EV Digest 2679
Topics covered in this issue include:
1) Re: WOT! Monster cars was:( Better range from less weight)
by Lee Hart <[EMAIL PROTECTED]>
2) Related but slightly OT. Federal govt. says one thing does another. Loopholes
and bike related in Oregon might affect electirc bikes.
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
3) Re: New and improved bumper sticker design
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
4) Re: Electric Supra? ( long )
by Richard Bebbington <[EMAIL PROTECTED]>
5) RE: New and improved bumper sticker design
by Humphrey Timothy H Contr AFRL/IFEC <[EMAIL PROTECTED]>
6) (OT): RE: New and improved bumper sticker design
by "Grannes, Dean" <[EMAIL PROTECTED]>
7) Re: Escort EV limbo?
by "Christian T. Kocmick" <[EMAIL PROTECTED]>
8) RE: Electric Supra? ( long )
by "Mark Fowler" <[EMAIL PROTECTED]>
9) Re: AC controllers
by "Mark Thomasson" <[EMAIL PROTECTED]>
10) RAV4 EV gets 104 mpg
by Bruce EVangel Parmenter <[EMAIL PROTECTED]>
11) Re: RAV4 EV gets 104 mpg
by Lonnie Borntreger <[EMAIL PROTECTED]>
12) Re: RAV4 EV gets 104 mpg
by Michael Hurley <[EMAIL PROTECTED]>
13) Re: RAV4 EV gets 104 mpg
by Bruce EVangel Parmenter <[EMAIL PROTECTED]>
14) Re: Fort Pierce EV rally
by Andrew <[EMAIL PROTECTED]>
15) Re: AC controllers
by Peter VanDerWal <[EMAIL PROTECTED]>
16) Ni-Cd and Ni-MH from China... an ad I got in the mail
by murdoch <[EMAIL PROTECTED]>
17) Re: batteries for cold weather?
by Andrew <[EMAIL PROTECTED]>
18) Re: AC controllers
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Humphrey Timothy H Contr AFRL/IFEC wrote:
> OK I found a link [monster Camaro]... Most of them, that I've seen,
> are not this "refined" and really do look like some backyard
> freakazoid weekend project thingy.
Yes; that's it. The ones I've seen around here are also in that
category. Badly done.
However, it's the concept I find interesting. Start with a truck frame
that already has the wheels, brakes, springs, suspension, and weight
carrying capacity. Place a small light streamlined car body on it. Use
the weight savings to add more batteries than could have been safely
carried by the original car or truck.
Forget the silly monster truck tires and 3 foot ground clearance, of
course.
--
Lee A. Hart Ring the bells that still can ring
814 8th Ave. N. Forget your perfect offering
Sartell, MN 56377 USA There is a crack in everything
leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
--- End Message ---
--- Begin Message ---
2.
DEAN OF EMISSIONS
The federal government has changed its tune on air quality in
California, with the U.S. EPA easing pressure on the state to impose
more stringent air-pollution controls on farms. Just last month, the
EPA said the state should repeal a law exempting large farms from
air-pollution monitoring permits; now, it is calling instead for an
amendment requiring only "major" farm-based pollution sources to seek
permits. That position echoes the preference of the farm lobby, and
state Sen. Dean Florez (D), who supports complete repeal, suspects
politics played a role in the switch. Farms are responsible for as
much as 20 percent of San Joaquin Valley smog, but for decades, they
have been exempt from the kind of air-quality programs that apply to
power plants and factories. Clean-air advocates are trying to close
that loophole, and Florez says they will not be deterred by the
position change of the EPA: "We are not interested in doing the
minimum. We want to clean the air."
straight to the source: Sacramento Bee, Mark Grossi and Lesli A.
Maxwell, 25 Mar 2003
<http://www.gristmagazine.com/forward.pl?forward_id=932>
3.
LIGHT TRUCK AT THE END OF THE TUNNEL
What's in a name? In the case of "car" versus "light truck," the
name means a lot -- so the auto industry and environmentalists are
watching closely as the Bush administration begins redefining cars
and trucks as it revamps fuel-economy standards. Currently, light
trucks are subject to far weaker gas-mileage requirements than
passenger cars, a difference environmentalists have long accused
automakers of exploiting to escape more stringent rules. It's
unclear whether the new fuel-economy standards will close the
loophole; some fear they will go the other direction. An anonymous
Bush administration official said the goal of the rewrite is to
achieve "even greater fuel economy in model years 2008 and beyond
while simultaneously protecting safety and American jobs." But the
Sierra Club's Daniel Becker expressed concern that Bush
administration officials will back a plan "that increases our gas
guzzling to please their friends in Detroit and Houston."
straight to the source: New York Times, Danny Hakim, 25 Mar 2003
<http://www.gristmagazine.com/forward.pl?forward_id=933>
only in Grist: A new class of SUV -- a cartoon by Suzy Becker
<http://www.gristmagazine.com/ha/ha092200.asp?source=daily>
do good: Take action and tell Ford to focus on fuel standards
<http://www.gristmagazine.com/dogood/autos.asp?source=daily#fordfuel>
4.
SPOKES PERSON
Meanwhile, good news for those who entirely eschew the internal
combustion engine: If a representative from Oregon gets his way,
people who commute to work by bike will soon get a tax break. Rep.
Earl Blumenauer (D-Ore.), founder and chair of the bipartisan
Congressional Bike Caucus, has biked to his Capitol Hill office for
years; he is now pushing for cyclists to get the same benefits as
those who drive or use mass transit to get to work. Under current
law, employers can offer a commuter tax-exemption benefit of $180 for
qualified parking plans or $100 for public transit and van-pool
expenses. Blumenauer's Bike Commuter Act, co-sponsored by Rep. Mark
Foley (R-Fla.), would offer similar benefits to cyclists. The act
has been proposed before, but Blumenauer says that this year, with
war in Iraq and soaring gas prices, support for cycling is gaining
momentum. Almost 1 million U.S. workers cycle to work regularly,
making bicycles second only to cars as the preferred mode of
commuting, according to statistics from bike advocates and the
federal government. Do you bike to work? Or do you get road rage
when lycra-clad cyclists zip past you in traffic? Share your
thoughts in The Gristmill, our online discussion forum, only on the
Grist Magazine website.
straight to the source: Anchorage Daily News, Associated Press,
Matthew Daly, 25 Mar 2003
<http://www.gristmagazine.com/forward.pl?forward_id=934>
grind your axe: Put your pedal to the metal -- join the
conversation in The Gristmill, our discussion forum
<http://www.gristmagazine.com/gristmill>
--- End Message ---
--- Begin Message ---
Could you put the 100% back in in the white area after powered by. I like
it better and I have 100% electrons here in San Francisco. We charge at
night from Hetch Hetchy. Lawrence Rhodes.....
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, March 25, 2003 8:58 AM
Subject: Re: New and improved bumper sticker design
> Grannes, Dean wrote:
> >
> > Folks,
> >
> > Many thanks to Chip Gribben for helping clean up (and improve) my
> > original bumper sticker design. The latest version is again posted at:
> >
> > http://www.geocities.com/ironstephanie
> >
> > There may be one final revision to adjust the size and/or aspect ratio
> > depending upon what the printer says.
> >
> > We took off the "100%" text after some discussion about our electrical
> > energy mix. I like this new design better.
> >
> > I have a meeting with the printer today. The final revision will go in
> > by Monday. I should know by the end of today what kind of time frame
> > and costs we are looking at (note that I will be selling these at cost).
> > I've already gotten a few order requests. Feel free to submit more
> > (off-list).
>
> I wanted to order a couple, but lost track of your email with the final
> cost and where to mail my check. Could you refresh my memory?
> --
> Lee A. Hart Ring the bells that still can ring
> 814 8th Ave. N. Forget your perfect offering
> Sartell, MN 56377 USA There is a crack in everything
> leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
>
--- End Message ---
--- Begin Message ---
Hi everyone,
This morning the Haynes overhaul manual I ordered
from Amazon dropped through my letterbox....
Someone "up there" must be smiling on me at the moment,
because several of the things that worried me about
converting this car to electric have been cleared up
( not all, weight being one issue still to grapple with )
First, the car I've got has ABS, but this system is
controlled by it's own independent computer and an
electro-hydraulic pump. So, no nasties there, apart from
the need for a 60amp capable feed from the 12v system !
The auto box has 3 solenoids, two for some sort
of gear selection, one for locking the TC, and again
it's own computer and speed/throttle sensors.
Again, it's a separate system that could be "hacked"
without upsetting every other CPU in the car...
I'm pretty sure the car doesn't have Toyota's electronicly
controlled suspension ( no sign of the actuators on
the tops of the strut towers ), so that's one less thing
to think about.
Since it's a 1990 turbo model, it already has a pretty
stout rear end, with independent rear suspension & LSD
( yeehaw! ), so putting the torque from an electric
drive down onto the tarmac shouldn't present too much
problem.
The other slightly annoying thing is the power-steering
and air-con. Air-con's not too much of a problem, since
I've never had a car with it, and so won't miss it if I took
the air-con system out completely. Plus it just doesn't get that
hot here in the UK, if you want air-con, just open the window!
As for the power steering, well I'll probably take the easy
route out and just drive the existing pump from the motor tailshaft.
Oh, and the gas tank is right at the rear of the vehicle,
just behind the rear bumper!!! Can you believe that a big
manufacturer would still think of placing a gas tank there,
in the 1990's, for goodness sake!
So first order of business is to get the car MOT'd, taxed
and legally back on the road. Then I need to sell the Smart,
( and maybe sell the pickup, Mellow Yellow )
and use the cash to fix my Mini Cooper. Once that's done,
the Supe could become a monster fun & commuting EV....
All this is likely to take a long time, knowing me, but
a bit of planning now will make a much nicer EV when it's
all done.
The recent discussion of Evercells gave me an idea:
( light bulb appears over head :)
Even though the Supra is a heavy car, by putting
Evercells in it, I could get a respectable range, by
being able to carry more energy without overloading the car.
The real questions I suppose are:
Can the Evercells dish out the power to give adequate
performance for a Supra? Remember, this car is the
3 litre turbo version with 250+ HP
Maybe twin strings of them, each string supplying
half the current ( 500A max. each string, giving 1kA total )
I'm thinking of a 240 V pack here, that's a lot of batteries.
That's also one heck of a BMS to look after it all...
Lots of stuff the think about..
I'll go away now :-)
Richard Bebbington
Electric Mini pickup
--- End Message ---
--- Begin Message ---
Beside's, Canada is on The North American Continent, so in the strictest
sense their electrons are American electrons too!
As are the Mexicans(Central America) and Brazilians(South America) and just
about everybody else in the western hemisphere.
That oughtta keep ya Charged!
Hump
-----Original Message-----
From: Lawrence Rhodes [mailto:[EMAIL PROTECTED]
Sent: Tuesday, March 25, 2003 5:40 PM
To: Lee Hart; [EMAIL PROTECTED]
Subject: Re: New and improved bumper sticker design
Could you put the 100% back in in the white area after powered by. I like
it better and I have 100% electrons here in San Francisco. We charge at
night from Hetch Hetchy. Lawrence Rhodes.....
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, March 25, 2003 8:58 AM
Subject: Re: New and improved bumper sticker design
> Grannes, Dean wrote:
> >
> > Folks,
> >
> > Many thanks to Chip Gribben for helping clean up (and improve) my
> > original bumper sticker design. The latest version is again posted
> > at:
> >
> > http://www.geocities.com/ironstephanie
> >
> > There may be one final revision to adjust the size and/or aspect
> > ratio depending upon what the printer says.
> >
> > We took off the "100%" text after some discussion about our
> > electrical energy mix. I like this new design better.
> >
> > I have a meeting with the printer today. The final revision will go
> > in by Monday. I should know by the end of today what kind of time
> > frame and costs we are looking at (note that I will be selling these
> > at cost). I've already gotten a few order requests. Feel free to
> > submit more (off-list).
>
> I wanted to order a couple, but lost track of your email with the
> final cost and where to mail my check. Could you refresh my memory?
> --
> Lee A. Hart Ring the bells that still can ring
> 814 8th Ave. N. Forget your perfect offering
> Sartell, MN 56377 USA There is a crack in everything
> leeahart_at_earthlink.net That's how the light gets in - Leonard
> Cohen
>
--- End Message ---
--- Begin Message ---
Lawrence (and others),
> Could you put the 100% back in in the white area after powered by. I
like
> it better and I have 100% electrons here in San Francisco. We charge
at
> night from Hetch Hetchy. Lawrence Rhodes.....
We did have a discussion about this very item. We felt that "100%"
definitely makes a stronger statement, if it were true. In SF, CA, and
indeed much of the West, it is true. However, in many places in the
U.S., it isn't true. We do import electricity from Canada, and imported
oil is used in some U.S. power plants.
We decided that we didn't want to have stickers that could be discounted
out-of-hand as being false (even though 99% of the population wouldn't
know the difference), so, to be 100% accurate, we needed to lose the
"100%".
As it is, the new design is much cleaner and conveys the same message.
Hopefully, it makes people think where THEIR motive power is coming
from.
Also, it's kind of a moot point. The stickers are already designed and
printed. For better or worse, the "100%" is gone. I feel you can still
make a strong statement even without the "100%", and for a buck or two,
the price is pretty good.
Dean
--- End Message ---
--- Begin Message ---
I think, at least for me, the biggest obstacle to purchasing an EV is
getting the bank to recognize the vehicle price for what it its. I mean, the
Kelly Blue Book doesn't show anything for a conversion. Banks, being
conservative, won't finance a newly-converted older car at the new car
price. Some folks may have no trouble getting a signature loan for $6,000,
or just paying out of pocket, but I don't know that most people can. If the
banks were a bit more open-minded, I would have bough that EV VW Pickup by
now.
Christian
--- End Message ---
--- Begin Message ---
Hi Richard,
Considering batteries, size and power.
Based on the various discussions over that past week or so, it sounds like an AC
system with a 300+ V pack is probably the way to go.
Victor's mails say he is confident that the Siemens gear will give you quite decent
performance.
John Wayland's mails say that even though Evercells don't have the current capacity of
YTs, by going to higher voltages you get more power with currents your batts can
provide.
By the sounds of it, there will be quite a few Li-Ion and Evercell powered EVs being
put together by ev-listers in the coming months, along with info of what sort of
real-world power is available, and what sort of BMS is required.
Good luck with your research,
Mark
-----Original Message-----
From: Richard Bebbington [mailto:[EMAIL PROTECTED]
Sent: Wednesday, 26 March 2003 10:10 AM
To: [EMAIL PROTECTED]
Subject: Re: Electric Supra? ( long )
Hi everyone,
...
The recent discussion of Evercells gave me an idea:
( light bulb appears over head :)
Even though the Supra is a heavy car, by putting
Evercells in it, I could get a respectable range, by
being able to carry more energy without overloading the car.
The real questions I suppose are:
Can the Evercells dish out the power to give adequate
performance for a Supra? Remember, this car is the
3 litre turbo version with 250+ HP
Maybe twin strings of them, each string supplying
half the current ( 500A max. each string, giving 1kA total )
I'm thinking of a 240 V pack here, that's a lot of batteries.
That's also one heck of a BMS to look after it all...
Lots of stuff the think about..
I'll go away now :-)
Richard Bebbington
Electric Mini pickup
--- End Message ---
--- Begin Message ---
John, This works ok on my minibike. I don't rotate my batteries, but I do
charge them individually ( I only have one 12v charger). I use 3 12v
batteries, one by itself and the other two in series for 24 volts. On the
12 v battery I get to 10 mph. The 24v bank takes me to 20 mph. With both
in series I get 30 mph, which is really to fast for a 150 pound minibike
with only a rear brake. You can see how the circuit works in the patent
file at http://www.geocities.com/thomassonmj/us6140799.pdf , see figure 1.
Or go to http://www.geocities.com/thomassonmj/electric_drive.html for more
general information. I can send you details of the relay control circuit
and where I got my parts if you are interested. Its all pretty simple
stuff. Mark Thomasson
See the bike:
http://www.austinev.org/evalbum/439.html
----- Original Message -----
From: "Shelton, John D. AW2" <[EMAIL PROTECTED]>
To: "'Peter VanDerWal'" <[EMAIL PROTECTED]>; "Ev (E-mail)"
<[EMAIL PROTECTED]>
Sent: Tuesday, March 25, 2003 2:58 PM
Subject: RE: AC controllers
> Would this be a good arrangement for a go-kart ev? What if you you three
12
> volt deep cycle batteries and rotate them. Not too difficult a task with a
> go-kart.
>
> John Shelton
>
>
> -----Original Message-----
> From: Peter VanDerWal [mailto:[EMAIL PROTECTED]
> Sent: Monday, March 24, 2003 2:08 AM
> To: EV
> Subject: Re: AC controllers
>
>
> Oops, forgot to mention.
> Contactor controllers normally rearrange the pack into series/parallel
> setups.
> IE. a 48V pack of 4 12V batteries will be arranged as all four in
> parallel for 12V, two sets of two for 24V and all together for 48V. Plus
> usually a starting resistor in series with the 12V setup. This gives
> four steps, plus stop.
>
> Tapping the pack at individual batteries like you suggest means that
> none of the batteries will be discharged to the same level. The first
> battery gets used all of the time and the one at the other end of the
> string hardly ever gets used.
>
> This causes the pack to become unbalanced(a bad thing). Your range will
> be limited by the first battery which will run out fairly quickly, while
> 1/2 the batteries are hardly discharged at all.
>
> Range from this setup will be about 1/4 the range of using all the
> batteries as one pack with a PWM controller or a series/parallel
> contactor controller.
>
> > > various voltages. For example, with seven batteries in the bank, it
is
> > > possible to rearrange them to get seven voltage steps, from zero volts
> to
> > > the voltage of all the batteries in series. With 15 batteries, 15
steps
> are
> > > possible. The trick is to rearrange the batteries without using an
> > > unreasonable number of contactors. See
> > > http://www.geocities.com/thomassonmj/electric_drive.html for a
diagram
> of
> > > how this may be done. http://www.austinev.org/evalbum/439.html shows
> the
> > > test platform. I started small with a minibike and only 3 voltage
steps
> > > (using three 12 volt batteries) in the control system. The three
relays
> and
> > > a multiposition switch comprising the control system cost less than
$20.
> > > Electro-mechanical relays are much easier to trouble shoot and repair
> that
> > > electronic FET's and integrated circuits, and more efficient. Solid
> state
> > > relays could also be used. Regenerative braking occurs automatically
as
> you
> > > back off the throttle, or not at all if the throttle goes immediately
to
> > > zero.
> > >
> > > Criticize freely... I can take it!
> > >
> > > Thanks for your feedback.
> > >
> > > Mark Thomasson
> > >
> > >
> > > ----- Original Message -----
> > > From: "1sclunn" <[EMAIL PROTECTED]>
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Saturday, March 22, 2003 6:59 PM
> > > Subject: Re: AC controllers
> > >
> > >
> > > > Hi Mark
> > > ...................
> > > >
> > > > Tell us of your project? what do you want it to do?
> > > >
> > > ....................
> > >
> > --
> > EVDL
> >
> --
> EVDL
>
--- End Message ---
--- Begin Message ---
As per
http://www.fueleconomy.gov/feg/noframes/16424.shtml
I suppose it depends on how you look at it?
Or are they using funny numbers?
=====
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & RE newswires
. (originator of the above ASCII art)
=====
__________________________________________________
Do you Yahoo!?
Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
http://platinum.yahoo.com
--- End Message ---
--- Begin Message ---
On Tue, 2003-03-25 at 21:35, Bruce EVangel Parmenter wrote:
> As per
> http://www.fueleconomy.gov/feg/noframes/16424.shtml
>
> I suppose it depends on how you look at it?
> Or are they using funny numbers?
Don't those numbers match the advertised Miles per Charge? My guess is
that they just don't have an acronym other than MPG to show.
Lonnie
--- End Message ---
--- Begin Message ---
As per
http://www.fueleconomy.gov/feg/noframes/16424.shtml
I suppose it depends on how you look at it?
Or are they using funny numbers?
They are probably using the DOE's equation for equivalent MPG. It
takes into account energy usage, power-plant efficiency and pollution
output, and other factors. I thought I had it archived somewhere, but
of course I can't find it anymore. Perhaps someone on list could help?
--
Auf wiedersehen!
______________________________________________________
"..Um..Something strange happened to me this morning."
"Was it a dream where you see yourself standing in sort
of Sun God robes on a pyramid with a thousand naked
women screaming and throwing little pickles at you?"
"..No."
"Why am I the only person that has that dream?"
-Real Genius
--- End Message ---
--- Begin Message ---
I was looking at the numbers for the cost of fuel
and electricity on that page
http://www.fueleconomy.gov/feg/noframes/16424.shtml
I did not see where they got the mpg figure.
I would have wanted their equation of where the came
up with that mpg.
Fuel prices change, but it will not go down.
Lets up grade the fuel cost to $2/gal (regular).
and electricity has gone up too. The cost of
electricity varies on who your utility is. SMUD
is the best in CA, followed by LAWPD, SDG, some
others, and PGE coming in at the highest.
The lion's share of production EVs were targeted
to California, so lets say the cost of CA electricity
is $.17 pkwh
If they were doing some sort of hokey fuel energy
to kilowatt conversion, it would not be real life.
Reality would be how many miles per charge at 65 mph
by the cost as compared to a RAV4 ICE mpg fuel cost
for the same miles.
RAV4 EV drivers have easily achieved 90 miles on a
full charge with a few miles left just like an ICE
reading empty with a few miles left.
Its my understanding that the RAV4 EV charger is about
5kw into the pack, but 6kw from the source and it takes
6 hours hours for a complete charge, but 4 hours to 80%
(the last two hours a slow taper).
So lets assume 6kw of electricity for 5 hours or 30kwhs.
At $.17 pkwh, that would cost $5.10 .
According to
http://www.toyota.com/html/shop/vehicles/rav4/specs/rav4_specs.html
a RAV4 ICE would get 24/29 mpg. Lets call it 26.5mpg
At $2 per gallon, 90 miles would be ((90/26.5)*2)= $6.80
Using a cost ratio comparison in a 90 mile run to derive
the mpg of the RAV4 EV:
$6.80 $5.10
----- -----
26.5 mpg x mpg
((6.8/5.1)*26.5)= 35.3 mpg
My calculation is coparinsing only the cost out of pocket,
and makes me think that the page
http://www.fueleconomy.gov/feg/noframes/16424.shtml
was using emission factor costs that isn't on the Toyota
spec page. Automaker mpg figures do not include pollution
costs or factors.
Perhaps that page gave a high mpg because they included
all the pollution costs?
How does my math look?
=====
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & RE newswires
. (originator of the above ASCII art)
=====
__________________________________________________
Do you Yahoo!?
Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
http://platinum.yahoo.com
--- End Message ---
--- Begin Message ---
>Subject: ev
>From:"1sclunn" <[EMAIL PROTECTED]>
>Date:Tue, 25 Mar 2003 01:54:37 -0800
>
>I'm going to be having my Fort Pierce EV rally on May 3
Steve
I'm sorry I'm going to miss your rally.
I'm actually going to spend a week in Florida but it's a few weeks
earlier and on the gulf coast (Tampa).
I am hoping to check out a VW bus conversion and Jerry's trike,
--
Andrew King
Ann Arbor Michigan
technology is the answer, what was the question?
--- End Message ---
--- Begin Message ---
I was finally able to get into your site and see your diagram.
Regardless of what you think your arrangement will definitely result in
an unballanced pack and reduced range.
I spend about 1/2 the time driving around at 35 mph (that's the speed
limit on most streets in my area). This means that the 12V and 24V
sections of your pack would not be used during the constant speed
portion of my trips (most of it).
The other 1/2 the time I'm driving on the bypass at 55 mph, this uses
the 48V section which is also used at 35 mph. This section will get
drained long before the rest of the pack and will limit range.
You are also subjecting portions of the pack to isolated high current
draws which will cause Peukert to further reduce range.
It is a clever idea and would be great for low power vehicles if it
weren't for the possibility of shorting out the pack if a relay failed
by welding shut (not uncommon).
On Tue, 2003-03-25 at 15:23, Mark Thomasson wrote:
> Thanks, lots of good background here. See my comments below. Mark
> Thomasson
>
>
> ----- Original Message -----
> From: "Lee Hart" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Monday, March 24, 2003 10:13 PM
> Subject: Re: AC controllers
>
>
> > Lee Hart wrote:
> > >> The first problem is that you are not loading the batteries equally.
> >
> > Mark Thomasson replied:
> > > In actual city traffic conditions, all the batteries get used almost
> > > equally.
> >
> > That has not been my experience. For many years I drove a ComutaVan,
> > which has a 3-step 3-contactor controller (36v with resistor, 36v
> > direct, and 72v direct). Its top speed was 55 mph (at 72v), but my daily
> > commute was on streets with a maximum 40 mph speed limit (which only
> > needed 36v). Thus, I only used 72v while accellerating or on hills. Most
> > of the time was spent cruising at 36v.
> >
> > With your arrangement, I would have had half the range. I'd arrive at
> > work with the lower 36v half of the pack dead, but plenty of charge
> > still left in the upper 36v half.
>
> No, The method I am proposing does not work like this and does not suffer
> this problem, or at least not in the manner you describe. Referring to the
> circuit shown at http://www.geocities.com/thomassonmj/electric_drive.html ,
> suppose that you have a 6v, 12v, 24v, and a 48v battery (represented by B1
> to B4 in the circuit diagram). Also suppose your top speed is 60 MPH at
> full voltage of 90v, and assume that speed is directly proportional to
> voltage. For the 15 available voltage steps, the table below shows the
> motor voltage, the speed, and the batteries used:
>
> step 1 6v 4 mph 6v
> step 2 12v 8 mph 12v
> step 3 18v 12 mph 6v 12v
> step 4 24v 16 mph 24v
> step 5 30v 20 mph 6v 24v
> step 6 36v 24 mph 12v 24v
> step 7 42v 28 mph 6v 12v 24v
> step 8 48v 32 mph 48v
> step 9 54v 36 mph 6v 48v
> step10 60v 40 mph 12v 48v
> step11 66v 44 mph 6v 12v 48v
> step12 72v 48 mph 24v 48v
> step13 78v 52 mph 6v 24v 48v
> step14 84v 56 mph 12v 24v 48v
> step 15 90v 60 mph 6v 12v 24v 48v
>
> If your usual speed is 40 mph (step10), you would be using batteries12v and
> 48v. If you're on a hill or need to speed up some, you go to step 11
> (batteries 6v, 12v, 48v) or step 12 (batteries 24v, 48v), or maybe higher
> with other battery combination. If you need to slow down, step 9 uses
> batteries 6v and 48v. The point is that the batteries are shuffled in and
> out of the circuit in a manner that tend to balance their loading during the
> normal variations of driving speeds. However, if you spend most of your
> time below 32 mph, then, with this design, the 48 volt bank will be under
> utilized. For this and other reasons, the control scheme shown at
> http://www.geocities.com/thomassonmj/motor_circuit.html has some definite
> advantages. Using a shunt field motor, the armature voltage steps described
> above control speed up to 20 mph. Then, with armature voltage at maximum
> and all batteries in service, field voltage is weakend to control speed up
> to 60 mph. Since the field current of shunt motors is typically only 5% of
> the armature current, controlling this current uses relatively inexpensive
> components. Also, speed control above 20 MPH is continuous with no steps.
> With this arrangement, you could think of the armature voltage control as a
> soft starting system, with the field weaking as the main speed control.
> >
> > >> Next problem; you still have a lot of contactors. The way they are
> > >> arranged, if one fails shorted, it could be disastrous to close the
> > >> next one.
> >
> > > Good point. Each battery bank should be fused.
> >
> > Note that a fuse is a resistor. It will have more voltage drop than a
> > contactor. They are also amazingly expensive for ones that is guaranteed
> > to work at high DC voltages and currents. You always need at least some
> > fuses, but want to minimize the number of them.
> >
> > I think a better solution is not to use SPST contactors; use SPDT
> > contactors, built so it is physically impossible to close both contacts
> > at once even in the event of a welded contact. This is always done in
> > commercial contactor controllers.
>
> Unfortunately, this control scheme does not allow the use of SPDT
> contactors. The interlocking you mention could be accomplished with
> auxiliary contacts off each contactor tied back into the control circiut of
> the appropriate interlocked contactor.
>
> >
> > >> This problem has been studied for a very long time by some great
> > >> minds. You might want to look at some of their solutions.
> >
> > > Exactly, that's why I'm asking you guys for input!
> >
> > Most of the "guys" today have never even seen a contactor controller.
> > :-) So, you'll have to study old equipment, books, articles, patents,
> > etc. to see how they were done in their "golden age". Nowdays, most of
> > the engineers who knew how to design them are dead. So, the ones you see
> > today are often naive designs by people who lack the knowledge and
> > experience to do it right.
> >
> > Thus, it's easy to find a high-mileage 1920 Detroit Electric with its
> > original contactor controller that still works. And, it's easy to find a
> > low-mileage CitiCar or golf cart with a contactor controller that's
> > destroyed.
> >
> > >> For example, the batteries can be switched in series-parallel
> > >> combinations so the load is always divided equally between them.
> > >> Twelve 6v batteries can be wired for... 6v, 12v, 18v, 24v, 36v, 72v
> >
> > > This arrangement would take 33 contacts and gives only 6 steps.
> >
> > Correct; though that's 11 series/parallel contactors.
>
> Thanks, good catch.
>
> >
> > > If you are willing to give up on the symmetry, you could get all
> > > 12 evenly spaced steps.
> >
> > If you are using a PM motor, then you need more steps because its speed
> > is directly proportional to voltage. With a series motor (much more
> > common in EVs), you need fewer steps because motor speed is a function
> > of both voltage and load. With a series motor, roughly 2:1 voltage steps
> > turns out to be adequate (6v, 12v, 24v, 48v, 96v, ...)
>
> The new method gives you smooth 6v increments all the way up.
>
> >
> > > The new method would give 15 steps with 15 6v batteries, but only
> > > use 9 relays. Balancing of battery discharge would depend on the
> > > natural variability of driving speed.
> >
> > There was a streetcar controller similar to what you describe. However,
> > they had a scheme to balance the discharge. All the batteries were in
> > series. There were two *big* rotary switches, that could select any tap
> > from 0v to full pack voltage in 1-battery steps. One wire of each rotary
> > switch went to each side of the motor.
> >
> > Start with both rotary switches fully counterclockwise, so both motor
> > leads were at the 0 volt tap. To accellerate, turn ONE of the rotary
> > switches up. 6v, 12v, 18v, 24v... the farther you advance it, the faster
> > you go.
> >
> > But, this would discharge the batteries at the lower end faster, because
> > they are used less. So, to slow down, leave the first switch where it
> > was, and move the SECOND switch up to meet it. This brings the motor
> > voltage back down. 24v, 18v, 12v, 6v, and 0v when both switches are on
> > the same tap. This discharges the batteries at the higher end of the
> > pack faster, thus compensating so all batteries average out to the same
> > discharge rate.
> >
> > There was a voltmeter between the two taps, so the operator could see
> > the battery voltage. It was a manual process; he looked at the voltages
> > to see where his weakest battery was, and avoided using that one.
> >
> > The rotary switches were big slate panels, with coin-sized contacts
> > arranged in a circle. The two switch arms were concentric cranks that
> > the operator controlled manually.
> >
> > >> The classic series-parallel switch is a single contactor with 3
> > >> contacts:
> > >> ______________________
> > >> + __|__ K1b |
> > >> battery 1 ___ normally closed / K1c
> > >> |__________/___________| normally open
> > >> | K1a __|__+
> > >> / normally open ___ battery 2
> > >> |______________________| -
> > >>
> > >> If you don't need to do regen (carry current in both directions),
> > >> then K1a and K1c can be replaced by a big diode. Then series-
> > >> parallel switching is done with a single SPST contactor.
> >
> > > The new method also lets you reduce relay count by using diodes,
> > > but diodes always have a forward biase voltage drop (~.7 v for
> > > silicon) and therefore energy loss
> >
> > Contactors have a voltage drop too, especially as they age.
>
> Mine have .004 ohms each after light usage.
>
> >
> > For low voltage systems you wouldn't use silicon diodes; you'd use
> > Schottky diodes (0.5v drop), germanium diodes (0.25v drop), or MOSFETs
> > (even less)
>
> I wonder how the cost of these alternative device compare to silicon?
> .
> >
> > Diodes have other big advantages. They provide a path for the inductive
> > motor current during switching, which greatly reduces contact arcing to
> > extend life.
>
> I planned to use a free wheeling diode, but after seeing very little voltage
> spiking across the relays on the oscilloscope, I left it out.
>
> >They also eliminate the timing problem between opening one
> > contact and closing another "simultaneously".
>
> I originally used doides in the circuit for this purpose, but the
> multiposition switch I use for speed control has enough "break before make"
> that they were not needed and I left them out.
>
> >
> > Peukert effects
> >
> > There's another factor you may not be aware of. The amphour capacity of
> > a lead-acid battery depends on the load current. The higher the current,
> > the lower the capacity. It's called the "Peukert effect".
> >
> > Suppose you have golf cart batteries rated at 6v 225ah (at the 20-hour
> > rate). If you load them at 75 amps, they only deliver 144 amphours. If
> > you load them at 150 amps, they only deliver 122 amphours.
> >
> > Now suppose you have twelve of these batteries (a 72v pack). You want to
> > cruise at a speed that requires 36v at 150 amps. With your controller,
> > only half the batteries are supplying this current. Each has to provide
> > 150 amps, so you can only drive for 122ah / 150a = 49 minutes.
>
> As discussed above, at half speed I have the 48v bank in service. Speed up
> a little and I pick up the 6v bank also. Slow down a notch and the 48v bank
> drops out and the 6v, 12v, and 24v banks come into service. Small
> variations in driving speed will balance out the discharge on the banks.
>
> >
> > With a series/parallel controller, the two halves of the pack would be
> > in parallel, so each battery delivers half the current or 75 amps. Now
> > you can drive for 144ah / 75a = 115 minutes. That's a big difference --
> > more than 2:1!
>
> It is definitely a good thing to have all the batteries in service all the
> time, but this old method gives those big jumps in voltage and uses more
> hardware for much fewer voltage steps.
> >
> > With an electronic PWM controller, it would leave the pack wired for
> > 72v. It would draw 72v at 75 amps from the pack, but deliver 36v at 150
> > amps to the motor. As for the series-parallel case, you could drive for
> > 115 minutes.
> >
>
> You lost me here. How did the PWM increase 75 A of input current to 150 A
> of output current? Where did all those extra electrons come from?
>
>
> > For your scheme to be viable in any but very small vehicles that run at
> > full speed almost all the time, I think you really must have some way to
> > equalize the loading on all the batteries.
> > --
> > Lee A. Hart Ring the bells that still can ring
> > 814 8th Ave. N. Forget your perfect offering
> > Sartell, MN 56377 USA There is a crack in everything
> > leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
> >
>
--
EVDL
--- End Message ---
--- Begin Message ---
getting a lot of spam these days from businesses in China. This was
one. For anyone who might be tempted:
From: michael <[EMAIL PROTECTED]>
Date: Wed, 26 Mar 2003 13:56:02 +0800
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www.unitechbatt.com or www.globalsources.com/unitech8.co
--- End Message ---
--- Begin Message ---
Subject:> Re: Evercells versus Yellow tops
From:> Seth <[EMAIL PROTECTED]>
Date:> Tue, 25 Mar 2003 06:56:51 -0500
In really broad terms, this is what most nickel based batteries do. They
are as a rule, much less affected by the rate at which the energy is
withdrawn, and much less affected by lower temperatures. Not immune (it
gets really cold near Boston) but less affected. NiMH starts to get soft
at 20F, for example. Lead by comparison, is near useless at that
temperature. I have ridden in vehicles powered by both chemistries and
there is a big difference when it is cold.
Seth
I've been leaning towards nicel batteries (I was thinking flooded
Ni-Cad) for the cold weather.
I'm planning a VW bus conversion for local (15 miles per day) driving
around Ann Arbor. Moderate hills, top speed 50 mph, all stop and go.
I figure I could live with 35 mph up hill (that's what people expect
from a VW bus anyway) but I don't want it to drop to 10 mph in the cold.
The bus will spend most of it's time in the garage (I work at home) so
lately I've been thinking that lead acid might be OK if heated and
insulated.
So the question is given a 12 mile round trip with an hour parked (no
charging) how cold can it get before my batteries cool down to the point
that I can't meet my performance goals.
Then again after I kill my first pack you guys will have the evercells
figured out so I can substitute a high voltage pack and try for a high
performance bus. Wouldn't that blow some minds!
Would I trash the power train if I had enough amps to spin the wheels?
I'm not sure I want to even consider the handling issues.....
--
Andrew (make no small plans) King
Ann Arbor Michigan
technology is the answer, what was the question?
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>> For many years I drove a ComutaVan, which has a 3-step 3-contactor
>> controller (36v with resistor, 36v direct, and 72v direct)...
>> With your arrangement, I would have had half the range. I'd arrive
>> at work with the lower 36v half of the pack dead, but plenty of
>> charge still left in the upper 36v half.
Mark Thomasson wrote:
> No, the method I am proposing does not work like this and does not
> suffer this problem, or at least not in the manner you describe...
> suppose you have a 6v, 12v, 24v, and a 48v battery... Also suppose
> your top speed is 60 MPH at full voltage of 90v, and assume that
> speed is directly proportional to voltage.
OK; that would imply a PM motor.
> For the 15 available voltage steps, the table below shows the
> motor voltage, the speed, and the batteries used:
>
> step 1 6v 4 mph 6v
> step 2 12v 8 mph 12v
> step 3 18v 12 mph 6v 12v
> step 4 24v 16 mph 24v
> step 5 30v 20 mph 6v 24v
> step 6 36v 24 mph 12v 24v
> step 7 42v 28 mph 6v 12v 24v
> step 8 48v 32 mph 48v
> step 9 54v 36 mph 6v 48v
> step10 60v 40 mph 12v 48v
> step11 66v 44 mph 6v 12v 48v
> step12 72v 48 mph 24v 48v
> step13 78v 52 mph 6v 24v 48v
> step14 84v 56 mph 12v 24v 48v
> step 15 90v 60 mph 6v 12v 24v 48v
>
> If your usual speed is 40 mph (step 10), you would be using
> batteries 12v and 48v.
Thus, while I was cruising at the speed limit, only these two sets of
batteries are being discharged. Note that with a PM motor, it tries to
hold constant speed despite hills. They run like you have the cruise
control on. So, I wouldn't have to keep stepping up or down to hold my
speed.
> If you're on a hill or need to speed up some, you go to step 11
> (batteries 6v, 12v, 48v) or step 12 (batteries 24v, 48v)...
> If you need to slow down, step 9 uses batteries 6v and 48v...
Or step 8 (48v alone). But in all 5 cases, the 48v battery is always
being used, so it goes dead first.
Yes, I see that you are shuffing the batteries in/out. But I don't think
it's often enough or random enough to guarantee equalizing the
discharge.
> For this and other reasons, the control scheme shown at
> http://www.geocities.com/thomassonmj/motor_circuit.html
> has some definite advantages.
Certainly. In fact, a seperately excited motor can do almost the entire
job of speed control with just field control.
> Since the field current of shunt motors is typically only 5% of
> the armature current, controlling this current uses relatively
> inexpensive components.
More importantly, field POWER is only 1-2% of armature power.
>> Next problem; you still have a lot of contactors. The way they are
>> arranged, if one fails shorted, it could be disastrous to close the
>> next one...
>> I think a better solution is not to use SPST contactors; use SPDT
>> contactors, built so it is physically impossible to close both
>> contacts at once even in the event of a welded contact.
> Unfortunately, this control scheme does not allow the use of SPDT
> contactors.
Why? I'm wondering why you couldn't do your 1-2-4-8 switching with 4
SPDT contactors like this (view with fixed width font):
_______
| | K4
+__|__ NC O ___________to motor +
48v ___ / COM
| NO O/
|_______|_________
|
_______ |
| | K3 |
+__|__ NO O _______|
24V ___ / COM
| NC O/
|_______|_________
|
_______ |
| | K2 |
+__|__ NO O _______|
12V ___ / COM
| NC O/
|_______|_________
|
_______ |
| | K1 |
+__|__ NO O _______|
6V ___ / COM
| NC O/
|_______|____________to motor -
This only requires 4 contactors. You can still get any voltage from 0v
to 90v in 6v steps. No combination of contactors K1-K4 being on/off ever
shorts any battery.
You might want a 5th contactor (K5) for an all-off condition (as shown,
when K1-K4 are all off they short the motor, which would brake it to a
stop).
The contactors could all be SPST if the NC-COM contact were replaced
with diodes. You couldn't do regen with the diodes, however.
>> If you are using a PM motor, then you need more steps...
>> With a series motor (much more common in EVs), roughly 2:1 voltage
>> steps turns out to be adequate (6v, 12v, 24v, 48v, 96v, ...)
> The new method gives you smooth 6v increments all the way up.
Yes, but you don't need it. You can't tell the difference between 90v
and 96v on a series motor.
>> For low voltage systems you wouldn't use silicon diodes; you'd
>> use Schottky diodes (0.5v drop), germanium diodes (0.25v drop),
>> or MOSFETs (even less)
> I wonder how the cost of these alternative device compare to silicon?
Schottkys are essentially the same price as silicon. They have about
half the voltage drop if rated at 20, 20-30% less if rated at 50v, and
aren't worth the trouble above 100v.
Germanium are more expensive, because they are only available from a
couple suppliers. But they have half the voltage drop of even Schottky,
and so cut your heatsink size in half again.
MOSFETs cost even more, and require circuitry to control their gate. But
their extra cost can be offset by practically eliminating heatsinks.
>> Diodes have other big advantages. They provide a path for the
>> inductive motor current during switching, which greatly reduces
>> contact arcing to extend life.
> I planned to use a free wheeling diode, but after seeing very little
> voltage spiking across the relays on the oscilloscope, I left it out.
That's because you are using a PM motor, which has low inductance.
Series motors have far more inductance. You *will* destroy you contacts
from arcing if you switch a series motor with no arc suppression!
>> Peukert effects
>>
>> There's another factor you may not be aware of. The amphour
>> capacity of a lead-acid battery depends on the load current.
>> The higher the current, the lower the capacity. It's called the
>> "Peukert effect".
> As discussed above, at half speed I have the 48v bank in service.
> Speed up a little and I pick up the 6v bank also. Slow down a notch
> and the 48v bank drops out and the 6v, 12v, and 24v banks come into
> service. Small variations in driving speed will balance out the
> discharge on the banks.
I think you are missing the point. Let's consider a simpler case.
Suppose you have two 24v pack. You connect them in parallel, and drive
until they are dead. Suppose you go 10 miles.
Now connect just one of the 24v packs, and drive until it is dead. Then
disconnect it, connect the second 24v pack, and drive until it is dead.
You would think each half-pack has half the amphours, and so would go 5
miles. 5 miles + 5 miles = 10 miles; the same range.
But, the Peukert effect says it doesn't work. You only get 4 miles per
half-pack, for a total range of 8 miles. That's because you are
discharging the half-pack at twice the current. Peukert says the higher
the current, the lower the amphour capacity.
So, with your switching system, batteries are always being discharged at
the full motor current. With a series/parallel system, batteries are
being discharged at lower currents; thus you get more amphours.
>> With an electronic PWM controller, you leave the pack wired for
>> 72v. It would draw 72v at 75 amps from the pack, but deliver 36v
>> at 150 amps to the motor. As for the series-parallel case, you
>> could drive for 115 minutes.
> You lost me here. How did the PWM increase 75 A of input current
> to 150 A of output current?
A PWM is not a resistor; it doesn't burn up the voltage difference.
Instead, it acts like a DC transformer. PowerOut = PowerIn (minus a
little because it isn't 100% efficient). So at half throttle (50% PWM
duty cycle) 72v at 75amps input produces about 36v at 150amps output.
--
Lee A. Hart Ring the bells that still can ring
814 8th Ave. N. Forget your perfect offering
Sartell, MN 56377 USA There is a crack in everything
leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
--- End Message ---
