EV Digest 6949
Topics covered in this issue include:
1) Re: firefly batteries?
by [EMAIL PROTECTED]
2) RE: FW: Regen with Sevcon and Etek
by "Garret Maki" <[EMAIL PROTECTED]>
3) RE: FW: Regen with Sevcon and Etek
by "Garret Maki" <[EMAIL PROTECTED]>
4) Re: Controler
by "Peter VanDerWal" <[EMAIL PROTECTED]>
5) Re: regarding the Solectria Sunrise
by "jerryd" <[EMAIL PROTECTED]>
6) Re: Controler
by "Andre' Blanchard" <[EMAIL PROTECTED]>
7) Re: EVgrin - RAVolt takes first EV trip
by "Joseph T. " <[EMAIL PROTECTED]>
8) Re: Understanding my motor (ADC L91 & X91 6.7' motors revisited)
by "Peter VanDerWal" <[EMAIL PROTECTED]>
9) Data Logging for Zilla
by "Mark Eidson" <[EMAIL PROTECTED]>
10) Re: FW: Regen with Sevcon and Etek
by [EMAIL PROTECTED]
11) Re: Make it
by Dan Frederiksen <[EMAIL PROTECTED]>
12) Re: Data Logging for Zilla
by MIKE WILLMON <[EMAIL PROTECTED]>
13) Re: VOLTS vs AMPS & RE: Make It
by Danny Miller <[EMAIL PROTECTED]>
14) Re: EVgrin - RAVolt takes first EV trip
by [EMAIL PROTECTED]
15) Re: Controler
by "Phelps" <[EMAIL PROTECTED]>
16) TdS Report #10: Photos - West Philadelphia High School "K1 Attack"
by [EMAIL PROTECTED]
17) Re: firefly batteries?
by "Joseph T. " <[EMAIL PROTECTED]>
18) Re: Cheap "balancer" for A123 pack
by Victor Tikhonov <[EMAIL PROTECTED]>
19) Re: Data Logging for Zilla
by "Joseph T. " <[EMAIL PROTECTED]>
20) An Ebay find?
by Tom Gocze <[EMAIL PROTECTED]>
21) Re: Manly EV's, RE: EV are for girls blog
by "Loni" <[EMAIL PROTECTED]>
--- Begin Message ---
Hello Lawrence
One other difference then regular lead batteries. If I remember right they
were to weigh like 1/4 the weight of lead acid batteries.
I read about these at least 2 or 3 years ago. They even had the city they
were in investing money into the new company. You would think they would have a
battery out by now?
Don Blazer
In a message dated 6/25/2007 2:11:18 PM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
If what they say is true there won't be any difference between them and
regular lead batteries except capacity, durability & reliability. I suspect
they won't even need regulators. Lawrence Rhodes....
----- Original Message -----
From: "Zeke Yewdall" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, June 24, 2007 8:22 PM
Subject: firefly batteries?
> Wondering if anyone has any thoughts on these? I sort of have an in
> with the company to test some in my EV (probably about 5 or 10%
> probability, but that's better than no contacts)... but as of yet all
> I've seen is hype, not specs. BMS required? Discharge rate? cycles?
> Thermal management? Not even sure if they really exist yet.... I
> supposed I could ask my contact there, but I figured someone on this
> list might have already researched them more than I have.
>
> Z
>
************************************** See what's free at http://www.aol.com.
--- End Message ---
--- Begin Message ---
Unfortunately the pack on there now is shot with only a mile or two of
range. I'll try to give this a try and report back. Thanks for the
info.
Garret
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Monday, June 25, 2007 12:35 PM
To: ev@listproc.sjsu.edu
Subject: Re: FW: Regen with Sevcon and Etek
Hello Garret
If it is a smart controller it will not allow your batteries to be over
charged during regen. Have you tried running down the batteries to say
60% and
then try?
Don Blazer
--- End Message ---
--- Begin Message ---
Rick,
I think I've got all this configured. I am using footbrake with a pot.
Honestly considering the minor stopping force I am getting now, there is
no advantage to the pot or over a switch, I am applying it full now with
little affect so being able to taper the regen isn't useful yet. I'll
try to drain the batteries more and try it again. I have the calibrator
on loan right now, but need to return it soon.
-Garret
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Monday, June 25, 2007 4:39 PM
To: ev@listproc.sjsu.edu
Subject: Re: FW: Regen with Sevcon and Etek
The Sevcon Millipak is a very smart controller. It is basically made for
fork truck and Walkie operation which means it has features you'll never
use. It
is not really set up to be a electric vehicle controller but with all of
the
features it can work very well as one.
Sevcon Millipak braking levels are set using personalities 1.01, 1.02
and
1.03. each is stated in %.
1.01 is direction braking, it is activated by going from forward to
reverse.
1.02 is Neutral braking level, it is activated by going to drive to
neutral.
1.03 Footbrake braking, for use if you have a footbrake configured.
Choose 100% for maximum braking or lower for less braking.
There are also finish levels you can set (1.05) and start voltage levels
(1.04) I'm not entirely clear on these but my finish voltage is at max
255 which
will leave the regen braking on as long as possible.
There are other controls at 11.1, and 11.11 which can be set up when
using a
pot for a footbrake.
I am using the neutral braking option. It is easy to set up and gives
good
braking performance. I have it connected to the back footbrake pedal by
microswitch. I wish I could use the footbrake option with pot so that I
could get
variable regen but I haven't figured that out yet.
Because I have a 4 speed on my bike I can always get good regen. I see
my
ammeter at -100 occasionally even though I am only using 13Ah Hawkers
(tough
little bastards) For accelleration I can ask 250A monentarily on a fresh
charge. Not too good for them, but they were surplus and cheap.
One thing I almost never hear when people are discussing the merits of
regen
is that the large surface charge will really get you off the line
without
taxing the remaining battery charge too much.
Back to the tech. My regen with this controller does taper a bit with
speed
but in my first gear I can regen right to a stop. Regen is strong enough
to
be the noisiest operation due to reverse torque on the transmission.
Regen is
also stronger when the batteries are not fully charged.
So it sounds like your etek and millipak is operating just like mine
except
my gearing is lower.
Of course none of this will be of help to you if you don't have a
calibrator.
Oh and if you learn to use a footbrake pot for variable regen please let
me
know I would love to try it out.
Rick Miller
Dirty Green Kawasaki
************************************** See what's free at
http://www.aol.com.
--- End Message ---
--- Begin Message ---
Mechanical PWM has been used in the past and mostly abandoned. If you
want to try this route, there are some considerations you need to take
into account.
As we have already pointed out, changing the frequency has no effect on
speed, so youll need to figure out how to vary the pulse width ratio (on
to off times)
Also, when a mechanical switch opens while carrying hundreds (or
thousands) of amps it will normally ARC across the contacts. THis is
exactly the same kind of arc that welders use to melt pieces of metal
together and will have exactly the same effect on your contacts, i.e. it
will try to weld them together.
Even if you can avoid the welding, the arc will vaporize a portion of the
contacts every time they open, so eventually you will wear away the
contacts.
You will need to do something to quench this arc. What they usually have
done in the past is to add electronic components (inductors, capacitors,
Didoes, etc.) to temporarily route the current somewhere else while the
switch opens. The better solutions tend to be as complicated and
expensive as electronic PWM controllers.
ANother option is to replace the mechanical switch with an electronic one
that is cheaper than the transistors commonly used today. SCRs were
popular 30-40 years ago. SCRs are much cheaper than MOSFETs or IGBTs, but
have their own set of problems associated with turning off the current.
They needed additional components similar to what the mechanical switchs
required. THey also are not as efficient as modern transistors. Aside
from a few hobbiests, I don't think anyone builds SCR based controllers
anymore.
Another option is to use contactors to rearrange the batteries in you
battery pack to provide different voltages. THis is commonly called a
"contactor controller" (google it). THe big problem with these is that
high power contactors are very expensive. If you use new components it
will usually cost more than an electronic controller.
However, if you are good at scrounging you might have some luck locating
used/surplus contactors so this might be a viable "cheaper" option.
The contractor controllers usually have only a limited number of "speeds"
Perhaps three or four different steps. You control your desired speed by
switching back and forth between steps, i.e. high speed until you get
going to fast and then medium speed until you slow down to much and then
back to high speed.
Also be aware that almost everyone who changes from contactor controllers
to PWM controllers rarely ever goes back to contactors. THat says a lot
about how much nicer PWM controllers are.
> -------Original Message-------
>
> From: Phelps
> Date: 6/25/2007 5:40:49 PM
> To: ev@listproc.sjsu.edu
> Subject: Controler
>
>
> Just to keep it all straight.. When I wrote the short message about
> (making
> It.).I lost most everybody here you assumed that I was thinking about
> making
> a
> Electronic controlled controller....
>
> Nope never said that and never wanted to do that..
>
> I was just thinking about a mechanically driven switch.. Not as nice as
> What you are all use to.. Probably noisyer if it could be done ..
> But if it could be done.. It would be cheaper..
>
> Building a fancy mechanically switch .. Is that so hard .. Maybe .. Maybe
> Not.
>
> I don't know but I sure do Have the thought.
>
>
> Mitchell
>
>
>
> Maybe a motor spinning a switch that contacts for a longer period of time
> as
> you draw the contact closer to the spinning contact..
>
> Maybe brushes from a motor the same size on you EV could be used to make
> the
> contacts in the switch..
>
> Mitchell
>
>
>
>
>
>
--
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 ---
--- Begin Message ---
Hi David and All,
----- Original Message Follows -----
From: "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Subject: Re: regarding the Solectria Sunrise
Date: Mon, 25 Jun 2007 12:27:15 -0400
>> What was so special about the construction of this car
>> that it could get 375 miles on a charge ?
>
>It was partly a battery with a high specific energy, and
>partly detailed attention to high energy efficiency.
>
>The Sunrise was a purpose built EV design with composite
>structure and was very light. It had good aerodynamics
>and a lightweight, low friction drivetrain. The AC
>induction motor and controller were built to be as
>efficient as possible. The battery was Nickel Metal
>Hydride from Ovonics. Every element of the design was
>carefully optimized for the highest possible efficiency
>consonant with a design that could be mass-produced.
Well said. But not only did it do that 377 mile
range, it did Boston to NYC, over 250 miles on a single
charge with range left on I-95 with 3 people onboard
including a Car and Driver magazine reporter. So it can
hardly be said it can do it's range at only a slow steady
speed.
It, I believe is the finest EV ever built.
>Reportedly Azure Dynamics, which purchased Solectria a few
>years ago, is not interested in commercializing the
>Sunrise design. However, the design's current status
>isn't clear to me.
Azure owns the rights as far as I can tell to the
original Sunrise. That said I bought the body,chassis with
the help of several List and other EV'ers, especially Bob
Rice, from James Worden and went to the Azure's Mass.
factory to get the chassis mold and they knew what I was
going to do, make a bunch for EV'ers in kit form and they
had no objections.
James was rather pissed when he found out about my
offer 4 yrs ago to bring it back into production was not
passed on to him as he would have done it then he said.
Actually only the excellent Aero shape and even that
will be changed, will be the same on the Selectria Sunrise
and Lee's version so really 2 different vehicles with the
same goals, just updated for better, more cost effective
composite layup and completely redesigned chassis and front,
rear clips.
>
>Azure and/or James Worden, who designed the car, sold off
>some or most of the prototypes. Several EV hobbyists
>bought them, and a couple have expressed interest in
>trying to reproduce the design. My understanding is that
>James Worden isn't opposed to this, and presumably Azure
>isn't. However, whether any of these hobbyists actually
>has a signed document giving him the legal right to use the
>Sunrise design, I don't know.
There are about 4-6 Sunrises finished and another 6
or so body/chassis composite parts, of which I bought one.
The others went to companies like Hexel, Ciba, other
composite, ect, companies and may still be waiting t be
finished to put back on the road.
>
>> Are there any owners of this car on the list at present ?
>
>Lee Hart has one of the prototypes, and is one of the
>enthusiasts trying to reproduce it. He is working on
>turning the Sunrise into a kit car. Perhaps it would be
>more accurate to say that he is designing a kit car that
>looks like the Sunrise and is based on its design.
Yes, that's the way it is.
>
>I have a great deal of respect for Lee, but I must say that
>from his description I doubt that the result will have the
>range of the original. (But I don't think that's his
>objective; see below.) Although the body will still be
>aerodynamic, I believe he is using a construction method
>that differs from Solectria's. I don't know how this will
>affect the weight.
It will be better, lighter. The Selectria version was
made with double sided mass production molds that were not
real accurate so even using medium tech composites, it's
weight will be lower for the same strength by doing it in
hand layup.
As for crash protection, I just recieved the crash
vid, thanks Beth!!, for the Sunrise hitting a wall frontal
test and it did very well. Sadly little if any data on the
Sunrise in any form is left. If anyone has any like the
layup shcedules, crash test data, ect please let me know.
>
>His most substantial changes are in the drivetrain. As I
>understand it, the original used mostly Geo Metro (Suzuki
>Forsa?) suspension parts, one of Solectria / Brusa's
>purpose built lightweight, low loss transaxles driving the
>front wheels, and a well-tuned lightweight AC induction
>motor and inverter combination.
As most of it is changed, it's hard to say which is a
bigger one, the new chassis, the suspension,
motor/controller, the new crash protection methods, ect.
>
>Lee is using a DC motor instead of the AC motor. It would
>be difficult for such a motor to match the very light
>weight of the original Solectria Sunrise motor.
But it would be difficult to match the DC motors
torque. With good suspension tuning and many racing parts
for the ones Lee picked, a Wayland EV drive, Li batts this
would have a fair chance giving the Tesla a hard time at the
track, road or drag. And with 4 seats!! If one were to use
Li batts, they could eliminate the tunnel and have a 6 pass
EV as it's rather wide.
>
>His motor will drive the rear wheels, rather than the
>front. It will use a drive axle from a Thunderbird. This
>has to be appreciably heavier (but no doubt cheaper and
>more readily available) than the very light, custom
>designed front drive transaxle of the original.
Not much more and much heavier duty. And it
eliminates the trans/clutch.
>
>I believe the car will most likely use lead batteries.
>There are very few practical and affordable options for
>using NiMH batteries in road EVs. Probably lithium
>batteries could be fitted.
I think Lee is being modest about the Lead range as
you can really load it up with batts, 1782 lbs of T145's
would easily give 100-200 mile range depending on speed,
ect. Same could be done with Ni-cads at 1/3 less weight.
With max amount of Li batts, range could go as high as 450
miles if you are really rich.
>
>Lee is an outstanding engineer too, but I think a rather
>different one from Worden. Lee reminds us, quite
>correctly, that "the perfect is the enemy of the good." I
>think he'll make the Sunrise II good - very good. It will
>be an efficient EV, surely more so than the typical
>conversion. I also expect it to be affordable, costing a
>fraction of the lowest price Solectria quoted.
I can't think of a better person than Lee to do this
right and why I picked him to do it. It was clear it would
take too long if I waited until I was ready to do it.
>
>I don't think it will be as efficient as the original
>Solectria Sunrise, and I doubt that it will approach the
>Sunrise's remarkable range.
With Li, it can easily beat the old range. Do the
math.
However, it will be an EV kit
>(and perhaps eventually a turnkey EV) that hundreds or
>thousands of people can buy, something that Solectria
>never achieved with the design.
There is a big difference between a composite EV done
by a bunch of not very experienced engineers and one
designed by someone who builds composite vehicles for a
living. As designed, the Selectria could never be cost
effectively produced due to material costs and labor to
build. It had to be modified.
>
>> Where can I get detailed information, blue prints,
>> technical specifications or even some hi-res photos of
>this car ?
>
>I don't know. Maybe if you flew over to the States, one of
>the owners of a prototype would let you examine it.
If you Yahoo, Google Selectria Sunrise, there are a
bunch of things like the chassis mold I almost got is
featured on one composite company's website and other
things. The old Car and Driver article is somewhere and
Wiki's too.
Jerry Dycus
>
>David Roden
>EVDL Administrator
>http://www.evdl.org/
>
--- End Message ---
--- Begin Message ---
At 05:17 PM 6/25/2007, you wrote:
If you want to build a mechanically driven drum switch circuits for motor
controller, it is best to get a early addition copy of The Standard Handbook
for Electrical Engineers from the year 1933 or so.
You will not be able to down load this handbook, but you may luck out and
get a copy from the public library. The new later handbooks will set you
back more than a cost of a controller and they are not that detail.
It has complete design section on any type of controller you want to build.
There even sections on how to different type of batteries are made, how
motors are made and different winding configurations.
With this handbook, all you need is a shop with machine tools, the raw
material, and it will show you how in detail to design and build any
electronic and electrical systems.
Roland
I did not find the entire books but I did find part of it.
Section 13 from the Standard Handbook for Electrical Engineers 1908
http://books.google.com/books?id=tkAFAAAAMAAJ
Some other books
http://books.google.com/books?id=SsIJAAAAIAAJ
http://books.google.com/books?id=UOjpsFsWSrAC
http://books.google.com/books?id=iDASAAAAIAAJ
http://books.google.com/books?id=cgsAAAAAMAAJ
http://books.google.com/books?id=UP8HAAAAMAAJ
http://books.google.com/books?id=P_m7webHng8C
http://books.google.com/books?id=5WGfE9UR_AEC
http://books.google.com/books?id=ZlCLIxkECvwC
__________
Andre' B. Clear Lake, Wi.
--- End Message ---
--- Begin Message ---
Congratulations! Tell us later about the performance! And a little
question for you...In order to go in reverse do you need a
forward/reverse contactor? You can just shift in to reverse instead,
right?
On 6/25/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
All,
I know the list loves good news: the RAVolt made her maiden voyage
over the weekend!
YouTube: http://www.youtube.com/watch?v=hUv3wZQTcQE
Rob H
RAVolt.com & EValbum 995
--- End Message ---
--- Begin Message ---
>
> Since I have the L91, can I assume that the opposite applies? Fewer
> commutator bars and windings so I will use more current to get a given
> amount of torque and that means that I will probably use more of my amps
> to
> accelerate to a particular speed but that I can get more RPM's per volt?
Yes it would take more amps, unless you take advantage of the higher RPMs
and change to a higher reduction ratio. If you change to a higher
reduction, then you will get similar acceleration.
The design of the motor trades torque for RPM, so if your transmission
swaps them back then you end up at the same place.
>
> What does this mean for my driving style? Any recommendations?
>
> Thanks,
>
> Rich A.
>
> _________________________________________________________________
> Hotmail to go? Get your Hotmail, news, sports and much more!
> http://mobile.msn.com
>
>
--
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 ---
--- Begin Message ---
Is there a data logging program for a laptop PC that can put the Zilla
in data streaming mode and log the data?
--- End Message ---
--- Begin Message ---
It may be the dead batteries thats stopping you (or not as the case might
be). Because of their condition they probably have a relatively high internal
resistance. This would cause the voltage to float pretty high with only 10 or
so amps going in. The Sevcon probably limits voltage during regen. My hawkers
can take tremendous surges at only 52V when their at around 50%. Because
their small I only get about 3 miles range also.
Got any details how did you hook up your footbrake pot. Was it Analogue
input 2? Did you change anything else like 12.15, 12.16 or 12.17.
Rick Miller
************************************** See what's free at http://www.aol.com.
--- End Message ---
--- Begin Message ---
Granted I'm coming from the outside and many aspects are unknown to me
but I'm no dummy and I still believe it can be done and you are just
naysaying because the vision is not clear to you.
It's true I was disappointed to hear of the need for high derating but I
did already know about it in the small packages and I'm not sure I got a
satisfactory answer from Lee whether derating was just as bad in the
large IGBT modules like int-A and above. more importantly though the
price did not triple as you suggest since Oatmeal has said that the
IGBTs he uses for a zilla1k cost him 165$. so you're wrong.
Similarly JB Straubel's ad hoc controller seemed very simple. the kind
of simple I'm aiming for although I wouldn't be using 6 500A modules!
A smart man could easily convey the needed knowledge to someone like me.
Genius makes the complex simple.
The reason I'm not so concerned with the microcontroller code is that
I've already done some experimentation with an AVR. I am a computer
scientist.
It's a common fallacy to blindly trust those that went before.I've heard
that the reality of flight was denied even years after the wright
brothers flew. that despite public demonstrations the press wouldn't
cover it because it was known to be impossible. don't be that monkey
Dan
Eric Poulsen wrote:
Dan,
You're not asking for a meatloaf recipe. To be frank, you're naivete
in the area of power electronics (1) leads you to believe that
controllers should be much cheaper than they really are.
I'm personally developing a MOSFET based controller for my own use,
but I am documenting my progress (nuancesystems.net). Right now,
there isn't much there, but when I have a barely-working prototype up,
I'll post more information than you can shake a stick at.
Having said that, I've done many _MANY_ hours of research, and put
many hours into my shop (garage) measuring, cutting, drilling,
mounting, testing, etc. I've also put a lot of $$$ into it, and I'm
realizing that while a lot of that money is a good investment (tools,
etc), there are a lot of failed experiments that lead ... nowhere.
And that's just for the mechanical layout.
The task you're speaking of is not a 60 minute job. You _will_not_
find a "simple and practical" design for a 320KW controller.
With regard to "help out a little bit," it's a bit like asking a
doctor how to cure a rash, and getting upset that he doesn't teach you
everything he learned in medical school. Even if he were willing to
do so, it would take too much time, and there's no chance you'll be a
doctor when he's done.
(1) You seemed surprised to learn that the transistor current rating
is often derated to 40% or less. Guess what? Your transistor budget
nearly tripled just now. Don't forget diodes, capacitors, bus bars,
good control and protection electronics, heat sinks, etc. A controller
is so much more than the cost of the transistors alone. Heck, I'd
personally rather get a good look at Otmars microcontroller code --
it's at _least_ as important as the devices used or their layout.
It's a little strange you haven't asked about it, unless you don't
really know it's value. Which is exactly my point.
Complex problems often need complex solutions, despite belief to the
contrary.
Dan Frederiksen wrote:
I feel the same way. a cheaper controller certainly can be done. a
lot cheaper
a sub 500$ zilla1k equivalent if someone foxconn'ed it (mainstream
mass production, not typical b2b pricing mentality)
unfortunately those with experience don't want to take the 60 minutes
it takes for them to design a simple practical circuit to this effect
so others have to do the much greater task of getting training and
experience first and then doing it
some few will help out a little bit if asked about something isolated
but most here will rather fight it
Dan
--- End Message ---
--- Begin Message ---
You can use most free Terminal programs, like Hyperterminal, to capture the
data to a file.
Someone on the list mentioned using a program called Snag-It for the Palm to do
the same thing.
Mike,
Anchorage, Ak.
----- Original Message -----
From: Mark Eidson <[EMAIL PROTECTED]>
Date: Monday, June 25, 2007 4:12 pm
Subject: Data Logging for Zilla
To: ev <ev@listproc.sjsu.edu>
> Is there a data logging program for a laptop PC that can put the Zilla
> in data streaming mode and log the data?
>
>
--- End Message ---
--- Begin Message ---
I think you're grossly underestimating the complexity of the task.
Starting with a bunch of transistors, caps, diodes, and a PWM source is
still pretty far from a viable controller when we're talking many
hundreds of amps. Special knowledge and design techniques are required,
and there's a lot of reasons why your parts' basic specifications will
be far reduced for the application.
For example, look up the ripple current for the $0.87 capacitors. I
doubt we're talking 10-20 amps per cap here. In fact 1 amp is more
likely- 32x capacitors, 32 amps of ripple rating here not counting
balancing issues and a generous safety factor. Even the big names in
controllers have a hard time meeting ripple requirements and getting a
decent assurance of an acceptable lifetime in this application is tough-
that's not something that a spec sheet will really be able to show for sure.
The IXFK120N20's die be rated at 120 amps with more than ideal
heatsinking and not at elevated temps, and at DC only. Switching losses
are significant and will take away a lot of that rating. But the spec
sheet indicates a common hidden limitation- the die may be rated at
120A, but the leads are rated for only 76A. Since one cannot use the
device without leads I don't even know why they spec something where
there is no possible scenario that would use that specification.
Not that this means the IXFK120N20 is a "bad" device. It's fine. But
there's a long string of subtle "gotchas" here that will reduce the
effective rating in your application. Wait till you see the issues in
getting hundreds of amps through PCB traces and getting the ideal
driving waveform at the MOSFET gate- any ringing can greatly increase
losses and potentially destroy the device once under load.
I don't wanna discourage you from getting into it- far from it. But
understand the complexity of the job first to avoid just making one
flaming prototype after another.
Danny
Ian Hooper wrote:
OK, I wasn't picking on their component choice so much as saying you
can build your own speed controller for a lot less than it costs to
*buy* a Curtis. The retail price of the 1221s is about $1100,
correct? For power stage component cost, going on quantities of 1000
units, prices from digikey are:
32x 220uF 200VDC electro caps @ $0.87ea = $27.84
36x BUZ30A @ $1.13ea = $40.68
12x 300V 60A diodes @ $1.08ea = $12.96 (couldn't find SR4180R-C,
this is actually the higher-rated STTH60P03SWs)
TOTAL = $81.48
So, $1100 seems a bit much to me. I realise these three components
aren't the only expense, but still..
As for component selection, they're fine I guess but I tend to think
it's more elegant to go with a smaller number of higher-rated semis,
such as the IXFK120N20 (200V 120A 0.017ohm MOSFET) @ ~$10ea or the
STTH60L06C 80A diodes @ ~$2ea, even though it may end up costing a
tad more.
-Ian
On 25/06/2007, at 10:10 PM, Lee Hart wrote:
Ian Hooper wrote:
Out of interest, I'm building a motor speed controller at present
and I will have to agree that it can be done quite a lot cheaper
than the price of the Curtis units. They are a 20 year old design
now, and semiconductor technology (both transistors and
microcontrollers) has improved quite a lot in the last few decades.
e.g you can now get individual MOSFETs with about 1/10th the
on-resistance of those used in the Curtis controllers.
Really? A Curtis 1221 controller's power section has 32 220uf 200vdc
electrolytic capacitors, 36 BUZ30A 200v 21a 0.1 ohm MOSFETs, and 12
200v 40a SR4180R-C diodes. Look up the prices, and add up the cost.
Now tell me what you would use in their place that's any cheaper.
--
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 ---
--- Begin Message ---
Yes! Now that is good news!
Another EV on the road!
Yeaaaa! Congratulations Rob!
Ken
In a message dated 6/25/2007 3:07:07 PM Central Daylight Time,
[EMAIL PROTECTED] writes:
All,
I know the list loves good news: the RAVolt made her maiden voyage
over the weekend!
YouTube: http://www.youtube.com/watch?v=hUv3wZQTcQE
Rob H
RAVolt.com & EValbum 995
************************************** See what's free at http://www.aol.com.
--- End Message ---
--- Begin Message ---
Ok .. I got a stupid question.. I got the welder point a few times now and
have been thinking about it .. Why don't out eclectic motors brushes weld
and melt when we run our E Vs??/
And what ever the reason is that they don't.. Why can not that be the same
kind of contact for a switch?
Mitchell
-------Original Message-------
From: Andre' Blanchard
Date: 06/25/07 19:43:30
To: ev@listproc.sjsu.edu
Subject: Re: Controler
At 05:17 PM 6/25/2007, you wrote:
>If you want to build a mechanically driven drum switch circuits for motor
>controller, it is best to get a early addition copy of The Standard
Handbook
>for Electrical Engineers from the year 1933 or so.
>
>You will not be able to down load this handbook, but you may luck out and
>get a copy from the public library. The new later handbooks will set you
>back more than a cost of a controller and they are not that detail.
>
>It has complete design section on any type of controller you want to build.
>There even sections on how to different type of batteries are made, how
>motors are made and different winding configurations.
>
>With this handbook, all you need is a shop with machine tools, the raw
>material, and it will show you how in detail to design and build any
>electronic and electrical systems.
>
>Roland
I did not find the entire books but I did find part of it.
Section 13 from the Standard Handbook for Electrical Engineers 1908
http://books.google.com/books?id=tkAFAAAAMAAJ
Some other books
http://books.google.com/books?id=SsIJAAAAIAAJ
http://books.google.com/books?id=UOjpsFsWSrAC
http://books.google.com/books?id=iDASAAAAIAAJ
http://books.google.com/books?id=cgsAAAAAMAAJ
http://books.google.com/books?id=UP8HAAAAMAAJ
http://books.google.com/books?id=P_m7webHng8C
http://books.google.com/books?id=5WGfE9UR_AEC
http://books.google.com/books?id=ZlCLIxkECvwC
__________
Andre' B. Clear Lake, Wi.
--- End Message ---
--- Begin Message ---
TdS Report #10: Photos - West Philadelphia High School "K1 Attack"
Photographs from the Tour de Sol:
http://www.AutoAuditorium.com/TdS_Reports_2007/photos_004.html
West Philadelphia High School "K1 Attack"
This car has turned heads since the first time it showed up at the Tour de Sol
in 2004.
But since we last saw it the high school team has given it a snazzy paint job
that makes it stand out even more!
The front end of the car is virtually empty.
The original plan was to make the "Attack" a hybrid, with electric drive in the
front and biodiesel engine in the back.
The engine is there, but all the electric components are removed.
Maybe someday ...
With the driver door up, you can get a hint of where some of the batteries will
eventually go.
The channels below both doors have lots of room for batteries.
At the start of one of the Attack's Autocross runs, that black plume shows that
just stomping on the accelerator is not the best way to accelerate.
That is just unburnt fuel, even if it is "green" biodiesel.
Even so, the Attack won the Autocross.
- - - -
The 2007 TdS Reports are actually about the "21st Century Automotive
Challenge" hosted by the The Eastern Electric Vehicle Club (EEVC).
The complete set of Tour de Sol Reports for 2007 can be found at:
http://www.AutoAuditorium.com/TdS_Reports_2007
The complete set of past Tour de Sol Reports can be found at:
http://www.FovealSystems.com/Tour_de_Sol_Reports.html
- - - -
The above is Copyright 2007 by Michael H. Bianchi.
Permission to copy is granted provided the entire article is presented
without modification and this notice remains attached.
For other arrangements, contact me at +1-973-822-2085 .
- - - -
For more on the "21st Century Automotive Challenge", see the web page at
http://www.EEVC.info
--- End Message ---
--- Begin Message ---
I think they saidth that they already do have a battery; they say it's
going to be used in real life for some company or something.
On 6/25/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Hello Lawrence
One other difference then regular lead batteries. If I remember right they
were to weigh like 1/4 the weight of lead acid batteries.
I read about these at least 2 or 3 years ago. They even had the city they
were in investing money into the new company. You would think they would have a
battery out by now?
Don Blazer
In a message dated 6/25/2007 2:11:18 PM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
If what they say is true there won't be any difference between them and
regular lead batteries except capacity, durability & reliability. I suspect
they won't even need regulators. Lawrence Rhodes....
----- Original Message -----
From: "Zeke Yewdall" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, June 24, 2007 8:22 PM
Subject: firefly batteries?
> Wondering if anyone has any thoughts on these? I sort of have an in
> with the company to test some in my EV (probably about 5 or 10%
> probability, but that's better than no contacts)... but as of yet all
> I've seen is hype, not specs. BMS required? Discharge rate? cycles?
> Thermal management? Not even sure if they really exist yet.... I
> supposed I could ask my contact there, but I figured someone on this
> list might have already researched them more than I have.
>
> Z
>
************************************** See what's free at http://www.aol.com.
--- End Message ---
--- Begin Message ---
Jukka Järvinen wrote:
Bill, You have your hands in the basket. What kind of large size cells
are coming from A123 ? I'm keenly waiting for a 200 Ah cell from them to
do some comparing. Will they also achieve 10000 cycles with 90% DOD ?
Jukka,
Hi Energy density by Kokams, high discharge rate by 123's and high
charge rate by Alteriano's have been measurably demonstrated.
Has this claim (10k 90% DOD cycles) been demonstrated by TS? Only low
price has, but that's about it. Let's wait until verifiable and
repeatable substance and not promises will stand behind the price (so,
no, your
own EV' while cool, does not count as proof for anyone else).
Now even the fact that those who got lucky to have performing cells
proves little. We're not debating LiFe technology, we know it works.
We're talking about particular company - TS.
I haven't seen any changes the way TS operate. They didn't care
about me then, still don't today and I'm pretty sure won't in future.
Please understand, the words "10000 cycles and low prices TS battery"
have no value for many. I wish it would be different and it's up to TS
to make it different, but as I said, unfortunately (mostly for them)
they are failing to make it different.
Victor
--- End Message ---
--- Begin Message ---
What sort of data do you get from the Zilla controller?
On 6/25/07, MIKE WILLMON <[EMAIL PROTECTED]> wrote:
You can use most free Terminal programs, like Hyperterminal, to capture the
data to a file.
Someone on the list mentioned using a program called Snag-It for the Palm to do
the same thing.
Mike,
Anchorage, Ak.
----- Original Message -----
From: Mark Eidson <[EMAIL PROTECTED]>
Date: Monday, June 25, 2007 4:12 pm
Subject: Data Logging for Zilla
To: ev <ev@listproc.sjsu.edu>
> Is there a data logging program for a laptop PC that can put the Zilla
> in data streaming mode and log the data?
>
>
--- End Message ---
--- Begin Message ---
Message-ID: <[EMAIL PROTECTED]>
From: "Loni" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Subject: Re: Manly EV's, RE: EV are for girls blog
Date: Mon, 25 Jun 2007 18:40:08 -0700
MIME-Version: 1.0
Content-Type: text/plain;
format=flowed;
charset="iso-8859-1";
reply-type=original
Content-Transfer-Encoding: 7bit
This thread is getting a bit unwieldy. Perhaps I should make my perspective
clear. I'm a master mechanic with 23 years' experience. I spend my days
maintaining the enemy 8^O and correcting the mistakes of engineers 8^), but
I'm no longer a friend of I.C.
My concern is with building reliable mass-produced electric scooters and
motorcycles with an AC small motor of modest output. The problem: American
motorcycle consumers will want a vehicle with rapid 0-60mph acceleration and
a top speed near 100 mph to even consider buying in larger quantities. Even
with A123's newest batteries, a compact invertor/controller/BMS system, a
120V+ system and a lightweight, aerodynamically efficient design, what motor
would you realistically put forward as a direct-drive solution? I can't
imagine one, and apparently neither can Vectrix
http://www.vectrix.com/Portal/1/Language/47/Page/68/Intellectual_Property.aspx
>> Broader torque curves??? I think you'll see that the torque curve
>> for even the best electric motor falls off precipitously with rpm
>
> Well then you'd think wrong. On electric motors torque is almost always
> related to current. If you can provide enough current over the full
> operating range of the motor, then it will have a flat torque curve.
> Again the Seimens and Solectric AC motors have a flat torque curve from
> zero to well over 7,000 rpms. I believe the Seimens will go to 10,000 or
> so.
You mention dumping extra current into a motor to sustain torque, but how
Ah-efficient is that?
>>> CV transmissions make the most sense for motors or engines that work
>>> best
>>> at a very narrow RPM range. For EVs, a CV transmission would be a
>>> solution without a problem.
>>>
>>
>> I take it you're on the direct-drive side of the EV fence, but the fact
>> is
>> that even electric motors have continuous duty ratings for a reason.
>
> What does Continuous duty ratings have to do with the torque
> characteristics of the motor? You are talking apples and oranges.
> The contiunous duty rating is ONE point on the torque curve.
Apples and oranges? Wasn't it you who said additional current is necessary
to sustain a flat torque curve at high rpms? The fact is, I was thinking
about Ah-efficiency on the supply side more than torque at that point in the
discussion. And you can hardly say that running a motor to higher rpm than
the manufacturer's continuous duty rating to sustain freeway speeds will not
tax the motor and run the batteries down excessively quickly without a shift
in gearing. As you say, 2-3 gears are nice to have, even with a flexible
motor.
>> closer you keep your motor to ideal efficiency/temperature/amp draw, the
>> longer it will last and the happier your controller and batteries will
>> be.
>> In a high-voltage system for a daily driver, for example, would you
>> rather
>> have motor speed at 6500 rpm at 80 mph, or 3500?
>
> Well that would depend entirely on the motor. An AC motor with a 12,000
> rpm redline would probably be sitting in it's sweet spot at 6500 rpm.
> On the other hand a motor with a 6,000 rpm redline would probably be
> hurting.
Absolutely true. This begs the question of the intended application for a
given motor.
> Also, something many people don't realize, the sweet spot (max efficiency)
> on a motor CHANGES depending on applied voltage and load.
> Generally speaking, at low voltage and low load (like when you are moving
> slowly) the sweet spot is at a fairly low RPM (handy that) whereas when
> you are moving fast and the aerodynamic drag is putting a large load on
> the motor, so you are applying more voltage to get more current through
> the motor (and therefor getting more Torque and More RPM) the sweet spot
> will typically move up to a higher RPM.
>
> The wide power band and moving sweet spot means that most conversions will
> work best (efficiency) with 2 or 3 gears.
> A CVT has enough losses that it will eat up any small gain in motor
> efficiency and then some.
The last sentence is what I feel needs further examination, particularly at
high speeds. I have a design drawn for a single-variator-pulley CVT that
will have dramatically decreased frictional and inertial losses over a
conventional CVT or manual gearbox, and signifantly less weight. I'd like to
directly compare Wh-usage between designs (i.e. a direct-drive scooter, a
scooter with a 2-speed gearbox, and a scooter with my CVT at a sustained 65
mph for 10 minute on a flat surface, then another 10 minutes on a 6% uphill
grade), but I don't have that luxury.
Another consideration will always be economy of scale. How many powerful,
flexible, and reliable motors will I find available at a reasonable price if
I go with a direct-drive design? Alternatively, if I find a
readily-available motor with solid power all day at 3000 rpms at half the
unit-price, the CVT option becomes much more attractive.
Does that clarify things?
Lon Hull,
Portland, OR
--- End Message ---
