EV Digest 5184
Topics covered in this issue include:
1) Re: Tire smoke.
by Rush <[EMAIL PROTECTED]>
2) RE: Why not more AC conversions vs DC conversions...
by "Andre' Blanchard" <[EMAIL PROTECTED]>
3) Re: Driving 45 mph on the freeway?
by Meta Bus <[EMAIL PROTECTED]>
4) RE: Tire smoke.
by "Pestka, Dennis J" <[EMAIL PROTECTED]>
5) Braking energy to heat cabin?
by Mike Ellis <[EMAIL PROTECTED]>
6) Re: Driving 45 mph on the freeway?
by David Dymaxion <[EMAIL PROTECTED]>
7) Re: Why not more AC conversions vs DC conversions...
by Electro Automotive <[EMAIL PROTECTED]>
8) Re: Driving 45 mph on the freeway?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
9) gimme time! was Why not more AC conversions vs DC conversions...
by Matt Milliron <[EMAIL PROTECTED]>
10) Re: Driving 45 mph on the freeway?
by "Bob Rice" <[EMAIL PROTECTED]>
11) Re: Why not more AC conversions vs DC conversions...
by Neon John <[EMAIL PROTECTED]>
12) Re: Why not more AC conversions vs DC conversions...
by Neon John <[EMAIL PROTECTED]>
13) Re: Why not more AC conversions vs DC conversions...
by Christopher Zach <[EMAIL PROTECTED]>
14) Re: Why not more AC conversions vs DC conversions...
by "David Roden" <[EMAIL PROTECTED]>
15) Re: gimme time! was Why not more AC conversions vs DC conversions...
by Matt Milliron <[EMAIL PROTECTED]>
16) Re: Driving 45 mph on the freeway?
by "David Roden" <[EMAIL PROTECTED]>
17) Re: Why not more AC conversions vs DC conversions...
by "David Roden" <[EMAIL PROTECTED]>
18) Re: Lithiums in Parallel (was: RE: Jesse James & Monster Garage Go
Lithium!!!)
by Lee Hart <[EMAIL PROTECTED]>
19) Re: Volumetric energy density of Lithium battery
by "Peter VanDerWal" <[EMAIL PROTECTED]>
20) Re: Why not more AC conversions vs DC conversions...
by "Rich Rudman" <[EMAIL PROTECTED]>
21) Re: Jesse James & Monster Garage Go Lithium!!!
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Neat!
Looks like your right tire is smoking more than the left, traction?
Tell me about your batteries - how many? where are they, how many do you fit
between the frame rails? Looks like you might have space between the top of the
frame and the bottom of the new bed? Does the bed tilt?
Thanks
Rush
Tucson AZ
www.ironandwood.org
----- Original Message -----
From: "STEVE CLUNN" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, February 17, 2006 7:44 AM
Subject: Tire smoke.
>I took my pick up with the 11" net gain motor and 2k zilla to a SCCA (
> sports car club of america) event last week end which has a auto cross once
> a month in my town . There where about 50 cars there ( all gas and all fast)
> . They set up a coruse with cones on this big paved driving range that the
> collage uses with the police to teach driving . The course is set up with
> lots of truns along with a few straight a ways . A great bunch of people ,
> but I could tell that they where thinking , " an electric truck , is this
> guy nuts " . The girl who was checking me in , " electric , neat , is like
> a golf cart ?" . I didn't say anything about how fast it went , just that I
> wanted to see what it would do and there where some people there with their
> plane cars , also seeing what their daily dirve would do. This is a 2 day
> event with the first day as a practice . Auto cross is much more a driver
> skill , and car handling thing than a power thing and a corvette can get
> beat by a mini copper easy. We where to each get 4 runs at the course ,
> after each run we would get back in line for the next run. The 50 cars where
> in two groups and my group would run after lunch on the first day. The event
> was about 2 miles for my house , I had used 2 ah to get there . Would I even
> be able to do 4 runs on a charge? Any one that wanted an instructer to
> drive with them or drive while they sat in the passanger seat could , and I
> took this oppstion . I had two reasons , one I knew that after the ride the
> instructer would be telling his friends about it and 2 so I could learn a
> little about driving . There are some momunits in life , where you get to
> supprize sombody with somthing so different , and seeing them see that
> reality was not what they though. " electicrec , whow , do I shift it like a
> car ?" " no just leave it in 4th " " 4th , will it take off in 4th ?" "
> yep" . Well as I had not done any tire spinning and up to this point as we
> pulled up to the starting line nobody knew what what was on the other end of
> that go peddle. I got to see the driving instructer deal with a major change
> in his reality. Lots of whow's as he soon found he had more power than the
> wheels could put to the ground. He got very busy driving , not alot of
> instructing now just whow, and ooo , . less that a minunite later we where
> done , and all of a sudden people are looking at my electric pick up in a
> different light , lots of thumbs up and now comes the questions. When I get
> my trun again the anowser has a lot to say about the electric truck ,
> talking about it being in 4 th gear , and the low end troque. The e meter
> was the only meter I had time to look at , and I only got to see that
> becuse I looked at it before the run and after , the run took 2.5 ah , which
> is about what the BBB 1/4 mile took so I'm thinking I'm good for the 4 runs.
> I had a blast driving the next 3 runs , last run , on the last stright a way
> , I felt the voltage sage ( no I never saw any meter while driving , this
> must be a trick that the pro's know how to do) and knew this was the last
> run. There was still plenty for regular driving but after 10 ah is used ,
> the truck is not so peppe . The next event is March 11 and 12 , more info
> at www.cfrsolo2.com , There is also a car show on March 11 that I go to so
> I may not go on the 11 , ( so many events to go to ) but on the 12th I'll be
> there for sure , any other EV'er that can make it let me know . I got a
> shot of some tire smoke and net gain put in on their site it a 1 minunit
> move , it takes some time to load.
> http://www.go-ev.com/images/Steve_Clunn.mov.
>
> Steve Clunn
>
>
>
--- End Message ---
--- Begin Message ---
At 05:51 PM 2/16/2006, you wrote:
Andre said > " No reason they could not be built in EV sizes with
RPM's in the 10,000 to 12,000 range.
Actually there may be a good reason why not, Jim can aswer this better.
The force excerted on the comm bars goes up with square of the comm
diameter and the number of bars and size of these bars are in conflict
for high rpm and high amps. So while it is easy to build a small
diameter high rpm commutated motor, it is impractical to build a large
diameter high rpm motor.
I think that we have gone backwards in recent years. The old steel comms
were much stronger but have all but been replaced with "molded mica
comms" , It doesn't seem to take much to blow them up :-(
One other thing is that the brush surface speed goes up and there is a
limit where the film won't form and the brushes grind to dust.
I have thought of other ways of doing a commutator for high rpm the
torpedo drone motors are a good example and so are the face type used in
fuel pumps(kinda scary to find out fuelpumps in our cars are commutator
motors until it is understood that it is sparkless because it is
carbon-carbon.)
I agree that it would be pushing on some practical limits, I think 10K is
possible if you really want to do it.
The other question, is it really needed. What is the difference between a
system with a 0 - 12,000 RPM motor with a torque curve T driving a car with
a gear reduction of R, and a system with a 0 - 6000 RPM motor with a torque
curve of 2T driving a car with a gear reduction of 0.5R, the output is the
same. The slower speed motor will be more weight but that is a tradeoff
some could live with.
The advantage of a high RPM motor is not a single ratio gear box as so many
claim, that can be done with a slow speed motor, it is simply more HP per
pound of motor.
Imagine if you were to invert the whole series motor. The wedges would
be stationary and their section gets wider from point of contact, not
skinnyier. The rotating plate with the brushes on it comes out to slip
rings that can handle rpm well and some large high silver brushes since
there is little to no sparking on them. The plate would look like a
distributer and perhaps could have weights and springs for rpm dependent
advance! The outside windings are the armature and perhaps we could
put caps between the now stationary segments to limit sparking, but the
sparking is needed or we don't get the needed film. I don't know how
this would effect cooling of the motor. The "field" in the center would
be small and simpler, so it could be on a hollow shaft with air running
thru it? Maybe then we can crank out some rpms.
This would be a lot of work and I am sure people would see that this is
not really a step forward. more of a sideways step. Would it be worth
it? I think no
I wonder if there is a way to wind an armature such that you have a
commutator at each end with the positive brushes on one and the negative
brushes on the other. It could be a way of using smaller diameter comms
with high voltages.
How about 6-step on an induction motor. Would that be the "ford"
Induction motor? Simpler(cheaper?) control on AC wound motor, regen and
"fail on" safe.
A few days back there is a thread about an electric tractor project I am
working on. I had planned on using an aircraft starter/generator to have
regen for speed control, more important on a tractor then a car as the
braking systems on old tractors are not that good and you need engine
braking to safely go down a hill. This may be a good conversion to play
with an AC motor with a simple, maybe mechanical inverter system. I have
an old 15HP 3PH motor about 300 lbs., it is wired for 480 and only has 3
wires in the connection box. I may pull an end cap off and look at the
windings see if there is any way to cut and paste and rewire it for a lower
voltage without a complete rewind. Or if I disassembled the thing and just
took the stator in it may not cost that much to have it wound for say 60 volts.
__________
Andre' B. Clear Lake, Wi.
--- End Message ---
--- Begin Message ---
Steve et al,
Here in Florida they just recently raised the minimum interstate speed
to 50 MPH (from 40) as of July 1st, 2005 (The old signs are still being
replaced, I suppose). They cited the hazard of slow-moving vehicles as
the thought behind the law-change.
This is a subject of some importance to me, since I intend to drive
across the country in my RV-E, or E-RV, or REV, and I will only be able
to obtain 45 as a top speed. To get out of Florida, I am forced to
meander on some back roads, or blend in with snowbird congestion.
I disagree with the opinion that slow vehicles in the right lane pose a
particular hazard. All decent drivers know to expect this. The right
lane is where the on and off ramps are (99% of the time), where semi's
come lumbering down from rest stops, where RVs and trailer-pullers stay,
and anybody traveling the interstate at an aggressive speed (the normal
5 to 10 MPH over the limit) knows how to surf the waves, to avoid the
stones in the stream.
STEVE CLUNN wrote:
I drive freeways in California at 45mph.
I strongly advocate personal choice and I absolutely support
Lawrence's right to do this. While I am very glad to hear he stays in
the right lane and has not had problems to date, going 45 mph on the
freeway in California is very dangerous behavior, in my opinion.
I did a 65 mile drive to west palm , with the 40 golfers in my work
truck , at 50 mph , What I do is watch the mirror , the traffic comes in
waves and when I would see a new wave coming fast I'd speed up a little
, after they passed it's an empty road behind and I could slow down a
little . Not bad really . Funny there are sighs saying mim 40 , I wish ,
but all in all 50 was ok. More that once I've seen a cop in the rear
view mirror and sped up.
Steve clunn .
--- End Message ---
--- Begin Message ---
Steve;
What battery set up are you using?
-----Original Message-----
From: STEVE CLUNN [mailto:[EMAIL PROTECTED]
Sent: Friday, February 17, 2006 8:44 AM
To: [email protected]
Subject: Tire smoke.
I took my pick up with the 11" net gain motor and 2k zilla to a SCCA (
sports car club of america) event last week end which has a auto cross once
a month in my town . There where about 50 cars there ( all gas and all fast)
. They set up a coruse with cones on this big paved driving range that the
collage uses with the police to teach driving . The course is set up with
lots of truns along with a few straight a ways . A great bunch of people ,
but I could tell that they where thinking , " an electric truck , is this
guy nuts " . The girl who was checking me in , " electric , neat , is like
a golf cart ?" . I didn't say anything about how fast it went , just that I
wanted to see what it would do and there where some people there with their
plane cars , also seeing what their daily dirve would do. This is a 2 day
event with the first day as a practice . Auto cross is much more a driver
skill , and car handling thing than a power thing and a corvette can get
beat by a mini copper easy. We where to each get 4 runs at the course ,
after each run we would get back in line for the next run. The 50 cars where
in two groups and my group would run after lunch on the first day. The event
was about 2 miles for my house , I had used 2 ah to get there . Would I even
be able to do 4 runs on a charge? Any one that wanted an instructer to
drive with them or drive while they sat in the passanger seat could , and I
took this oppstion . I had two reasons , one I knew that after the ride the
instructer would be telling his friends about it and 2 so I could learn a
little about driving . There are some momunits in life , where you get to
supprize sombody with somthing so different , and seeing them see that
reality was not what they though. " electicrec , whow , do I shift it like a
car ?" " no just leave it in 4th " " 4th , will it take off in 4th ?" "
yep" . Well as I had not done any tire spinning and up to this point as we
pulled up to the starting line nobody knew what what was on the other end of
that go peddle. I got to see the driving instructer deal with a major change
in his reality. Lots of whow's as he soon found he had more power than the
wheels could put to the ground. He got very busy driving , not alot of
instructing now just whow, and ooo , . less that a minunite later we where
done , and all of a sudden people are looking at my electric pick up in a
different light , lots of thumbs up and now comes the questions. When I get
my trun again the anowser has a lot to say about the electric truck ,
talking about it being in 4 th gear , and the low end troque. The e meter
was the only meter I had time to look at , and I only got to see that
becuse I looked at it before the run and after , the run took 2.5 ah , which
is about what the BBB 1/4 mile took so I'm thinking I'm good for the 4 runs.
I had a blast driving the next 3 runs , last run , on the last stright a way
, I felt the voltage sage ( no I never saw any meter while driving , this
must be a trick that the pro's know how to do) and knew this was the last
run. There was still plenty for regular driving but after 10 ah is used ,
the truck is not so peppe . The next event is March 11 and 12 , more info
at www.cfrsolo2.com , There is also a car show on March 11 that I go to so
I may not go on the 11 , ( so many events to go to ) but on the 12th I'll be
there for sure , any other EV'er that can make it let me know . I got a
shot of some tire smoke and net gain put in on their site it a 1 minunit
move , it takes some time to load.
http://www.go-ev.com/images/Steve_Clunn.mov.
Steve Clunn
--- End Message ---
--- Begin Message ---
My understanding is that regen is limited to AC or very high end DC
systems. But I was thinking about how much a waste it is, all that
energy going to heat the brake pads.
What if instead of using the generated power to recharge the pack, you
used it to help heat the cabin.
Thoughts?
-Mike
--- End Message ---
--- Begin Message ---
The guys on the Porsche list claim that drivers going under the speed
limit are 600% (six times) more likely to be in an accident than
people going up to 15 mph over. Makes sense when you consider a good
chunk of that group are drunk drivers, very old drivers, overloaded
vehicles, or old and poorly maintained vehicles.
Even if you are a very safe and aware driver, if you are going well
under traffic speed you are introducing new hazards. Right or wrong,
people will be making lane changes they wouldn't have and tailgating.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
I don't think AC offers really anything much in the way of efficiency per se,
What do you call .174 - .288 kWh for AC vs. about .3-.5 for DC?
Shari Prange
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
--- End Message ---
--- Begin Message ---
Ken thanks for the friendly warning and the stats. However anyone breaking
the speed limit and zipping through the slow lanes is very aware of their
surroundings. Where I do this the slow lane average is about 60mph. Lane
one is 75. Lane 2 is between 75 & 70. Lane three is around 65mph to 55
mph and conservative drivers camp there. Lane 4 is where I drive and there
is enough traffic comming on and off the freeway that I can stay there
without much conflict. Anyone not wanting to wait behind me just changes
lanes. Lawrence Rhodes...
----- Original Message -----
From: "Ken Trough" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, February 16, 2006 2:48 PM
Subject: Re: Driving 45 mph on the freeway?
I drive freeways in California at 45mph.
I strongly advocate personal choice and I absolutely support Lawrence's
right to do this. While I am very glad to hear he stays in the right lane
and has not had problems to date, going 45 mph on the freeway in
California is very dangerous behavior, in my opinion.
Of course this doesn't matter so much during heavy stop and go rush hour
traffic, but studies have shown that vehicles travelling well outside of
the average speed of traffic (either much faster or much slower) are
involved in many accidents.
According to recent data compiled by the National Highway Traffic Safety
Administration, while "inattentive drivers" pose the single greatest risk
to your health on the road, in California 32% of all traffic related
fatalities are speed related crashes, and many of these (~40%) occur on
Interstate and non-interstate roads where the speed limit is posted at 55
mph or higher.
California freeways have one of the highest average speeds for a traffic
dense environment of anywhere I have driven in the US.
I am not being critical of anyone for making this choice, rather just
providing a friendly word of caution for those considering this in the
future.
-Ken Trough
V is for Voltage
http://visforvoltage.com
AIM/YM - ktrough
FAX/voice message - 206-339-VOLT (8658)
--- End Message ---
--- Begin Message ---
On Fri, 17 Feb 2006 09:30:05 -0600, you wrote:
>
>>How about 6-step on an induction motor. Would that be the "ford"
>>Induction motor? Simpler(cheaper?) control on AC wound motor, regen and
>>"fail on" safe.
>
>A few days back there is a thread about an electric tractor project I am
>working on. I had planned on using an aircraft starter/generator to have
>regen for speed control, more important on a tractor then a car as the
>braking systems on old tractors are not that good and you need engine
>braking to safely go down a hill. This may be a good conversion to play
>with an AC motor with a simple, maybe mechanical inverter system. I have
>an old 15HP 3PH motor about 300 lbs., it is wired for 480 and only has 3
>wires in the connection box. I may pull an end cap off and look at the
>windings see if there is any way to cut and paste and rewire it for a lower
>voltage without a complete rewind. Or if I disassembled the thing and just
>took the stator in it may not cost that much to have it wound for say 60 volts.
I have a 30 hp, three phase for free in Lubbock Texas.
US ELECTRIC MOTORS
UNIMOUNT 125
model B535A 30 hp 3ph 60
frame 286TS type UT
volts 208-230/480 nema nom efficiency 90.2
fl amps 82.2-71.6/35.8
sf amps 93.2/46.6 insul class F
About 250 pounds. it has a keyed shaft. I know its out in the
boondocks.
Matt Milliron [EMAIL PROTECTED]
1981 Jet Electrica, Ford Escort
My daughter named it, "Pikachu".
It's yellow and black, electric and
contains Japanese parts, so I went with it.
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "STEVE CLUNN" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, February 17, 2006 10:03 AM
Subject: Re: Driving 45 mph on the freeway?
>
>
>
> >> I drive freeways in California at 45mph.
> >
> > I strongly advocate personal choice and I absolutely support Lawrence's
> > right to do this. While I am very glad to hear he stays in the right
lane
> > and has not had problems to date, going 45 mph on the freeway in
> > California is very dangerous behavior, in my opinion.
> >
> I did a 65 mile drive to west palm , with the 40 golfers in my work truck
,
> at 50 mph , What I do is watch the mirror , the traffic comes in waves and
> when I would see a new wave coming fast I'd speed up a little , after they
> passed it's an empty road behind and I could slow down a little . Not bad
> really . Funny there are sighs saying mim 40 , I wish , but all in all 50
> was ok. More that once I've seen a cop in the rear view mirror and sped
up.
> Steve clunn .
> But the REST of us in our ICE'S SLOW down, below the limit, trying to
REMENBER what it was about there!
> Hi All;
Steve's strategy is a good one. I have had to limp along on the freeway,
below 50, put the damn flashers on! Then there is no excuse that they didn't
SEE you! I don't feel that the speed folks go is so bad ,it is that they
arent paying attention! Hopw many times you are going about the speed limit,
ya look in the rear view mirror and see somebody closing on you at a
fearsome rate,they slam on the brakes , THEN look to see if it is clear to
pass, then they do, and fly off. If I were the driving instructer I woulda
flunked then right there! Not paying attention!!When you drive you hafta use
ALL your eyes, even the ones in the back of your head<g> Be aware of what's
going on ALL around ya. Many people do, if you have watched those " Scariest
Police Chases" on TV where the freeway traffic somehow ,magicly gets out of
the way, of the yahoo that thinks he's faster than Motorola. I think the
cops show increadable restraint! You would think they would wait for a clear
spot and take these guyz out with a few bursts of automatic weapon's fire,
like in thr Governator Movies! BEFORE they slam into your wife an' kid
coming home from school. Or Grandma ,in her Baker Electric<g>!
When you drive somebody else's wreck WITHOUT any rear view mirrors or
they go limp when ya try to adjust them, you feel so volnerable!Of course
your car ALL your mirrors work? Right? If they don't ,get your a... out
there and FIX them! Safety tip for the day.
When I towed my Rabbit to Power of DC with my trusty, rusty ,Ford van,
I hung in the right lane at about 50 as the van is old and tired, just want
to prelong the agony of it's wearing out. Had no problems flat towing at
this leasurly pace. Hell I even passed a few folks SLOWER than me. I couild
count these EVents on one hand, though.A few spots like on the GW Bridge I
kept up with everybody else, just to be nice.But in flat towing I like to
poke along, it isn't a power thing but a BRAKE thing as the Ford's brakes
have to do ALL the stoppin'! Balasting the van with about 10 batteries to
help put more weight over the wheels with the brakes helps in the stopping
dept, no wheel sliding, under hard braking.Not often in EV dom do we WANT
more weight, by piling in more batteries!
Seeya, in the right lane!
Bob
>
>
--- End Message ---
--- Begin Message ---
On Thu, 16 Feb 2006 15:51:42 -0800, Jeff Shanab
<[EMAIL PROTECTED]> wrote:
> Andre said > " No reason they could not be built in EV sizes with
>RPM's in the 10,000 to 12,000 range.
>
>
>Actually there may be a good reason why not, Jim can aswer this better.
>The force excerted on the comm bars goes up with square of the comm
>diameter and the number of bars and size of these bars are in conflict
>for high rpm and high amps. So while it is easy to build a small
>diameter high rpm commutated motor, it is impractical to build a large
>diameter high rpm motor.
Rubbish.
No reason for a theoretical discussion since high speed DC motors have
been in common use in the machine tool field for decades. In fact,
until the development of the high frequency AC drive, a DC motor was
the only way to achieve high spindle speeds. Typically, a multi-HP
(20 to about 50hp) motor would be geared 2:1 with a speed limit in the
15krpm range to produce twice that on the spindle.
Another field is aerospace where speeds higher than possible with 400
hz induction motors are needed. Before BLDC, brushed DC motors were
very common in relatively high HP applications.
The armature in this type of motor has all the features one would
expect - a molded, streamlined armature for low drag, a strong, small
diameter commutator (only a few bars needed for high speed) and a
long, relatively small diameter form factor.
Power generation is another area. In the past it wasn't uncommon to
find direct-driven DC generators in the hundreds of KW range that
operated in the 7-10,000 rpm range when coupled to a steam turbine.
Now it's cheaper to make AC and rectify it so few if any are still
manufactured. The comm bars on these machines fit into keyed slots on
the shaft, mechanically retained and insulated with mica and ceramic.
Each comm bar may weigh several pounds. I've seen them cast with
steel reinforcements in the center for added strength.
For that matter, I can point you to the humble wood router. Multiple
HP at around 25,000 RPM. Yet another humble example is the Bear on-car
wheel balancer, the unit that can spin a car tire up to 60mph or so.
That motor is a universal motor of about 8 hp rating. Around 15krpm.
We used to rewind a lot of those when they were in common use because
mechanics would try to spin up wheels with dragging brakes which would
burn out the motor. None of these motors use anything special in
construction since efficiency isn't the prime objective. Loose
windings, ordinary commutators, etc.
You need to stop and realize that the world of DC motors does not end
with cheap-sh*t converted fork-lift motors with plastic commutators.
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
--- End Message ---
--- Begin Message ---
Except that it is incorrect. The brush formulation varies for the
particular application. There are/were thousands of high speed motors
with perfectly acceptable brush life and pretty brown comms.
John
On Thu, 16 Feb 2006 19:07:54 -0600, Ryan Stotts
<[EMAIL PROTECTED]> wrote:
>Jeff Shanab wrote:
>
>> One other thing is that the brush surface speed goes up and there is a
>> limit where the film won't form and the brushes grind to dust.
>
>I was unaware of that.
>
>Information like that is tremendously valuable. For some reason
>though, it tends not to be common knowledge or even written anywhere.
>Thanks for sharing.
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
--- End Message ---
--- Begin Message ---
Electro Automotive wrote:
I don't think AC offers really anything much in the way of efficiency
per se,
What do you call .174 - .288 kWh for AC vs. about .3-.5 for DC?
Possibly a weaker motor? The Prizm is an AC powered car with a peak
power that seems to equal a zilla+9 inch motor. So far it seems to match
the power usage rating of another member's Toyota Corolla 4 door same
model car with a DC motor.
While it's true that the Force can't be beat for sheer around-town range
it's a smaller motor (20kw vs. 50kw) than the Prizm and seems to have a
different inverter mapping. Feels a lot different from my car in more
ways than just performance.
Also is this .174 from a 2 door Force on the highway at 60mph (more like
a Metro, lighter, smaller, etc) or a 4 door Corolla Force (more like my
car). I'd be willing to wager that at 60mph steady a Corolla-based Force
will probably pull the same number of watts from a pack as my Prizm or
as someone's DC powered Corolla.
Chris
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On 17 Feb 2006 at 8:39, Electro Automotive wrote:
>
> What do you call .174 - .288 kWh for AC vs. about .3-.5 for DC?
I take it this is in otherwise identical vehicles?
Some of the difference can no doubt be ascribed to the excellent
regenerative braking in these AC systems. Solectria Forces were almost wig-
wag cars. But I think some of it is also a result of the simple fact that
both Brusa and Solectria have always kept efficiency as a primary goal in
their system design, and make few compromises against that goal.
Check out Axel Krause's 1997 Alp crossing in a Mini-Evergreen with a Brusa
AC drive (see link below). Consumption at the destination amounted to
10.7kWh / 100km, or 173 Wh/mi >>>at the input to the charger<<<.
http://www.brusa.biz/applications/e_mini_evergreen.htm
Could the same thing be done with DC, if sufficient attention were paid to
efficiency? Perhaps. A couple of people have built very efficient Karmann
Ghia conversions. But the point is that these drive systems are designed
from the ground up to be as efficient as possible. If efficiency and
optimum range are what you want, there's your answer. OTOH, if tire smoke
is what you want, well, that solution already receives PLENTY of discussion
on this list.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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I relly should read what I type. What I ment to say is I want to
give this to someone. OK!
Matt Milliron [EMAIL PROTECTED]
1981 Jet Electrica, Ford Escort
My daughter named it, "Pikachu".
It's yellow and black, electric and
contains Japanese parts, so I went with it.
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--- Begin Message ---
The problem is not caused by the slow drivers, but by the impatient, angry
ones who feel they need to "teach us a lesson" and demonstrate by
tailgating, swinging close round us, and cutting in front, how terribly
unfair it is for us to slow them down from their mad dash for all of 15
seconds.
The best way to disarm this rage is with humor. Post a sign on the back of
your car. Use your best creativity. Something like "Not so close, you
might get hamster poop on your windshield."
If you take yourself and your car seriously and you can't imagine doing
something like that, I'm sure there are other ways to handle it. I heard
(here I think) of a Think driver who posted a sign to the effect of "Sorry,
my top speed is only 51 mph" (or whatever the top speed was). It worked.
I realize there are those who believe that we have to dispel the myth that
EVs are slow. That's fine, and a laudable goal. But not all of us are able
to (or want to) do that. Besides, there are plenty of slowpokes with gas
cars, and a few inherently slow gas cars too. If your EV can make the
minimum speed required on the highway, and is able to make the trip without
obstructing traffic (which is almost always true if there is a passing
lane), I don't see the problem.
BTW : no, I did NOT try to drive my Comuta-Car on the expressway. ;-)
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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On 17 Feb 2006 at 12:22, Christopher Zach wrote:
> 4 door Corolla Force ...
There is / was no such animal. Solectria Forces were all conversions of Geo
Metros.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- Begin Message ---
Lawrence Rhodes wrote:
> 3 18650's with a BMS protection chip & charger... 50 bucks each...
> 96 cells plus 32 bms plus the 10 chargers. About 68 amp hours...
> This doesn't seem so bad especially since you could have a 30 mile
> range scooter.
It could be done, but I think you're doing it the hard way. For a
scooter, I'd rather use a few big Li-Ion cells. The four crappy TS-90LP
Thunderskys I have only cost around $400, and deliver 14.4v 70ah at 25a.
Use an Etek or Lemco motor and small PWM controller and you're in
business.
But why would you want to ride a scooter for 30 miles? Sounds painful!
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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--- Begin Message ---
Thanks Victor that is interesting and I'll update my notes.
However, getting back to the original idea....
Any ideas on how big (weight AND volume) TS Li-Ions would be that could
dish out 100 kw for at least 10 minutes?
I'll have to look into the Li-Pol (Kokam?) unless you have that data
available also.
Thanks.
> Peter, this gets interesting.
>
> When I said that Li has more volumetric energy density
> than lead battery did not take into account discharge rate.
>
> Technically, if I store 20 kWh in 1m^3 volume and you store
> only 15 kWh in the same volume, my battery has higher
> volumetric energy density period, even if I can discharge
> mine only at 1/5 of the rate you can discharge yours.
>
> I may not need (or can't take advantage of) higher discharge
> rates, so this is not specified.
>
> Siemens inverter in ACRX is limited to 282A battery current,
> this gives 100 kW power at highest voltage. Practically
> very rarely see anything above 180A.
>
> My 90Ah TS cells need to dish out 2C to provide that.
> 4 of them together are about the voltage of Optima under
> the same load (OCV more, but sag is more too),
> and are "about" the same volume as one Optima.
> Say, I drive at 90A at all times (actually it is
> [EMAIL PROTECTED] and [EMAIL PROTECTED]). Optima at that rate will have
> about 30Ah available (my guess); good TS cells still have 90Ah.
> So TS cells have 3 times volumetric energy density than
> Optima. Who cares that Optima can give 500A or 1,500A
> out if I can only possibly consume 280A out of a battery?
> So power capability is of no relevance *to me*.
> If you care, compare then to LiP with higher power
> output, but volumentic energy density advantage over lead
> will be about the same as for less powerful LiIons.
>
> Since we're not comparing power, we're comparing energy
> stored per volume *provided* the battery
> is usable for the application. I wouldn't need an
> amazing (energy density wise) 100kWh battery size of a
> cell phone if I can discharge it only at 1uA rate.
>
> So, my TS cells are *usable* because can provide
> more power than drive system can take. How much
> more beyond that is of no concern then.
>
> Now, LiPo are more powerful ones (10C-20C are common)
> but not more energy dense than LiIons by volume.
> So racers could benefit from it but not long rangers.
>
> I'd say in general, today Lithium batteries have 3x
> volumetric energy density of a lead battery *at usable
> discharge rates* (though not as high rates as for lead,
> which may or may not be relevant, see above).
>
> Victor
>
> --
> '91 ACRX - something different
>
>
> Peter VanDerWal wrote:
>> Victor,
>>
>> My statement was based on my memory of research I did several years ago,
>> it's quite possible that I'm wrong, especially when you consider that I
>> wasn't thinking about 5C-10C discharges when I was looking into it.
>>
>> Obviously you are in a better position to comment on this. How many wh
>> does you pack store when drained at the 5C rate, we can compare this to
>> YTs/Orbitals.
>>
>> Thanks.
>>
>>
>>>Peter VanDerWal wrote:
>>>...
>>>
>>>>FWIW though the Li-Ions/Li-Poly weigh less than Lead-Acid, they take up
>>>>almost the same amount of physical space.
>>>
>>>Peter,
>>>
>>>If you mean space per Wh, stored (volumetric energy density),
>>>I find this statement somewhat inaccurate. Do you have numbers
>>>by chance? I can compare with what I had physically in ACRX.
>>>
>>>Victor
>>>
>>>
>>
>>
>>
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
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Atta Boy Neon...
Some folks just can't get thier head out of a Cheap Advanced DC motor.
They are actually a pretty good step back when it comes to industrial DC
motors.
It's only been rectenly that Vector drive AC could come close to DC in size
per Hp. And also have variable speed and control.
Nice brutal way of stating the Obvious.
Madman
----- Original Message -----
From: "Neon John" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, February 17, 2006 9:46 AM
Subject: Re: Why not more AC conversions vs DC conversions...
> On Thu, 16 Feb 2006 15:51:42 -0800, Jeff Shanab
> <[EMAIL PROTECTED]> wrote:
>
> > Andre said > " No reason they could not be built in EV sizes with
> >RPM's in the 10,000 to 12,000 range.
> >
> >
> >Actually there may be a good reason why not, Jim can aswer this better.
> >The force excerted on the comm bars goes up with square of the comm
> >diameter and the number of bars and size of these bars are in conflict
> >for high rpm and high amps. So while it is easy to build a small
> >diameter high rpm commutated motor, it is impractical to build a large
> >diameter high rpm motor.
>
> Rubbish.
>
> No reason for a theoretical discussion since high speed DC motors have
> been in common use in the machine tool field for decades. In fact,
> until the development of the high frequency AC drive, a DC motor was
> the only way to achieve high spindle speeds. Typically, a multi-HP
> (20 to about 50hp) motor would be geared 2:1 with a speed limit in the
> 15krpm range to produce twice that on the spindle.
>
> Another field is aerospace where speeds higher than possible with 400
> hz induction motors are needed. Before BLDC, brushed DC motors were
> very common in relatively high HP applications.
>
> The armature in this type of motor has all the features one would
> expect - a molded, streamlined armature for low drag, a strong, small
> diameter commutator (only a few bars needed for high speed) and a
> long, relatively small diameter form factor.
>
> Power generation is another area. In the past it wasn't uncommon to
> find direct-driven DC generators in the hundreds of KW range that
> operated in the 7-10,000 rpm range when coupled to a steam turbine.
> Now it's cheaper to make AC and rectify it so few if any are still
> manufactured. The comm bars on these machines fit into keyed slots on
> the shaft, mechanically retained and insulated with mica and ceramic.
> Each comm bar may weigh several pounds. I've seen them cast with
> steel reinforcements in the center for added strength.
>
> For that matter, I can point you to the humble wood router. Multiple
> HP at around 25,000 RPM. Yet another humble example is the Bear on-car
> wheel balancer, the unit that can spin a car tire up to 60mph or so.
> That motor is a universal motor of about 8 hp rating. Around 15krpm.
> We used to rewind a lot of those when they were in common use because
> mechanics would try to spin up wheels with dragging brakes which would
> burn out the motor. None of these motors use anything special in
> construction since efficiency isn't the prime objective. Loose
> windings, ordinary commutators, etc.
>
> You need to stop and realize that the world of DC motors does not end
> with cheap-sh*t converted fork-lift motors with plastic commutators.
>
> John
> ---
> John De Armond
> See my website for my current email address
> http://www.johngsbbq.com
> Cleveland, Occupied TN
> A foolish consistency is the hobgoblin of little minds.-Ralph Waldo
Emerson
>
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--- Begin Message ---
Myles Twete wrote:
> But Lee, aren't you discounting the very real effect that with
> massively parallel connections between batteries (e.g. the spot-
> welded grid used on the ACP 68P2S Lithiums I referred to) it's
> highly unlikely that you'd see the kind of current variance you
> refer to if the batteries are of similar capacity and age?
It all boils down to this -- I don't know. Every battery manufacturer
always claims you can parallel their cells "no problem". But they
haven't done anything but cursory tests with brand new cells. I listed
all the things that *have* gone wrong with other batteries when you
parallel them. Will all of them apply to these lithiums? I don't know.
If you're in a hurry, just parallel them anyway and go racing off.
You'll find out the hard way whether it works or not. You may have some
spectacular wins -- and some spectacular failures.
If you're trying to design a product to mass produce (even if it's just
100s of modules for one car), and you want it to be safe (someone other
than you is going to own or drive it), then it makes sense to "go slow".
Do some research, do some testing. See what kind of variations you
actually see.
Get yourself a bunch of cells. Test them to find the best and worst of
the batch. Parallel them, and charge/discharge them while measuring the
current through each one.
- How much variation is when they are new? (Will you have to hand-sort
cells)
- Does the variation get larger as they age? (You may have to catch
and replace weak ones before they fail)
- Do the cells tend to stay at the same state of charge? (Check the
amphours in each cell separately after they have been in parallel
a while)
- What if one is hotter than the other?
- Does a hot cell deliver less, or more current? (if more, you have
to worry about thermal runaway)
- How much variation is there in the resistance of your connections?
(Are they large compared to the cell's internal resistance)
Once you have some definitive answers, we can talk more meaningfully
about the consequences of parallelling these cells.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
