EV Digest 4007
Topics covered in this issue include:
1) Re: Follow-up on Valence Li-Ion batteries in 12V size
by "S. David Lalonde" <[EMAIL PROTECTED]>
2) Re: Air conditioning - dumb questions
by Evan Tuer <[EMAIL PROTECTED]>
3) Re: Jeep EV (Battery LED, Raptor controller questions)
by Bob Bath <[EMAIL PROTECTED]>
4) Blueprinting electric motors (was: RE: DIY Controller? (DIY Motor))
by "Chris Tromley" <[EMAIL PROTECTED]>
5) Re: Electravan 750 (Ford Courier)
by "Kirk A. Reinkens" <[EMAIL PROTECTED]>
6) Re: Planatery gear set
by [EMAIL PROTECTED]
7) Re: Blueprinting electric motors (was: RE: DIY Controller? (DIY Motor))
by [EMAIL PROTECTED]
8) Re: KISS AC EV Drive System
by [EMAIL PROTECTED]
9) Power supply question
by [EMAIL PROTECTED]
10) Re: Sundancer whereabouts?
by Lee Hart <[EMAIL PROTECTED]>
11) Re: Follow-up on Valence Li-Ion batteries in 12V size
by Lee Hart <[EMAIL PROTECTED]>
12) Re: Blueprinting electric motors (was: RE: DIY Controller? (DIY Motor))
by Lee Hart <[EMAIL PROTECTED]>
13) Re: Sundancer whereabouts?
by "David Chapman" <[EMAIL PROTECTED]>
14) RE: The Amazing Little Hawkers.
by "Roger Stockton" <[EMAIL PROTECTED]>
15) RE: The Amazing Little Hawkers.
by "Roger Stockton" <[EMAIL PROTECTED]>
16) RE: The Amazing Little Hawkers.
by "Roger Stockton" <[EMAIL PROTECTED]>
17) Re: Blueprinting electric motors (was: RE: DIY Controller? (DIY Motor))
by "Roland Wiench" <[EMAIL PROTECTED]>
18) Re: Sundancer whereabouts?
by "David Chapman" <[EMAIL PROTECTED]>
19) 79 Mazda Rx7 FOR SALE
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
20) Re: Follow-up on Valence Li-Ion batteries in 12V size
by Victor Tikhonov <[EMAIL PROTECTED]>
21) Re: Blueprinting electric motors
by Victor Tikhonov <[EMAIL PROTECTED]>
--- Begin Message ---
This is a silly debate. How do you define capacity? The capacity is the
amount of current (depends on the application need) provided for a time
until the battery voltage falls below a usable level (for the application).
To define capacity during use as anything else is bogus. If you need 50 to
100 A to drive around then you are not going to drive around at 5 to 10 A to
get more capacity out of your batteries.
Sure, you can define a cell's capacity as the C/20 rate, or C/5 rate, or
using a reducing current discharge (C, C/2, C/5, C/10, C/20) but that is the
ultimate cell capacity, not the capacity you see in the application when you
discharge at higher currents.
Anyway, a much better measure of cell performance is energy, units of
watt-hours, the amount of watts provided for a time until the battery
voltage falls below a usable level. This shows the effect of lower voltage
on the energy provided from the cell, because watts = current x voltage. A
TS cell has much more energy at low current than at high current discharge
because of increased impedance and voltage sag. Not only do you reach the
low voltage cut-off sooner, giving you less capacity, but you do it at an
overall lower average voltage, giving you lower energy. The point is you
need a way to reduce the current required from these batteries, or get
bigger capacity cells.
David
S. David Lalonde / [EMAIL PROTECTED]
Liion Power Products Inc. / http://www.liionpower.com
Li-ion & NiMH batteries for electric cycles & more!
http://groups.yahoo.com/group/liion_power_products/
http://liionpower.blogspot.com
Ph: 604 880 1928
----- Original Message -----
From: "Victor Tikhonov" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, January 05, 2005 5:06 PM
Subject: Re: Follow-up on Valence Li-Ion batteries in 12V size
> I was going to say that this is true for other chemistries,
> but forgot. Yes, but I believe for PbA it is rather drastic
> change. If you spend 25Ah out of optima and it is at min voltage,
> another 25Ah (C/20 rating) are perhaps still there, but
> C/20 is just 2.5A. So you cannot even move at 2.5A.
>
> In You can perhaps use 30A to drive 10 mph to get another
> 5Ah out (get you less than a mile), than 10A for another
> 2Ah. The remaining capacity may be also there, but you
> indeed can't take it out at any *still usable for driving*
> rate. With LiIons this is more gradual process and you
> can *drive* until last 5-6 Ah are there. Not that it is good
> idea....
>
> So, in strict theory you are right.
>
> Victor
--- End Message ---
--- Begin Message ---
On Tue, 4 Jan 2005 15:46:34 -0500, David Roden (Akron OH USA)
<[EMAIL PROTECTED]> wrote:
>
> True, the EV's air-con doesn't have to fight engine heat; but solar gain can
> be huge, and vehicles are notoriously poorly insulated. The automakers
> seldom bother with much thermal insulation; for winter the ICE produces all
> that waste heat and, for summer, there's plenty of energy on board in the gas
> tank.
Also, remember that cars use forced ventilation - air comes in at the
front via the vents and numerous gaps, under pressure. It flows
through the cabin and exits either via louvres near the rear window or
vents out of the trunk somewhere. So, you'll need to reduce that flow
considerably when your AC is on to avoid losing all your cold, which
can be difficult on older cars!
The alternator and battery should cope with the load although some of
the cheaply made inverters I've seen recently are truly horrible!
--- End Message ---
--- Begin Message ---
If your WOT LED isn't coming on, I see two potential
issues:
a) Your slug is not properly calibrated (coming in
and out of the coil at the proper places, or
b) You have the DIP switches on the controller set for
throttle ramp rate slow, instead of fast (or
visa-versa)-- I can't remember.
Might try these two things, as I had similar issues
with the Civvy, until Damon (DCP) calibrated it.
--- Nick Viera <[EMAIL PROTECTED]> wrote:
> (Hmm, I don't think this went through the first
> time):
>
> Hi,
>
> > That the LED was not lit
> > means you still had some more to go.
>
> I don't understand what you mean here.
>
> I had the throttle to the floor, and saw pack
> voltage at the motor (at
> least for a few seconds until I had to let off the
> throttle). However,
> the WOT LED was NOT on. I don't understand what I
> "had some more to go"?
>
> Another thing which I'm not sure I've mentioned
> before is anytime I
> floor it and the WOT LED does NOT come on, It
> actually does flicker a
> bit. By flickers I mean it lights dimly for just a
> fraction of a second,
> with about 1 to 1.5 second intervals in between
> flashes. Oh and this is
> usually accompanied by a squealing sound from the
> Raptor which is
> audible inside the Jeep.
>
> I try not to keep the controller like this for any
> amount of time (as
> the squealing worries me), but sometimes I *have* to
> if I want
> to avoid getting plowed into by impatient drivers...
>
> Thanks
> -Nick
> 1988 Jeep Cherokee 4x4 EV
> http://Go.DriveEV.com/
>
> ------------------------------------------------
> On Tue, 2005-01-04 at 19:09, Rich Rudman wrote:
> > Pack voltage on the motor IS the definition of
> WOT. That the LED was not lit
> > means you still had some more to go.
> >
> > It now looks like this is all your batteries are
> going to give...
> >
> > Still... What is the Maximum Motor loop
> currrent??? It should be over 600
> > amps. That's what you paid for...How much over
> depends on how generous Damon
> > and Crew were at the tuneup
> > Time.
> >
> > I know how these controllers were tuned. And on
> our test rigs we usually
> > gave you more than you paid for.
> > Well, that was true while I was at DCP....
> >
> >
> >
> > > I don't know if this info is significant in any
> way, but I found it odd
> > > that *decreasing* the "max current" setting
> would cause me to see an
> > > *increase* in the amount of current I could draw
> from the batteries, and
> > > cause me to actually see pack voltage in the
> motor loop during WOT.
> > >
> > > Thanks
> > > -Nick
> > > 1988 Jeep Cherokee 4x4 EV
> > > http://Go.DriveEV.com/
> > >
> > > ------------------------------------------>
>
>
=====
'92 Honda Civic sedan, 144V
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering wheel?
Are you saving any gas for your kids?
__________________________________
Do you Yahoo!?
Yahoo! Mail - Find what you need with new enhanced search.
http://info.mail.yahoo.com/mail_250
--- End Message ---
--- Begin Message ---
Victor Tikhonov wrote:
> Lee Hart wrote:
> > Victor Tikhonov wrote:
> >
> >>Lee, are you joking or seriously suggest someone to try
> >>to perform these "not strictly nesessary improvements"?
> >
> > I am quite serious. People spend a lot of time
> "blueprinting" normal
> > ICEs to squeeze out just a little more power. The same
> thing works for
> > electric motors.
>
> Sure, people do all kind of things. Lot of time for
> questionable improvement (vs. buing a motor for the job)
> makes sense only if that time worth little.
>
> > You can improve cooling, install better bearings, precision balance
> > the rotor, superinsulate the windings, etc. all to get more power.
> > These are the same things the factory does, but they charge a lot.
>
> If if would be that easy and effective, we'd see it being
> done by now on regular basis. Why don't we? Perhaps not worth
> to bother.
>
> So, yes, technically it can be done, just like a motor can be
> built from scratch. Heck, even fabricating a battery is suggested.
>
> If one would know how much calculation and tweaking of
> inter-related parameters is happening in design stage (a
> software for the matching inverter involved too, it must
> contain a model for
> *that* motor), one would drop this idea. Of course,
> if one is willing to accept loosing all the advantages
> optimisation provides just to save few bucks and prove that
> it can be done good enough, he can do it.
>
> Advantures like this are very american thing. People
> don't afraid to fail and be laughed at, even though
> prospect of the failure was obvious to begin with.
> So at the end, people is proud of achievements portion
> of outcome, and that is enough.
>
> "I saved $873 on the motor and my EV is driveable!"
>
> I like this spirit, but from the engineering stand
> point it is often just demonstration of ignorance.
I'm inclined to back Lee on this one, based on admittedly unrelated
experience. In the '80s I worked on a racing team that won two national
championships, running Kawasaki 1000 motorcycles in the AMA Superbike
series. Our engines were surprisingly stock. I was astounded to see how
little effort was devoted to finding killer performance parts compared to
what was spent on carefully assembling engines and then laboriously getting
all the adjustments to work in concert with each other. And how sensitive
the engine became to individual adjustments as you brought all the tweaks
together into an optimized whole. Blueprinting works.
But that's an ICE. How much of my experience with racing ICEs applies to
electric motors? When I read about Rich spending long hours lovingly
massaging the brush end of an ADC, I can personally relate. He claims all
that effort pays off. I tend to believe him, and I look forward to seeing
his dyno results. What he's doing is exactly what we were doing in many
ways on the Superbike team - trying to get *our* engine (as opposed to a
production-line engine) to be what the designers originally intended. That
is, correcting all the deviations from ideal that occur in the transition
from theory to production.
In an ICE there are many things that work together to produce power - intake
runner length, cam profile, intake closing timing, piston dome shape,
ignition timing, exhaust length and shape, etc., etc. Are the things you
can optimize in an electric motor as inter-related? In other words, are
they simply additive, or can they be coordinated to produce more of an
improvement than the sum of the individual tweaks? How much could an
off-the-shelf ADC or Siemens AC motor be improved by blueprinting?
And then there's the next level. I wonder what might be possible by
optimizing *everything* in a motor. I mean, really go nuts. Machine (not
stamp) your laminations from the best alloy, plated to allow the densest
stack possible. Precisely shape your slots to allow the densest windings.
Use the best copper for your wire, coated thinner for denser windings (maybe
oxide plated instead of varnished), then permeate the armature with epoxy
under vacuum to eliminate wire chafing. You get the picture. What would be
the incremental improvement of a full-gonzo motor like this over the
blueprinted stock motor?
Chris
--- End Message ---
--- Begin Message ---
James & others:
Wondering. Still having dreams of my own classic truck conversion, but keep
seeing the messages about starting with a previous conversion to build my
own
experience. I figure I should probably listen up to good advice.
That said my questions are:
1. James, What's the condition and component configuration of these pickups?
I'm in Washington so I would have to ship it, but I do have family in NC.
Please let me know how many are available and the condition of body and
general condition when you know it. I've been down the ICE Courier road and
wouldn't mind going back in EV. I deleted your original post with the
details.
2. Others, I was figuring on an AC conversion for my classic truck project
when it starts. Will the practical experience I would be gaining be
different significantly between AC and DC systems? Is there real world
experience with these vehicles out there that can be shared regarding
typical range for around town driving?
3. Would be fun to pursue Hybrid Pusher Trailer if needed for longer days.
Other comments welcome!
Thanks, Kirk
5-Window Electric Dreams (61-67 Econoline Pickup)
----- Original Message -----
From: "James Jarrett" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, January 05, 2005 10:47 AM
Subject: Re: Electravan 750 (Ford Courier)
> Right,
>
> I've seen those, and that is what I want. I had been told that
> ElectraVan 750's were Ford Courier's and the owner listed these as Ford
> Couriers.
>
> James
>
> Bill Dennis wrote:
> > There's a picture of the one Mike is talking about at:
> > http://www.austinev.org/evalbum/011.html
> >
> > Bill Dennis
> >
>
--- End Message ---
--- Begin Message ---
In a message dated 1/6/2005 2:34:40 A.M. Pacific Standard Time,
[EMAIL PROTECTED] writes:
P.S. Occasionally I've run across someone who has just cleaned a ball
bearing in solvent. Then they blow it off with an air hose to dry it while
holding it with two fingers through the inner race. They quickly discover
that the air stream can get the bearing spinning up to a pretty high speed.
"Cool!", they say, and see how fast they can get it spinning. Think about
it - no lubricant, so no viscous losses. Extremely smooth, polished
surfaces. Even windage (air resistance) losses are small, since the bearing
is not moving much air from place to place, just setting up a little vortex.
Many thousands of rpm are possible (maybe over 100k?). Until what little
friction you're generating catches up to you, the bearing seizes, and the
stupendous angular momentum starts the inner race spinning at thousands of
rpm and tries to tear your fingers off.
Just another note about using air to spin bearings: you are right in that
the outer race is spinning VERY fast, way beyond its design and will actually
explode in your hand like a handgernade. I've seem the after affect, very
bloody.
Jim Ludiker
--- End Message ---
--- Begin Message ---
In a message dated 1/6/2005 8:00:46 A.M. Pacific Standard Time,
[EMAIL PROTECTED] writes:
And then there's the next level. I wonder what might be possible by
optimizing *everything* in a motor. I mean, really go nuts. Machine (not
stamp) your laminations from the best alloy, plated to allow the densest
stack possible. Precisely shape your slots to allow the densest windings.
Use the best copper for your wire, coated thinner for denser windings (maybe
oxide plated instead of varnished), then permeate the armature with epoxy
under vacuum to eliminate wire chafing. You get the picture. What would be
the incremental improvement of a full-gonzo motor like this over the
blueprinted stock motor?
Chris
This is why Dennis's dragster runs so quick and fast he's been constantly
tweaking his motors for the last 10 years.
Jim Ludiker
--- End Message ---
--- Begin Message ---
It sounds like you are considering manufacturing and selling systems like
you just described. How would it be different from what is already
available? You mention that it is AC, "simple", must use an automatic
transmission, etc. Because of this, I assume it won't be considered high
performance. What will make it better than a similar DC setup? Price?
Performance? Features (will it do regen)? It sounds like it will easily
be cheaper than current commercial AC setups.
I guess without knowing more about how it will perform, I can't really
answer what my interest level would be.
Thanks for taking the time to sumerize; I never saw Lee's origional post
(before my time). Please keep us updated on your progress!
Steve
<snip>
I already have designed the
> inverter. Is this system for you?
>
> Russ Kaufmann
> RUSSCO Engineering
> The Other PFC Battery Charger Company
>
--- End Message ---
--- Begin Message ---
For my eLamby, I had planned on using a 1500watt power supply as my charger and
as part of the hybrid section (i.e.- fed by a portable generator). However, it
is internally wired for 240V and when I open it up, there is no obvious ways to
reroute the AC. It will put out the right voltage, but at very low current.
Because it's an old surplus unit (ACDC brand, part of Emerson and no longer
supported), I have been unable to get any technical help on it.
I either need a step-up/step-down transformer, which would probably weigh as
much as the 20# power supply, or I need another charger/power supply. What I'd
love to find is a Vicor FlatPac or two, since these could fit "under the skin"
instead of under the generator on the spare mount, but searching the surplus
sites and eBay has yet to be fruitful. I can get an Iota 15A charger for about
$375, which is better than 20 times what I paid for the power supply, so if
anyone has cheap alternative or a lead on the parts I'm looking for, please
contact me directly: cowtown @ spamcop.net - Thanks!
--- End Message ---
--- Begin Message ---
David Chapman wrote:
>
> Lee,
> I got curious about this and looked back in my e-mail logs, found a url for
> the original E-bay listing and the e-mail was titled "McCulloch prototype
> EV".
Yes; it does sound like that's one of the Sundancers. I asked Roderick
to see if it's still around, or he knows it whereabouts.
The McKee chassis were so well designed that few EVs even today can top
their performance. I get the impression from the McCulloch literature on
it that they "bulked it up" with a heavy body and inefficient drive
train, and so lost most of the weight advantage -- it weighed 2700 lbs
with 18 batteries, while the smaller Sundancers were 1600 lbs with 12
batteries!
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
S. David Lalonde wrote:
> This is a silly debate. How do you define capacity? The capacity
> is the amount of current... provided for a time until the battery
> voltage falls below a usable level (for the application). To
> define capacity during use as anything else is bogus.
Not quite. Let me try to explain the difference between lead-acid and
most other battery chemistries in this regard.
Most rechargeable battery chemistries (nicad, nimh, li-ion, etc.) act
like an ideal battery in series with a resistor. The voltage is fairly
stable, changing perhaps +/-10% due to SOC, temperature, and all other
effects. The resistor value stays "relatively" constant -- it might vary
2:1 as SOC goes from 10% to 90%. There's a similar change over
temperature, and it gradually increases over life.
Lead-acids are different, because the acid is one of the active
materials. The voltage is still fairly stable, but the resistance varies
drastically with SOC. As the battery approaches 0% SOC (dead), the acid
approaches zero. The electrolyte becomes nearly pure water, and the
resistance approaches infinity (an open circuit)!
This is what leads to the Peukert effect; that the higher the discharge
current, the lower your usable amphour capacity. The internal resistance
of a lead-acid battery can vary more than 100:1 from 10% SOC to 90% SOC.
This means you can easily have a lead-acid battery with half its charge
left, but you can't use it because its internal resistance is too high
for the current you need. For example, your EV needs 50 amps to drive at
reasonable speed. But your batteries are old, cold, and at 50% SOC.
You'll find their voltage goes under 1.75v/cell at 50 amps. They are
"dead" -- you will ruin them if you keep driving.
But there's a complicating factor. Deeply discharged lead-acids will
"recover" if allowed to rest. Park a while, and what little acid is left
will diffuse throughout the electrolyte, lowering the internal
resistance significantly. Park, go have a cup of coffee, and try again.
You will find that you *can* draw that 50 amps again -- for 1/4 mile or
so.
If you don't mind repeating this process (drive and rest, drive and
rest), you will make it home without damaging your batteries. Your
ultimate range will still be about normal (you'll still get almost all
the amphours) -- but it will take a *long* time! I've crept home under
conditions like this where a 10-minute drive took an hour.
Other rechargeable batteries don't have this large increase in internal
resistance -- but they don't have this "recovery" effect, either.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Chris Tromley wrote:
> Are there things you can optimize in an electric motor as
> inter-related? In other words, are they simply additive, or can
> they be coordinated to produce more of an improvement than the
> sum of the individual tweaks? How much could an off-the-shelf
> ADC or Siemens AC motor be improved by blueprinting?
Of course. You can make just one improvement, for a slight gain. If the
thing you improve happens to be the performance "bottleneck", the gain
can be substantial. Improved cooling is usually one of the main
bottlenecks -- improve it, and performance can go up considerably.
But lots of things are inter-related. I think this is Victor's point. If
you are just an ignorant "backyard engineer" and don't know what you're
doing, you won't know what the inter-related factors are, or even what
the bottleneck is -- you can waste time improving things that are good
enough as-is, or even make "improvements" that make things worse.
But, motors have been around for over 100 years. A lot of brilliant
people have worked on them, and written down their findings in books.
And there are lots of good working designs on the market, that you can
take apart and copy. You can *learn* to be an expert motor designer and
builder. Electric motors, after all, are a *lot* simpler than piston
engines -- and there are *lots* of shade-tree mechanics that have
performed miracles with them that surprised even professional engineers!
> And then there's the next level. I wonder what might be possible by
> optimizing *everything* in a motor. I mean, really go nuts. Machine
> (not stamp) your laminations from the best alloy, plated to allow
> the densest stack possible. Precisely shape your slots to allow the
> densest windings. Use the best copper for your wire, coated thinner
> for denser windings (maybe oxide plated instead of varnished), then
> permeate the armature with epoxy under vacuum to eliminate wire
> chafing. You get the picture. What would be the incremental
> improvement of a full-gonzo motor like this over the blueprinted
> stock motor?
This is how you go from 80% to 90% efficiency. The trouble is, all that
precision machining and handcrafted assembly really drives up the cost.
You can pay someone $50-$100 an hour to do it. Or, you can learn to do
it yourself ("free" if you have the time).
And, humans make mistakes. The reliability or performance can be ruined
if the assembler slips up. For instance, most motors only try to fill
the wiring space about 90%, because it is easy to get the wire in
without pinching. You can increase the wire size, and pack it tighter,
but you may have trouble squeezing the last few turns in. And, you might
nick the insulation (and not know it), causing a later high voltage
breakdown.
The other problem with super-optimization is that you have to optimize
it in one direction. What do you want to maximize? Power/weight,
efficiency, size, cost? Pick one, and forget the others. Maximizing one
tends to minimize the rest.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Looking at the photos of the Sundancer on an automotive picture archive site
I can say that I am pretty sure that the body on the E-bay car did NOT
resemble the Sundancer in the archives. The E-bay car was much better
looking IMO. However I do now remember that it was indeed Mckee that was
attributed as the builder.
I did a bit of research on Bob McKee last night and while i didn't find much
on the man himself or his career I found that he was quite a facinating and
prolific designer builder of all kinds of racing and prototype cars, even
built at least 3 turbine cars and possibly had a hand in a LSR electric car
that looked like it had a a flopper type can am body. Oddly enough I
couldn't find a biography or listing of the cars he built. I did see 2 of
his cars on a vintage racing site that sold for 60K and 90K each and they
classify the cars as "McKees". Im am not sure but he might even still be
around, the E-bay seller did offer to put me in touch with the builder.
McKee seems like a perfect example of Bens "do something worth the writing"
advice. And yes I am really kicking myself about not stepping up and buying
that car, as I said it went for less than 3K and was only 1 state away. My
only justification is that I couldn't afford to buy the car AND afford to do
the restoration right then and I didn't want to have another project just
laying around.
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, January 06, 2005 12:55 PM
Subject: Re: Sundancer whereabouts?
David Chapman wrote:
Lee,
I got curious about this and looked back in my e-mail logs, found a url
for
the original E-bay listing and the e-mail was titled "McCulloch prototype
EV".
Yes; it does sound like that's one of the Sundancers. I asked Roderick
to see if it's still around, or he knows it whereabouts.
The McKee chassis were so well designed that few EVs even today can top
their performance. I get the impression from the McCulloch literature on
it that they "bulked it up" with a heavy body and inefficient drive
train, and so lost most of the weight advantage -- it weighed 2700 lbs
with 18 batteries, while the smaller Sundancers were 1600 lbs with 12
batteries!
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Joe Smalley [mailto:[EMAIL PROTECTED] wrote:
> The 3 amp bypass is being applied to only a few monoblocks in
> the string. All the others are still charging at the full
> rate. This allows the fuller monoblocks to remain at a safe
> terminal voltage while continuing to charge the other ones at
> the higher rate.
Thanks for the reply, Joe. This is precisely what I meant when I stated
that the only beenfit I could see is that of being able to maintain a
charge rate 3A higher than without regs.
If the active reg(s) were bypassing the full 3A they are capable of
(i.e. reg locked on solidly), you would potentially save a maximum of
20min charge time per Ah of imbalance. Since the normal reg behaviour
is for them to blink on and off, I would expect the actual charge time
savings to be even less than this per Ah of imbalance.
Cheers,
Roger.
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--- Begin Message ---
Joe Smalley [mailto:[EMAIL PROTECTED] wrote:
> The give he alludes to is the ability to charge to a higher
> pack voltage once the first monoblock reached gassing voltage.
>
> For instance, if one monoblock (of 20) comes up to 15.0 volts
> while the rest of the string is sitting at 13.5, then the
> pack would read 271 volts. If the charger was controlled by
> the individual monoblock voltages, the charger would taper
> back and finish charging with only one monoblock fully
> charged.
No. If the charger were controlled by individual monoblock voltages, it
would continue charging until all monoblocks had reached the required
level, and would do so at a rate that didn't push the full(er) ones over
a safe maximum voltage.
Even if simpler voltage sensors were used which could only alert the
charger that a monoblock had exceeded the safe maximum voltage, a
reasonably intelligent algorithm would still result in all monoblocks
fully charged. The undesirable behaviour you describe is due to the PFC
charger's lack of intelligence.
> With regulators installed on each monoblock, the 15.0 will be
> clamped to ~14.5 to keep it from gassing excessively while
> the other monoblocks continue charging at 3 amps. This allows
> all the monoblocks to reach ~14.5 volts and to all be full
> and to have a pack voltage of 290 volts.
Tapering the current without regs will not prevent the other monoblocks
from filling up, although it is true that they may not all reach at
least 14.5V before the current has tapered to an unacceptably low level
(from a charge duration perspective) in order to prevent the highest
voltage module from exceeding the max safe level.
What you seem to be describing here (non-bypassed modules charging at
3A) is the constant current finish portion (or the very tail end of the
absorption), such that the charger is pumping a constant 3A into the
string and the active reg(s) are locked full on so that the bypassed
modules are seeing *no* charge current.
> Please keep in mind two things are going on here: 1)The 3 amp
> bypass is used for equalization. 2) The voltage sense is used
> to allow safe fast charges. A monoblock can get in a lot of
> trouble real quick at 60 amps.
Yes, understood. My observation is that a simple voltage sense instead
of a full-blown reg provides exactly the same safety, and that suitably
intelligent charge algorithms can achieve full charge and equalisation
at the expense of a longer charge duration.
Cheers,
Roger.
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--- Begin Message ---
Joe Smalley [mailto:[EMAIL PROTECTED] wrote:
> PFC chargers are current source devices. The current changes
> very little for a very large change in voltage. In last
> night's test, the current was varying about an amp and a half
> whereas the pack voltage was varying about 15 volts. The
> voltage was varying because when a regulator fires and turns
> on the load, the battery voltage drops about a volt because
> the Orbitals have such a high internal impedance when they
> get so close to full. We have not fully analyzed the data
> because some of the variance can be feedback through the
> charger control loops.
>
> The chasing LEDs occur when the battery is so close to being
> fully charged that just a slight variance in the current can
> push the voltage over the threshold and turn on the bypass
> load. Using a voltage regulated power source exacerbates the
> chasing reg problem making it happen at a much larger
> variance in the state of charge.
Thanks for the response, Joe. This seems to confirm what I expected.
You state that the PFC chargers are current source devices, however,
they *do* operate as a voltage regulated power source once the
absorption voltage target is reached, do they not? It is specifically
the constant voltage portion of the charge curve I had in mind when
describing the possibility of the charger briefly increasing its output
current (to try to maintain the set voltage) in response to the pack
voltage dipping due to a reg firing. Obviously, during the constant
current bulk or finish portions of charge, the charger current should
vary only as a result of the control loop lag in responding to a
variation in pack voltage due to one or more regs firing.
Cheers,
Roger.
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Also for long life. My GE motor made in 1975 of which only 6 has the
following specifications, has now been running for 30 years:
The commentator segments are made from a very hard alloy of bronze, which
was micro mirror. The brushes are slightly one or two hardness less then
the commentator alloy, which ran for 20 years and only the front set worn
down 1/2 the length while the rear set worn down only 1/4 the length.
Could not feel any difference of wear between the brush riding areas and
non-brush areas.
I just reversed the front to the rear and still running them today.
The commentator segments have a interlocking design as where it was not
effected by a 10000 RPM spin balancing.
The flywheel adapter, flywheel, pressure plate, clutch was also balance in
sequencer order.
The field windings are not wound close together between insulation cloth,
each winding layer is space by using 1/8 to 1/4 inch insulation square rods.
Then it was dip and bake until it was smooth and hard as porcelain. This
allow a cleaner air flow from front to the rear exhaust ducts.
The brush seat angle is set, so that it bridges just about 4 segments of the
commentator. This reduces the arcing , but will reduce the power of many of
the drag racers won't like.
There are also 4 commentator poles that are in series with the commentator
brush circuit. This brush circuit is between the commentator poles and
field windings, not before or after the field windings. This greatly
reduces any arcing.
The flywheel adapter is not just a steel unit that is that uses a straight
key and two set screws, one on the shaft and one on the key. It was found
that this causes a unbalance, because of the slip on fit and one key is
extended further from the surface of the motor shaft.
So the flywheel adapter inside motor shaft diameter was reduce about 0.03
inch with brass metal that was welded on or fuse on. There is four 5/16
inch set screws of one was shorter that went against a 3/8 inch half moon
key that set deeper into the motor shaft. All four sets screws extended the
same distance above the motor adapter.
It was spun to 10000 RPM and did not need any balance adjustments.
A master mechanic of who I work with ask a vehicle manufacturer, why don't
you use best materials and design. The units would run over 500,000 miles
as some of are larger industrial units do, They said, it would last too long
and put them out of business!
Roland
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, January 06, 2005 10:31 AM
Subject: Re: Blueprinting electric motors (was: RE: DIY Controller? (DIY
Motor))
>
> In a message dated 1/6/2005 8:00:46 A.M. Pacific Standard Time,
> [EMAIL PROTECTED] writes:
>
>
> And then there's the next level. I wonder what might be possible by
> optimizing *everything* in a motor. I mean, really go nuts. Machine
> (not
> stamp) your laminations from the best alloy, plated to allow the densest
> stack possible. Precisely shape your slots to allow the densest
> windings.
> Use the best copper for your wire, coated thinner for denser windings
> (maybe
> oxide plated instead of varnished), then permeate the armature with epoxy
> under vacuum to eliminate wire chafing. You get the picture. What would
> be
> the incremental improvement of a full-gonzo motor like this over the
> blueprinted stock motor?
>
> Chris
>
>
>
> This is why Dennis's dragster runs so quick and fast he's been constantly
> tweaking his motors for the last 10 years.
>
> Jim Ludiker
>
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--- Begin Message ---
Ryan, yep same McCulloch. They were involved in many things that were
seemingly unrelated to chainsaws. For instance they made a # of 2 and 4
cylinder 2 stroke ICE engines ( I have one designated O-100 IIRC that puts
out 72 hp at 4,500 rpm, weighs like 50 lbs) for use in military target
drones, these eventually were adopted as the engine for the Benson B-8
Gyrocopter and are collectable and still somewhat popular today for gyros
and airboats. I have run across other things the company made or played
with, basically anything they thought they might make money producing they
checked out. Also damn good racing go kart engines that are still quite
collectable and valuable. Saw one go on E-bay recently for almost a grand.
Heading OT so I better cork it. TTYL David Chapman.
----- Original Message -----
From: "Ryan Stotts" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, January 05, 2005 6:10 PM
Subject: Re: Sundancer whereabouts?
McCulloch? Would this be the company that I know of that
makes chainsaws or another company? If so, how did they get
involved in EV's?
http://www.mccullochpower.com/
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--- Begin Message ---
Hey all:
I am selling my 79 Mazda Rx7, fully operational with a battery pack 3 days old.
Interested parties should contact me direct and off this discussion list.
More info and pictures are available.
Jim Donovan
[EMAIL PROTECTED]
Kansas City, MO area
___________________________________________________________________
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Now includes pop-up blocker!
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--- End Message ---
--- Begin Message ---
I don't find this "debate" silly, in fact it may be educational
for others. There is a problem with your definition, since
your capacity of a battery will not be the same as my capacity
of that particular battery (I can drive on 10 amps and you cannot).
So what capacity number should we put on the label on the side
of a battery? Useful for your application of mine?
Say, definition of capacity at 50A discharge (mininum useful
for average EV) is almost meaningless to me since I will not
use that current.
This all isn't a rocker science, but not simple black and white
either.
Victor
S. David Lalonde wrote:
This is a silly debate. How do you define capacity? The capacity is the
amount of current (depends on the application need) provided for a time
until the battery voltage falls below a usable level (for the application).
To define capacity during use as anything else is bogus. If you need 50 to
100 A to drive around then you are not going to drive around at 5 to 10 A to
get more capacity out of your batteries.
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--- Begin Message ---
YEs, this was my main point. You sure can try to improve the
motor by, say, changing their shape of the laminations near
rotor to change air gap. Or, change the "twist" of the rotor
(you know some motors have turns not parallel to the shaft).
The problem is, you don't know how the gap shape impacts
performance in all regimes high speed, high torque etc.
How do you introduce water cooling? Is it better to cool
off middle of the windings or split cooling lines in several?
Do you have to pre-magnetize your rotor? Aside from the question
how are you going to do that, you don't even know to what
pre-magnetization value. Not even mentioning that you have
no way to measure.
The bottom line - a lot of computing power went to modeling
before particular shape, material or parameter was implemented.
If you disassemble the motor, its construction is simple as you
look at it, just like a shape of a plane wing, but there was a
lot of calculations put into it to come up with particular
compromise. Try to "improve something and you ruin other
inter-related characteristics almost certainly. This is because
whole system is too complex to understand by plain mortal.
Even you Lee :-) - I mean to understand to the degree that
after looking at it for 2 minutes you can come up with bright
idea which indeed improves some aspect of operation without
making worse the other - something many men-hours and CPU cycles
were spent to determine. Mot that large companies have better
brains than sharp minds in our garages, but they have luxury of
truing to actually build many prototypes to test out their
idea and refine theories - like make 20 stator laminations
with 1 mm increments in some size, put these 20 motors on the
bench and measure. Sometimes it is cheaper than have 100
software engineers working for 3 month modeling that (and still
having to verify).
The machines are still not perfect, but it is virtually guaranteed
that it you take, say Siemens EV motor and "improve" it, you will
fail. Now, if you buy a cheaper industrial motor and implement
some ideas seen in Siemens motor, you indeed may gain performance,
I think this is what Lee is referring to by learning from other
designs. But you will be copying shapes dimensions and solutions
without understanding why *that* solution was implemented.
Thus you can't make it better - you have no idea which way to
change it and no resources to empirically find out.
Victor
Lee Hart wrote:
Of course. You can make just one improvement, for a slight gain. If the
thing you improve happens to be the performance "bottleneck", the gain
can be substantial. Improved cooling is usually one of the main
bottlenecks -- improve it, and performance can go up considerably.
But lots of things are inter-related. I think this is Victor's point. If
you are just an ignorant "backyard engineer" and don't know what you're
doing, you won't know what the inter-related factors are, or even what
the bottleneck is -- you can waste time improving things that are good
enough as-is, or even make "improvements" that make things worse.
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