EV Digest 6800
Topics covered in this issue include:
1) RE: Speaking of battery announcements ... What about Firefly
by "Guy Stockwell" <[EMAIL PROTECTED]>
2) desulfating.... 2 at a time?
by [EMAIL PROTECTED]
3) RE: Direct drive
by "Myles Twete" <[EMAIL PROTECTED]>
4) Please help, Aircraft Generator starting torque issue.
by Michael Barkley <[EMAIL PROTECTED]>
5) electric mower - corded or battery
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
6) Re: electric mower - corded or battery
by "Brandon Kruger" <[EMAIL PROTECTED]>
7) RE: electric mower - corded or battery
by "damon henry" <[EMAIL PROTECTED]>
8) Re: Solectra/Azure - A123 response + A Great Idea!!
by "Brandon Kruger" <[EMAIL PROTECTED]>
9) RE: electric mower - corded or battery
by "Obrien, Haskell W." <[EMAIL PROTECTED]>
10) Triangle wave generator
by Chet Fields <[EMAIL PROTECTED]>
11) Re: electric mower - corded or battery
by Ralph Merwin <[EMAIL PROTECTED]>
12) Re: Please help, Aircraft Generator starting torque issue.
by "(-Phil-)" <[EMAIL PROTECTED]>
13) Re: Solectra/Azure - A123 response + A Great Idea!!
by Tehben Dean <[EMAIL PROTECTED]>
14) electric riding mower
by "midiguy732" <[EMAIL PROTECTED]>
15) Re: electric mower - corded or battery
by [EMAIL PROTECTED]
16) Re: Solectra/Azure - A123 response + A Great Idea!!
by "Brandon Kruger" <[EMAIL PROTECTED]>
17) Re: contactor amps
by Paul <[EMAIL PROTECTED]>
18) Re: desulfating.... 2 at a time?
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
19) Re: desulfating.... 2 at a time?
by electro <[EMAIL PROTECTED]>
20) Re: Please help, Aircraft Generator starting torque issue.
by Michael Barkley <[EMAIL PROTECTED]>
21) Re: Please help, Aircraft Generator starting torque issue.
by "Roland Wiench" <[EMAIL PROTECTED]>
22) Re: contactor amps
by [EMAIL PROTECTED]
23) RE: Solectra/Azure - A123 response + A Great Idea!!
by <[EMAIL PROTECTED]>
24) Re: Reality check, Re: Permanent magnet motor question
by Victor Tikhonov <[EMAIL PROTECTED]>
25) Re: Reality check, Re: Permanent magnet motor question
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Any comments on these guys?
http://www.everspring.net/txt/product-battery.htm?gclid=CJfE-JDknIwCFQGPWAod
wm8k5w
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Jeff Shanab
Sent: Monday, May 21, 2007 10:29 AM
To: Electric Vehicle Discussion List
Subject: Re: Speaking of battery announcements ... What about Firefly
I looked through their site briefly but didn't see some basic info,
Wh/kg, wh/liter,w/kg, cycle life/C rate, (not to mention price and
Availability.)
Maybe it is not obvious, Do you have that info? (lots of adjitives, I
need some specs.)
--- End Message ---
--- Begin Message ---
Sulfur builds up on floodies, if they aren't kept topped off with a
charge.
The longer they sit (in a discharged state) - apparently the sulfur acts
like a fungus and 'grows' (crystalizes?) into the plates.
Hence the need for desulfating, so I've heard and read, but I've got zero
practical experience.
There are 6-volt desulfators, and 12-volt desulfators...
Is it possible (given that 2x6=12) to use a 12-volt desulfator on 2x6-v
batteries in series?
A google search for "battery desulfator" comes up with the following -
The first link below mentions NEVs; so I assume that a single desulfator
can be used on an entire pack (provided it is able to handle the voltage).
http://www.batterylifesaver.com/
Here are a couple of desulfator products:
http://www.batterylifesaver.com/car-auto-battery-charger-products.html
http://www.ctsolar.com/index.asp?PageAction=VIEWPROD&ProdID=42
someone's built a "homemade" one here....
http://www.flex.com/~kalepa/desulf.htm
dos and donts with regard to battery maintenance
http://www.independent-power.com/battery_maintenance.htm
I haven't bought my batteries yet, but I want to make sure that when I get
them, my TLC doesn't kill them...
I remember reading a log of a guy who had one of the sparrows when they
were new (circa 2001); he had an outstanding log of his experience with it
-
he mentioned that desulfating was a good thing.
Do I need to desulfate, if I recharge at the end of every day?
Does "desulfating" the battery in any way hurt it?
When do I need to start desulfating? (after a year of service?, 2 years?,
once every month?)
Thanks!
--- End Message ---
--- Begin Message ---
Dustin offered:
"(Originally, I thought direct drive meant electric motor to output wheels
via fixed gearing. I figured this would be valid regardless of how one
implemented coupling of the motor to the output wheels. In my case I have
an intermediate shaft...."
It's been interesting reading the viewpoints on "direct drive".
And regarding the use of the word "direct" in driving EVs, the debate is FAR
from new. Check out the EV ads from 95 years ago:
Detroit Electric: They referred to their electrics as "the Only Direct Shaft
Driven Electric Car Made". They referred to its lack of chains, external
gears or intermediate gearboxes other than the rear end as justification for
the word "direct".
1912 Detroit Electric ad:
http://www.megawattmotorworks.com/resource.asp?func=display&resid=1257&tree=
536
Hupp-Yeats: Nearly every ad from 1911-1913 emphasized the "direct"
transmission of energy from the motor to the axle. In those years, H-Y
mounted the Westinghouse motor "directly" to the rear differential housing
(as mine does). Theirs was as direct drive as most came in those days.
1911 Hupp-Yeats ad:
http://www.megawattmotorworks.com/resource.asp?func=display&resid=1408&tree=
624 No less than 3 instances of the word "direct" in one ad...
What has been funny in all this is how adamant some have been about what is
"direct drive". I mean, come on guys, we're talking about the English
language here----how many varied definitions are there for the word "direct"
anyway? Or even the definition of "is"?
The word itself is a natural buzzword---a salesman's favorite friend. It
offers no specifics, carries no quantitative measure and gives the listener
or reader undue confidence that the product, explanation, path or strategy
is the best one simply because the person said it was the "direct" solution
to the problem at hand. Just look at the most annoying commercial on TV
these days: "Head ON---apply directly to the forehead"...repeat. They don't
keep using this strategy for fun...
Given the amazing potential for abuse by using the word "direct", the best
thing to do is avoid its use unless you want to sound like a salesman...
Myles Twete, Portland, Or.
1911 Hupp-Yeats Electric ---- soon to be repowered by Westinghouse V33F
motor attached "directly" to the differential...
--- End Message ---
--- Begin Message ---
Please, if anyone can help me with a solution, to my
torque problem from a deadstop, I sure would like to,
off list talk with you. I don't want to bother the
list with an ongoing discussion, as I know using an
aircraft generator as a motor, isn't the smartest way
to go (Dang you "MotherEarthFarce" for hooking me with
that 75mpg article) before I found this EV'r list.
That disclaimer aside, here's my problem, I think:
I'm using an Aircraft Generator J29 to be exact, it's
not a combo, starter/generator and therefore it seems
to be lacking in starting torque as a motor.
Is there anyway to salvage my EV and still use this
motor somehow? It has plenty of pep and speed once it
gets going, but the EV will not go if it's on an
incline using an AXE 7245 controller @ 72vdc. I just
purchased brand new batteries, and although it's
better, the car will not overcome an incline from a
deadstop.
Please, if you have any ideas - send them to me off
list, as I don't want to fill up email boxes of the
others that aren't interested in this issue.
Thanks in advance - Mike
Michael Barkley
www.texomaev.com
--- End Message ---
--- Begin Message ---
Okay, this is the electric vehicle discussion list. I am asking about an
electric push mower. It is a little off topic, I imagine, but I can't think of
anyone else I would rather ask, or who would be more qualified.
I had the opportunity to buy a 12 amp, electric mower that requires to be
plugged in. I don't like the idea of having to stay plugged in, so I wondered,
if it is still available, would I be able to battery power this thing? Would I
need to change the motor? If so, what would be a good motor to use? Or is the
corded mower better?
I like the idea of not using a gas mower, and thought about using a push reel
mower, but having talked to someone about it, it sounds as if it would require
mowing more often than I really have time for. He mentions at least twice a
week. So the next best thing is electric. So now I ask what to use.
If this is too off topic, I would love to hear from you off list. And I
appreciate your help.
Brian
---- Msg sent via @=WebMail - http://webmail.usu.edu/
--- End Message ---
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It's likely that you can run it on DC, so you can make it battery powered,
but you will need to use 120 volts worth of batteries to power it. You will
also need to use a properly rated contactor or switch to turn it on or off.
If someone handed me a perfectly good plugin lawn mower I would not bother
making it battery powered, I would just make sure I have a long enough
extension cord. I have a Black and Decker battery powered motor that I have
had for 7 or 8 years now. I love it, but since I can buy a brand new one
for $400 I would not feel like it is worthwhile to try and convert a corded
mower to battery power.
damon
From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: electric mower - corded or battery
Date: Mon, 21 May 2007 14:48:23 -0600
Okay, this is the electric vehicle discussion list. I am asking about an
electric push mower. It is a little off topic, I imagine, but I can't
think of anyone else I would rather ask, or who would be more qualified.
I had the opportunity to buy a 12 amp, electric mower that requires to be
plugged in. I don't like the idea of having to stay plugged in, so I
wondered, if it is still available, would I be able to battery power this
thing? Would I need to change the motor? If so, what would be a good
motor to use? Or is the corded mower better?
I like the idea of not using a gas mower, and thought about using a push
reel mower, but having talked to someone about it, it sounds as if it would
require mowing more often than I really have time for. He mentions at
least twice a week. So the next best thing is electric. So now I ask what
to use.
If this is too off topic, I would love to hear from you off list. And I
appreciate your help.
Brian
---- Msg sent via @=WebMail - http://webmail.usu.edu/
_________________________________________________________________
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--- Begin Message ---
Anyone used a bully electric mower? I'm thinking about using one as the
basis for a R/C electric mower. (There, it's back on topic, sortof)
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of damon henry
Sent: Monday, May 21, 2007 4:03 PM
To: ev@listproc.sjsu.edu
Subject: RE: electric mower - corded or battery
It's likely that you can run it on DC, so you can make it battery
powered,
but you will need to use 120 volts worth of batteries to power it. You
will
also need to use a properly rated contactor or switch to turn it on or
off.
If someone handed me a perfectly good plugin lawn mower I would not
bother
making it battery powered, I would just make sure I have a long enough
extension cord. I have a Black and Decker battery powered motor that I
have
had for 7 or 8 years now. I love it, but since I can buy a brand new
one
for $400 I would not feel like it is worthwhile to try and convert a
corded
mower to battery power.
damon
>From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
>Reply-To: ev@listproc.sjsu.edu
>To: ev@listproc.sjsu.edu
>Subject: electric mower - corded or battery
>Date: Mon, 21 May 2007 14:48:23 -0600
>
>Okay, this is the electric vehicle discussion list. I am asking about
an
>electric push mower. It is a little off topic, I imagine, but I can't
>think of anyone else I would rather ask, or who would be more
qualified.
>
>I had the opportunity to buy a 12 amp, electric mower that requires to
be
>plugged in. I don't like the idea of having to stay plugged in, so I
>wondered, if it is still available, would I be able to battery power
this
>thing? Would I need to change the motor? If so, what would be a good
>motor to use? Or is the corded mower better?
>
>I like the idea of not using a gas mower, and thought about using a
push
>reel mower, but having talked to someone about it, it sounds as if it
would
>require mowing more often than I really have time for. He mentions at
>least twice a week. So the next best thing is electric. So now I ask
what
>to use.
>
>If this is too off topic, I would love to hear from you off list. And
I
>appreciate your help.
>
>Brian
>---- Msg sent via @=WebMail - http://webmail.usu.edu/
>
_________________________________________________________________
Like the way Microsoft Office Outlook works? You'll love Windows Live
Hotmail.
http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migr
ation_HM_mini_outlook_0507
--- End Message ---
--- Begin Message ---
OK, I've actually gotten started designing/prototyping my very own home made
SepEx controller
thanks to alot of you guys (and gals ;^) here on the list.
I am trying to generate the triangle wave for the PWM circuit and I am using
the good ol' 741 Op
Amp with a single +5V power supply. Now I have been experimenting a bit and I
can get a pretty
good wave, BUT it is only good to about 50% Duty Cycle. with + peak at 4V and
the 50% flat part at
about 1V.
Is it possible to get a full triangle wave between 1 and 4v? Or even 1.5V to
3.5V? Or do I have to
go with a different Op Amp and/or a split power supply?
Thanks again,
Chet
____________________________________________________________________________________Get
the Yahoo! toolbar and be alerted to new email wherever you're surfing.
http://new.toolbar.yahoo.com/toolbar/features/mail/index.php
--- End Message ---
--- Begin Message ---
Brandon Kruger writes:
>
> I regularly use a Black & Decker CMM1000 Cordless 24V Mower and it's always
> worked great.
Same for me. I've had a CMM1000 since 2002 and am going on the sixth
season on the original batteries. I figure that I use about half of
the charge for one mowing. It's a mulching mower, so there's no raking
afterwards.
Ralph
--- End Message ---
--- Begin Message ---
I for one think this kind of discussion is interesting and definitely
on-topic. Having this kind of thing discussed and in the archives will help
people in the future!
Do you have any volt/amp readings from your setup? When you are trying to
go up the incline it would be very informative to read the controller
amps/volts. On the alltrax I believe all you need is a laptop and a serial
cable (plus their software, which you can download)
-Phil
----- Original Message -----
From: "Michael Barkley" <[EMAIL PROTECTED]>
To: "EVDL.ORG EVDL.org" <ev@listproc.sjsu.edu>
Sent: Monday, May 21, 2007 1:17 PM
Subject: Please help, Aircraft Generator starting torque issue.
Please, if anyone can help me with a solution, to my
torque problem from a deadstop, I sure would like to,
off list talk with you. I don't want to bother the
list with an ongoing discussion, as I know using an
aircraft generator as a motor, isn't the smartest way
to go (Dang you "MotherEarthFarce" for hooking me with
that 75mpg article) before I found this EV'r list.
That disclaimer aside, here's my problem, I think:
I'm using an Aircraft Generator J29 to be exact, it's
not a combo, starter/generator and therefore it seems
to be lacking in starting torque as a motor.
Is there anyway to salvage my EV and still use this
motor somehow? It has plenty of pep and speed once it
gets going, but the EV will not go if it's on an
incline using an AXE 7245 controller @ 72vdc. I just
purchased brand new batteries, and although it's
better, the car will not overcome an incline from a
deadstop.
Please, if you have any ideas - send them to me off
list, as I don't want to fill up email boxes of the
others that aren't interested in this issue.
Thanks in advance - Mike
Michael Barkley
www.texomaev.com
--- End Message ---
--- Begin Message ---
A lot of messages are being Truncated it seems... ?
On May 21, 2007, at 1:05 PM, Brandon Kruger wrote:
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--- Begin Message ---
> Anyone used a bully electric mower? I'm thinking about using one as
the
> basis for a R/C electric mower. (There, it's back on topic, sortof)
No, but I am considering converting my gas powered murray to a fully
electric mower. I did the robot-mower thing already, but with an old
riding mower deck repowered with a B&S engine simply because of parts
availability.
When I joined this list a few weeks ago, I posted about this but the
post didn't make it through for some reason. I'll repost.
Hello folks,
I recently joined this list because electric vehicles have always
fascinated me, even though there are some drawbacks as compared to
gasoline/diesel vehicles, mostly relating to range.
Before I embark into a more expensive project like a vehicle conversion,
I was pondering taking a "baby step" and converting an old riding mower
to fully electric, mostly as a learning tool about the process,
fabrication required, and enhance my somewhat basic of electrics.
After researching fairly extensively (on and off for approximately a
month or so) I'm left with a few questions, which I wish to pose to the
membership.
The riding mower has a 12HP B&S engine, with two pulleys. One to drive
the transmission, one to drive the dual 22" mower blades. Obviously I
could do this conversion the "easy way" and purchase a large motor and
extend the shaft to drive the two belt systems, leaving the motor to run
at 3000-3600 RPM and call it a day.
It's unclear to me how to properly size a motor to replace a gasoline
engine. I understand gasoline engines are rated at max RPM and peak HP
and torque figures are given whereas electric motors are rated with
their continuous duty hp/torque figures. Are there any mathematics or
at least a "rule of thumb" that might offer some clarity in sizing?
Another option I thought about was to purchase three smaller motors.
Two motors that would drive the two blades on the mower deck, and one
motor to drive the transmission directly. The advantage I see with this
method would be to fully eliminate the two clutch mechanisms which are
simply pulleys that move, tightening the two belts. These mechanisms
are troublesome at best, and wear the belts out fairly quickly (I find
flipping the mower on its side to replace them annoying, but that's me!)
I could instead use two contactors or relays - one switch/button to
actuate the drive motor, one to actuate the mower deck.
So I guess my second question is also about sizing. How much HP or
wattage would an electric motor need to be to mow grass with a razor
sharp 22" blade?
It seems logical to me to size the motor(s) correctly first based on HP
and torque requirements, then use those figures to determine wiring,
controller, and battery sizing.
Because the mower has a 5-sp transmission, I would imagine I don't need
to install a variable speed controller though maybe for the drive motor
if I go with separate motors. I'd also like to retain the transmission
because there are cases where having a low first and second gear has
been useful (I've towed 1500lbs of patio blocks in a trailer with this
mower).
I see no reason for the mower deck to have any controller other than
current limitation to protect the motors. On/Off would be more than
adequate.
Comments, thoughts, flames welcomed.
--- End Message ---
--- Begin Message ---
Brian> I had the opportunity to buy a 12 amp, electric mower that
Brian> requires to be plugged in. I don't like the idea of having to
Brian> stay plugged in, so I wondered, if it is still available, would I
Brian> be able to battery power this thing? Would I need to change the
Brian> motor? If so, what would be a good motor to use? Or is the
Brian> corded mower better?
I've owned a Toro E24 (24VDC) mower since 2001. I just replaced the battery
pack for the first time a few weeks ago with a slightly higher capacity pack
(18ah v. 12ah I believe) than that available from Toro. It was also
substantially cheaper to boot.
If you want to go cordless I imagine there are a few of them floating
around. I'd prefer that to converting a corded electric to cordless.
--
Skip Montanaro - [EMAIL PROTECTED] - http://www.webfast.com/~skip/
--- End Message ---
--- Begin Message ---
Ahg! I swear I fixed this before. I don't know how it gets reset. Sorry all.
From last message:
Good idea. I would support and help in any way I could. Another
thing to keep in mind is you might be able to write off various things
on taxes. Possibly utility bills for recharging EVs, etc. Anyone
else willing to contribute?
Brandon Kruger
On 5/21/07, Tehben Dean <[EMAIL PROTECTED]> wrote:
A lot of messages are being Truncated it seems... ?
On May 21, 2007, at 1:05 PM, Brandon Kruger wrote:
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--- Begin Message ---
On May 20, 2007, at 5:42 PM, mike golub wrote:
How many amps does it take for a contactor to close,
and
how much amps does it use to remain shut.
Any guesses?
No guesses, I have 2 of the very common Albright SW200 contactors
(with 12v coils) in my garage. They are generally operated without
any type of economizer circuit. The coils have a 4.2 ohm resistance.
Depending on the voltage in your 12 volt system you will be looking
at 3 to 3.5 amps.
I also have a Cozonka III contactor in my garage, but it has a built
in economizer circuit (I can't just take my ohm meter to it.) The
manufacturer's spec sheet tells me it demands 1.7 to 1.8 watts to
hold it on at 12 volts. Experience tells me that thing must pull
around 6 amps for a fraction of a second while it pulls in. After
that it draws very little.
Paul "neon" G.
--- End Message ---
--- Begin Message ---
On 21 May 2007 at 15:29, [EMAIL PROTECTED] wrote:
> Hence the need for desulfating ...
Otherwise known as "charging."
--- End Message ---
--- Begin Message ---
David Roden (Akron OH USA) wrote:
On 21 May 2007 at 15:29, [EMAIL PROTECTED] wrote:
Hence the need for desulfating ...
Otherwise known as "charging."
http://www.dallas.net/~jvpoll/Battery/aaDesulfatorSurvey.html is a page
I found in a quick search that says it is different than charging.
--- End Message ---
--- Begin Message ---
Phil, thanks for your support in this matter - I have
produced controller data for Alltrax by attempting to
drive up on auto service ramps and logging the data.
Alltrax came back, telling me that the controller was
immediately going into current limit. If anyone wants
that data, I'd be happy to send it to them. I believe
it was pulling 400+ amps at the motor, and the 72vdc
pack voltage was sagging down to around 66vdc. As
long as I stop on level grade, the car takes off fine,
and will climb inclined grades.
Alltrax, hasn't offered a resolution, I asked about a
controller bypass, (at say 24vdc) at least for the
initial boost to get the car rolling, and then switch
back to the controller, but haven't heard anything
from them on that idea. Some of the seasoned EV'rs
might know of a way to make something like that work.
--- "(-Phil-)" <[EMAIL PROTECTED]> wrote:
> I for one think this kind of discussion is
> interesting and definitely
> on-topic. Having this kind of thing discussed and
> in the archives will help
> people in the future!
>
> Do you have any volt/amp readings from your setup?
> When you are trying to
> go up the incline it would be very informative to
> read the controller
> amps/volts. On the alltrax I believe all you need
> is a laptop and a serial
> cable (plus their software, which you can download)
>
> -Phil
> ----- Original Message -----
> From: "Michael Barkley" <[EMAIL PROTECTED]>
> To: "EVDL.ORG EVDL.org" <ev@listproc.sjsu.edu>
> Sent: Monday, May 21, 2007 1:17 PM
> Subject: Please help, Aircraft Generator starting
> torque issue.
>
>
> > Please, if anyone can help me with a solution, to
> my
> > torque problem from a deadstop, I sure would like
> to,
> > off list talk with you. I don't want to bother
> the
> > list with an ongoing discussion, as I know using
> an
> > aircraft generator as a motor, isn't the smartest
> way
> > to go (Dang you "MotherEarthFarce" for hooking me
> with
> > that 75mpg article) before I found this EV'r list.
> >
> > That disclaimer aside, here's my problem, I think:
> > I'm using an Aircraft Generator J29 to be exact,
> it's
> > not a combo, starter/generator and therefore it
> seems
> > to be lacking in starting torque as a motor.
> >
> > Is there anyway to salvage my EV and still use
> this
> > motor somehow? It has plenty of pep and speed
> once it
> > gets going, but the EV will not go if it's on an
> > incline using an AXE 7245 controller @ 72vdc. I
> just
> > purchased brand new batteries, and although it's
> > better, the car will not overcome an incline from
> a
> > deadstop.
> >
> > Please, if you have any ideas - send them to me
> off
> > list, as I don't want to fill up email boxes of
> the
> > others that aren't interested in this issue.
> >
> > Thanks in advance - Mike
> >
> > Michael Barkley
> >
> > www.texomaev.com
> >
> >
>
>
Michael Barkley
www.texomaev.com
--- End Message ---
--- Begin Message ---
Hello Michael,
A engineer friend of mine built his first EV using a 28 volt Aircraft
Starter that was use in a VW BUG. Use 48 volts of floor cleaner batteries,
a controller he built himself. The axle gear ratio something over 4 to 1.
The EV could out accelerated my EV and could go up some steep grades.
It was found by experimentation, that it took about 2400 watts of battery
power to move about 100 lbs of weight with a overall ratio of 1:1 or one to
one.
So if the vehicle weighs about 3000 lbs, than 3000/100 = 30. Then 30 x
2400 watts = 72000 watts to move the vehicle with a 1:1 final gear ratio.
This vehicle had about 4:1 ratio, so 72000 watts / 4 = 18000 watts or 18kw.
Therefore 18,000 watts / 746 = about 24 hp.
If the motor does not have the hp or the torque, then try to add more
overall gear ratio by changing the axle ratio or shift to a lower gear
transmission.
Roland
----- Original Message -----
From: "Michael Barkley" <[EMAIL PROTECTED]>
To: "EVDL.ORG EVDL.org" <ev@listproc.sjsu.edu>
Sent: Monday, May 21, 2007 2:17 PM
Subject: Please help, Aircraft Generator starting torque issue.
> Please, if anyone can help me with a solution, to my
> torque problem from a deadstop, I sure would like to,
> off list talk with you. I don't want to bother the
> list with an ongoing discussion, as I know using an
> aircraft generator as a motor, isn't the smartest way
> to go (Dang you "MotherEarthFarce" for hooking me with
> that 75mpg article) before I found this EV'r list.
>
> That disclaimer aside, here's my problem, I think:
> I'm using an Aircraft Generator J29 to be exact, it's
> not a combo, starter/generator and therefore it seems
> to be lacking in starting torque as a motor.
>
> Is there anyway to salvage my EV and still use this
> motor somehow? It has plenty of pep and speed once it
> gets going, but the EV will not go if it's on an
> incline using an AXE 7245 controller @ 72vdc. I just
> purchased brand new batteries, and although it's
> better, the car will not overcome an incline from a
> deadstop.
>
> Please, if you have any ideas - send them to me off
> list, as I don't want to fill up email boxes of the
> others that aren't interested in this issue.
>
> Thanks in advance - Mike
>
> Michael Barkley
>
> www.texomaev.com
>
>
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--- Begin Message ---
That's a shame. I've spoken to A123 on the telephone in the last few
months, and the rep was exceptionally knowledgeable and helpful and
recommended several resell outlets. At the time we didn't talk about series
32 (I also looked at the website today - nice batteries).
I know they're the supplier for the Volt (I forgot where I read it, but
several news sources said they, and not Cobasys, had been chosen to supply
batteries). They also supply batteries to the Prius (among other hybrids)
PHEV supplies (thanks Bill Dube for pointing that out). On top of that, the
military sucks up batteries as well, and I have a strong suspicion the
military is ramping up purchasing of phosphate batteries for radios and the
like. So I doubt A123 was being caustic - they probably really don't have
manufacturing capacity to cover their 2007-2009 demand. Battery demand is
going through the roof.
The good news is that A123 and similar battery suppliers will probably
respond by opening more factories and increasing supply...which should lead
to some oversupply and price reductions. Already lithium ions are going
down.
By the way, does anyone know what's happening with Valence? Are they going
to add any new batteries or increase production? I like their batteries
because the have built in BMSs, they just don't have much amperage.
Dustin
-----Original Message-----
From: Tehben Dean [mailto:[EMAIL PROTECTED]
Sent: Monday, May 21, 2007 1:38 PM
To: ev@listproc.sjsu.edu
Subject: Re: Solectra/Azure - A123 response + A Great Idea!!
Azure responded fast to my email and sent me pdf's on the controller
and motor like I asked.
Also a123 responded and said:
"Good morning. Our capacity for the 32 series cells is committed to OEM
programs through 2007. Thanks."
So I suddenly thought... why don't we all form a company, UEVH.inc
(United Electric Vehicle Hobbyist's incorporated) or something and
then we can make large orders of "OEM only blah blah" products (think
lithium batteries) for all the members and anyone else we can sell to
at a markup?
Or we can not sell and be a non-profit... I don't no what the
benefits are to that, but I'm sure there are some.
Think, a non-profit promoting environmentally friendly
transportation.... there has got to be government subsidies or
something... well thats already gone to Exxon, Walmart and Corn
growing I guess. (It was a good idea ;)
Tehben
"United We Stand" :)
--- End Message ---
--- Begin Message ---
FWIW, something 99% efficient is ~5 times more efficient than 94%
efficient (while, yes, it's only 5% in absolute difference).
To illustrate difficulty, to go from 99% to 99.5% you *double
existing 99% efficiency. Add "just" 1% and you made something
infinitely more efficient (100%)...
Victor
Lee Hart wrote:
(-Phil-) wrote:
I don't believe a contactor controller can be much [more] efficient
than PWM.
Not "much" more efficient; but a *little* more efficient. Like I said,
99% vs. 94%. That's only 5% better, which isn't enough to even notice
without careful measurement.
--- End Message ---
--- Begin Message ---
(-Phil-) wrote:
Okay, I'll give you that on a contactor controller that complex.
I just drew a schematic for one like you describe, and it's got a
lot of contacts!
I don't think I've ever heard anyone call a contactor controller
"complex" in comparison to a PWM controller.
I posted this on 5/8/2004: "Here's a 3-step contactor controller
schematic. It is basically what is in the CitiCars. Four contactors and
a resistor provide forward/reverse and 4 speeds (off, 18v with resistor,
18v direct, 36v with resistor, 36v direct). View it with a fixed width
font like Courier:"
K2 (NO)
resistor bypass
________________________/____________
| | | | _|_
| | |__/\/\__| / \ motor armature
| __|__+ starting \___/
/ K1a ___ B1 resistor |
| (NO) | - __/____|____/__
| | | K3a K4a |
|____/____| | (NC) _ _ (NC)|
| K1b | forward |_____| | |_____| reverse
| (NC) | | motor |
__|__+ | | field |
___ B2 / K1c |__/_________/__|
| - | (NO) K3b | K4b
| | (NO) | (NO)
|_________|___________________________|
Here's a more elaborate one I posted on 1/28/00: "This is the rectactor
arrangement, which uses diodes to replace about half the contactors. It
uses 5 contactors to provide 6 speeds; off, 24v with resistor, 24v, 48v,
96v, and 96v with field weakening. Note the snubber capacitor across K1,
and that R1 is used for both a starting resistor and field weakening
resistor."
_________________________________||__________||___
| _|_ __|__+ | || | | || |
| D1 /_\ K4a ___ B1 | K1 | | K2 |
_|_ |____||____| - | | |_ R1 _|
D5 /_\ +__|__ || _|_ |___|/___| \/\/\/ |
| B2 ___ /_\ D2 +|\- | |_
| - |__________| C1 _|_ _| MOTOR
| K3 | K5 ___ _| FIELD
|______||_________| | _|
| || | | |
____|_____ | |____|
_|_ __|__+ _|_ |
D3 /_\ K4b ___ B3 /_\ D6 _|_
|____||____| - | MOTOR / \
+__|__ || _|_ | ARMATURE | |
B4 ___ /_\ D4 | \___/
|__________|___________|________________________________|
Interesting exercise.... But it offends my "sense of engineering"
to want to put something like that in my EV.
Could be... but how do you think the speed controller for your car's fan
or windshield wipers work? Resistors and switches. :-)
I noticed you'd also have problems with running a DC-DC converter to
power all those coils. You'd pretty much be resigned to an Aux battery
to run them, and if you had to have the DC-DC; then only switch it in
either at the highest voltage or maybe also "idle". Tricky!
Why? Most contactor controllers use pack voltage to run their coils (no
auxiliary supply needed). Others use an auxiliary 12v supply if it was
already there for some other purpose.
Lots of arcing because of the front-end capacitors in the DC-DC though.
The DC/DC in a vehicle with a contactor controller is normally modular,
with as many modules as there are steps. For example, my CoumtaVan had
two 36v half-packs, which the controller wired in series or parallel.
The DC/DC had two 36v input / 12v output modules, each one permanently
connected across half the pack. Their outputs were summed with commoning
diodes to balance the load. An advantage of this arrangement is
reliability; if one DC/DC fails, the other still works.
Soon I'm going to put together a siamese motor configuration with a
large PM DC and a 3-phase AC motor so I can use the resulting test-bed
to develop my own AC controller.
That's a good strategy. I did it when I was playing with AC controllers.
It made it much easier to test, and I could regen the power back into
the battery pack, eliminating the need for a huge power supply.
The devices on the market now enable much better specs than you are
quoting for the Curtis designs.
Not really. The Curtis controllers are practical product that you can
actually buy. Most others are lower power, or backlogged, or have even
worse specs for on-state voltage drops.
Run low-side switching instead of diodes and use state-of-the-art MOSFETs
and lots of them, and I'll trump your contactor controller efficiency...
I'll bet you won't. :-) Even with zero conduction losses, your switching
losses alone will exceed that of a contactor controller.
Have you noticed that contactor controllers don't have any heatsinks or
fans or cooling systems? What does that tell you about their efficiency?
--
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 ---
