there are discussions about new
facilities. I really should be driving something that needs the EV
charging so I can plug in and report back on how great it is, when they
finally turn the power on. It sounds like we may be getting close to
having charging in the park-and-ride locations.
Thanks again for the hybrid info.
Gail
On Sun, 31 Jul 2005, Bob Rice wrote:
>
> ----- Original Message -----
> From: "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
> To: "EV Discussion List" <[email protected]>
> Sent: Saturday, July 30, 2005 10:58 PM
> Subject: Re: hybrid battery question
>
>
> > Eee gads, Gail is talking about using GASOLINE! What is the world coming
> to?
> > BB
> > Hi All;
>
> The OILIES are winning! Sigh, when EVen Gail is looking for a gasser.
> But at least she is looking in the right place.IMHO I think you would be
> very happy, for now, with a Insite. Ask John Wayland about his, they are
> still honeymooning at 70 MPG or better.
>
> Seeya
>
> Bob
--- End Message ---
--- Begin Message ---
Hey Everybody,
What an interesting discussion. There is a lot of potential for development
in 3 wheelers. Delta, tadpole, leaning, rear wheel steering.
I would think the biggest advantage to 3 wheels is the potential for a
cleaner streamline aero package. This advantage is nullified a bit by the
tremendous downforce that can be produced by the underbody of a wider car.
< As the tooling is about done on the Freedom EV, we
will see fairly soon, won't we?
I hope to join the Imp EV soon on the SCCA courses
here in Fla within a yr. >
Excellent! Racing fun aside, learning what the Freedom EV will do under the
demands of autocross will translate back into an improved road vehicle.
I am not sure how whether the autocross organizers will be able to allow a 3
wheeler to run. Maybe if you carry a fourth wheel in the passenger seat<G>.
Worse comes to worse, we will find a parking lot and some cones and have an
all EV shoot-out!
Cliff
www.ProEV.com
--- End Message ---
--- Begin Message ---
Very good question. Different makes of tires of the same size may have
different rolling resistances (RR). Most computations I have seen regarding
tire RR looks like:
Drag force due to rolling resistance = Vehicle Mass * Gravitational
Force * Tire rolling resistance coefficient.
There are two interesting things to note:
1) Note that there is no vehicle speed in the equation at all (which
surprises me), therefore the force due to RR is constant throughout the
vehicle speed range.
2) The coefficient is directly proportional to the RR force
The force is quite large. For my New Beetle, 30-50% of the energy used (at
a constant speed) is overcoming poor rolling resistance tires with a coeff
of 0.015. Of course compared to the energy required to accelerate the car,
it is about 8-10%.
At 80kmh (50mph) it takes 15kW of power to overcome rolling resistance, air
resistance and drive train resistance on a flat surface. If I had tires
with a RR of 0.008, it would take 11kW of power.
Every bit helps.
Here are a few articles found on the web:
http://www.greenseal.org/recommendations/CGR_tire_rollingresistance.pdf
http://www.school-for-champions.com/science/frictionrolling2.htm
http://webphysics.davidson.edu/faculty/dmb/PY430/Friction/rolling.html
Don
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 Gnat
Sent: July 31, 2005 10:14 PM
To: [email protected]
Subject: Cost of using wide tires
Does anyone have any hard figures on what the cost would be of running a
wider lower profile tire compared to a hi pressure skinny low resistance
tire? Just curious how much it would kill the range or speed or anything
else as I've not seen any figures on this.
Dave
--- End Message ---
--- Begin Message ---
I'm looking for a battery with more weight(for more range, About a 60 to
70pound battery) for a 156v pack. How would the Deka batteries stack up?
LR.......
----- Original Message -----
From: "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, August 01, 2005 8:43 AM
Subject: RE: Deka dominator gel batteries
On 31 Jul 2005 at 18:26, Ralph Goodwin wrote:
What is the shelf life of Deka 8G47 batteries? Assuming they are stored
in a air conditioned building, without being charged, how long can they
sit without losing significant capacity.
I'm not familiar with 8G47s. However, I have several 8G24s sitting idle
right
now. I put a charger on them every 6 months or so, but they seldom take
more than a couple of amp-hours before the charger shuts off. I've never
seen
any other lead batteries with such low self-discharge.
As far as capacity loss, I haven't measured their capacity recently, so I
can't
say. It's normal for batteries to decline in capacity when they're not
used,
but they should "wake up" when put into service and cycled.
--- End Message ---
--- Begin Message ---
I don't know about rolling resistance, but for high speeds narrower
tires have less frontal area, so less wind resistance.
--- Gnat <[EMAIL PROTECTED]> wrote:
> Does anyone have any hard figures on what the cost would be
> of running a wider lower profile tire compared to a hi pressure
> skinny low resistance tire? Just curious how much it would kill
> the range or speed or anything else as I've not seen any figures
> on this.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
I put Continental ContiEcoContact3 185/70-R14 under my Berlingo and been
quite happy. I can get as low as 0,65 Ah/km (105,3 Wh/km = 168,5
Wh/mile) in normal city speeds(50-60 km/h (31-37mph)). These new tires
extends the range from previous set 20%. (~190 miles/charge now)
Previous tyres were already somewhat driven and M+S type Michelins if I
remember correctly.
With previous Ni-CD batts and old tires I could get 100 km range (60
miles).This calculates to 162 Wh/km = 260 Wh/mile.
Same car in postal use (lots of stop and go driving with full load) they
got 280 Wh/km (448 Wh/mile).
I did one 250 km = 156 miles trip with trailer (just stuff for 200 kgs
on it, no extra batts). I charged in middle point for few hours. During
that trip I consumed ~1,4 Ah / km = 227 wh /km = 363 Wh /mile . So I had
with 90 km/h =56 mph about 140 km = 90 mile range.
summary: I have actually very little to compare with the exsisting
results. :) I have some different tyres which I could put under and test
for a while. I'll get thet info posted up here if some one needs such info.
btw. I use 2,2 bar pressure.... This will be fun to test how much
actually tire pressure affects too...
I think they have your tire size too available.
-Jukka
fevt.com
Joel Silverman wrote:
I am looking into new tires for my EV. I would like
to get a low rolling resistance tire if possible. I
am looking for a 195/50/15. Any recommendations from
the list?
Thanks,
Joel
__________________________________________________
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Tired of spam? Yahoo! Mail has the best spam protection around
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--- Begin Message ---
Several people on the web have done a self-balancing segway-like
unicycle.
<http://tlb.org/eunicycle.html>
--- Lee Hart <[EMAIL PROTECTED]> wrote:
> ...
> Let's carry this one step further. Suppose you wanted a very small
> vehicle for efficiency and easy parking; yet you want it tall
> enough to
> see and be seen by SUV drivers. And, we allow changes in the
> vehicle's
> geometry -- leaning *and* repositioning the wheel contact points.
> Now a
> ONE-wheel vehicle could provide the best handling! A unicycle!
>
> Normally, the driver provides all the balance and control. But you
> could
> (theoretically) have a very elaborate control system to rapidly
> move
> this one wheel relative to the C.G. wherever it needs to be to
> maintain
> balance. So, you "just get on and drive", and let the control
> system do
> all the hard work. Essentially what the Segway does, but with one
> wheel
> instead of two.
> ...
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
Of course a wide low profile tire has less tire deformation....
My 165/70/13's had lower rolling resistance than my current 155/80/13's
Lynn Adams
G
See my 100% electric car at http://www.austinev.org/evalbum/379.html
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David Dymaxion
Sent: Monday, August 01, 2005 2:28 PM
To: [email protected]
Subject: Re: Cost of using wide tires
I don't know about rolling resistance, but for high speeds narrower
tires have less frontal area, so less wind resistance.
--- Gnat <[EMAIL PROTECTED]> wrote:
> Does anyone have any hard figures on what the cost would be of running
> a wider lower profile tire compared to a hi pressure skinny low
> resistance tire? Just curious how much it would kill the range or
> speed or anything else as I've not seen any figures on this.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: Ryan Stotts<mailto:[EMAIL PROTECTED]>
To: [email protected]<mailto:[email protected]>
Sent: Monday, August 01, 2005 12:53 PM
Subject: Re: Cost of using wide tires
Dave wrote:
> Does anyone have any hard figures on what the cost would be
> of running a wider lower profile tire compared to a hi pressure
> skinny low resistance tire? Just curious how much it would kill
> the range or speed or anything else as I've not seen any figures
> on this.
I was just thinking about this earlier today. If we had two cars of
the same make and weight, and one had 3" wide tires, and the other had
12" wide tires, and we were to get behind each of them and push them
for a distance from a standing stop: Would the 3" tired one
absolutely roll easier then the 12" one? If so, how much easier?
What about at highway speeds?
If you put in the same PSI into each tire, the 3 inch tire will have a longer
foot print then the 12 inch tire. The 12 inch tire has a narrow or short foot
print but it is wide.
Example, for the same given weight, the 3 inch tire could have a foot print
about 3 inches wide by 6 inches long. The 12 inch tire may have a foot 12
inches wide by 2 inches long.
The 12 inch tire is great for fast acceleration but is not great for side
slipping threw the corners with the same compound on both type of tires unless
you used a modified thread pattern for road racing.
On my sports car which I modified a mid engine Cam Am race car for the
street. The rear tires are 12 inches wide with a foot print of 6 inches by 12
inches or 72 sq.in. tire area. The actual tire contact is about 64 sq.in.
subtracting the very narrow spaces between the tire lugs.
The front tires are 8 inches wide with a foot print of 8 inches by 4 inches
or 32 sq.in. The actual tire contact is about 16 sq.in subtracting the very
large spaces between the tire lugs.
The front to rear weight ratio is about 80% on rear and 20% on front of a
1600 lb car. That is about 1200 lbs on the rear and 300 lbs on the front.
The ratio of weight is about 4 to 1 and the tire contact is also about 4 to 1
make the pounds per square inch on each tire the same.
This would all be true, if the tire is air up right. The tire deflection
must be correct for the best performance you want.
Tire deflection is the amount of change in height of tire unloaded (jack off
the surface) and the loaded (on the surface).
Example of choosing the correct tire and adjustments of the deflection rate:
1. Weigh the car, weigh the front and then weigh the rear.
(lets say the car is 50% front and rear and the car weighs 4000 lbs -
that is 1000 lbs per wheel and tire)
2. A wheel should be chosen that has its load rating above 1000 lbs
(normally at 1500 lbs)
3. A tire also should be chosen that has a load rating above 1000 lbs
(normally it will read 1500 lbs at 40 PSI on the side of the tire)
4. Air up the tire to the 40 PSI, and with the weight off the ground, but
let the tire just touch the ground, measure from the ground to the bottom wheel
rim.
(lets say this reads 5 inches)
5. Now lower the tire to the ground with the full weight of the car on the
tires. Measure again, and lets say it is 4.75 inches.
6. 5 inches - 4.75 inches = 0.25 inches. The 0.25 inches is the deflection
rate which is 5 percent. This will be a very firm ride if you have a stiff
suspension.
7. If the car weight is 1000 lbs on that tire, than:
(1000 lbs x 40 psi)/1500 lbs = 26 PSI
8. Retest it at 26 PSI. If the deflection rate goes above 10 percent or
more than 0.50 inch for that tire, than that is too much. Add more air until
you are between 5 and 10 percent.
My rear tires on my EV are rated for 2560 lbs at 65 PSI. I have them air up
to 60 PSI for a 0.5 inch deflection. The tires are have are not the best type,
which are nylon steel radial. The best type should be polyglass non-steel
radial. These are not subject to flattening when setting at a cold temperature.
If you go to a tire place and give them specifications like above, they will
not know what you are talking about. They only go by application which may at
times fit a modified car.
Roland
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--- Begin Message ---
Theoretical and reality.
Car & Driver, Motor Trend, and Road and Track test drivers, drove and
reviewed the Trihawk. Not a theoretical discussion, several road tests with
stop watches, 4th wheels, and other instruments..
Read the results here: http://designmassif.com/trihawk/articles/index.htm
Why argue facts and data? One article reported an understeered skid pad
figure of .83 exceeded only by a Ferrari Boxer, a Lamborghini Countach, BMW
M1, and Porche 930 Turbo.
The very fact that any 3 wheeler would be compared to those 4 super handling
cars, to me, makes the handling issue a mute point. Would any of us
complain if our car handled on that level?
Look how easy it is to build a 3 wheeler: Front steering, and a powered
rear wheel.
I am planning to use the front end of a small pickup truck with manual
steering, the Kawasaki 550 and a 10Hp motor driving the rear wheel. You can
get it licensed easily, etc. Why not?
IMHO We have had enough arguing about N wheels.
BoyntonStu
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David Dymaxion
Sent: Monday, August 01, 2005 4:27 PM
To: [email protected]
Subject: Re: N-wheel vehicle stability
Several people on the web have done a self-balancing segway-like
unicycle.
<http://tlb.org/eunicycle.html>
--- Lee Hart <[EMAIL PROTECTED]> wrote:
> ...
> Let's carry this one step further. Suppose you wanted a very small
> vehicle for efficiency and easy parking; yet you want it tall
> enough to
> see and be seen by SUV drivers. And, we allow changes in the
> vehicle's
> geometry -- leaning *and* repositioning the wheel contact points.
> Now a
> ONE-wheel vehicle could provide the best handling! A unicycle!
>
> Normally, the driver provides all the balance and control. But you
> could
> (theoretically) have a very elaborate control system to rapidly
> move
> this one wheel relative to the C.G. wherever it needs to be to
> maintain
> balance. So, you "just get on and drive", and let the control
> system do
> all the hard work. Essentially what the Segway does, but with one
> wheel
> instead of two.
> ...
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
Snippage and comments interspersed.
--- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> If you are cornering hard enough to lift a wheel on the 4wh, then
> the
> equivalent 3wh has already flipped over. Do the math, the physics
> and
> geometry involved are pretty simple.
If you assume no suspension this would be true. Lots of cars in
autocross will lift a wheel. All that means is one end of the car is
stiff (or has limited wheel travel), the other end is soft. The
"equivalent" 3 wheeler would be OK in this case.
This is sometimes touted as an advantage for 3 wheelers. In a 4 wheel
car, wheel loads can go from 0 to about 2x static (and often do for
the rear wheels of front wheel drives in autocross). 3 wheelers tend
to have a more constant load on each wheel, especially over uneven
terrain. This can be destabilizing, though, as a 3 wheeler will tilt
more if a wheel drops in a hole.
> > There is a situation where a 3 wheeler could beat an "equivalent"
> 4
> > wheeler: Autocross.
> >
> > If you do the math, you'd be amazed how much time it adds to miss
> the
> > cones by even half a meter. A relatively easy to compute case is
> a
> > slalom, assume a sinusoidal path. With the four wheeler, you have
> to
> > make your turn a bit bigger to make sure the rear wheels don't
> hit a
> > cone. With the tadpole 3 wheeler, you can come closer to the
> cones.
>
> Hmm, maybe, maybe not. The front end is going to be the same
> width, so
> unless you tighten the corner after the front wheels pass the
> cone, it
> won't make any difference. And since the equivelent 3wh won't be
> able to
> corner as tightly as the 4wh...
I think we might be doing some apples-to-oranges comparisons here. If
you mean lateral g's, in general the 4 wheeler wins. If you mean time
to go through a corner, then the same width and length 3 wheeler can
win.
Here's an example: Assume a 90 degree turn with a sharp corner. The
four wheel car has to do a shorter radius turn to keep the rear
wheels from hitting the corner. The 3 wheeler can come closer to the
inside of the corner without hitting the rear wheel. So if both are
tire limited and make the same lateral g's, the 3 wheeler can go
through the corner faster, even if the front track is identical.
> > You can make the 3 wheeler chassis much
> > lighter than a 4 wheeler. The trend continues: 2 wheelers can
> carry
> > even more weight per wheel (or have an even lighter chassis), and
> the
> > winner is the unicycle.
>
> Lighter, perhaps, but "much" lighter? I doubt it.
>
> I'll grant you that triangles have structural advantages, but even
> without
> the higher forces on the corners of the frame, it's not going to
> reduce
> the totatl vehicle weight by 1/4.
> Take a look at the frame in the book "Build your own sports car". I
> particularly like the photo of the author holding up the completed
> frame.
> The complete frame weighs less than 1/10 of the total vehicle
> weight,
> probably less than 1/12.
I think we might be doing an apples-to-oranges comparison again. If
you assume the same width and length of vehicle, the 3 wheeler should
be much lighter, but will have about 1/2 the interior volume. If you
keep interior volume constant, then the weight savings would be less.
In general, the fewer the number of wheels, the more weight per wheel
the vehicle can handle.
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
From: "Don Cameron" <[EMAIL PROTECTED]>
Very good question. Different makes of tires of the same size may have
different rolling resistances (RR). Most computations I have seen regarding
tire RR looks like:
Drag force due to rolling resistance = Vehicle Mass * Gravitational
Force * Tire rolling resistance coefficient.
Sorry to be picky, but you really mean "Gravitational Acceleration", not
"Gravitational Force", right? Mass time acceleration is force ( or weight
in this case) .
There are two interesting things to note:
1) Note that there is no vehicle speed in the equation at all (which
surprises me), therefore the force due to RR is constant throughout the
vehicle speed range.
This just means that most people use an approximation which says the rolling
resistance is not affected by speed - they choose a straight line fit
because it is easier to understand and use - and probably accurate enough
for most uses.
I would bet, though, that there is some speed-related effect. Has anyone
seen any real data that shows RR versus speed?
Phil
_________________________________________________________________
On the road to retirement? Check out MSN Life Events for advice on how to
get there! http://lifeevents.msn.com/category.aspx?cid=Retirement
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--- Begin Message ---
OK, here's been my thought lately.
Lithium has a much better cycle efficiency than lead acid. I believe
that difference gets wider when we are talking about very rapid charging.
From what I understand, lithium is also not harmed by deep discharges
as long as the low voltage shutoff point is respected.
These may point to a separate solution. Using the lead acid for overall
storage but a smaller lithium as a bank for regenerative braking
storage- where we care a lot about cycle efficiency- seems to make a lot
of sense.
Just an idea. The lithiums, though having great power-to-weight ratios,
seem quite expensive for large scale storage, but I could see them as
able to do this part.
Danny
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I think they would be good transportation for short trips. At Earth Day
this year there were a couple being demonstrated and I got to try one.
They are very easy to manoeuver but I found it a bit difficult to get used
to stopping without squeezing the handles, as I am accustomed to doing on
my bike. You have to lean back to stop. I lost control at one point and
ran into a flower bed but did not tip over. This probably would not have
happened had I not been wearing my ice skates and a cumbersome bird
costume I had on for the Earth day show we were doing on some plastic ice.
If I had not been within months of retiring I would have considered buying
one for my 2.73 mile commute to work. In Nevada they are recognized as
equal to pedestrians so can be ridden on the sidewalk. I need to find out
if that rule applies to taking them on the bus. That might be difficult
to do since they would be too heavy to lift and I don't think they can
climb steps.
Gail
On Mon, 1 Aug 2005 [EMAIL PROTECTED] wrote:
> Met a guy last night that is supposedly the largest Segway dealer in the US
> (met him in Thailand of all places).
>
> Anybody know anything about these things? What's your opinion?
>
> S.
>
>
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A variable resistor AND the little guy to turn the knob. He got a new
name with his new job: "transistor man"
He keeps both eyes on the base voltage and adjusts the big resistor knob
accordingly. (modified for mosfet)
Sorry, I couldn't resist. I remember this from some really old book on
transistors when they were new to hobbiest.
But it helps to understand heat dissapation and wear to think of
semi-conductor as another way of saying variable resistor
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A person halfway through training to lead a symphony orchestra is called a
"Semi-Conductor".
stU
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Jeff Shanab
Sent: Monday, August 01, 2005 6:56 PM
To: Electric Vehicle Discussion List
Subject: RE: Tubes (semiconductor = resistor)
A variable resistor AND the little guy to turn the knob. He got a new
name with his new job: "transistor man"
He keeps both eyes on the base voltage and adjusts the big resistor knob
accordingly. (modified for mosfet)
Sorry, I couldn't resist. I remember this from some really old book on
transistors when they were new to hobbiest.
But it helps to understand heat dissapation and wear to think of
semi-conductor as another way of saying variable resistor
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Remember, people here is not as enthusiastic about metric as the
rest of the world and some may not even know about a "bar" (0.01 of Pa)
being a pressure unit.
Info for those, 2.2 bar is 31.9 psi.
Victor
Jukka Järvinen wrote:
..
btw. I use 2,2 bar pressure.... This will be fun to test how much
actually tire pressure affects too...
I think they have your tire size too available.
-Jukka
fevt.com
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John G. Lussmyer wrote:
> I just tried the AMP website.
> Not only do they have one of the worst search systems I have ever
> seen, the Strato-Therm parts don't even come in the size I need, with
> the hole I need.
> I did find some plain copper terminals that match, but they can't
> tell me if any exist, or what they cost.
>
> I did call SMH about their terminals, you can't buy direct from SMH
> until you have a credit-checked account setup, which takes about 2
> weeks. (They don't care if you will pay first, you still have to
> have credit with them.) They also couldn't tell me a local
> distributor that carried their parts.
Oh well... we tried. There are some companies that seem to think
customers should beg and grovel to do business with them.
What usually works for me with companies like that is to call their rep
and pretend to be a big customer.
--
The two most common elements in the universe are hydrogen and stupidity.
-- Harlan Ellison
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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FWIW, the name "Freedom car" (program) was taken by GM for quite a
long time, for instance part of this program is GM's Sequel(FCEV):
http://www.gmeurope.com/technology/downloads/BURNS_SequelLon1119.pdf
Jerry couldn't care less of course, but this may be confusing
to someone who already read of existing "Freedom" vehicles before
this name appeared on EVDL. Usually the trade marks and such program
names are respected *at least* to avoid confusion.
Victor
ProEV wrote:
Hey Everybody,
...
< As the tooling is about done on the Freedom EV, we
will see fairly soon, won't we?
I hope to join the Imp EV soon on the SCCA courses
here in Fla within a yr. >
--
Victor
'91 ACRX - something different
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There's a fellow here in Austin who does city tours with them; he brought
one to a charity event I attended a few months ago, and for a few dollars
I got to ride around on it.
Some folks took to it immediately, some were a bit shaky at first. Those
who know me would probably not be surprised that by the time I got off it
the guy didn't seem too happy to have me as a customer. Guess he got
tired of asking me to slow down and be careful.
I found that what they say about riding the Segway is true -- it really is
an intuitive control method and riding it feels just wonderful, far better
than it looks in my opinion. After a few seconds riding on it, I found it
completely natural to accelerate to exactly the speed I wanted, brake
under complete control, and turn on a dime. Leaning to the side for a
high-G turn is actually pretty thrilling; the tires are grippy and the
solid quality of the machine invites a great deal of trust.
The only potential drawback is the practicality of the Segway when you're
not riding it. It's something like having a mid-size electric scooter in
that it's too massive and heavy to carry if it runs out of juice. Unlike
a board scooter though, I don't imagine you'd be able to coast on it with
no power.
To sum up, it's an extremely well-built machine that feels like it's
obeying your will. Nothing felt or looked cheap about the one I rode, and
the handling and ride were solid and comfortable. It's big, but that may
or may not matter depending on how you intend to use it.
--chris
[EMAIL PROTECTED] said:
>
> I think they would be good transportation for short trips. At Earth Day
> this year there were a couple being demonstrated and I got to try one.
> They are very easy to manoeuver but I found it a bit difficult to get used
> to stopping without squeezing the handles, as I am accustomed to doing on
> my bike. You have to lean back to stop. I lost control at one point and
> ran into a flower bed but did not tip over. This probably would not have
> happened had I not been wearing my ice skates and a cumbersome bird
> costume I had on for the Earth day show we were doing on some plastic ice.
> If I had not been within months of retiring I would have considered buying
> one for my 2.73 mile commute to work. In Nevada they are recognized as
> equal to pedestrians so can be ridden on the sidewalk. I need to find out
> if that rule applies to taking them on the bus. That might be difficult
> to do since they would be too heavy to lift and I don't think they can
> climb steps.
>
> Gail
>
> On Mon, 1 Aug 2005 [EMAIL PROTECTED] wrote:
>
>> Met a guy last night that is supposedly the largest Segway dealer in the
>> US
>> (met him in Thailand of all places).
>>
>> Anybody know anything about these things? What's your opinion?
>>
>> S.
>>
>>
>
>
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On 2005-08-01, [EMAIL PROTECTED] wrote:
>
> Yeah, I knew all that (sorry). Those are the "trees." I wanted the
> "forest," which you (thankfully) just provided. You just told me it
> was a variable resistor. That's what I wanted. Thanks anyway, though.
Well, now you've had a glimpse of the forest, you'd better zoom
in and look a bit closer at some of those tree species.
Particularly: picture a power source, a variable resistor
and a load all in series. For the sake of simplicity,
let's imagine the power source is a constant 100 Volt and the
load is a constant 1 Ohm.
Now, set the variable resistor to 0 Ohms. There'll be
a total resistance of 1 Ohm, so 100 Amp will flow
through the circuit and there'll be a 100 volt drop across
the load -- the load will get 100 Volt * 100 A = 10 kiloWatts
of energy, and the VR will see no voltage drop and so
get no energy (power = voltage * current)
Now, set the VR to an infinite resistance. No current
will flow -- and since no current is flowing, neither
the load nor the VR will get any energy.
Okay, so let's imagine that we'd like to regulate the
load so it's getting 2500 Watt of energy. We set the
VR to 1 Ohm, so there's a total resistance of 2 Ohm
in the circuit and 50 Amp flows through the circuit. There's
50 Volt drop across the load, it gets 50V * 50A = 2500 Watt of energy.
But the VR also sees a 50 Volt drop, and so it soaks
up just as much energy as the load. Which is
a) a waste of energy and b) going to cause it to burst into flames.
But ... what if we twiddled the VR on and off, so it was
at 0 for some of the time and Infinity for some of the time.
When it's at 0 it absorbs no energy. When it's at Infinity
it absorbs no energy. But if the load is on half the time,
the load absorbs half the energy it'd absorb if it was on all the
time, right? And if the load is on a quarter of the time,
it'll absorb a quarter. So by twiddling the VR on and off very
quickly, we're regulating power without wasting any energy.
Now, consider that a MOSFET is a variable resistor which
can be twiddled very quickly between a very high resistance
and a very low resistance ...
-----sharks
--
AUSTIN, TEXAS: Sabrina, 6, was abducted by her non-custodial mother on
April 19, 2002. She has been sighted in Mexico City. Reward Offered.
<http://findsabrina.org/> <http://www.fbi.gov/mostwant/parent/llorens.htm>
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On 2005-08-01, [EMAIL PROTECTED] wrote:
> I recently purchased a 1994 Kawasaki Ninja EX500 that has been converted to
> electric. Here are a few facts and opinions for your project.
Yep, we don't get them here I think but that's the kind of thing I'm
thinking of. It's partly a matter of seeing what chassis turns up.
Thanks for your input! Any idea what it's cost you, or are you
strictly in denial :-) ?
-----sharks
--
Nick 'Sharkey' Moore <[EMAIL PROTECTED]> <http://zoic.org/sharkey/>
"The reasonable man adapts himself to the world. The unreasonable man persists
in trying to adapt the world to himself. It follows that all progress depends
on the unreasonable man." -- George Bernard Shaw
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Hi Peter and All,
--- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> >> Leaning three wheelers are (IMHO) the most
> >> > promissing.
> >
> > If you want narrow, then you are correct.
> Though
> > a lot has to be said for just 2 wheels for real
> eff.
>
> True, but 2wh are not self-stable when stopped. Well
> not generally, I've
But it's quite easy to put your feet down!! Or you
can do outriggers, ect. Many ways to skin that cat.
> seen a harley with such a wide rear wheel that it
> didn't need a kick
> stand, then again it supposedly didn't corner very
> well.
>
> >> I'm currently trying to work out the geometry so
> >> that
> >> > when it leans to the
> >> > left, the front wheel moves over to the right.
> >
> > ?
> > I like turning the handlebars directly just
> like a
> > regular MC give perfect lean and control without
> > complications.
> > Check out the articles on the GM Lean
> Machine
> > online for more info on this type. I'd like to
> > eventually build one of them in EV drive.
>
> IIRC the GM lean machine used hydraulics and a
> computer to control the
No it doesn't.
It uses foot pedals cconnect to the rear wheel
chassis at slow or high speed for upright, tilt and
steering though at any but dead slow you can also
control steering, tilt just with the handle bars. So
you really have 2 control systems.
One could use many methods like a lever, brake,
pedals working on the rear wheel chassis for upright
at dead slow, stopped. Quite easy though I prefer feet
on the ground. KIS
> leaning. I'm trying to come up with a design that
> doesn't use anything
> other than your arm strength.
Many ways as per above.
>
> > The secret is have the side to side pivot as
> low
> > as you can or the rear chassis can flip if higher
> than
> > the axle. Honda did a great job on these.
>
> I'm also trying to use just one axis to both lean
> and steer, rather than
> two, like the Gyro.
The Gyro can use either though with it's small
dia front wheel with little gryo effect you must have
good speed for leaning to work.
>
> The main reason is that I'm trying to minimize size
> and frontal area. My
> current idea has the front wheel between the riders
> legs with the rider in
> a recumbent position. I'd like to avoid having to
> have room for the wheel
> to turn.
But how would you turn at very low speeds? If you
have an angled gooseneck in the middle at higher
speeds it will have high forces in a turn and always
need to fight it from the crown in the road.
While very low height and frontal area gives low
aero drag, I refuse to do it despite the drag savings
as you have too much chance of being road kill! I
believe in enough height, eyes at 48", to see and be
seen as the best way to stay alive.
I could have made the E woody, Freedom EV,
1.5'lower, 30% less frontal area but I'd rather be
safe and get my eff in other ways like good aero
shape.
And I want to keep you around as who would always
tell me I'm wrong? ;-))
HTH's,
Jerry Dycus
>
>
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