--- Begin Message ---
OK Otmar, let's try to clear this up.
Thanks Victor, it looks like we're getting closer.
You seem to have missed my point on the controller comparison.
My point is you chose the wrong Zilla. You choose to compare your
78 kW system to my 600 kW $4000 system. Features or not, YOU made
the choice to compare them. My point was only this:
Why did you compare your 78 kW system to my $4900 600 kW system?
I didn't. IF you'd have patience to read the paragraph to the end, you
will see that I chose Z1k, not Z2k precisely because features set
is the same and power is closer. Here is copy/paste of that paragraph
entirely:
========
Controller. Thus far, there are no water cooled programmable DC
controllers taking 380V input, providing 100 kW output, featuring
regenerative braking and having integrated DC-DC converter, so no apples
to apples comparison will be possible. One of the best ones - water
cooled Zilla 2K comes to mind, but it is too powerful for a single 8"
ADC motor - classic problem of big mismatch. Besides, at $4900 the total
cost with a DC motor becomes $6100, just $800 less than complete AC
solution (still no regen) and we didn't even start shopping for a DC-DC,
and main + reversing +precharge contactors yet. Once we're done, it will
certainly cost MORE than AC setup. So we will have to settle for 348V
water cooled Zilla 1K. Compared to an AC inverter, it still provides
more raw power. At $2850 no regen, no DC-DC, no contactors, no dash
interface harness, no throttle sensor, no power cables and 10 times less
warranty period (comparing to Simovert 6SV1). With this choice, $4050 so
far.
=====================
Stand alone, this paragraph appears to be taken out of context because
cost calculations are preceding it and following it, so it may be
difficult to comprehend by reading it alone. But I repeat: Z1K is being
compared to Simovert short inverter (prices at the time it was written).
Considering this cleared, skipping forward.
Ah, I see now I did mis-read what you wrote. I was confused by your
first comparing the Z2K-EHV, and you are correct, I just skipped to
the conclusion and did not carefully read the details used to get
there. I agree with others that your paragraph is difficult to
follow, but yes it is quite a bit closer to reasonable when read
slowly and completely (which clearly I failed to do). I think most
people would expect that if you picked the wrong controller for a
comparison, as you did with the Z2K-EHV, you would just edit it out
of the review to avoid confusion. While it looked to me like you were
trying to insult it with: "classic problem of big mismatch" and your
price calculations. Or wait, maybe I misunderstood you. Maybe with
"classic problem of big mismatch" you were talking about your own
selection process and it just meant that you were unable to match the
controller to the more normal motor arrangement, which for that
controller is usually more than one motor.
The primary reason I wonder about your choice to use the Z2K-EHV is that
Again, this is not what I did.
It looks to me that you are comparing apples to freight trains.
It looks like you can't read Otmar.
As if you were intentionally misleading to your readers.
I need to think how to react on this statement without ruining
your reputation Otmar. What you're trying to do here, won't work.
I expect you to apologize here.
Don't worry Victor, I doubt you could say anything that would ruin my
reputation! :)
I'm happy to admit my errors when they are pointed out to me.
I see no need for me to apologize about that part yet, maybe I can't
read as well as I thought I could, but my point is still as valid as
it was before and you still haven't addressed it.
I reiterate my point: A logical controller for comparison would be
the Z1K-LV (which is still quite a bit less expensive than the
Z1K-EHV which you chose). The Z1K-LV package costs $1975 which is
$850 less than the one you used for your comparison.
Yes, I misunderstood which of my controllers you were comparing in
the end (and yes, I apologize for that error) but my point was still
valid, and you conveniently seem to have ignored that.
The reason I stated that you seemed to think high voltage is better
is because you chose to compare one of my more expensive high
voltage controllers rather than what I feel is the more practical
low voltage unit.
I don't know what you feel. I have only high voltage units and compared
to also identical high voltage controllers.
I'm sorry Victor. But I must call you on that statement. Did you
intend it to sound as misleading as it sounds to me? "Identical" as I
understand it, means something which is "similar in every detail".
You have gone to great lengths to try to explain that AC and DC
controllers are very different, and that they are hard to compare. I
completely agree with you there. They are different and hard to
compare.
So what is the most reasonable way to compare two systems? When
comparing drive systems it is common to compare power ratings. Don't
worry, I'm not trying to say we need to do that, I will be the first
to admit that my lowest power controller has more power than most
people need. So for most people the power difference between your
78kW drive and my Z1K-LV is unimportant. Power ratings are broken
down into voltage and current ratings. Some controllers get their
power ratings from high voltage since on the controller side of the
system it is less expensive to do it this way. Comparing the voltage
alone, and ignoring the current or power rating, as you have done
seems unreasonable to me. I think it would be reasonable, when
comparing the cost of systems, to compare your 78kW system to my
least expensive system. Does this not seem logical to you?
I do have low voltage inverters now, for 1/2 cost of high voltage,
but this tells people nothing: my pricing depends on the discounts
I get from my supplier and may range from unproportionally high to
almost give away based on the situation.
If you don't feel high voltage is better, then it makes sense for
you to change which Zilla controller you are comparing to yours. By
the way, for your future reference all Zilla prices are on my
website here:
http://cafeelectric.com/products/price/
OK. You know where to see mine. Ignoring Siemens, we can discuss MES
inverters, their prices are not surplus and more stable. Power/features
wise about the same.
so you do not need to go to my dealers who are not required to show
all the models or options that Cafe Electric offers. Maybe the site
you consulted did not have my most popular low voltage model.
If you want to compare apples to apples, compare high voltage systems.
Or, let's compare low voltage systems I have how:
http://www.metricmind.com/misc/5109/1fv5104ws09_001.jpg
http://www.metricmind.com/misc/5109/1fv5104ws09_002.jpg
http://www.metricmind.com/misc/5109/1fv5104ws09_003.jpg
http://www.metricmind.com/misc/5109/1fv5104ws09_004.jpg
http://www.metricmind.com/misc/5109/1fv5104ws09_005.jpg
http://www.metricmind.com/misc/5109/1fv5104ws09_006.jpg
As I stated: $2.3k inverter, $2.3k motor (up to supplier
to change that). Identical feature set, only low voltage (72-160V)
and proportionally lower power.
Thank you. I'm glad to hear that. It's good to see more options
available. I can see how they could be very nice in a very light car
(which we should be seeing more of with lithium batteries), but as
you admit, you don't expect to sell many since they are pretty low
power so I don't think those would be a reasonable comparison with my
systems for most people since those power levels can be gotten from
much less expensive DC systems than mine, and at those power levels
the lack of safety features of the cheaper units is much less
important. Those being closer to NEV power ranges, they could
probably compare well with Alltrax controllers.
Since you brought it up, I'll discuss controller efficiency and
rating related to voltage. It is true that controller efficiency
goes up with higher voltage (once you are running IGBTs which both
Siemens and Cafe Electric controllers are doing).
The thing to consider is this:
The cost of IGBT based power electronics is relative to the current
carrying capacity. IGBT's make sense for any system over 144V
nominal, so they are primarily what we use today for on road EVs.
(Victor, I know you know this, but many of our readers surely do
not) Of course the "efficiency sucks" (your words) on a AC drive
that is run below its maximum rated voltage. And I will add that
the power of course drops too. This is one of the disadvantages of
the AC drive.
The power for DC controller drops too - no difference.
Well, there is a difference, when you start with twice the power
needed, then you can choose to drop the power in half and still get
the required performance. It all depends on the power required. My
personal opinion is that 50kW is as low as most people want to let it
drop for a street machine.
If your silicon handles 1000A, then at 200V it's 200kW, and
at 100V is only 100kW, at 50V is 50kW isn't it? Provided
you stay at 1000A silicon limit.
Correct.
It needs so much silicon that they can't afford to overbuild the
rating as much as I can with the simple (and yes I'll say it, Crude
) DC system.
/side note
Good. Why don't you say honest on your commercial web site then:
Crude Cafe electric DC controllers. $1,975 (or whatever).
Misleading your customers? I hole you got my point.
/side note
True, I don't do that. And I'm sure you understand why.
But there is a big difference between trying to make my own product
look bad, and trying to make someone elses' product look bad. I
believe that if you are going to publish a website that says things
about the "competition" with a critical or disrespectful attitude,
then what you say should be true and reasonable.
As I see it the real question for people regarding voltage choice is this:
Can you get sufficient power for your needs, while using the
batteries you want to use, with the controller you can afford?
Often this comes down to the controller being able to make enough
power at low voltages since 6 volt golf car batteries are by far
the lowest cost per mile (usually by a factor of four compared to
AGM and other higher tech batteries). So you see, this is why for
most people who don't have unlimited funds, the battery choice is a
integral part of the drive system choice.
Of course I understand that. People with limited funds don't buy
Mercedeses either. So why Mercedes (company) has to struggle
to make them as cheap as possible? We're talking about systems for
OEM market and I can name many OEM production vehicles (in Europe)
where they are used. Your have to think about people on budget who
prefer 6V golf cart batteries. OEM systems are NOT suppose to cost
the same as non-OEM ones.
OK, If I understand your point many of your customers basically have
unlimited funds. But those people don't care about price comparisons.
So I must assume that the section on your site addressing the price
comparison of AC to DC drives is intended for the same customers who
buy my product, those who find price is important.
Next point, where Victor claims my writing is BS. :-)
I claim that my controller costs $1975. Victor says this is BS.
What can I say? I've sold well over a hundred of them for less that
$2000.
Don't twist what I said. I said if your controller will include
everything included in AC inverter package (same parameters
DC-DC, same throttle pot, same contactors, pre-wired interface, etc), it
will NOT cost $1975.
Matter of fact, here is the whole exchange:
At 156 Volts and 1000 amps it's
almost twice as powerful as his AC drive but only costs $1975.
(Sorry, at the moment I don't make a smaller one)
BS, Otmar. Siemens AC drive includes 60A DC-DC converter, main
contactors, "reverse contactors" (as a software function but for
comparison purposes you'd need to shell out for these), the Bosch
throttle sensor, the battery cables, the motor cables, dash
instrumentation interface all pre-wired.
Add these to your controller cost. Still $1,975??
Yes, I say my controller still costs $1975. What's so hard about that?
I was talking about the controller price, which you in your QA also
showed separately and then later mentioned that it did not include
the accessories that your drive systems includes. I just wasn't
buying your attempt to redirect the conversation and confuse people.
For example, here is a quote direct from your site:
Controller. Thus far, there are no water cooled programmable DC
controllers taking 380V input, providing 100 kW output, featuring
regenerative braking and having integrated DC-DC converter, so no
apples to apples comparison will be possible. One of the best ones -
water cooled Zilla 2K comes to mind, but it is too powerful for a
single 8" ADC motor - classic problem of big mismatch. Besides, at
$4900 the total cost with a DC motor becomes $6100, just $800 less
than complete AC solution (still no regen) and we didn't even start
shopping for a DC-DC, and main + reversing +precharge contactors yet.
It seems that on your site you knew that what I am selling is called
a "controller". You also made it quite clear that it didn't come with
all the things that your "solution" comes with. I call these other
parts accessories since they are not what is primarily controlling
the motor. I was addressing the part of your site where you were
illogically listing the prices of my "controllers" at $4900 and then
$2850. Both of which were well above the closest comparable unit at
$1975. On the site where you then make it clear (quite rightfully so)
that my controller came with "no regen, no DC-DC, no contactors, no
dash interface harness, no throttle sensor, no power cables and 10
times less warranty period" I was just following your lead in the
choice of how to show the breakdown in cost.
It's when you try to change language (or the scope of the discussion)
like this in the middle of the exchange that I have the frustrating
feeling that I am having a discussion with a politician who is hiding
something.
Victor then babbles
I'm asking you to watch your language if you want to have conversation.
Oh I watched it when I wrote it, and it still seems appropriate to
me. Babbling is what politicians do when they are trying to distract
you from the point you brought up. As the saying goes, "if the shoe
fits, wear it".
...about the balance of system components. Well yes, I
didn't say my "complete drive package" costs $1975, I said my
controller costs $1975. It seems to me that if you want to price a
complete drive package you should at least include the battery
price since it is often dictated by which controller is chosen.
I disagree. Battery impacts everything but is not part of the
drive systems cost we're comparing. For comparison wee can both
use 24 Optimas (so the battery cost has no impact AC vs DC).
And I disagree with that choice. 24 Optimas have a very high cost per
mile and are optimized for high power. They would be better for a
short range fast car with fewer batteries. With those my smallest
system might put out 120kW+, but I would be paying for it in
expensive short lived batteries. At those power levels I might use
flooded 8V batteries, or DEKA gells if I wanted maintenance free, but
Optimas, not so much. Of course, to choose a battery we would first
need a hypothetical car and desired use.
We're not discussing how people should build cars (so tie battery
parameters to the electronics. We discuss the cost of non-disposable
hardware.
(I notice Victor strongly denies this fact, but to those who are
building a car it matters a lot)
This is true, but irrelevant for discussion. We are not
talking about overall building a car.
We're not eh? Ok, but I thought the whole reason of your Q and A was
to help people decide which components to use in building a car.
As for the number of features, others have addressed this. The
simple fact is that AC drive requires more features in order to
protect the more fragile motor. Rotor overheating is a big issue
with powerful AC drives (yes I've built AC drives too) and the
software has to be pretty clever to keep this part of the motor
which does not have a temperature sensor from turning into a molten
hunk of aluminum (or copper, on the high performance ones I work
with).
I'm not only talking about features specific for AC motor needs
(though they are there and cost money). But I admit, I have not
read functionality description of a hairball interface, I never cared.
I understand. But you seem to represent that you are capable of
comparing our systems despite that you never cared enough to read the
functional description, much less the manual. Now I'll admit I never
read your manual either, but I am not publicly dissing your
controller on the web either.
I find it rather amusing that Victor says this: "We're not
discussing if you need them or want them. I'm telling you what
exactly cost money."
Why would I pay money for something that I did not need or want!?
Why should anyone else pay for a unwanted and unused feature? I
think we ARE discussing if you need or want the features. Why else
would someone pay money for them?
Interesting. By the same talking why should I pay for 300kW zilla
if I have to limit power to lower value not to break anything or
prevent clutch from slipping? Why do I pay for 1000A silicon
if my battery is rated for, say, 250A? I don't have to. Yet, you
specified above 1000A zilla's silicon was what, $700? So, waste
of money for me?
Well no. First of all, I sell a cheaper 150kW Zilla, so you do not
need to buy a 300kW unit. Also I never said that Zilla Silicon cost
$700, it doesn't.
Were you referring to this discussion?
At 2:56 AM -0700 5/18/06, Otmar wrote:
Heck, you notice my smallest system is 1000 amps. Yes most users
don't use more that 700 amps peak. Since it's simple DC, the extra
300 amps of silicon are such a small part of the production cost
(about $100) that I can just throw them in there for more security.
Glad to see I'm not the only one who "can't read". I guess we're both
human. :-)
And, yes, people who pay for features use them. For instance
10 years warranty. (This though rather exception, MES systems
are two years warranty). OR the fact that the motor is sealed
and practically indestructible. You will never overheat it.
That's very nice.
Or that there are no exposed high voltage connections.
Or, you can listen to the radio while driving because of
EMI is taken care of.
True, I leave those two up to the flexibility of the installer.
Sometimes they do better than other times.
Or, you're 100% assured it will not fail full on.
I think you're pushing it on this. A pedal can still get stuck full
on in either system. Since you have not read about my controllers,
you may not be aware of the advanced protection features included.
And of course a AC drive can lock up the wheels causing an accident
in a way which is much less likely in a DC system.
I believe both scenarios are highly unlikely in our modern systems.
Or record any of 512 running parameters (any 16 at the time
I believe) as you drive to plot and inspect them later,
Yup, much better, mine only does ten at a time, and I don't provide
the plotting software.
Or...
Who cares, right Otmar? The only fun is shredded rubber!
You seem to have this strange image of me. I think you might be
confusing me with Mad Man Rudman, or maybe Wayland who I think just
went through another set of tires. As a matter of fact, I've had the
same tires on my car for five years now. They still have legal tread.
Despite that I'm thinking the Eco-Contacts have too much rolling drag
and I am contemplating the (rather low traction) option of some
taller low rolling resistance tires.
Yes, I enable the worlds most powerful controllers for electric cars
because a number of racers pestered me so much I couldn't say no. But
your image of me seems to be disregarding my work of the last several
years where I've done nothing but try to provide a reasonable cost
drive controller for normal cars. Can I help it if many of my
customers like shredding rubber? No. Still my smallest controller is
about 80% of my volume. I think it's just that the many people who
use my controllers on fun normal (and low power) EV's don't post to
this list about it as much. So maybe you don't see that side of my
business.
AS I said, I'll revise it. I think I'll just describe what it
is, what it can do and what it cost, and throw out comparisons
with any DC systems. It will be more professional.
I agree. That sounds like a professional thing to do. Thank you.
If someone wants to host comparison page, I'll supply technical info.
And I'll gladly do the same. I'd like to see such a page.
The only reason I have what I have is because every second email I get
is question asking to help to choose, why do I want AC?
I get a lot of those questions too. More like "should I go AC or DC?"
I think it might have been one of those that I told to check out the
discussions on this list that may have started this whole exchange.
(Sorry about that everyone. Hopefully we'll get the archives or a FAQ
working soon.) Of course, I was hoping he would be hearing from
people other than Victor and I since I know we are both busy, and
others seem to present the issues with less bias.
Better for you then, less competition from me :-)
No please! Take my customers! My backorder list is too long as it is. :-)
That is why the Hairball that comes with every Zilla has
adjustments for sixteen different voltage and current limits. You
get to set the limits to a safe value for the rest of your car.
Ah, so you do charge for unused potential of the controller?
I do realize it is impossible for one person to build
a line of controllers with 20kW increments so the user
could pick only as much power as he wants to pay for.
MES builds motors from 9kW to 30 kW (rated) with fine
3kW increments and proportional cost. That would be too much
effort.
Yup, when my controller costs $100 extra for the overkill, as
described above, then I feel I would need to sell many hundred before
it justified redesigning it. As you clearly understand it does come
down to a business decision. For the market that I see, I think the
six power levels I offer are appropriate, though I must say the two
of them in the middle rarely sell.
I never said Otmar that Zilla is not flexible. I'm maintaining
that AC systems I have while cost more dollars also offer more
and so worth every penny. I don't believe you can name any worthless
feature. Yes, I promote AC systems. Because they are that good.
And, I did not set the "price of features".
And I agree with that. For many people they are worth every penny.
Nothing wrong with that. Very nice systems too!
And now, for those who have sat through this long exchange, I return
you to your regularly scheduled EV discussion list...
--
-Otmar-
914 EV, California Poppy,
http://evcl.com/914/
http://www.CafeElectric.com/
The Zilla factory has moved to Corvallis Oregon.
Now accepting resumes. Please see:
http://www.cafeelectric.com/jobs.html
--- End Message ---
--- Begin Message ---
I haven't been reading the list for quite some time
but came across this post on three wheeled go cart and
thought I would add my input. I have a 4 three
wheelers and they are all tadpole design one with rear
stearing and all are stable and quick. one being
worked on by hi schoolers is a fully suspended tilting
trike with an e-tec/sevcon and 48v of Hawkers in a
quick swap battery pack configuration . It has a
yamaha 250 rear wheel,swing arm and shock and a
warrior Quad front end with lever stearing.
I hope for a top speed in the 40/50mph range and very
quick excelleration. When it was originally built it
was done with bicycle parts but the speed soon
exceeded the saftey concerns so we went to motorcycle
parts at some sacrifice in additional frame weight but
by changing from orbitals to hawkers we achieved about
the same net wieght but a reduced range...This is
intended to be a toy not street legal...our goal is to
make something scary fast and swap the batteries
often.
--- Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> It's all about design. You can design a delta style
> trike (single front
> wheel) to handle braking safely. All you have to do
> is make sure the
> central of gravity stays inside the triangle formed
> by the wheels.
> Basically if you take the CoG and draw a cone
> extendeding downward at a 45
> degree angle, and make sure the base triangle is
> outside this cone, then
> it can't tip even when braking at 1G (nearly
> impossible in a simple cart)
> This arrangement will skid before tipping.
>
> Delta trikes might not perform as nimblely as
> tadpole designs, but they
> are easier to build.
>
> > I have to tell you guys, I don't think the two in
> the back and one in the
> > front is all that good of an idea. I know there's
> that new trik EV on the
> > west coast but think about it, what happens when
> you are hard on the
> > brakes
> > and you turn the wheel. How many times is it going
> to roll over.
> >
> > I've seen some nice trikes with one drive wheel in
> the back and two
> > steering
> > in the front. Makes a lot more sense to me.
> >
> >
> > Mark Grasser
> > 78 #358
> > BIG REDs
> > http://members.rennlist.com/mgrasser
> > ----- Original Message -----
> > From: "Roger Stockton" <[EMAIL PROTECTED]>
> > To: <[email protected]>
> > Sent: Thursday, May 18, 2006 7:15 PM
> > Subject: RE: Three-wheel Go-cart
> >
> >
> >> Neon John wrote:
> >>
> >>> Peter is correct, as a brief look at any web
> site selling kart parts
> >>> will show. Suggest Northern tool as a good
> place to look. I'm using
> >>> one of their differential axles (they sell a
> name brand but I can't
> >>> recall the name at hte moment), cut down to an
> appropriate length for
> >>> a 3 wheel scooter that I'm working on at the
> moment.
> >>
> >> Nope. Check a kart parts supplier, such as
> >> <http://www.gokartsupply.com/partcat.htm>. Most
> karts use a solid rear
> >> axle with a full-length keyway that allows one to
> positively attach the
> >> hubs that the rear wheels mount to, as well as
> the single driven
> >> sprocket and single brake disc that attach to
> this solid axle.
> >>
> >> I've driven a number of rental karts, and all
> have been of this drive
> >> configuration, as have been the few electric
> karts I've seen, and the
> >> few 'higher end' karts I've seen. I won't go sop
> far as to way that all
> >> karts run solid rear axles with both wheels
> driven, but a quick online
> >> search suggests that may well be the case... The
> only axles available
> >> from kart suppliers seem to be of the solid
> variety, and even at the
> >> 100-125cc shifter kart class the solid rear axle
> is used.
> >>
> >> Cheers,
> >>
> >> Roger.
> >>
> >
> >
>
>
> --
> 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.
>
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Dave said :-
item 4640056459 - Looks nice!
"Those Yuasa batteries are supposed to last 10 years? "
Do you really think they will?
What can you tell us about them?
I can tell you that they are 6volt 160 ampere hour and that the Yuasa rep in
the UK told me that they should last 10 yrs if they are not discharged to
<30% on a regular basis and that the charging regime is in accordance with
their spec (which is quite a few pages), but is actually quite simple.
I know of another EV in the UK who has been running these for 6yrs and he
says they are still as good as they day he fitted them.
My own have done about 2500 miles now and the cells (2v) are all within 5mv
of each other on a 30 amp discharge tester. I get 50 miles range and 50mph
on the flat increasing to 60 on even the smallest slope.
So at the moment I really think they have every chance of reaching their
10th Birthday - by which time Li-poly will be "cheap as chips" and we will
all be happy EV'ers
There is a huge amount of interest on the ebay auction with 643 visits to
the listing, and 57 watchers and 6 test drives so far. Now of course this
could all be "general interest" in EV's but people seem very taken with the
concept of an electric van with a 1 Tonne payload that costs less than
2p/mile (4c) and is free of other taxation levied in the U.K.
It is only up for sale because I do not have the space for 5 vehicles and
"she who must be obeyed" says its time to thin them out !.
Kind Regards
John
----- Original Message -----
From: "David Roden" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, May 20, 2006 7:27 AM
Subject: Re: UK Electric Van on Ebay 4640056459
On 13 May 2006 at 14:53, John Luck Home wrote:
My electric Van now listed on ebay in the UK
item 4640056459
Looks nice!
Those Yuasa batteries are supposed to last 10 years? Do you really think
they will? What can you tell us about them?
Thanks,
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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> I disagree about efficiency podium !
>
> Gates GT2 Belt and similar like Contitech synchropower with 98% have
> better
> efficiency than chain which can't pass 95%.
You need to read up on this a bit more. Gates poly chain can achieve 98%
efficiency, but ONLY when operating at it's maximum torque level.
The belt losses are almost constant regardles of power, so you only hit
maximum efficiency at just before the point where it starts stripping
teeth off the belt.
So if you size the belt system to have just enough torque to climb a hill,
and assuming that on the flats you are running at approx 10% of the torque
used for climbing the hill, then if the losses stay the same the 2% loss
when climbing the hill becomes a 20% loss on the flats.
This is why many/most of the solar racing teams no longer use belt drives.
A well oil chain stays at approx 96% across a wide band of torque/power.
.. for racing, type without
> o-ring, well lubrificated, new, good tensionning force etc .
> Let me know about a chain (oring is worst) which is 98% efficient, ...and
> still 98% efficient all is time life ?
>
> cordialement,
> Philippe
>
> Et si le pot d'échappement sortait au centre du volant ?
> quel carburant choisiriez-vous ?
> http://vehiculeselectriques.free.fr
> Forum de discussion sur les véhicules électriques
> http://vehiculeselectriques.free.fr/Forum/index.php
>
>
> ----- Original Message -----
> From: <[EMAIL PROTECTED]>
> To: <[email protected]>
> Cc: <[email protected]>
> Sent: Friday, May 19, 2006 6:52 PM
> Subject: Re: Fw: Vectrix - Now Belt verses Chain verses Shaft drive types
>
>
>> This note is primarily a response to Mike Phillips question related to
> drive
>> types for a donor EV motorcycle. Most of the posts here have hit well on
> the
>> characteristics of belt or chain or shaft type final drives for 2
>> wheeled
>> applications. I just wanted to touch on some of the other points in a
>> bit
> more
>> comprehensive evaluation.
>>
>> Efficiency in order best to worst
>> 1) chain
>> 2) belt (in this case I am referring to a toothed synchronous type like
>> Gates Poly Chain GT2)
>> 3) shaft
>>
>> Please note that drive chains come in two basic types, industrial and
>> "O-Ring". Modern motorcycle applications all use the o-ring type that
> seals a small
>> reserve of oil to allow a longer wearing chain with less attention to
>> maintenance. O-Ring types do reduce efficiency compared to industrial
> types. Over
>> the past few years manufacturers have created things like X-Rings to
> address
>> the efficiency loss issue.
>>
>> Weight in order lightest to heaviest
>> 1) belt (aluminum cogged pulleys, kevlar fiber reinforced toothed belt)
>> 2) chain
>> 3) shaft
>>
>> Most people do not realize that in a typical motorcycle application the
>> chain and sprockets are fairly heavy. This is why you see aluminum
> sprockets and
>> slotted chain side plates used in racing applications. On my 750cc
>> Suzuki
> ICE
>> street bike (all steel) a 14t front sprocket, 41t rear, and 96 links of
> #630
>> chain weigh ~12 pounds.
>>
>> Noise in order of quietest to noisiest
>> 1) belt
>> 2) shaft
>> 3) chain
>>
>> My Kawasaki Ninja EV uses a std. motorcycle type #525 chain drive. Once
> the
>> ICE is gone the noise of the drive chain is really LOUD. This is true
>> on
>> every EV motorcycle I have ridden. The noise is enough to be really
> annoying even
>> when wearing a full coverage helmet. Of course this helps in parking
>> lots
> as
>> people can hear me coming and I don't scare my neighbors. I have to
>> admit
>> that I lust after a quiet belt drive.
>>
>> Handling
>> Note that the shaft drive has an unusual behavior under hard
>> acceleration
>> like exiting a corner. I think of the shaft drive as much like the ring
> and
>> pinion gears in the rear end of a rear drive car. This may not be
> completely
>> accurate for a motorcycle, but bear with me. When accelerating hard the
> ring
>> gear attempts to climb the pinion causing the rear seat of the
>> motorcycle
> to
>> rise instead of the expected squatting behavior. This feels funny to
>> most
> riders
>> the first time they are on a shaft drive bike. The short story is that
>> you
>> get used to it and modern motorcycles have attempted to minimize this
> behavior.
>>
>> Durability most to least
>> 1) shaft
>> 2) chain
>> 3) Belt
>>
>> The average well maintained O-Ring type chain should last well over
>> 15,000
>> miles which might be 8 to 10 years on the average EV motorcycle. The
> downside
>> is that periodic adjustments ~ every 1,000 miles are required to
> accommodate
>> for the chain stretching and of course there is some throw off of the
>> oil
> used
>> to lubricate the chain. The oil throw off on my rear wheel and electric
>> motor really offends my EV sensibility.
>>
>> Also note that riders may want to factor in their riding conditions
>> before
>> choosing a belt drive. Small rocks form dirt, gravel, or even a freshly
> coated
>> blacktop rock chip type surface can tear the crap out of belt quickly
>> causing complete failure while driving.
>>
>> Cost cheapest to most expensive
>> 1) chain
>> 2) belt
>> 3) shaft
>>
>> A good chain set up costs $150 to $200 including replacing the
>> sprockets.
>>
>> Conclusions
>> - I really don't mind the maint. associated with a chain drive, but the
>> weight, noise and mess are unpleasant. Cost and availability of modular
>> replacement parts is also an advantage.
>> - I recognize that a shaft drive does offer quiet operation with no
>> mess,
>> little maint. and great durability at the expense of weight and
>> handling.
>>
>> - However I believe that the ideal drive for an EV motorcycle is a
>> synchronous belt drive. The benefits are no messy oil, light weight and
> quiet
>> operation. The downside is cost, potential durability issues and
> maintenance to
>> adjust for belt stretch.
>>
>> Mike Bachand
>> DEVC
>> Colorado
>>
>
>
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