EV Digest 6802
Topics covered in this issue include:
1) Re: Please help, Aircraft Generator starting torque issue.
by Michael Barkley <[EMAIL PROTECTED]>
2) Re: electric mower - corded or battery
by "mike young" <[EMAIL PROTECTED]>
3) RE: electric mower - corded or battery
by [EMAIL PROTECTED]
4) RE: Low cost battery materials
by "Peter VanDerWal" <[EMAIL PROTECTED]>
5) Re: Main Contactor Ebay Search Criteria
by Steve Condie <[EMAIL PROTECTED]>
6) Re: 10,0000 cycles (was: Battery chart for a hand-out...)
by "Timothy Balcer" <[EMAIL PROTECTED]>
7) Re: electric riding mower
by Jeff Major <[EMAIL PROTECTED]>
8) RE: Charging Stations
by "Chuck Hays" <[EMAIL PROTECTED]>
9) RE: Please help, Aircraft Generator starting torque issue.
by Michael Barkley <[EMAIL PROTECTED]>
10) 15k DIY Porsche. 20k Installed.
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
11) Re: Reality check, Re: Permanent magnet motor question
by Lee Hart <[EMAIL PROTECTED]>
12) Re: Please help, Aircraft Generator starting torque issue.
by Lee Hart <[EMAIL PROTECTED]>
13) Re: electric mower - corded or battery
by Lee Hart <[EMAIL PROTECTED]>
14) Re: Triangle wave generator
by Lee Hart <[EMAIL PROTECTED]>
15) Re: Low cost battery materials
by Lee Hart <[EMAIL PROTECTED]>
16) Re: Triangle wave generator
by tt2tjw <[EMAIL PROTECTED]>
17) Thanks for Charging Station Input!
by "Chuck Hays" <[EMAIL PROTECTED]>
18) RE: 15k DIY Porsche. 20k Installed.
by "Michael Wendell" <[EMAIL PROTECTED]>
19) Re: Triangle wave generator
by Chet Fields <[EMAIL PROTECTED]>
20) Re: 15k DIY Porsche. 20k Installed.
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
21) Re: Triangle wave generator
by Danny Miller <[EMAIL PROTECTED]>
--- Begin Message ---
It has two large terminals, and two small
terminals. Terminals A & D are small, Terminals E & B
are large. Terminal A & B are wired together and tied
to the Positive wire of the pack. Terminal E is tied
to the Negative wire of the pack. Terminal D is
unused. I apologize in earlier posting, the motor is
a G-29 Generator made by J&H, not a J29. Darn typo's
I had tried a SEPEX controller to begin with, and it
wouldn't run the motor, so I went to the Alltrax 7245
and wired it as above to make it a shunt motor, I
purchased the motor from SurplusCenter, and they had
the wiring layout as above to use the generator as a
motor.
Thanks for your help.
>
> Mike,
>
> It is hard to see in the pictures. Is this a 4
> terminal machine? Two large (armature)? Two
> smaller
> (field)? How it wired to the controller? I might
> have an idea about what's going on.
>
> Jeff
>
>
Michael Barkley
www.texomaev.com
--- End Message ---
--- Begin Message ---
I have 5 corded black and decker push mowers and my kids and i mow a huge
lawn with them.We just start close to the outlet and work our way away from
the cord. got them at auctions and yard sales average price $5.
Mike young-- solectria force cars
----- Original Message -----
From: "Tim Humphrey" <[EMAIL PROTECTED]>
To: "EV" <ev@listproc.sjsu.edu>
Sent: Tuesday, May 22, 2007 10:00 AM
Subject: RE: electric mower - corded or battery
Corded, 4 years, 150ft of stench cord, haven't run it over yet. Well,
that's not entirely true. I did run it over once, BUT the blades won't
pick the
cord up out of the grass. That's good to know, but I'm not going to make
it a habit of running over my cord.
Ironically, I did cut it with the corded chainsaw. I looked down and said
"I better move that cord or I'm going to cut it". I was right. Sometimes
I
don't like being right.
Why corded?
1. more efficient
2. cheaper initial purchase ($179 for 21" cut)
3. never replace batteries
4. lighter
5. unlimited run time
6. generally more powerful
I have to replace my corded mower this year. 25yrs old. Deck finally
rusted out. The new B&D's are plastic, I figure it will be my last push
mower
purchase. Unless B&D has gone to crap quality on the mower's like they
have on the rest of their product line.
--
Stay Charged!
Hump
I-5, Blossvale NY
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Deanne Mott
Sent: Tuesday, May 22, 2007 9:03 AM
To: ev@listproc.sjsu.edu
Subject: Re: electric mower - corded or battery
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.
I agree - go cordless. I just bought a Ryobi from a local EV'er that
finds them at thrift stores, abandoned after the batteries die. For
$50-60, he replaced the batteries and it was good to go. We really
like the mower, it does the job and is pretty quiet - about like an
electric weedeater. I think I would go insane keeping the cord from
around trees and flower beds, and there's no doubt in my mind I would
mow the cord at some point...
--
"That car has some get-up-and go and it don't make no racket."
-Richard Petty, after driving Shocker, Northhampton East HS's EV Grand
Prix winner
--- End Message ---
--- Begin Message ---
B&D's need new motor brushes every so often.
for the original poster, yes the motor should be Permanant Magnet DC, since
there is a rectifier in the diagram (which would make it a 120 VDC) motor.
I trash picked two so far waiting for the right parts to get one working.
I think they are long lasting except the one I trash picked had a cracked
magnet (missing in some places and bent blade. The owner must have really
meant to break the mower.
Also, trash picked a 6 Volt cordless weed wacker and removed the battery
and plug it into one battery on my Elec Trak. Never ending weed wacker
--- End Message ---
--- Begin Message ---
Lemons make pretty good batteries. They are about as practical as any
other home-made battery.
>I realize some here only want the highest performance.
>But I would like to find the lowest cost materials for homemade
> batteries.
>The point has been made that lead is expensive.
>All metals have some electrolytic properties even if perhaps not as good
> as
>lead of the more advanced ones.
>What else can a battery be made of?
--
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 ---
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--- Begin Message ---
Bill,
Can you answer the question of whether or not the A123 cells have a
time dependent degrading factor, like the old Lithium chem does?
Thanks muchly,
--T
On 5/19/07, Bill Dube <[EMAIL PROTECTED]> wrote:
Here is the cycle life info on their new website:
http://www.a123systems.com/newsite/index.php#/applications/phev/pchart2/
Notice that it is a straight line for % capacity remaining versus
cycles. As I mentioned earlier, if 50% remaining capacity is OK with
you, then the cycle life is 10,000 cycles.
Like I said, I don't just make this stuff up. :-)
Many (perhaps most) of the battery manufacturers use 50% remaining
capacity for the "end" of the cycle life.
Bill Dube'
At 07:53 PM 5/17/2007, you wrote:
>You need to dust off your calculator and actually do the math.
>
>At 50% capacity loss (10 times 5%) you will get 10,000 cycles (10
>times 1,000.) This is direct quote from the engineers a A123
>Systems. I don't make this stuff up.
>
>By the way, can you find another brand of battery that lists the
>cycle life for 10 C discharge?
>
>At 08:33 PM 5/17/2007, you wrote:
>>What that chart shows:
>>
>> 1C the loss is 5% at 25C after 1000 cycles
>> 2C the loss is 10% at 45C
>> 2C the loss is 20% at 60C
>>
>>All I can really say is you are now Bill the Battery Salesman
>>to say expect 10,000 cycles for an EV.
>>
>>Jack Murray
>>
>>Bill Dube wrote:
>>>As I mentioned in a post yesterday, (in answer to YOUR post) the
>>>temperature is what really matters in the cycle life. The
>>>high-current cycle tests makes the cells run at high temperatures,
>>>and thus shorten cycle life.
>>>If you look at the chart
>>>http://www.a123systems.com/newsite/pdf/ANR26650M1_Datasheet_FEB2007-1.pdf
>>>you will notice that the 25 C curve indicates a 5% capacity loss
>>>after 1,000 cycles. (This is what you would expect in the typical
>>>EV environment.)
>>>Looking at the 60 C curve, you see that the capacity loss is about
>>>25%. after 1,000 cycles. At the same current, but at 45 C, the
>>>curve shows about 12% loss after 1,000 cycles.
>>>EVs typically discharge batteries at 1C, sometimes less, sometimes
>>>a bit more. Low internal resistance keeps the cell temperature at
>>>30 C or below. Thus, in an EV, you can expect the cycle life of
>>>about 10,000 cycles to 50% capacity.
>>> Why don't you dig up the cycle life of an Optima at 10 C
>>> discharge at 60 C? You can't find this chart because the battery
>>> would be a puddle of smoking molten goo at this temperature.
>>>Bill Dube'
>>>
>>>At 06:49 PM 5/17/2007, you wrote:
>>>
>>>>So the chart that A123 publishes that shows 20% loss at 1000
>>>>cycles at 10C discharge is not correct?
>>>>
>>>>
>>>>Bill Dube wrote:
>>>>
>>>>>The cycle life on A123 Systems cells is actually much more than
>>>>>1,000 cycles, if you rate it the same way other manufacturers'
>>>>>do. The 1,000 rating is for just 5% loss of capacity. If you
>>>>>rate it to 50% loss of capacity, (like lead-acid AGMs are rated)
>>>>>the cycle life is 10,000 cycles.
>>>>>I don't think Li-Ion FePo has a calender capacity loss like
>>>>>conventional Li-Ion does. The chemistry is much more stable.
>>>>>Bill Dube'
>>>>>
>>>>>At 05:35 PM 5/17/2007, you wrote:
>>>>>
>>>>>>I'm manning a booth at the Maker Faire (San Mateo County Fairgrounds, May
>>>>>>19-20, http://www.makerfaire.com ) over the weekend and wanted to give a
>>>>>>hand-out regarding EVs. In addition to some white papers by
>>>>>>Tesla, I wanted
>>>>>>to put together two charts.
>>>>>>
>>>>>>The first one, I was hoping to put gas price over time, vs
>>>>>>battery cost over
>>>>>>time. Does anyone know where I'd get data for battery
>>>>>>cost? Say, for NiMH
>>>>>>and LiIon, over the past 10 years or so?
>>>>>>
>>>>>>The second one was inspired by
>>>>>>http://www.madkatz.com/ev/batteryTechnologyComparison.html
>>>>>>and it's a chart of battery specs, with an added emphasis on
>>>>>>total cost of
>>>>>>the battery, per kilowatt-hour, over the lifetime of the battery.
>>>>>>Here it
>>>>>>is so far... does anyone have good info on what a modern NiCad
>>>>>>would be to
>>>>>>use? Anyone had experience (and pricing) with Valence's U-Charge?
>>>>>>Also,
>>>>>>what's the realistic peak power out of a flooded lead-acid or hawker
>>>>>>Genesis? (I figure the racers on this list would know for real...)
>>>>>>
>>>>>>Tech Density #Cycles Discharge Cost
>>>>>> Wh/kg W/kg (per month) $/kWh $/kW
>>>>>> $/LifeTimekWh
>>>>>>Est Range
>>>>>>Flooded lead-acid 47 600 20%? $85 $0.14
>>>>>>"AGM" lead-acid 35 412? 500 5%? $145 $12?
>>>>>>$0.29 ~60
>>>>>>NiCad 50? 2000? 100%? $300? $0.15
>>>>>>NiMH (Nilar) 55 385 4000 $960 $137
>>>>>>$0.24 ~110
>>>>>>LiIon (18650) 176 631 500 ??% $535 $149
>>>>>>$1.07 ~250
>>>>>>LiPho (A123) 110 3000 1000* $1300 $47
>>>>>>$1.30 ~180
>>>>>>
>>>>>>Notes:
>>>>>>LiIon loses 5% of capacity per year, regardless of whether you
>>>>>>use it. See
>>>>>>http://www.buchmann.ca/Article5-Page1.asp
>>>>>>NiCads have severe memory effects.
>>>>>>
>>>>>>W/kg is max possible "peak" rate.
>>>>>>Wh/kg is "average" or "nominal" discharge rate.
>>>>>>Range is affected by how much extra packaging must surround the
>>>>>>battery, for
>>>>>>example extra temperature monitoring that affects 18650 cells.
>>>>>>18650 cells est. at $5 each
>>>>>>* - cycles claimed by A123
>>>>>>
>>>>>>Sources:
>>>>>>
>>>>>>http://www.nilar.com/index.php?pageID=33&languageID=1
>>>>>>NiMH based on Nilar 24V 9AHr=216WHr @3.9kg $208 each
>>>>>>
>>>>>>http://www.madkatz.com/ev/batteryTechnologyComparison.html
>>>>>>
>>>>>>http://www.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf
>>>>>> => 56kWH, 200kW, 200 miles, 375V, 450kg (317kg batt weight est)
>>>>>>6,831 cells, 46.5g each at $5 each would be $34,150 for 56kWHr
>>>>>>
>>>>>>http://libattery.ustc.edu.cn/english/introduction%203.htm
>>>>>>
>>>>>>Flooded specs based on US Battery US185 spec 195AHr=2340WHr @49kg $200
>>>>>>
>>>>>>AGM Specs based on Hawker G70EP 72AHr=864WHr @24.9kg $125
>>>>>>
>>>>>>A123 specs based on 3.3V, 2.3Ah, 7.6WHr @70g $10.00 (dev kits
>>>>>>are $20 each
>>>>>>in much smaller quantity)
--- End Message ---
--- Begin Message ---
Hi midiguy732,
You got a better name? Anyway, I think electric
riding mowers (or just the tractor part) are a lot of
fun. I have a 30 year old(?) Sears tractor which
originally had a 10 to 12 hp engine. Bought it 15
years ago without engine or deck for like $20. Had
decent tires and seat. Put in an old 6" dia 24 volt
floor sweeper motor and a 48 volt Crutis 275 amp
controller and 4 garden tractor batteries. Kept the 3
spd transmission (or transaxle). Works great. I
don't mow with it, but about everything else. Lawn
sweeping puts the biggest load on it, about 40 amps.
So I cannot do that very long, but who wants to?
So as far as what size motor to use, for
traction(propulsion) a 6 to 6.6" dia motor with a 275
amp limit at 36 or 48 volts is probably more than
enough. I can do Wheelies if I fool the controller.
Don't have many hills, but never met a ramp I could
not do even pulling a half ton of firewood or dirt or
rock.
Blade motors are a bit trickey. You probably are
going have trouble with that. Direct drive (blade
attached to the motor shaft) can be difficult and if
you hit a rock and bend the shaft, the motor is
screwed. You might consider using the belt-pulley
system and a single motor to drive both blades. A
6.6" dia motor would probably work here as well. I
did a motor drive for a guy with a big 3 blade deck
using a single 7.2" motor. Works great.
Another thing I'd suggest, look up Elec Trak mowers by
GE from the early 70's. You can find them sometimes
on eBay, or parts or manuals.
Good luck and have fun.
Jeff
--- midiguy732 <[EMAIL PROTECTED]> wrote:
> > 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.
>
>
____________________________________________________________________________________
No need to miss a message. Get email on-the-go
with Yahoo! Mail for Mobile. Get started.
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--- End Message ---
--- Begin Message ---
From: Ricky Suiter <[EMAIL PROTECTED]>
First you might want to talk to Tom Dowling at
EVchargernews.com about this.
Thanks!
As far as paying for power, for a college it would
probably be relatively insignificant money wise (and
maybe I'm thinking on the scale of Arizona State with
78,000 students).
We're pretty small. About that many people in
the whole town. :)=)} Our enrolment is in
the 10,000 range.
You make some good points re: enforcement and
payment. Close enough to be attractive and far
enough not to be full all the time would be ideal.
As for payment -- of course my preference would
be to see how much of a hit it generates, but
of course the folks in the Power Tower would
like to see it be "self supporting."
I saved your comments to pass along to others.
Thanks again.
Chuck
_________________________________________________________________
See Fireworks On Live Image Search
http://search.live.com/images/results.aspx?q=Fireworks&mkt=en-ca&FORM=SERNEP
--- End Message ---
--- Begin Message ---
Hey guys; I posted wiring diagrams of the current
configuration on my website. They should shed light
on the wiring, and application this discussion is
talking about.
www.texomaev.com
Click on the "My Current Conversion Project" link
towards the bottom of the page.
Thanks again so much for all your help on this matter.
:>) Mike
--- Jeff Major <[EMAIL PROTECTED]> wrote:
>
> Yea, Tim,
>
> That's what it looks like to me. I think Father
> Time
> hit the nail on the head. If he has the machine
> wired
> as a shunt motor, both field and aramture coming off
> the controller, then in current limit he may have
> too
> low voltage for the field. A weak field at stall on
> a
> shunt motor will give you crappy torque. And on the
> other hand, at high voltage, he'll probably burn
> those
> field coils. If this is the case, he should
> separately excite.
>
> Jeff
>
>
>
> --- Tim Humphrey <[EMAIL PROTECTED]> wrote:
>
> >
> > Jeff,
> >
> > The second pic down shows what clearly looks to me
> > to be a 4 terminal strip. Two large terminals with
> > two small terminals outside them, all in a line.
> >
> > In another pic I see a (red?) wire on one of the
> > small term's but can't tell where it's going.
> >
> > --
> > Stay Charged!
> > Hump
> > I-5, Blossvale NY
> > >
> > >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] On
> > > Behalf Of Jeff Major
> > > Sent: Tuesday, May 22, 2007 9:35 AM
> > > To: ev@listproc.sjsu.edu
> > > Subject: Re: Please help, Aircraft Generator
> > starting torque issue.
> > >
> > >
> > > Mike,
> > >
> > > It is hard to see in the pictures. Is this a 4
> > > terminal machine? Two large (armature)? Two
> > smaller
> > > (field)? How it wired to the controller? I
> might
> > > have an idea about what's going on.
> > >
> > > Jeff
> > >
> > >
> > > --- Michael Barkley <[EMAIL PROTECTED]> wrote:
> > >
> > >> 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
> > >>
> > >>
> > >
> > >
> > >
> > >
> > >
> >
>
____________________________________________________________________________
> > > ________Sick sense of humor? Visit Yahoo! TV's
> > > Comedy with an Edge to see what's on, when.
> > > http://tv.yahoo.com/collections/222
> >
> >
>
>
>
>
>
____________________________________________________________________________________Need
> a vacation? Get great deals
> to amazing places on Yahoo! Travel.
> http://travel.yahoo.com/
>
>
Michael Barkley
www.texomaev.com
--- End Message ---
--- Begin Message ---
I was just looking at the www.electroautomotive.com site and their AC kit is
around 15k with batteries. After all the talk of what's available I'm
begining to think that is a bargain. If you are a miser it will go 150
miles on the flat. I'm not sure what it will do on the freeway or going
from San Jose, CA to Santa Cruz over the mountain. It just seems with kits
like that available no one should have to go without an electric vehicle.
Lawrence Rhodes......
--- End Message ---
--- Begin Message ---
Victor Tikhonov wrote:
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%)...
You should be in marketing, Victor! :-)
I think it would be deceptive marketing to advertise something as "5
times more efficient" if you improved efficiency from 94% to 99%. But, I
do see people making claims like this (usually to sell stock in some
scheme).
But that's not how I was taught to do it. You can say "5 times lower
losses", because the power lost was indeed reduced by 5:1. But not "5
times higher efficiency", because that would imply going from 94% to
5x94% = 470% which is over unity and impossible.
--
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 ---
Michael Barkley wrote:
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...
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 agree that this is on-topic, as a number of people have used, or are
interested in using these old beasts.
I used a Jack & Heinz 30v 500a aircraft generator in my first EV, too.
Torque was lower than a series motor, but I made up for it by hitting it
with 1000+ amps. I used a contactor controller (Zillas had an even
longer deliver time in those days) :-) Tire burnouts were no problem;
I'd lose traction before failing to climb any hill.
Both the generators and the starter/generators have series windings. The
generators have only two large terminals, and a small series field which
is internally connected as a compensation winding (to boost voltage
under load so the output voltage does not sag).
The starter/generators have three large terminals, and a larger series
field. When you connect to the outer two large terminals, you are
getting the armature and series field in series.
It is important to run it in the right direction. The correct direction
of rotation was stamped right on mine. Since you can't reverse the
phasing of the series field, the correct direction will also reveal
itself if you power the outer two of the three large terminals.
The shunt field has one end internally connected to the armature. This
also forces it to turn in only the correct direction (assuming the field
is powered with a supply of the same polarity as the armature). You can
easily disconnect this internal connection, so both sides of the shunt
field are available externally. This allows you to get electrical
reverse *BUT* I found that torque in reverse is significantly lower
because the two fields are now opposing rather than aiding each other.
What are you using for your field supply? If you simply switch it to a
constant voltage of less than 30v, you will get a low-speed moderately
high-torque motor. To increase speed, you must reduce field current; but
that will also reduce torque.
I found that you can supply a significantly higher shunt field voltage
to get significantly higher torque -- but only for a very short time
before the field winding overheats. I had a 72v pack, and could connect
the field to 72v for perhaps 30 seconds max. This produced drastically
higher torque; enough to slip the clutch or spin the tires on dry pavement.
Hope this helps!
--
Patent examiner to applicant: "No, your application seem to be legal.
I'm just having trouble classifying it as intellectual property."
-- Frank and Ernest
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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--- Begin Message ---
[EMAIL PROTECTED] wrote:
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 used a corded electric mower for many years. About half of them it was
powered from batteries.
All of these mowers seem to have brushed DC motors, with a bridge
rectifier off the AC line to convert it to DC. In my case, I had a flat
yard but with a lot of trees, so the cord was a nuisance. So I bought a
bunch of surplus Gates Cyclon 2v 2.5ah cells (sealed cylindrical lead
acid, about the size of a D-cell). I arranged 60 of them in a
donut-shaped ring that fit around the motor. The "controller" was just a
contactor, switched on/off by the switch in the handle.
I used it for about 5 years this way. Over the years, the cells died one
by one and had to be eliminated, until I got down to about 80v left. At
that point I moved to a house that had a full story height difference
between the front and back yards, so I converted it back to a corded mower.
--
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
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--- Begin Message ---
Chet Fields wrote:
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?
A 741 doesn't work very well at only 5v. Its inputs and outputs can't
get very close to the supply voltages. It was normally used with +/-15v
supplies.
Here's a schematic of a debugged PWM controller with current limiting,
overtemperature protection, etc. It is suitable for a sepex motor field,
or even a small PM or series motor (and could be expanded to drive
larger ones).
http://austinev.org/evalbum/tech/petroson.pdf#search=%22petrosonics%20controller%22
--
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 ---
GWMobile wrote:
I realize some here only want the highest performance.
But I would like to find the lowest cost materials for homemade batteries.
The point has been made that lead is expensive.
All metals have some electrolytic properties even if perhaps not as good
as lead of the more advanced ones.
What else can a battery be made of?
Start with the "electromotive series", which is a table found in any
good chemistry or physics textbook. There's a simplified one online at
http://www.diracdelta.co.uk/science/source/e/l/electromotive%20series/source.html
The complete chart lists hundreds of elements and compounds, and the
corresponding voltages for all sorts of oxidation/reduction reactions.
Hydrogen is about in the middle, so they arbitrarily assigned it a value
of 0 volts. Every other material develops some voltage relative to this.
To make an electrochemical cell (what most people call a battery), take
any two materials from this chart, and put them in an electrolyte (a
liquid that conducts electricity), with some insulating spacer between
them so they don't actually touch (like a woven fiberglass mat or screen).
The voltage that this cell produces is the difference in their voltage
in this chart. For example, copper is -0.47v and iron is +0.44v, so
copper and iron in a bucket of water produce 0.91v.
Now, this will give you a primary cell; the iron will rust in the water,
as it discharges, and you can't turn the rust back into iron by charging
it. The challenge is to find a pair of materials that can undergo
*reversible* chemical reactions, where both the oxidized and reduced
forms (like iron and iron oxide) are both electrical conductors, and
will stay attached to the plates.
Also note that the really good materials with high numbers are either
violently reactive (like lithium, +3.02v, which explodes in water) or
obscenely expensive (like gold, -1.42v, at hundreds of dollars an ounce).
The surface area of your plates determines the maximum current you can
draw. Thus, you want to find materials that you can process to produce
very large surface areas; spongy or porous etc.
The weight of the materials determines the amphour capacity. This is the
killer for expensive materials.
Hundreds of the material combinations in this table have been explored,
but there are hundreds of combinations that haven't been tried (yet).
--
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 ---
Chet,
is there any reason not to use a microcontroller with PWM outputs?
Chet Fields wrote:
I am trying to generate the triangle wave for the PWM circuit and I am using
the good ol' 741 Op
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--- Begin Message ---
Quite the discussion, thanks for all the input.
It's good to have several people's experience
to draw on for this -- particularly people who
are doing it right now!
So a big thanks and tip of the propellor beanie
to Matt, Phil, Ralph, Rich, and Ricky.
Chuck
_________________________________________________________________
Windows Live Hotmail gives you the control you need to help you keep your
e-mail private, safe and secure. See for yourself!
www.newhotmail.ca?icid=WLHMENCA147
--- End Message ---
--- Begin Message ---
> I was just looking at the www.electroautomotive.com site
that link is http://www.electroauto.com
> ...and their AC kit is around 15k with batteries. After all
> the talk of what's available I'm begining to think that is a
> bargain. If you are a miser it will go 150 miles on the flat.
i'm a lurker, still in the dreaming stage with this, but i didn't realize
their kits had that kind of range. i'm hoping to have the time to seriously
begin tinkering this fall.
the 914 seems to be a somewhat popular conversion, and electro's kit may
have something to do with that.
while i like the 914, i've been wondering if the boxster might be a better,
more modern equivalent. what does the list think, too heavy? i've seen beat
up boxsters selling for reasonable prices on ebay, and i'd imagine that
parting out the ICE equipment would yield a nice payback.
thanks, i'll go back to lurking.
m.
Michael Wendell
Web/Graphics Guy
Speedgoat Bicycles
724.238.7181
[EMAIL PROTECTED]
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--- Begin Message ---
I had thought first of using a microcontroller, but then good advice from the
list suggested that
it may not be a good idea as it may lock up and cause the MOSFETs to be stuck
on. I don't really
know of a good way to protect from that happening except for maybe some fuses
or something.
I did think that a microcontroller like a PIC would give me alot of flexibility
though. I am a
programmer professionally so I would definitely be more in my element instead
of designing these
discrete analog circuits, although I have to admit it has been and still looks
like a lot of fun
if I can get it working.
I thought of starting with the analog and then moving later (perhaps) into the
PIC if I can come
up with the proper scheme to protect against a dangerous situation with a lock
up.
Chet
--- tt2tjw <[EMAIL PROTECTED]> wrote:
> Chet,
>
> is there any reason not to use a microcontroller with PWM outputs?
>
> Chet Fields wrote:
> >
> > I am trying to generate the triangle wave for the PWM circuit and I am
> > using the good ol' 741
> Op
> >
> >
> >
>
>
____________________________________________________________________________________
Looking for earth-friendly autos?
Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center.
http://autos.yahoo.com/green_center/
--- End Message ---
--- Begin Message ---
http://www.electroauto.com/ sorry here is the right url. Lawrence
Rhodes.....
----- Original Message -----
From: "Lawrence Rhodes" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <ev@listproc.sjsu.edu>;
<[EMAIL PROTECTED]>; "SFEVA"
<[EMAIL PROTECTED]>
Sent: Tuesday, May 22, 2007 9:49 AM
Subject: 15k DIY Porsche. 20k Installed.
> I was just looking at the http://www.electroauto.com/ site and their AC
kit is
> around 15k with batteries. After all the talk of what's available I'm
> begining to think that is a bargain. If you are a miser it will go 150
> miles on the flat. I'm not sure what it will do on the freeway or going
> from San Jose, CA to Santa Cruz over the mountain. It just seems with
kits
> like that available no one should have to go without an electric vehicle.
> Lawrence Rhodes......
>
--- End Message ---
--- Begin Message ---
That's pretty close to nonsense. IIRC the person claiming this has no
experience with microcontrollers.
A uC is a fine way to generate a PWM signal. It is far easier to design
a system- and do it right- with a uC. There's an awful lot to designing
an analog controller. The analog controller has a lot more that can go
wrong with it. You need a lot of inside information on how each type of
component may fail to start to work the problems out.
It's important to understand however that being able to generate a PWM
is only a small part of the design problem for an EV controller. The
output transistors are large and expensive to obtain and very tricky to
mount where you can meet their extreme thermal, mechanical, and
electrical needs. The transistor driver, where we take 0 to 5v or
whatever PWM and turn it into a transistor drive with the appropriate
voltage level and best waveform shape is tricky too.
Danny
Chet Fields wrote:
I had thought first of using a microcontroller, but then good advice from the
list suggested that
it may not be a good idea as it may lock up and cause the MOSFETs to be stuck
on. I don't really
know of a good way to protect from that happening except for maybe some fuses or something.
I did think that a microcontroller like a PIC would give me alot of flexibility
though. I am a
programmer professionally so I would definitely be more in my element instead
of designing these
discrete analog circuits, although I have to admit it has been and still looks
like a lot of fun
if I can get it working.
I thought of starting with the analog and then moving later (perhaps) into the
PIC if I can come
up with the proper scheme to protect against a dangerous situation with a lock up.
Chet
--- tt2tjw <[EMAIL PROTECTED]> wrote:
Chet,
is there any reason not to use a microcontroller with PWM outputs?
Chet Fields wrote:
I am trying to generate the triangle wave for the PWM circuit and I am using
the good ol' 741
Op
____________________________________________________________________________________
Looking for earth-friendly autos?
Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center.
http://autos.yahoo.com/green_center/
--- End Message ---
