EV Digest 4458
Topics covered in this issue include:
1) Re: ADC Torque Curves
by "David" <[EMAIL PROTECTED]>
2) RE: Contactor Voltage Ratings
by "Bill Dennis" <[EMAIL PROTECTED]>
3) Reed Switch Posts
by "Bill Dennis" <[EMAIL PROTECTED]>
4) Re: ComutaCar "rescue"
by [EMAIL PROTECTED]
5) Re: Need Charger Recommendation
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
6) solar battery charge controller - control of the EV charge process?
by Tom Watson <[EMAIL PROTECTED]>
7) Re: Contactor Voltage Ratings
by Lee Hart <[EMAIL PROTECTED]>
8) Re: ComutaCar "rescue"
by "David Roden" <[EMAIL PROTECTED]>
9) Re: ComutaCar "rescue"
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Contactor Voltage Ratings
by Lee Hart <[EMAIL PROTECTED]>
11) Re: Need Charger Recommendation
by "Joe Smalley" <[EMAIL PROTECTED]>
12) Re: ComutaCar "rescue"
by "Mark Hanson" <[EMAIL PROTECTED]>
13) '05 Gasless on Greenwood...what fun!
by John Wayland <[EMAIL PROTECTED]>
14) Re: Reed Switch Posts
by Lee Hart <[EMAIL PROTECTED]>
15) Re: ComutaCar "rescue"
by Lee Hart <[EMAIL PROTECTED]>
16) Acceleration Calculations
by "Don Cameron" <[EMAIL PROTECTED]>
17) on Ebay: 2004 Toyota Prius Wrecked Salvage
by [EMAIL PROTECTED]
18) RE: Acceleration Calculations
by "Philip Marino" <[EMAIL PROTECTED]>
19) Re: reduction gear
by Victor Tikhonov <[EMAIL PROTECTED]>
20) RE: Acceleration Calculations
by "Don Cameron" <[EMAIL PROTECTED]>
--- Begin Message ---
The key here is the behavior of the steel in the motor.
If the steel had constant permeability, and constant losses,
then the torque would be equal to a constant times the product of
the armature and field currents, which are the same in a series motor,
therefore giving a k*I^2 torque for this condition. Decreasing permeability
and increasing magnetization and hysteresis losses change this relationship.
I used to have some ADC motor curves and while the torque does have
a relatively constant exponent over a large operating range, you should
find that it does get larger for very small currents and decreases for very
large
currents. If you don't see this for any values,you may very well have some
"adjusted" curves which have an averaged value to be applied over the
expected useful
operational voltages and currents for ev use.
----- Original Message -----
From: "Brian M. Sutin" <[EMAIL PROTECTED]>
To: "EV List" <[email protected]>
Sent: Thursday, June 23, 2005 10:40 PM
Subject: Re: ADC Torque Curves
>
> The theory that this effect is due to decreasing permiability is testable.
> Dividing the currents at a torque=20 by torque=10 gives a ratio of 1.7.
> Doing the same for T=140/T=70 gives 1.7 also. I therefore conclude that
> the power law holds for all field intensities over which this motor
> operates, and that there are no saturation effects.
>
> The idea that the voltage is not correct will certainly throw off the
> efficiency, but that won't change the torque/current, though.
>
> Any other suggestions?
>
> -------------------------------------------------------------------------
> Someone wrote:
>
> > The change in exponent is due to non-linear behavior in the
> > magnetic properties in the motor's steel. I^2 is for linear material.
> >
> > Less than second power is the result of decreasing permeability in
> > the motor's steel.
> >
> > Also, on some curves ADC included pack resistance in the voltage
> > plot i.e. the voltage is not motor terminal voltage, but the ideal pack
> > voltage.
> >
> > This will through off your projected eff. if they have done this.
>
> Someone else wrote:
>
> > As you have observed, torque is not proportional to I^2, but closer to
> > I^1.3.
> > Magnetic saturation is the main effect that makes torque less than
> > proportional to I^2. If you do curve fitting at various current ranges,
you
> > will find a larger exponent will fit better at lower values of current
and a
> > smaller exponent at higher currents.
>
> Brian wrote:
> >> I found a set of curves on the web for the motor I am using, the ADC
X91-4001.
> >> I have been trying to fit them with a set of smooth curves, but I do
not
> >> understand the results I get. According the my random web searches,
series
> >> motors should have T = k I^2, where T is the torque and I is the
current.
> >> What I get is a very good fit to T = k I^1.268. Does anyone have any
idea
> >> what this is due to, and if there are better equations to explain the
effect?
> >> I muse that it could be a commutation effect of some sort, or leakage
> >> inductance, or somesuch. Or ADC mislabeled a plot for a compound DC
motor...
> >>
> >> Brian
> >> http://www.skewray.com/alfa
>
> --
> Brian M. Sutin, Ph.D. Astronomical Optical Engineering and Software
> Skewray Research/316 W Green St/Claremont CA 91711 USA/(909) 621-3122
>
>
--- End Message ---
--- Begin Message ---
My original question to Lee was about the voltage rating, not the current
rating. So I think he was saying that when the contactors are in series,
each breaks half the voltage, not half the current.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David Chapman
Sent: Sunday, June 26, 2005 7:51 PM
To: [email protected]
Subject: Re: Contactor Voltage Ratings
No ignorance there, wondering the same thing myself. Only way to do assure
simultaneous action is having them mechanically linked, like using all three
contacts on a 3 phase contactor in parallel to increase its rating. What I
am not sure of is how putting contacts in series makes them carry or break
more current. Seems like parallel is the only WTG. I must be missing
something. DC.
----- Original Message -----
From: "Dave" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, June 26, 2005 7:12 PM
Subject: Re: Contactor Voltage Ratings
> Please excuse my ignorance, but wouldn't it be very difficult to open the
2
> contacts at the exact same moment? It seems like one would always open
> before the other, which would carry the entire load, and the second would
> have no load.
>
> David C Wilker Jr.
> USAF (RET)
> "The Bush administration's priorities are "a little bit different now
> and veterans aren't a priority,"
> ----- Original Message -----
> From: "David Chapman" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Sunday, June 26, 2005 7:06 PM
> Subject: Re: Contactor Voltage Ratings
>
>
> >I always thought you would want to >parallel< the contacts so they each
> > carried a portion of the load, effectively increasing the current
rating,
> > that was why I was wondering about the "series" comment. Still
cornfused.
> > Will try to Ascii it below. David C.
> >
> > Series contactors below. Each carries and breaks the entire current.
Seems
> > like there might be slight differances in opening time that could be
> > significant if for instance this was being used for an emergency cutout.
> > Then again, if one welds shut the other >might< clear.
> >
> > ---->O---O<------>O---O<--------
> >
> > Parallel contactors, each carries and breaks half the current? Just
seems
> > to
> > be a better config. Still could be sequencing issues I guess. Could be
> > problem if one welded and the other didnt, current would still flow.
Hmm.
> >
> > |->O---O<-|
> > -----| |------
> > |->O---O<-|
> >
> >
> > ----- Original Message -----
> > From: "Lee Hart" <[EMAIL PROTECTED]>
> > To: <[email protected]>
> > Sent: Sunday, June 26, 2005 10:31 AM
> > Subject: Re: Contactor Voltage Ratings
> >
> >
> >> Dave wrote:
> >> >
> >> > So the two sets of contacts would open at exactly the same instant?
> >>
> >> Yes; precisely. It can be done with a single contactor or switch that
> >> has two sets of contacts. Or, with two separate contactors or switches
> >> that are wired or mechanically connected so they operate at the same
> >> time.
> >> --
> >> Humanity is acquiring all the right technology for all the wrong
> >> reasons.
> >> -- R. Buckminster Fuller
> >> --
> >> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
> >>
> >
>
--- End Message ---
--- Begin Message ---
Lee,
I thought that in the past 6 months or so, you wrote some suggestions
about using a reed switch to make sure the heater fan was running before
allowing the heater core to get power--but I can't find those posts in the
archives.
My EV will be a battery hybrid, with TS cells and BB600s. There will be
separate amp meters for both packs, of course, but I just noticed that
there's a big unused light on the dash called "Turbo"--and I thought it
might be neat when I was showing off the EV (if that day ever comes!) that
the bright "Turbo" lamp would light up when a certain level of amps was
being drawn from the BB600s. I was thinking that your reed switch idea
might be a good solution, but then I couldn't find the posts.
Thanks again.
Bill Dennis
--- End Message ---
--- Begin Message ---
http://api-assembled.com/electric/catalog/ordermenu.html
These people have been supplying me with Citicar and ComutaCar parts for
many years. They always have whatever I need, including brake parts.
Gail
On Sun, 26 Jun 2005, Nick Viera wrote:
> Hi,
>
> So I just got back from Houston, where my uncle has had a ComutaCar
> sitting for years in his garage in a non-working state. Back in the
> early 1980s when he bought the car, he drove it everyday to and from
> work for about 3 years. He began having problems with it (poor range,
> poorer than normal performance, etc) and gave up on it. It had about
> 8400 miles on it when he finally "moth-balled" it in 1986. It has been
> sitting ignored since then.
>
> Well, I've been bugging him for the past two years now to let me come
> help him get it running again. Although it was/is certainly not the
> perfect EV and is limited in many ways, I still think it is an
> interesting little car and hate to see it just sitting there to rot. So
> with my presence in Houston this past weekend we uncovered the little
> ComutaCar in hopes of reviving it.
>
> As you can imagine, the car was very dirty and a little rusty after
> sitting around for 18 years! After cleaning the dust off and evaluating
> the situation, we decided we should test as much of the electrical
> system as possible before buying a new set of batteries. Fortunately,
> the old traction battery pack had been recycled years ago, so the only
> "messy battery" situation we had to face was the old die-hard 12-volt
> accessory battery which was still in the car and had never been
> disconnected. It of course, had died hard and was reading about 3 volts
> when we removed it... yuck.
>
> After cleaning up some of the electrical connections, I connected up a
> 12-volt battery charger to the car and turned the ignition switch. As I
> had hoped, all the 12-volt control circuitry came to life again working
> just fine, and the original contactor controller clunked (rather loudly)
> to life. We also lifted each wheel off the ground one at a time to check
> that none of them had locked up, and that the motor would still spin...
> it did.
>
> So off we went to Republic Battery co. to pickup eight new Trojan T-105s
> for the ComutaCar. As I feared, the new T-105s came with that single,
> large oval cell top for each battery. Because the old pack interconnects
> from the ComutaCar are pretty short and have automotive post lugs that
> are big and square, we were afraid the big battery cell covers would
> interfere with the interconnects. The battery company was sympathetic to
> our problem and was able to dig up 24 individual cell covers for us
> instead. Once the batteries were back at the garage, we cleaned up all
> of the old pack interconnects and figured out which ones fit where.
>
> We installed and hooked up four batteries in the rear of the ComutaCar
> so we could test if it would move under its own power. I turned the car
> on, flipped the little toggle switch on the dash to reverse, and slowly
> pressed the accelerator. The contactor controller engaged in its first
> position, and for the first time since 1986 the ComutaCar came to life
> and moved under it's own power again!... and that's when I discovered
> that the brakes didn't work!!!
>
> I really should learn to make a list of things to check _*before*_
> applying power to a traction motor, but I forget things when I get
> excited...
>
> So, the bottom line is that the car runs but has no foot brakes (just a
> minor inconvenience, LOL). Although there are (I'm sure) many little
> things that still need to be done to the car before it is completely
> ready for driving, the brakes are the main hold-up. It appears the
> problem is that the piston in the brake master cylinder is frozen up.
>
> So here's a question to end my long-winded story: where do you find
> brake components for these ComutaCars? For example, is the master
> cylinder a pretty standard part or something that is going to be hard to
> find a replacement for? How about wheel cylinders?
>
> P.S. I'll have some pictures of this project up soon...
>
> Thanks for any info,
>
> --
> -Nick
> http://Go.DriveEV.com/
> 1988 Jeep Cherokee 4x4 EV
> ---------------------------
>
>
--- End Message ---
--- Begin Message ---
This charger and my motorcycle. 4 optimas. About 20 minutes to 80% charge
or would that take a PFC 50? Seeing this new fast charging technology
promising 15 to 20 minutes to 80% (well not new just out there) what would
it take to get that performance in a big pack using PFC technology? 440
three phase. 10k of charger? I'd sure like to know. Lawrence Rhodes....
PFC20B
$1800 list.
5 days lead time from order.
12 to 450 volts output
110VAC to 240 VAC input. 30 amps output with 240 VAC and a 20 amp feed.
Or just check the Manzanitamicro.com Website
Rich Rudman
Manzanita Micro
--- End Message ---
--- Begin Message ---
Hi all
I was digging around for a solar battery charge
controller for my boat the last few days and I started
realizing how well something like this would work in
an EV...
Does anyone use something like this?
this one(Xantrex) has a 3 stage Pulse Width Modulation
charge controller. The display (Link 2000) offers
Digital display of volts, amps, amp-hours consumed and
time remaining until full discharge
what do you think?
Tom
-----snip-----
web links:
c-40
http://www.affordable-solar.com/86.html
Link 2000
http://www.affordable-solar.com/608.html
index
http://www.affordable-solar.com/ind.html
Xantrex/Trace C40: 40A, 12/24/48V 3-stage Charge
Controller
Shown with optional CM LCD Digital Display must order
separately(see below)
A Controller for Virtually any DC Charging Source. The
C40 is a fully solid state, microprocessor-driven
controllers that is UL and cUL listed. The C Series,
Xantrex/Trace C40 charge controller may be configured
for 12, 24, or 48 VDC operation. It can be used as a
battery charge, DC load control or DC diversion
operation and comes with a standard multi-color charge
status LED.
Standard Features
Silent Microprocessor Control
All C Series controllers have a powerful
microprocessor at their core which increases system
performance and maximizes battery life. They are fully
solid state and operate silently.
PWM Charge Performance
C Series controllers all use Pulse Width Modulation
(PWM) charging profiles which are designed to provide
a full charge to your battery while, at the same time,
minimize gassing which can shorten battery life.
3-Stage Battery Charging
All C Series controllers automatically initiate a
3-stage battery charging cycle. Bulk, Absorption, and
Float modes are used to ensure that voltage and
current settings accurately match the batteries'
actual state of charge. This means fast-as-possible
charging and extended battery life. An auto equalize
mode can be easily switched off when the controller is
used with sealed batteries. C Series controllers are
factory set for solar PV battery charging operation.
Field Adjustable
There are a number of field configurable, user
adjustments for C Series controllers. The C40 may be
configured for 12, 24 or 48 volt systems. Bulk and
Float voltage set points are user adjustable which
allows use with a wide variety of battery technologies
including; flooded lead acid, gel, and absorbed glass
mat. In addition, there are manually selectable
settings for Nicad batteries.
DC Load Controller Mode
When used as a load controller, the C Series will
automatically turn a DC load on or off at
predetermined battery voltage settings. Both LVD (low
voltage disconnect) and LVR (low voltage reconnect)
set points are user adjustable.
DC Diversion Mode
In this mode, all power, which is not used to maintain
a full charge on the batteries, is diverted to a load
dump such as water or space heaters. Diversion mode is
used to regulate microhydro and wind turbine systems
which need a constant load.
LED Status Indicator
A simple to read, multi-color LED indicates operating
status and is standard on all C Series controllers.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Dave <[EMAIL PROTECTED]> wrote:
> Please excuse my ignorance, but wouldn't it be very difficult to open the 2
> contacts at the exact same moment? It seems like one would always open
> before the other, which would carry the entire load, and the second would
> have no load.
That is correct; being mechanical devices, they never open at exactly the same
moment. But as long as they open at *almost* the same time, that is good enough.
When switching 60hz AC, there is a zero-crossing every 8 msec. Thus an arc
won't last any longer than 8 msec. AC contacts are therefore built knowing that
this is the longest time they need to survive an arc.
When switching DC, the arc will continue indefinitely; until the total contact
spacing is enough to break the arc. Putting two contacts in series doubles the
total distance; therefore it doubles the voltage rating. As long as the two
contacts open within 8 msec of each other, the arcing at the first one to open
is no worse than it would have been if switching a 60hz AC load.
--
Lee Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
On 26 Jun 2005 at 21:25, Nick Viera wrote:
> So here's a question to end my long-winded story: where do you find
> brake components for these ComutaCars? For example, is the master
> cylinder a pretty standard part or something that is going to be hard to find
> a replacement for? How about wheel cylinders?
I found wheel cylinders for mine at a local Cushman scooter workshop. The
counterman kindly matched mine up with stock, but didn't tell me which
Cushman model they were to suit. I don't recall the cost, but seem to
remember thinking at the time that it was pretty steep.
According to the auto parts jobber who matched it up for me, the master
cylinder is the same as the one used in a 1967 Rambler Ambassador with drum
brakes.
This was all in 1989; I don't know how readily available these parts are
today.
BTW, the problem is that when these cars are stored, moisture gets into the
brake systems and plays hob with the metal parts.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
Nick Viera <[EMAIL PROTECTED]> wrote:
> So I just got back from Houston, where my uncle has had a ComutaCar
> sitting for years in his garage in a non-working state....
> where do you find brake components for these ComutaCars?
I drove a ComutaVan for many years; it is quite similar.
The brakes are standard trailer brake parts. Kind of a poor choice; but cheap
and easy to get. Any place selling trailer parts will have them. As I recall,
the master cylinder was from a 1979 Chevrolet Chevette.
NuKar Engineering used to have parts for the CitiCars/ComutaCars/ComutaVans,
but last time I tried to contact them there was no response; they may have
changed names or gone out of business.
These vehicles are very rude-and-crude, but extremely simple to fix. Quality
control at the factory was nonexistent. Mine was full of assembly errors and
quick-fix engineering. You can make BIG improvements in reliability just by
checking and fixing things right. Do *not* count on the stock way it was
assembled being right!
--
Lee Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
David Chapman <[EMAIL PROTECTED]> wrote:
> I always thought you would want to >parallel< the contacts so they each
> carried a portion of the load, effectively increasing the current rating
Correct.
You wire contacts in series to increase their voltage rating.
You parallel contacts to increase their current rating. However, this doesn't
work very well in practice. A closed contact has a very low and highly variable
resistance. Thus, you can't predict exactly how the current will divide between
them. The one with the lower resistance hogs all the current, so instead of the
current dividing 50/50 you might get 90/10.
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
It takes about 80 amps to charge an Optima to 80% in 20 minutes. They taper
down to 15 amps at 20 minutes.
You will need at least a PFC-50B to do it.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Lawrence Rhodes" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, June 26, 2005 10:04 PM
Subject: Re: Need Charger Recommendation
> This charger and my motorcycle. 4 optimas. About 20 minutes to 80%
charge
> or would that take a PFC 50? Seeing this new fast charging technology
> promising 15 to 20 minutes to 80% (well not new just out there) what would
> it take to get that performance in a big pack using PFC technology? 440
> three phase. 10k of charger? I'd sure like to know. Lawrence Rhodes....
>
>
> > PFC20B
> > $1800 list.
> > 5 days lead time from order.
> >
> > 12 to 450 volts output
> > 110VAC to 240 VAC input. 30 amps output with 240 VAC and a 20 amp feed.
> >
> > Or just check the Manzanitamicro.com Website
> >
> > Rich Rudman
> > Manzanita Micro
> >
>
--- End Message ---
--- Begin Message ---
Bob Beaumont told me to put the batteries *back* in the middle (was on the
original CitiCar) and get them out of the bumpers for bettery handling. Jim
Tervort put them in the bumpers for crash test requirements. My handling
sucked (was unsafe) with the batteries in the bumpers when I had one in the
80's.
Mark
----- Original Message -----
From: "Nick Viera" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, June 26, 2005 10:25 PM
Subject: ComutaCar "rescue"
> Hi,
>
> So I just got back from Houston, where my uncle has had a ComutaCar
> sitting for years in his garage in a non-working state. Back in the
> early 1980s when he bought the car, he drove it everyday to and from
> work for about 3 years. He began having problems with it (poor range,
> poorer than normal performance, etc) and gave up on it. It had about
> 8400 miles on it when he finally "moth-balled" it in 1986. It has been
> sitting ignored since then.
>
> Well, I've been bugging him for the past two years now to let me come
> help him get it running again. Although it was/is certainly not the
> perfect EV and is limited in many ways, I still think it is an
> interesting little car and hate to see it just sitting there to rot. So
> with my presence in Houston this past weekend we uncovered the little
> ComutaCar in hopes of reviving it.
>
> As you can imagine, the car was very dirty and a little rusty after
> sitting around for 18 years! After cleaning the dust off and evaluating
> the situation, we decided we should test as much of the electrical
> system as possible before buying a new set of batteries. Fortunately,
> the old traction battery pack had been recycled years ago, so the only
> "messy battery" situation we had to face was the old die-hard 12-volt
> accessory battery which was still in the car and had never been
> disconnected. It of course, had died hard and was reading about 3 volts
> when we removed it... yuck.
>
> After cleaning up some of the electrical connections, I connected up a
> 12-volt battery charger to the car and turned the ignition switch. As I
> had hoped, all the 12-volt control circuitry came to life again working
> just fine, and the original contactor controller clunked (rather loudly)
> to life. We also lifted each wheel off the ground one at a time to check
> that none of them had locked up, and that the motor would still spin...
> it did.
>
> So off we went to Republic Battery co. to pickup eight new Trojan T-105s
> for the ComutaCar. As I feared, the new T-105s came with that single,
> large oval cell top for each battery. Because the old pack interconnects
> from the ComutaCar are pretty short and have automotive post lugs that
> are big and square, we were afraid the big battery cell covers would
> interfere with the interconnects. The battery company was sympathetic to
> our problem and was able to dig up 24 individual cell covers for us
> instead. Once the batteries were back at the garage, we cleaned up all
> of the old pack interconnects and figured out which ones fit where.
>
> We installed and hooked up four batteries in the rear of the ComutaCar
> so we could test if it would move under its own power. I turned the car
> on, flipped the little toggle switch on the dash to reverse, and slowly
> pressed the accelerator. The contactor controller engaged in its first
> position, and for the first time since 1986 the ComutaCar came to life
> and moved under it's own power again!... and that's when I discovered
> that the brakes didn't work!!!
>
> I really should learn to make a list of things to check _*before*_
> applying power to a traction motor, but I forget things when I get
> excited...
>
> So, the bottom line is that the car runs but has no foot brakes (just a
> minor inconvenience, LOL). Although there are (I'm sure) many little
> things that still need to be done to the car before it is completely
> ready for driving, the brakes are the main hold-up. It appears the
> problem is that the piston in the brake master cylinder is frozen up.
>
> So here's a question to end my long-winded story: where do you find
> brake components for these ComutaCars? For example, is the master
> cylinder a pretty standard part or something that is going to be hard to
> find a replacement for? How about wheel cylinders?
>
> P.S. I'll have some pictures of this project up soon...
>
> Thanks for any info,
>
> --
> -Nick
> http://Go.DriveEV.com/
> 1988 Jeep Cherokee 4x4 EV
> ---------------------------
>
--- End Message ---
--- Begin Message ---
Hello to All,
It's early Monday morning, still trying to get the cobwebs out with my morning
coffee and
female cat still giving me a hard time for being away from her all weekend.
This year's classic hotrod show in Seattle was even better than last year's
show, and
including my EV entry, I believe there were 12 hybrids and electrics on
display. Ryan
Fulcher returned in his Insight, and this year his hatch area was 'really' the
audio-video
epicenter. He had a high definition, super clear and bright BIG flat screen
display that
also sported clean and loud audio, and with videos of Rod Wilde's Maniac Mazda
smoking
Viper V10s, White Zombie running its front wheel lofting 12.99 against that
300+ hp
Mustang, and other NEDRA footage, there was a constant crowd of show goers
absolutely
stunned to see EVs doing such things...way cool, way effective!
Dave Cloud showed up with a very interesting all white machine, something that
started out
as an economy sedan, I think a Metro? Dave had chopped its top, added a custom
fastback sloping rear end, and had gutted the thing down to 1000 lbs. In the
rear, clearly
in view (I loved that part) through the windowless hatch (Lexan to be added as
he gets it
done), were count 'em, three of the planned eight E-Tech motors, all with
their own chain
drive to a fixed rear axle. I scanned the the drives' pulley sizes and made a
quick guess
at 3:50 ratio, which according to a surprised Dave Cloud, turned out to be
right on the
money. Dave's planning on running the car in the M/C category, and if what I
saw is any
indication, look for some new records to be set....using low voltage and wet
cell
batteries! Was it pretty?...no. Was it finished yet?...no. Was it
impressive?...absoulutely! Was it all Dave Cloud?...yes, classic Dave Cloud,
but this
time, he's running what will be recognized as a car. Sorry, I can't call this
one a
cockroach. To Dave's shock, I really found his latest creation, very cool.
Another cool EV was Kent Bakke's red VW Beetle with its big 'ol 9 inch ADC
hanging in the
back. I talked him into going against the grain and nosing his EV in (everyone
else's
machine was backed in), so that show goers would stop and say..."Whoa!" upon
seeing an
unexpected big electric motor instead of the usual air cooled VW flat four...it
worked!
All day long, that's exactly what happened, and I'd venture to say, his Beetle
drew the
biggest crowd, this, over Dave's wild looking machine, over the outrageous Gone
Postal,
and over Blue Meanie.
Speaking of Gone Postal, kudos to Rod Wilde, Tom True, and Madman Rudman for
the huge
effort to get this popular EV to the show...thanks guys. GP was staged directly
in front
of Cheryl and I as we made the EV convoy as we trekked from our meeting place
in a big
parking area at a local park to the Greenwood location, and what a view we
had! Even
knowing the machine intimately, it's still very intimidating to see it rolling
down the
street, let alone having it right in front of you....twin 8 inch motors hanging
down from
behind, not too unlike a bull strutting his stuff...use your imagination,
folks. With Tom
sporting his big straw hat in the left, and this crazed Madman at the right
hand drive
wheel, arms flailing as he never seemed to shut up....the combo of an
over-the-top ride
filled with these two characters made for total entertainment from behind.
Sorry, no one
noticed the two of us in our shiny Datsun....all eyes were on GP as we convoyed
to the
show.
Other EVs included Andrew Schwarz's red Mazda Miata, a cool convertible
conversion that
showed how an EV can be a fun open top way to get back and forth, John
Marshall's in your
face yellow VW pickup conversion (I love the style of the Rabbit truck), Gary
Longley's
Father Time created intense blue legend race car (another jaw dropper for show
goers),
Jamie Marshall's yellow Sparrow...who doesn't stop and inquire about one of
these?....Mark
Jacobson's Dynasty 'IT' factory NEV, Green Car Co's Greg Rock brought a Smart
car, and
last but never the least, Father Time arrived riding his latest motorcycle drag
bike, son
of FrankenBike....a 12V motor jammed with 72 volts stuck to the ground via a
monster rear
drag slick. There were three Insight hybrids, two red, one silver.
As usual, there were hundreds of gorgeous street rods, from a matched pair of
impeccable
hot orange colored Boss Mustangs ( (a Boss 302 and a Boss 429), to a pristinely
built
purple 36 Chev street rod, to Corvettes, to Ramblers, to Mini Coopers, to Datsun
roadsters, to a metallic gold SS 396 El Camino, to a polished aluminum AC
Cobra, to
Camaros, to tricked out pickups, to a euro police car, to well, you get the
idea...hundreds of exiting things to look at.....but, it was the EVs that
seemed to have
the constant crowd.
A big thank you has to go out to SEVA's prez, Steve Lough. Yes, I know others
worked hard
on this show too, but in my opinion, it's Steve who drives this club.
After the show, we had the tradition of hanging out at the Lough's for a fun
backyard
barbecue.
That's it for me. My wife and I had a great time again, thanks everyone.
See Ya.......John Wayland
--- End Message ---
--- Begin Message ---
Bill Dennis wrote:
> ...the bright "Turbo" lamp would light up when a certain level of
> amps was being drawn from the BB600s. I was thinking that your
> reed switch idea might be a good solution, but then I couldn't
> find the posts.
Reed switches are pretty easy to use. Basically, they are a glass tube
with a wire coming out each end. When a lengthwise magnetic field is
applied, the contact closes. Remove the field, and it opens.
The field can come from a permanent magnet, or an electromagnet. If an
electromagnet, the coil is wound around the reed switch (usually on some
kind of plastic form to protect the fragile glass).
Reed switches are rated in ampere-turns. If the rating is 100
ampere-turns, it means you need a 100-turn coil carrying 1 amp to pull
it in. For 100 amps, a single turn is all it takes. For 200 amps, just
placing the reed switch at right angles to a straight section of the
wire carrying the 200 amps will work.
Reed switches are kind of like semiconductors in that they have definite
limits on the voltage and current they can switch. Exceed their ratings,
and they fail very quickly! To switch a dash light that normally draws
100ma, you'll need a reed switch good for at least 1 amp (because the
"cold" inrush current of a 100ma light bulb is about 1 amp).
--
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
--- End Message ---
--- Begin Message ---
Mark Hanson wrote:
> Bob Beaumont told me to put the batteries *back* in the middle
> (was on the original CitiCar) and get them out of the bumpers for
> better handling. Jim Tervort put them in the bumpers for crash
> test requirements. My handling sucked (was unsafe) with the
> batteries in the bumpers when I had one in the 80's.
Yes; it's a trade-off. Typical of Citicar engineering, they went from
one extreme to the other. All in the center, or all in the ends. The
best compromise would be to distribute them more equally.
--
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
--- End Message ---
--- Begin Message ---
I am revisiting my calculations for acceleration and power and I seem to
find they are overly optimistic. I have compared them to other spreadsheets
and estimations and the results are wrong. If anyone else is doing
something similar, do you mind taking a look?
The approach is to base it on time:
1. Start with time t0,
2. determine velocity based on RPM,
3. calc force available to accelerate from motor graph,
4. adjust for aero drag and rolling resistance,
5. calculate max acceleration
6. then determine finish velocity for time increment.
7. go back to step 2, and use this velocity for the next time t0+0.5sec.
Here is the detail:
Given:
The car has fixed gearing (no transmission) overall gear ratio (R)
the tire diameter
the frontal area of the car (A)
the aerodynamic drag (Cd)
the drive train efficiency (Cdt)
tire rolling resistance (Crr)
vehicle mass (m)
Starting with times from 0 seconds to 90 seconds in 0.5 second increments
1. At time t, use the previous time's calculated final velocity V0
2. Determine the RPM of the motor based on the velocity, gear ratio and
wheel diameter: RPM = (V0 * OverallGearRatio)/(pi * WheelDiameter) * 60
3. Using the motor torque graph, determine the motor torque at the specified
RPM
4. Determine the force of the motor from the torque: F = (Torque *
OverallGearRatio) / (WheelDiameter/2)
5. Correct the force for drive efficiency: F(corrected) = F *
DriveTrainEfficiency
6. Force to overcome rolling resistance F(roll) = VehicleMass * 9.8
(gravitational acceleration) * TireRollingResistanceCoeff
7. Force to overcome air resistance at velolcity V0 F(air) = 1/2 * DragCoeff
* FrontalAreaOfCar * AirDensity * V0^2
8 Total force available for acceleration: F(total) = F(corrected) - F(roll)
- F(air)
9. Acceleration: a = F(total) / VehicleMass
10. Final velocity for time period : V1 = a * t + V0
11. Go back to step one for next time period, using V1 as the next time's V0
Since I use metric no real unit conversions were required. I have tried to
keep units out of this wherever possible.
If anyplace has an error, I think it is around step 9, 10 or 11. All the
other calculations appear to be OK.
thanks
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
--- End Message ---
--- Begin Message ---
I just found this on Ebay, thought someone in Califoria might be interested.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7983492807&category=6763
--------------
"This is a lightly wrecked 2004 Prius with 15,372 miles. "
Current bid: US $10.50
Time left: 4 days 10 hours
Item location: Carmichael, California
---------------
Michael Shipway
Maryland, USA
--- End Message ---
--- Begin Message ---
Hi, Don
Everything looks fine to me. In fact, I put together a very similar model
(also using a spreadsheet) when I was deciding what motor/batts/controller I
would use for my Echo.
The only thing I did different (and this would be a very small effect) was
to add a brake/bearing drag term.
Are you seeing a difference by comparing this model with real data, or other
peoples' models? How much difference are you seeing? ( a few percent ? a
factor of 10?) How consistent are the other peoples' models to each other?
The places I would look for errors ( or, differences compared to other
models) would be :
1. The torque calculation - can you give us more detail of how you calculate
torque? Are you assuming a constant voltage available at the motor
terminals, or are you limiting the current. etc ??
2. A typo in the spread sheet calculations ( I do this a LOT) where the
wrong entry is used in a calculation. One way to check this would be to do
the entire calcuation for one time step by hand, (example - start at the
spread sheet's predicted speed at 2 seconds) , and calculate by hand the
predicted speed at the next time step and see how that compares to the
spread sheet result. That would also check your calculations for the last
three steps, although they look pretty straightforward, and your equations
are certainly correct.
Good luck, and keep us posted on this
Phil
From: "Don Cameron" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: <[email protected]>
Subject: Acceleration Calculations
Date: Mon, 27 Jun 2005 09:08:06 -0700
I am revisiting my calculations for acceleration and power and I seem to
find they are overly optimistic. I have compared them to other
spreadsheets
and estimations and the results are wrong. If anyone else is doing
something similar, do you mind taking a look?
The approach is to base it on time:
1. Start with time t0,
2. determine velocity based on RPM,
3. calc force available to accelerate from motor graph,
4. adjust for aero drag and rolling resistance,
5. calculate max acceleration
6. then determine finish velocity for time increment.
7. go back to step 2, and use this velocity for the next time t0+0.5sec.
Here is the detail:
Given:
The car has fixed gearing (no transmission) overall gear ratio (R)
the tire diameter
the frontal area of the car (A)
the aerodynamic drag (Cd)
the drive train efficiency (Cdt)
tire rolling resistance (Crr)
vehicle mass (m)
Starting with times from 0 seconds to 90 seconds in 0.5 second increments
1. At time t, use the previous time's calculated final velocity V0
2. Determine the RPM of the motor based on the velocity, gear ratio and
wheel diameter: RPM = (V0 * OverallGearRatio)/(pi * WheelDiameter) * 60
3. Using the motor torque graph, determine the motor torque at the
specified
RPM
4. Determine the force of the motor from the torque: F = (Torque *
OverallGearRatio) / (WheelDiameter/2)
5. Correct the force for drive efficiency: F(corrected) = F *
DriveTrainEfficiency
6. Force to overcome rolling resistance F(roll) = VehicleMass * 9.8
(gravitational acceleration) * TireRollingResistanceCoeff
7. Force to overcome air resistance at velolcity V0 F(air) = 1/2 *
DragCoeff
* FrontalAreaOfCar * AirDensity * V0^2
8 Total force available for acceleration: F(total) = F(corrected) -
F(roll)
- F(air)
9. Acceleration: a = F(total) / VehicleMass
10. Final velocity for time period : V1 = a * t + V0
11. Go back to step one for next time period, using V1 as the next time's
V0
Since I use metric no real unit conversions were required. I have tried to
keep units out of this wherever possible.
If anyplace has an error, I think it is around step 9, 10 or 11. All the
other calculations appear to be OK.
thanks
Don
_________________________________________________________________
Dont just search. Find. Check out the new MSN Search!
http://search.msn.click-url.com/go/onm00200636ave/direct/01/
--- End Message ---
--- Begin Message ---
I may be able to get one for you, but can't promise.
Is 2:1 for one gear pair ratio and 1.75:1 the second pair
being your firm spec?
Don Cameron wrote:
Using AC drives one does not really need a transmission, as long as the
gearing is right. With a typical rear differential, the ratio is usually
from 3.5 to 4.4. However if a motor were to directly drive a popular 4.11
rear end using a common 23" tire diameter, the car would be sacrificing low
end acceleration for top end speed. (e.g. at 8000 RPM, the car would be
going 133mph) - this is a little too fast for typical street use. Even
hunting around for aftermarket ring and pinions all I can find is a 5.1:1
I have read various threads about two speed transmissions and such, as well
as I have seen the 8.3:1 reduction gear/differentials about, but what I am
looking for is a simple reduction gear box.
Has anyone seen an "off the shelf" reduction gear box in that I can get a
selection of gears (e.g. 2:1 or 1.75:1) that hopefully can handle 150hp???
thanks
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Phil, thanks for the quick reply.
I use a couple of web site's brute force calculators. I think they
simplistically do it by cube root of power and weight.
I also have a spread sheet from an associate that was used for other
projects.
In both cases, they estimate a 18 sec 1/4 mile (400m) and a 6 second 0-60
(0-90kmh). Mine has a 12.5 second 1/4 mile and a 3 second 0-60 (seems
pretty darn quick, but it is a 1500lb race car with a 220Nm torque motor).
I calculated torque by entering the actual chart for the motor in a spread
sheet in 300 rpm. Then I use a linear interpretation to calculate a value
between the points. I validated the numbers by comparing the charts between
the real motor and the spreadsheet.
I will go through it calculation by calculation and look for typos...
thanks
P.S. Any chance you can send me your worksheet?
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 Philip Marino
Sent: June 27, 2005 9:44 AM
To: [email protected]
Subject: RE: Acceleration Calculations
Hi, Don
Everything looks fine to me. In fact, I put together a very similar model
(also using a spreadsheet) when I was deciding what motor/batts/controller I
would use for my Echo.
The only thing I did different (and this would be a very small effect) was
to add a brake/bearing drag term.
Are you seeing a difference by comparing this model with real data, or other
peoples' models? How much difference are you seeing? ( a few percent ? a
factor of 10?) How consistent are the other peoples' models to each other?
The places I would look for errors ( or, differences compared to other
models) would be :
1. The torque calculation - can you give us more detail of how you calculate
torque? Are you assuming a constant voltage available at the motor
terminals, or are you limiting the current. etc ??
2. A typo in the spread sheet calculations ( I do this a LOT) where the
wrong entry is used in a calculation. One way to check this would be to do
the entire calcuation for one time step by hand, (example - start at the
spread sheet's predicted speed at 2 seconds) , and calculate by hand the
predicted speed at the next time step and see how that compares to the
spread sheet result. That would also check your calculations for the last
three steps, although they look pretty straightforward, and your equations
are certainly correct.
Good luck, and keep us posted on this
Phil
>From: "Don Cameron" <[EMAIL PROTECTED]>
>Reply-To: [email protected]
>To: <[email protected]>
>Subject: Acceleration Calculations
>Date: Mon, 27 Jun 2005 09:08:06 -0700
>
>I am revisiting my calculations for acceleration and power and I seem to
>find they are overly optimistic. I have compared them to other
>spreadsheets
>and estimations and the results are wrong. If anyone else is doing
>something similar, do you mind taking a look?
>
>
>
>The approach is to base it on time:
>1. Start with time t0,
>2. determine velocity based on RPM,
>3. calc force available to accelerate from motor graph,
>4. adjust for aero drag and rolling resistance,
>5. calculate max acceleration
>6. then determine finish velocity for time increment.
>7. go back to step 2, and use this velocity for the next time t0+0.5sec.
>
>
>Here is the detail:
>
>Given:
> The car has fixed gearing (no transmission) overall gear ratio (R)
> the tire diameter
> the frontal area of the car (A)
> the aerodynamic drag (Cd)
> the drive train efficiency (Cdt)
> tire rolling resistance (Crr)
> vehicle mass (m)
>
>
>Starting with times from 0 seconds to 90 seconds in 0.5 second increments
>
>1. At time t, use the previous time's calculated final velocity V0
>2. Determine the RPM of the motor based on the velocity, gear ratio and
>wheel diameter: RPM = (V0 * OverallGearRatio)/(pi * WheelDiameter) * 60
>3. Using the motor torque graph, determine the motor torque at the
>specified
>RPM
>4. Determine the force of the motor from the torque: F = (Torque *
>OverallGearRatio) / (WheelDiameter/2)
>5. Correct the force for drive efficiency: F(corrected) = F *
>DriveTrainEfficiency
>6. Force to overcome rolling resistance F(roll) = VehicleMass * 9.8
>(gravitational acceleration) * TireRollingResistanceCoeff
>7. Force to overcome air resistance at velolcity V0 F(air) = 1/2 *
>DragCoeff
>* FrontalAreaOfCar * AirDensity * V0^2
>8 Total force available for acceleration: F(total) = F(corrected) -
>F(roll)
>- F(air)
>9. Acceleration: a = F(total) / VehicleMass
>10. Final velocity for time period : V1 = a * t + V0
>11. Go back to step one for next time period, using V1 as the next time's
>V0
>
>Since I use metric no real unit conversions were required. I have tried to
>keep units out of this wherever possible.
>
>If anyplace has an error, I think it is around step 9, 10 or 11. All the
>other calculations appear to be OK.
>
>thanks
>
>Don
>
>
_________________________________________________________________
Don't just search. Find. Check out the new MSN Search!
http://search.msn.click-url.com/go/onm00200636ave/direct/01/
--- End Message ---
