EV Digest 6056
Topics covered in this issue include:
1) RE: Who owns Yahoo Group - electric_vehicles_for_sale?
by Cor van de Water <[EMAIL PROTECTED]>
2) Re: EV controllers? the 4th option...
by "Roderick Wilde" <[EMAIL PROTECTED]>
3) RE: EV controllers? the 4th option...
by "Roger Stockton" <[EMAIL PROTECTED]>
4) RE: Formula
by "Roger Stockton" <[EMAIL PROTECTED]>
5) Re: EV controllers? the 5th option...
by "David Roden" <[EMAIL PROTECTED]>
6) Inexpensive DC Motors with Keyed Shafts
by "Bruce" <[EMAIL PROTECTED]>
7) Re: Interstate Batteries vs. Optima's
by [EMAIL PROTECTED]
8) Re: EV controllers? the 4th option...
by "David Roden" <[EMAIL PROTECTED]>
9) Re: Formula
by "Peter VanDerWal" <[EMAIL PROTECTED]>
10) Power Battery
by Danny Miller <[EMAIL PROTECTED]>
11) Re: EV controllers? the 5th option...
by Danny Miller <[EMAIL PROTECTED]>
12) RE: Current multiplication, was: EV controllers? Practical parame
ters
by Cor van de Water <[EMAIL PROTECTED]>
13) RE: Inexpensive DC Motors with Keyed Shafts
by Cor van de Water <[EMAIL PROTECTED]>
14) Killacycle Vote
by Bruce Weisenberger <[EMAIL PROTECTED]>
15) Re: Interstate Batteries vs. Optima's
by "Roland Wiench" <[EMAIL PROTECTED]>
--- Begin Message ---
Yahoo.
But you should be able to locate the person to start it
and moderators by sending them an email on the group
or registering and checking the members list.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of David O'Neel
Sent: Sunday, October 22, 2006 11:30 AM
To: [email protected]
Subject: Who owns Yahoo Group - electric_vehicles_for_sale?
I am curious.
--- End Message ---
--- Begin Message ---
John, I'm going to have to have a difference of opinion here with you on the
compatibility of the 9" ADC motor with the Curtis 1221B. This particular
controller was responsible for the demise of one of the earliest EV
conversion companies in existence in the last century. Curtis refused to
warranty the controllers installed by Solar Electric in Melbourne Florida
run by Steve McCrea. Steve was also famous for the no longer available
publication, "Why Wait for Detroit". Steve was definitely one of the early
pioneers but when you Google him or Solar Car Corporation now you will get
hardly anything. This is very upsetting to me considering all the years and
hard work he had put into conversions and making EVs acceptable. Nowadays
history may be measured in seconds rather than years. We live in very sad
times!.
Roderick Wilde
----- Original Message -----
From: "John Wayland" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, October 22, 2006 8:03 PM
Subject: Re: EV controllers? the 4th option...
Hello to David and All,
The EVDL is a great place because you can always get different opinions,
then sift through them and pick what makes sense to you. Let's see how
much of what David says here, makes sense or no sense.
David Roden wrote:
John W. is passionate about this subject, that's for sure, but I have to
say that not everyone will react as strongly (and negatively) to Curtis
controllers as he does.
I would agree here. I 'am' passionate about the EVs we are building
ourselves, that ultimately, others will see, perhaps ride in, and then
perhaps go on to either build one for themselves, or at least demand that
EVs be made available. I want EVs to be the best they can be, and I want
them to wipe away the nearly set in stone stigmas of being weird, being
slow, being problematic, being short on performance, etc. Purposefully
choosing a sub-standard motor controller that makes what the majority of
those subjected to it feel is an awful irritating squeal, is simply a bad
idea that goes contrary to positively putting EVs in a good light.
Really, how often do Curtis controllers fail full on when powered up
without a precharge? I don't recommend omitting the precharge, but I ran
one that way for years with no ill effects (I didn't know any better ;-).
Quite often, thank you. I have a 1231C carcass here, with the end blown
clear off after it was powered up by another EVer who didn't heed my
advice of using a precharge circuit. I know of at least 10 instances of
this, not just one or two. David, you were lucky and it's bad advice to
spread around. You're statement 'I didn't know any better' seems
appropriate for many of your comments to follow.
I also disagree with John's recommendation to use a 1221B - unless the
motor is an 8" ADC or a Prestolite. From all the reports I've seen, the
1221B is a buckin' bronco with a 9" ADC.
I ran a 1221B in Blue Meanie from '93 to mid '94 with an ADC nine inch. It
was smooth, no bucking bronco, no ill effects whatsoever. Even White
Zombie had a Curtis 1221B and an ADC nine inch for a short while...it too,
was smooth, no bucking bronco, no ill effects. I helped design and build
the E-Car 65 Mustang powered by an ADC nine inch and a Curtis 1221B...it
was very smooth, had no bucking bronco simulations, and had no ill
effects. The last time I saw the car about three years ago and it still
had the Curtis 1221B and ADC nine incher. Then again, I used a precharge
circuit to protect the controller. I also used the Curtis 1221B in two
Rabbit conversions, and one had a GE nine inch stuffed into it...it was
smooth, had no bucking bronco, and had no ill effects. I also used a 1221B
and an ADC nine inch in at least three pickup conversions...they were all
smooth, had no bucking bronco, and had no ill effects. David, I just gave
you multiple reports, so I guess you should change your 'from all reports'
to 'I guess I didn't know'?
I am aware that most failures were indeed, with the ADC 9 inch, but that's
probably because most conversions at the time were using this more popular
motor and many of the period conversions were based on extremely heavy wet
cell powered vehicles where heavy footed throttle was often used trying to
lug the things up hills, more than to an inductance problem caused by the
ADC 9 inch. Curtis decided to redesign the controller, the birth of the
1221C and 1231C, what I believe to be the worse EV controllers ever made.
It seems as if the engineer in charge of the project was either hearing
impaired, or more probable, he had never made an EV himself and had never
actually test driven his awful creation in a real EV. It's simply a bad
design. Others at the same time with far less resources than a Curtis
engineer had at his disposal were able to make reliable controllers. They
didn't take the Curtis short cut with the two stage frequency thing, and
managed to build their controllers to operate silently.
Now, about that "irritating non-varying squeal." We've been round and
round on this before but I'll post it again for the newbies.
It may be that John's ears are especially sensitive to this frequency. I
suspect he also is bothered by that EVs that aren't totally silent
(although squealing tires don't seem to bother him ;-). There is
something to this.
I could look up and list at least 20 posts from others, not just me, who
have had non-EVers either complain or poke fun about the awful Curtis
squeal. The unfortunate reality is though, that they aimed their criticism
at the EV, not the controller, for these types didn't even know what a
controller was.
However, for most people the "Curtis squeal" is hardly bothersome. It
lasts for a second or so when you accelerate. You may hear it when you're
creeping into a parking space. You'll seldom hear it otherwise.
David, your nose must be growing longer! A second? Seldom hear it? My
friend John Tuss, against my advice, bought and installed a Curtis 1231C
squealer in his Datsun pickup. By the way, the previous controller was
also a 1231C, and when he bought the truck it still had the blown
controller mounted in the truck. It had not been connected with a
precharge circuit...care to guess how the controller died? With the
replacement 1231C installed, the truck was once again miserable to be
around. I drove it through my neighborhood at 15 mph, and it constantly
made a squeal that made folks in the yards look up, and yes, their dogs
barked, and in general it was totally embarrassing. Some of my neighbors
actually approached me about the truck, knowing that I am the local EV nut
I am, and asked why it made the LOUD squeal...really David, I'm not making
this up. EVs should not be an embarrassment, and we should not have to
make up excuses for them.
It is NOT loud, certaintly not as loud as an ICE's engine.
Come on, David! Today's modern ICEs are very quiet, no, not like an EV,
but way quieter and more pleasant than that irritating, non-varying
constant squeal of an EV with a 1231C.
People will NOT laugh and point at your car. Dogs will NOT run howling
from the vicinity. Indeed, most people (or dogs;-), inside the car or out,
won't notice it at all.
Again, not even close to being true, read the above. Just in case, here'
more.....
Example one:
At the 'Gasless in Seattle' EVent years ago, there were two EVs that had
these terrible controllers. One was coming across a grassy expanse at
around 10 mph, as I was with a small crowd of perhaps 20 show goers who
had come to get acquainted with EVs for the first time. One lady said to
her friends, "What's that noise? Is it that electric car coming towards
us? If so, that does it for me, I'd never want a car that makes THAT
noise!" David, this is almost a direct quote. I had to then go into my
EVangelist mode and tell her all about 'better' conversions that used more
advanced motor controllers that didn't make the noise. In short, I was
doing damage control....nice controller!
Example two:
Again, at a Seattle car show that included a parade, unfortunately for the
rest of us, we had a guy with his 1231C power EV in the parade...it
constantly squealed. I was in the crowd and someone other than me was
driving my EV. Again, a women made it painfully aware that the noise was
awful....she simply clasped her hands over her ears as the EV approached,
then after it passed by, released her ears and said loudly, "What's wrong
with THAT one?"
Example three:
At a NEDRA race, I was being interviewed about the positives of EVs that
day...fun, excitement, unbelievable acceleration, etc., when during the
video and interview someone cruised by with a Ford Escort with a 1231C
squealing away. They actually stopped the interview (an interview that WAS
positive) and followed the car with the camera/mike pointed at the car to
capture the noise as I heard the reporter guy saying copy something like,
"Well, they aren't ALL quiet, this one's making quite a racket!" David, I
couldn't make this stuff up, it happens all the time.
Example four:
I was at an EV get-together at a restaurant. Someone rolled up with their
1231 squealing upon where three people pivoted around to see what was
making the noise. One comment went like this, "That's like running your
fingers down a chalk board!"...nice image, huh?
The brief bit of whine when accelerating is NOT a big deal, and it
provides significant benefits. Having that short period of low frequency
chopping allows the controller to have a smooth takeoff with the commonly
used 9" ADC series motor.
Only required evidently, in a poorly designed Curtis 1231C. Funny, DCP
Raptors and T Rexes didn't need the squealing frequency to get the job
done....and, they were far smoother on take-off than the Curtis! Funny,
Auburn Kodiacs and Grizzlies didn't need the squealing frequency to get
the job done....and, they were far smoother on take-off than the Curtis!
Funny, Zillas don't need the squealing frequency to get the job
done....and, they are far smoother on take-off than the Curtis!
I used a Curtis PMC-25 controller for years. It chopped at 2 kHz all the
time (I think it used bipolar transistors).
Check my videos page and watch the '84 footage of the Long Distance SEVA
rally, where you can painfully hear this exact controller, a PMC-25 loudly
squealing!
Curtis controllers are more like Ford Escorts than BMWs.
You should maybe be more specific, because not all Curtis controllers are
bad. In fact, they make some very nice controllers, and in the forklift
world, they are leaders in affordable, reliable, silent AC controllers!
David, you were of course, referring to the 1231C being like a Ford
Escort....I'd say it's more akin to a Yugo with a a squealing fan belt!
See Ya......John Wayland
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--- End Message ---
--- Begin Message ---
John Wayland wrote:
> Considering how lame the Curtis is, a
> 'Curtis Killer' isn't much of a challenge.
Well, performance or features-wise, true. But, cost-wise there's still
a challenge, since the Curtis-Killer has to be priced enough less than a
Z1K LV for people to not just buy a Z1K instead.
> Roger, how on earth does one come up with such
> a wonderfully thought-out wish list, and leave out
> 'silent operation-no Curtis squeal!'???? Or, did
> you assume that no one in their right mind would
> ever again, design a road-going EV controller
> to make such an awful, irritating noise?
<GRIN> I did consider noting that as a feature, but (whether we think
he's in his right mind or not ;^), it was Rich who I was replying to and
I can't imagine him building a squealer! ;^>
> One more item to be added to Roger's list
> ...compact size.
Yep, good point!
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Don wrote:
> With all this talk about Curtis & Zilla controllers, trying
> to decide what amperage controller I might use to replace my
> existing GE EV1 SCR controller and advantages/disadvantages
> of doing this.
Performance-wise, you would need at least a Curtis 1231. The 400A 1221
is a step down in power/performance from the EV1 controller.
Advantages of going to a modern high-frequency controller are silent
operation (unfortunately, only if you avoid the 'C' model Curtis'),
better use of the batteries (you will use the same Wh/mi, but your
batteries will now seem considerably bigger than before), and better
battery life (you won't be continuously subjecting the batteries to
pulses of 450A+). The modern controllers will offer better low speed
control (i.e. smoother starts and backing up, etc.). The Curtis or
Zilla is more compact and less intimidating-looking under the hood.
Disadvantages are that if you go for the lower-cost Curtis option, you
lose a bunch of built-in safety features that the EV1 has, if you go for
a new Curtis, you end up with the 'C' model, which will make an annoying
squeal at light throttle (I find the high-pitched squeal more
objectionable than the 'growl' of the EV1, but the Curtis squeal will be
present less of the time).
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
On 21 Oct 2006 at 23:59, mike golub wrote:
> does anyone know about this guys controller?
>
> http://www.belktronix.com/dcmotorctrl.html
>
> he wants $2k for it and a PFC charger +BMS...
I don't know it personally, but at $2,000 it looks like a fairly attractive
price for the package. You get a 60kW 120v controller, precharge unit,
optical potbox, 1kW isolated switchmode charger, rudimentary BMS (bypass
type), 800W DC:DC, contactor, and even the cooling fans.
Add up the comparable bits for comparison (approximate prices) :
Curtis 1231C 1425
PB-5 65
Precharge ???
Albright SW200B 130
Zivan NG-1 900W charger (note - max 80v) 460
Zivan NG-1DC DC:DC 460
10 Rudman Mark 2 Regulators 450
Total 2990
And that doesn't include the precharge unit, which most folks homebrew.
You would still need various bits such as a main breaker and/or fuse and/or
panic switch, vacuum pump, heater, metering, possibly a drive for power
steering or air-con; and of course the motor, adapter, and motor mount.
Maybe you can find some of the above items cheaper; I just did a quick look
around at KTA Services and EVParts to see what they were getting these days.
This wouldn't make for a barnstormer conversion, but would be more than
adequate for a small commuter. Performance in a light glider such as an
early Civic or Geo Metro class car would probably be similar to a typical
70s-vintage subcompact car (I'd guess 0-50 in perhaps 15-20 seconds).
The main weak point I can see is that feeble charger. Ask anyone who owned
an early Solectria Force about 1kW chargers! You'd need a fair bit of
charging time.
If it meets the published specs, it could be a viable option for some folks.
Reliability would be an unknown. It's obviously low-production with a
somewhat homemade look (unfinished aluminum cases, stick-on labels, etc.) so
who knows whether the builder will still be around (and willing) to fix it
in 10 years.
Cor remarked on the 24v tap. That could be an issue, but pack tapping for
the logic supply worked fine for the early PMC DCC-xx controllers and I
think also for the Willeys. I suppose one could add a DC:DC if he were
concerned, but then the cost goes up. Or drop in a couple of small 12v gel
batteries to run the logic.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- Begin Message ---
Thanks for your help Peter. Has anyone used this $200 Surplus Center motor?
Is there any more information available for it other than what is listed in
the Surplus Center catalog?
And are there other suggestions for an under $400 EV motor that has a plain,
non-splined shaft?
_____________________________________________________________________
Peter VanDerWal wrote:
> Hmm not sure where yo uare looking that you are only finding splined
> shafts. Seems to me they are slightly raarer than plain shafts, unless
> you are looking at golf-cart or pump motors, or worse yet, surplus
> aircradt starter/generators.
...
> Take for example this 2hp 9" GE motor selling for $200 at Surplus Center:
>
http://www.surpluscenter.com/item.asp?UID=2006102212332689&item=10-2120&catname=electric
>
> This looks to me like GE took one of their nominal 96V 10hp motors and
> slapped a 24V 2hp label on it. Take particular note of the 1050RPM
> rating, this motor can easily handle 4 or 5 times this much. This is a
> huge motor, I think this is similar to the GE motor that many of the drag
> racers like to use. It's even bigger than the GE motor in my pickup.
> It's a bit too big for a motorcycle, but would work fine in a car.
> >
> > It seems like most surplus / inexpensive motors have splined shafts but
> > there must exist some that don't.
> >
> > What DC motors are there that might be suitable for a large motorcycle
or
> > small car that cost less than say $400 and have a non splined shaft with
a
> > keyway?
--- End Message ---
--- Begin Message ---
How about the Trojan AGM you can get an 80 Ah C20 rate for around 110
dollars.
Here you can see four trucks that are using them.
_http://southtownelanes.com/electric_pickups.html_
(http://southtownelanes.com/electric_pickups.html)
Don
In a message dated 10/20/2006 7:39:26 AM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
I have 13 C&D Dynasty DCS-100L AGMs in my Civic. I think these are
the same battery Interstate is selling. Mine are now 9 months old
and have less than 200 shallow cycles on them ( average discharge
12.7 AH). Their capacity has dropped to a fraction of their
ratings. When we tried a capacity test at 75 Amps most delivered
less than 20 AH. Under load test only two would hold even a 250 Amp
load. The Alber test found their internal resistance several times
higher than spec. Currently I have two going back to the factory,
one for disassembly and inspection, one for testing. The early
theory was that my Zivan NG5 was set wrong and chronically
undercharging them. After reviewing several of the charge/discharge
cycles I logged in the past using the E-meter and laptop, I no longer
believe this to be the cause. It looks to me like they were charged
correctly Hopefully the factory can determine exactly what is up.
Right now, I cannot recommend these batteries for EV use.
I have been looking at another possible battery for my car, the
Genesis XE95. Same size and weight as the DCS-100L but rated 73.5 AH
at the 1 hour rate, and much much higher cycle life. So far I
haven't been able to get a price quote, but I suspect they are much
more expensive than the Dynasty ones.
Honestly for your purposes, wouldn't flooded batteries make a better
choice? If range is your primary interest, and cost is an issue,
flooded batteries are really hard to beat.
Thanks,
Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace)
--- End Message ---
--- Begin Message ---
I don't want to get into a rebuttal war; I've long since learned that
there's no percentage in it. So I'll only say that I stand by my comments
about Curtis controllers, except to admit that I'll reserve further
observations on the requirement for precharge (I did >ask< about that,
please note).
I have great respect for John. One of the things I like about him is that
he and I often end up agreeing to disagree, but we still remain online
friends. This is because we're very different people with very different
needs and goals in our vehicles. He's very fastidious and particular, while
I'm more relaxed. He builds and drives cars that are beautifully finished
and spotlessly neat and clean; I'm usually somewhere between utilitarian and
slightly slovenly. He likes fast cars and driving fast; I prefer cars that
are cheap to run and I drive like your grandfather. ;-) And each of us
respects the other's differences.
Like the world, the EV list is made up of all kinds of people. We all have
opinions and will generally offer them. As John says, in time, you learn
which members' views match most closely with your own, and intuitively
balance them out.
PS - Don't forget your blood pressure medicine, John. =|:->
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
Sheesh, does nobody read the rest of the message? Like the parts that
listed the "given"? You know, 96V flooded battery pack,
electrovan/bradley GT?
Ok,ok. I should have said "MUCH" instead of "ANY" With the above givens,
a 'Zilla will give him a slightly faster 0-20mph and he can start off in a
higher gear and shift a bit less often.
> Hi all,
>
> Peter VanDerWal wrote:
>> Note the 'Zilla won't do you ANY good if you still have flooded
>> batteries.
>> These can't supply much more than 550amps anyway, at least not without
>> damaging them prematurely.
>
> I disagree, the Zilla can make an impressive difference even with
> flooded batteries! Even though you'll presumably have the battery
> current set to a lowish value (like 400A) to protect the flooded
> batteries, the Zilla is in most cases is still able to provide the full
> motor loop current due to the inherent current multiplication of a buck
> converter at low duty cycles.
>
> This can really improve the low-end torque relative to what you'd
> get from a Curtis or a Raptor 600 controller (which, from my experience
> never allowed more than about 650A in the motor loop). So if you use
> flooded batteries but still need a lot of low-end push to climb hills or
> because you have a heavy vehicle, etc... I think a controller like the
> Zilla /is/ worth using.
>
> --
> -Nick
> 1988 Jeep Cherokee 4x4 EV
> http://Go.DriveEV.com/
> http://www.ACEAA.org/
> --------------------------
>
>
--
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--- End Message ---
--- Begin Message ---
Say, anybody know about Power Battery?
http://www.powerbattery.com/products/Solar%20Series.htm
I actually just need a deep cycle for my regular van's accessories, and
the "Solar" series has some pretty good ratings as far as cycle life and
Peukert's coefficient. They do have a "marine" line which seems
designed for high starting current, but they didn't describe the cycle life.
Danny
--- End Message ---
--- Begin Message ---
I'd want some idea of what's inside that box. Amp ratings are somewhat
vague and homebrews can be great or ludicrously inadequate. I mean, you
could take 10 transistors with an Absolute Maximum Current of 50 amps
and call that a 500 amp controller in a sense.
The "internal fan circulation"... I don't see vents from any angles
shown and there's no fans on the sink. Did they actually just run a fan
to circulate air internally, did they? That would be an example of a
problem.
The connections appear to be through a flag connector. Never seen a
bulkhead mount flag, but that's what it looks like. If it is indeed
what i think, I'd say that's a major problem. Any of those wires can be
pulled out fairly easily and there's no strain relief on the connector.
Well, that's not a show-stopper to reconfigure that but I'd worry that
if they're capable of making the outside like that I'd worry what
mistakes might be present on the inside.
Danny
David Roden wrote:
On 21 Oct 2006 at 23:59, mike golub wrote:
does anyone know about this guys controller?
http://www.belktronix.com/dcmotorctrl.html
he wants $2k for it and a PFC charger +BMS...
I don't know it personally, but at $2,000 it looks like a fairly attractive
price for the package. You get a 60kW 120v controller, precharge unit,
optical potbox, 1kW isolated switchmode charger, rudimentary BMS (bypass
type), 800W DC:DC, contactor, and even the cooling fans.
Add up the comparable bits for comparison (approximate prices) :
Curtis 1231C 1425
PB-5 65
Precharge ???
Albright SW200B 130
Zivan NG-1 900W charger (note - max 80v) 460
Zivan NG-1DC DC:DC 460
10 Rudman Mark 2 Regulators 450
Total 2990
And that doesn't include the precharge unit, which most folks homebrew.
You would still need various bits such as a main breaker and/or fuse and/or
panic switch, vacuum pump, heater, metering, possibly a drive for power
steering or air-con; and of course the motor, adapter, and motor mount.
Maybe you can find some of the above items cheaper; I just did a quick look
around at KTA Services and EVParts to see what they were getting these days.
This wouldn't make for a barnstormer conversion, but would be more than
adequate for a small commuter. Performance in a light glider such as an
early Civic or Geo Metro class car would probably be similar to a typical
70s-vintage subcompact car (I'd guess 0-50 in perhaps 15-20 seconds).
The main weak point I can see is that feeble charger. Ask anyone who owned
an early Solectria Force about 1kW chargers! You'd need a fair bit of
charging time.
If it meets the published specs, it could be a viable option for some folks.
Reliability would be an unknown. It's obviously low-production with a
somewhat homemade look (unfinished aluminum cases, stick-on labels, etc.) so
who knows whether the builder will still be around (and willing) to fix it
in 10 years.
Cor remarked on the 24v tap. That could be an issue, but pack tapping for
the logic supply worked fine for the early PMC DCC-xx controllers and I
think also for the Willeys. I suppose one could add a DC:DC if he were
concerned, but then the cost goes up. Or drop in a couple of small 12v gel
batteries to run the logic.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- Begin Message ---
Hi Cory,
Note that my capacitor series/parallel setup is for 800V
which no DC controller has.
With the same 8 caps parallel for 400V the current per
cap is 1/8 of 900A or 'only' 125A per cap; with the
guesstimated 0.022 Ohms the drop amounts to 2.75V peak.
Stil a lot, so the ESR is likely a more important
selection criterium than the exact capacitance, as it is
a larger contributer to the ripple and to the internal
losses in the capacitors.
It is very sell possible that Otmar has 100 small capacitors
parallel instead of only a handful large ones, just to
optimize for ESR and in the process enlarging the surface
are of the capacitors, to improve power dissipation.
You get the idea: find the limiting factor and a creative
way to eliminate it or at least make it controllable.
(I have yet to hear of water-cooled capacitors ;-)
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
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-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Cory Cross
Sent: Sunday, October 22, 2006 1:18 AM
To: [email protected]
Subject: Re: Current multiplication, was: EV controllers? Practical
parame ters
Hi Cor,
Since your controller is a special model for V2G it may have extra
capacitors. Regardless, with my math below including ESR, the ripple is
calculated as 1.5V or 3Vpp. I'm surprised and previously incorrect. I
think my skepticism was due to looking at only film capacitors because I
mistakenly believed the electrolytics would not offer a low-enough
resistance. That said, a DC controller needs a lot of current at low
duty cycles: your same power draw with a DC motor at 10% duty would have
a voltage ripple of 12.4Vpp. Excessive? Probably not, but the power
dissipation likely exceeds the capacitor rating (1kW/8). The ripple also
increases as your minimum duty cycle drops. Feel free to go through my
math below.
Again, I'm surprised -- even the lowly Curtis 1221B seems to have
enough capacitance! Provided the caps are as low ESR as the example...
Thanks for including details from your controller for this little
exercise.
Cory Cross
One thing you did not compensate for is internal resistance (worse
numbers) and that capacitor current is [motor-battery] (better numbers
and something I forgot before). To get some numbers, I picked the most
expensive 1500uF, 400V electrolytic capacitor Digikey has:
ECE-P2GA152HA. Specs are:
50mm x 80mm
7.31Arms @ 105*C and 10kHz
.049 ohms ESR @ 20*C and 20kHz
This would give us a power dissipation capability of 7.31^2 * .049 = 2.6W ?
If your capacitors are 2.2x capacitance and same voltage, they likely
have an ESR of 22mOhms.
All eight of your capacitors would have a resistance of 11mOhms. This
contributes a voltage drop of [EMAIL PROTECTED] in each direction
(charging/discharging) -- without considering any inductance effects.
The capacitors, in this case, are either charging or discharging at
100A, wasting 110W of power in the capacitors. That's 13.75W each or 5
times the Digikey cap is for only 2.2x bigger, but that isn't excessive
and well within our error margin (which is, what, 500% by now? :) ) (I x
t) / C = V = .375 V, plus 1.1V for ESR: 1.5Vm or 3Vpp. Admittedly, much
lower than I thought.
Take into consideration, however, the DC motor controller which must
operate a low duty cycles and high currents. If we assume the same power
(312V*200A*50%duty) 31.2kW, a constant 20kHz frequency, and a duty cycle
of 10%, we still get an average battery current of 100A. Now our motor
current is 1000A. The first time period of 45us is where the capacitor
is receiving 100A and the second time period of 5us where it is
delivering 900A. In the first 45us, the capacitor has a voltage drop due
to ESR of 1.1V and a capacitance raise of .7V. During the discharge
cycle, it again loses .7V for capacitance, but now there is an ESR drop
of 10V! The power burned in the caps is 90% * 1.1V * 100A + 10% * 9.9V *
900A = 990W! They certainly cannot do that for long!
Cor van de Water wrote:
>Hi Cory,
>
>I apologize that I do not have exact numbers.
>The particular VFD is in the back of my garage, behind a
>stack of junk that will take me too long to pull out, also
>my controller did not open up far enough to be able to
>read the capacity of the bank of electrolytes, but let's
>throw some assumptions at it and see where we end up:
>
>I have a tiny VFD with a 1500uF 400V capacitor that is
>about 2" in diameter and 6" long.
>My controller is about 2' long and has 8 elco's in one row
>so that is about 3" diameter per capacitor and the length
>is another swag, but let's say it is not shorter than the
>1500uF one.
>Since 1.5 times the diameter packs 2.25 times the surface,
>the capacitors in my controller are likely to be at least
>3300uF if not more - I suspect them to be 4700 but lets stick
>with the minimum for now.
>The configuration of the 8 in two series banks of 4 parallel
>makes the total voltage and capacitance both double.
>So 800V and 6600uF minimum for the total.
>
>Since this is an AC drive with an inaudible (Sine) waveform,
>I guess that they switch at least at 20 kHz if not higher.
>This means that maximum AC current will likely be at 50%
>duty cycle, which is 25us on and 25us off. This gives us
>the time base. The max current my controller cranks out
>draws 200A from the batteries, I suspect that they limited
>the controller in SW.
>
>Now the formula to find the voltage ripple is:
>I x t = V x C and solving for V:
>(I x t) / C = V entering the values we found above:
>(200A x 25us) / 6600uF =
>200 x 25 x 10^-6 x 150 = 0.75V
>
>So my controller likely has less than 1V ripple at max
>switching power at its current 312V pack.
>I tell you that this capacitor bank is totally absorbing
>the switching effect and my batteries see a constant
>current being drawn by the controller with a very small
>ripple due to the size of the capacitors, while they supply
>the energy for the pulses to my motor.
>
>I trust Otmar that he has optimized the Zilla to include
>capacitors large enough to filter the ripple to a small
>enough factor that also there the batteries essentially
>see a constant current, although at 1000A the ripple
>may be larger than in my case, still I would expect it
>to be only a few percent of the DC current, so the
>batteries are not affected significantly.
>
>Cor van de Water
>Systems Architect
>Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
>Skype: cor_van_de_water IM: [EMAIL PROTECTED]
>Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
>Fax: +1 408 731 3675 eFAX: +31-87-784-1130
>Proxim Wireless Networks eFAX: +1-610-423-5743
>Take your network further http://www.proxim.com
>
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>Behalf Of Cory Cross
>Sent: Saturday, October 21, 2006 10:51 PM
>To: [email protected]
>Subject: Re: Current multiplication, was: EV controllers? Practical
>parame ters
>
>
>Hi Cor,
> The first purpose of capacitors is to protect the switching
>elements. In order to feed the motor they must be capable of around
>250Arms (in your case), which I doubt, in addition to needing enough
>capacitance inversely to PWM frequency and minimum duty cycle. Do you
>have part numbers and/or specs on those capacitors?
>
> None of the golf cart controllers have enough capacitance. Judging
>by the size of the Zilla, it does not either. I bet the VFD capacitors
>are for power faction correction.
>
>Cory Cross
>
>Cor van de Water wrote:
>
>
>
>>Hi Cory,
>>
>>Good controllers have large capacitors at the battery input
>>for this very reason - to smooth out the short pulses into
>>a constant battery current with very small ripple.
>>It is indeed a measure of how good the controller is, with
>>most SCR controllers this smoothing is not present, so they
>>will peak the same batetry current as the motor sees, making
>>the Peukert effect take a larger toll, that is why Lee
>>suggested to add large capacitors at the input of an SCR
>>controller, to increase range by drawing a constant current
>>
>>
>>from the batteries instead of short high peaks.
>
>
>>So - it depends on the controller!
>>
>>BTW, in my 700V 250A AC controller more than half the volume
>>of the controller is taken up by 8 huge capacitors.
>>I think they are switched as 2 series groups of 4 parallel
>>if they are using standard 400V electrolytes, but I have
>>not cut that deep into my controller yet.
>>
>>I have a salvage VFD (Variable Frequency Drive) that is
>>specified for 600V 3 phase and it also has 2 banks of
>>capacitors switched in series to take the voltage.
>>
>>Note that the higher the switching frequency, the smaller
>>the capacitors can be, as long as their internal resistance
>>is low enough to take the AC current of the charging and
>>in particular the discharging peaks.
>>
>>Cor van de Water
>>Systems Architect
>>Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
>>Skype: cor_van_de_water IM: [EMAIL PROTECTED]
>>Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
>>Fax: +1 408 731 3675 eFAX: +31-87-784-1130
>>Proxim Wireless Networks eFAX: +1-610-423-5743
>>Take your network further http://www.proxim.com
>>
>>
>>-----Original Message-----
>>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>>Behalf Of Cory Cross
>>Sent: Saturday, October 21, 2006 5:18 PM
>>To: [email protected]
>>Subject: Re: Current multiplication, was: EV controllers? Practical
>>parameters
>>
>>
>>Cor van de Water wrote:
>>
>>
>>
>>
>>
>>>The modern switching controllers allow the *motor* current
>>>to me many times larger than the *battery* current, in
>>>particular at low motor RPM.
>>>
>>>
>>>
>>>
>>>
>>>
>>Nitpick -- they allow AVERAGE battery current to be lower. I recently
>>requested information (on the evtech list) on any experiments to see if
>>the high-frequency, low-duty-cycle draws consume at a Peukert's rate of
>>the average or motor currents, but there don't appear to be any studies.
>>
>>Cory Cross
>>
>>
--- End Message ---
--- Begin Message ---
I did order this motor, then was warned off-list that it runs CCW
although the listing on the website says CW, so I called them
and had the order cancelled.
Since it's compound wound (a combination of sep-ex and series)
it is not trivial to reverse the motor.
Woops - I just checked and the listing is updated to read that
it is indeed a CCW rotation.
If I would have enough time, I would order one because I am
an engineer and like to take things apart first when they
arrive new, see how they work, try what I can improve
(like changing rotational direction), then put them back
again and then try if they actually work.
Hmmm - yes, that does void the warranty.
They would be very surprised if a motor comes back for
warranty and it runs the other direction....
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Bruce
Sent: Sunday, October 22, 2006 11:02 PM
To: [email protected]
Subject: Inexpensive DC Motors with Keyed Shafts
Thanks for your help Peter. Has anyone used this $200 Surplus Center motor?
Is there any more information available for it other than what is listed in
the Surplus Center catalog?
And are there other suggestions for an under $400 EV motor that has a plain,
non-splined shaft?
_____________________________________________________________________
Peter VanDerWal wrote:
> Hmm not sure where yo uare looking that you are only finding splined
> shafts. Seems to me they are slightly raarer than plain shafts, unless
> you are looking at golf-cart or pump motors, or worse yet, surplus
> aircradt starter/generators.
...
> Take for example this 2hp 9" GE motor selling for $200 at Surplus Center:
>
http://www.surpluscenter.com/item.asp?UID=2006102212332689&item=10-2120&catn
ame=electric
>
> This looks to me like GE took one of their nominal 96V 10hp motors and
> slapped a 24V 2hp label on it. Take particular note of the 1050RPM
> rating, this motor can easily handle 4 or 5 times this much. This is a
> huge motor, I think this is similar to the GE motor that many of the drag
> racers like to use. It's even bigger than the GE motor in my pickup.
> It's a bit too big for a motorcycle, but would work fine in a car.
> >
> > It seems like most surplus / inexpensive motors have splined shafts but
> > there must exist some that don't.
> >
> > What DC motors are there that might be suitable for a large motorcycle
or
> > small car that cost less than say $400 and have a non splined shaft with
a
> > keyway?
--- End Message ---
--- Begin Message ---
It is almost the end of Oct. And the Killacyle is
still nearly 200 Votes ahead. IF we all vote over the
next 8 days it will finally make it to the Drag Times
monthly pick. And will be done.
URL:
www.dragtimes.com
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
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--- End Message ---
--- Begin Message ---
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, October 23, 2006 12:25 AM
Subject: Re: Interstate Batteries vs. Optima's
The following data is from my manual for my alternator-inverter unit.
Using a deep cycle battery for a accessory battery, your charging system
either from a alternator or charger should be able to deliver the charging
current equal to 25% of the ampere-hour capacity of your battery.
It should be able to charge a 12 volt battery up to a minimum of 14.4 volts
and then drop back to 13.5 volts.
There is some battery chargers that have a selection mode for standard
(cranking type), deep cycle, AGM and Gel batteries which provides the
correct requirements.
A typical alternator may not be able to meet these requirements if a deep
cycle batteries are used. Alternators typically rated for the current they
can deliver when they are cold. In actual used, alternators heat up and
their output current capacity drops by 25% (as my standard alternator did
which I could fry a steak on).
The standard alternator, charger, or DC-DC power supply with ratings of 40
to 105 amperes will only deliver a maximum of 30 to 80 amperes in actual
used and will deliver even less as battery voltage rises.
Many alternators and some charging systems that is heat compensated cannot
produce more than 13.6 volts when they are hot.
I had a 135 AH deep cycle battery as my accessory battery with a standard
alternator plus a back up standard DC-DC unit which came from a HoneyWell
motor generator unit (which is mainly a 12 volt power supply).
After about a week of driving, I found that the accessory battery voltage
would keep reducing, and then had to charge it with a off-board charger.
To solve this problem, I install a high-out alternator which has a external
adjustment of the regulator circuit, to provide 14, 14.5, 15, and 15.5
volts.
I know longer have this problem and the battery is now running about 6
years.
Roland
--- End Message ---
