EV Digest 6751
Topics covered in this issue include:
1) RE: Over voltage in a pack
by "George Swartz" <[EMAIL PROTECTED]>
2) Re: Field weakening basics
by tt2tjw <[EMAIL PROTECTED]>
3) RE: Motor equations
by "Roger Stockton" <[EMAIL PROTECTED]>
4) Evil Bus Spec
by "Eidson, Mark" <[EMAIL PROTECTED]>
5) Re: Field weakening basics
by David Dymaxion <[EMAIL PROTECTED]>
6) RE: Field weakening basics
by "Roger Stockton" <[EMAIL PROTECTED]>
7) Re: Field weakening basics
by Jeff Major <[EMAIL PROTECTED]>
8) RE: Evil Bus Spec
by "Shawn Waggoner, FLEAA" <[EMAIL PROTECTED]>
9) RE: Motor equations
by "George Swartz" <[EMAIL PROTECTED]>
10) RE: ADC 8" red line...
by Jake Oshins <[EMAIL PROTECTED]>
11) Re: Motor equations
by "Marty Hewes" <[EMAIL PROTECTED]>
12) RE: Evil Bus Spec
by "Eidson, Mark" <[EMAIL PROTECTED]>
13) Re: ADC 8" red line...
by [EMAIL PROTECTED]
14) Re: EV's on Local Talk Radio
by "Michael" <[EMAIL PROTECTED]>
15) Re: EV's on Local Talk Radio
by MIKE WILLMON <[EMAIL PROTECTED]>
16) Re: EV's on Local Talk Radio
by "Marty Hewes" <[EMAIL PROTECTED]>
17) Re: Electric Mini Cooper Videos
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
18) Re: NI-Cad STM5-180 Auto watering hookup
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
19) Re: Electric Mini Cooper Videos
by "Ryan Stotts" <[EMAIL PROTECTED]>
20) New Materials For Twice as Powerful Lithium Batteries
by Geopilot <[EMAIL PROTECTED]>
21) Solar Powered Scooters Soon on the Streets
by Geopilot <[EMAIL PROTECTED]>
22) Re: EV's on Local Talk Radio
by Lock Hughes <[EMAIL PROTECTED]>
23) Re: Field weakening basics - Thank you for the info.
by Steve Condie <[EMAIL PROTECTED]>
24) Re: Parallel strings of unlike batteries
by "Brandon Kruger" <[EMAIL PROTECTED]>
25) Re: EV's on Local Talk Radio
by [EMAIL PROTECTED]
26) Re: Batteries or Charger funny?
by MIKE WILLMON <[EMAIL PROTECTED]>
--- Begin Message ---
Dale, Thanks for the reply. For the optimum, overall EV design, some
inefficiency in the controller may be offset by better battery performance
by having fewer, and larger cells. The largest IGBT controller I designed
was 0.5MW. Everything is relative. I have friends that work on multi
megawatt inverters for wind power machines. They say that it is
spectacular when they blow one up.
On Wed, 9 May 2007 08:34:09 -0600, Dale Ulan wrote
> A couple of point on AC motors: You cannot go to bypass in an AC
> system to overcome semiconductor voltage drop.
>
> Exactly right, so the semiconductor voltage drop needs to be considered.
> IGBT's drop 2 to 3 volts so a higher bus voltage = lower losses.
>
> You can rewind a three phase AC motor
> for any voltage you want. Its not that difficult.
>
> True, too. IGBT's normally come in 600V (or 1200V or 2400V) ratings,
> so it makes sense to maximize bus voltage (400V is good for a 600V
> IGBT) to minimize power loss in the drive system. Since power loss
> is current times voltage, if the voltage loss is constant (two
> IGBT's times, say,
> 2.5 volts), then power loss is, too. For a 20kW output at 100Vrms,
> thats 200Arms or 1000 watts of heat loss in the controller. For the
> same output power but at 230Vrms, that's 67Arms or 434 watts of heat
> loss in the controller. That is only considering steady-state loss
> and not switching losses, which would go up with voltage - but not
> as much as the conduction losses go down. At the 100V level, it
> makes sense to use a pile of MOSFET's instead. To reach
> approximately the same amount of loss at the 200 amp, 100 volt level
> that you get with the 67 amp, 230 volt region, you would need six
> IRFP90N20DPBF MOSFET's in parallel for each switch (that's a total
> of 36 MOSFET's). From an assembly point of view, bussing a pile of
> MOSFET's is a bit of a pain in the backside, when compared to
> getting a six-pack or even three half-bridge IGBT modules. Also,
> those IGBT modules in the 600 volt level are pretty inexpensive
> thanks to the industrial drive market.
>
> -Dale
--- End Message ---
--- Begin Message ---
I think the current in the armature will rise if the field is weakened
at a given RPM (because the back emf for a given rpm is lowered).
So if there isn't enough torque to raise the RPMs and you keep on
weakening the field the current in the armature will continue to rise
and eventually something will overheat, probably the armature windings.
David Dymaxion wrote:
Too much field weakening could lead to arcing, especially for higher voltages.
This is a reason a sepex motor should have interpoles, or adjustable brush
angle.
If the field suddenly goes to zero, the motor will try to spin very fast as the
field dies, and may overspeed.
----- Original Message ----
From: Steve Condie <[EMAIL PROTECTED]>
To: EV List <ev@listproc.sjsu.edu>
Sent: Wednesday, May 9, 2007 8:20:17 AM
Subject: Field weakening basics
...
I think this also implies that while the motor will spin faster with the field weakened,
available torque will be less. Yes? What's not clear to me is if there's any **other**
adverse consequence of field weakening on a regular basis as opposed to short term for a
burst of speed. To put it into a "real world" situation, most current road
going (and certainly freeway-capable) vehicles are designed with higher voltage systems
because higher voltage will allow a motor to spin faster (among other things. It also
allows the delivery of more watts with less current and thus smaller wires - but I
digress.) Could the same RPM range be accomplished with a lower voltage-based system by
going without FW during the first half of the motor speed range, then shifting to FW -
and keeping it activated - all the while the motor is in its upper RPM range? Is there a
hidden downside? Losses through the FW circuit, perhaps?
____________________________________________________________________________________
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--- Begin Message ---
Steve Peterson wrote:
> My question is: did you manage to come up with such a model?
No, unfortunately I never did get around to finishing up a more accurate
model for the motors in Uve's calculator.
> I ask because I'm trying to do some calcs for a *fan-cooled*
> ADC FB4001, but can't find the values for the parameters Uwe's
> calculator requires.
That's odd; do you mean an FB4001 that has had the internal fan removed,
or a stock 9" with the original internal fan?
The first entry on Uve's motor page is for the standard FB4001 (with
internal fan):
<http://www.geocities.com/CapeCanaveral/Lab/8679/motor.html>
At the top of this page are the equations that his calculator uses to
model the motor behaviour. The problem I have with them is that they
are not based on the actual physics of a series motor but rather are an
approximate fit to the motor curve over some range. The problem here is
that since they are not based on the underlying physics they generally
don't model the motor very well as the calculator extrapolates beyond
the range over which the parameters were calculated to result in a
decent fit to the actual motor behaviour.
Jeff Major has stepped up and offered the theoretical equations for a
series motor, and has noted that these strictly model the electrical
behaviour of the motor, they do not account for such practicalities as
the losses associated with the internal fan (a function of the second or
third power of the RPM), or bearing and brush friction, nor brush
losses, or armature reaction, or field saturation, etc. For instance,
notice that theory predicts that torque will vary with the square of the
current, yet the actual motor curves tend to show that it actually
varies by the current raised to about 1.2 or so.
If you are looking to model a stock FB4001, you can probably use Uve's
calculator and its model provided you don't trust any predictions it
makes for high RPM/low torque or low RPM/high torque extremes.
If you wanted to, you could plug Uve's model equations and parameters
into a spreadsheet and plot the resulting curves against the factory
curves for the motor and see where the error is, and if it is small
enough to ignore.
If you have removed the internal fan, then you can't rely on the factory
curves anymore if you want good accuracy. The internal fan represents a
loss that increases (rapidly!) with RPM, so if you did use the stock
motor data you should be confident that your real life results should be
a bit better than the predictions.
If you want to take up the challenge of modelling the FB4001 accurately,
I would start by plugging the manufacturer's data into a spreadsheet,
then plug in the theoretical equations for a series motor, and then add
to them equations to model the losses (drag) associated with the
internal fan/windage and bearings. Play with the parameters until the
curves are a resonably good match to the manufacturer's data. Now you
have a model that predicts the motor behaviour and isolates the
contribution of the internal fan so that you can remove the portion of
the equation associated with the internal fan losses and have a
resonable confidence that the predictions will yield a fair prediction
of the FB4001 behaviour with the internal fan removed.
This is the sort of thing I generally enjoy fooling around with, but I
just haven't got the spare time right now to do it...
Hope this helps,
Roger.
--- End Message ---
--- Begin Message ---
I've spent some time in the archive's but was unable to find a link to
the EVil spec. Does such a link exist? me
--- End Message ---
--- Begin Message ---
We are both right. If the motor is loaded (i.e. in gear going up a hill) it'll
draw too much current. If the motor is unloaded, it'll overspeed.
----- Original Message ----
From: tt2tjw <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Sent: Wednesday, May 9, 2007 10:12:22 AM
Subject: Re: Field weakening basics
I think the current in the armature will rise if the field is weakened
at a given RPM (because the back emf for a given rpm is lowered).
So if there isn't enough torque to raise the RPMs and you keep on
weakening the field the current in the armature will continue to rise
and eventually something will overheat, probably the armature windings.
David Dymaxion wrote:
> Too much field weakening could lead to arcing, especially for higher
> voltages. This is a reason a sepex motor should have interpoles, or
> adjustable brush angle.
>
> If the field suddenly goes to zero, the motor will try to spin very fast as
> the field dies, and may overspeed.
>
> ----- Original Message ----
> From: Steve Condie <[EMAIL PROTECTED]>
> To: EV List <ev@listproc.sjsu.edu>
> Sent: Wednesday, May 9, 2007 8:20:17 AM
> Subject: Field weakening basics
>
>
> ...
> I think this also implies that while the motor will spin faster with the
> field weakened, available torque will be less. Yes? What's not clear to me
> is if there's any **other** adverse consequence of field weakening on a
> regular basis as opposed to short term for a burst of speed. To put it
> into a "real world" situation, most current road going (and certainly
> freeway-capable) vehicles are designed with higher voltage systems because
> higher voltage will allow a motor to spin faster (among other things. It
> also allows the delivery of more watts with less current and thus smaller
> wires - but I digress.) Could the same RPM range be accomplished with a
> lower voltage-based system by going without FW during the first half of the
> motor speed range, then shifting to FW - and keeping it activated - all the
> while the motor is in its upper RPM range? Is there a hidden downside?
> Losses through the FW circuit, perhaps?
__________________________________________________
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Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Steve Condie wrote:
> Is there a hidden downside? Losses through the FW
> circuit, perhaps?
Weakening the field increases the motor power by allowing higher
armature current at a given motor speed, and losses are proportional to
the square of the current, so the motor will run hotter. Field
weakening also decreases efficiency.
I think it would be preferable to run a higher voltage pack or a
different motor, etc. than to design such that the vehicle will need to
run field weakening for extended periods.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Hi Steve,
Field weakening is a valid control appraoch for the
series wound motor and can be used for extended and or
frequent operation. However this is dependant on the
particular motor design and application. There are a
wide varity of series motor designs, some have strong
fields and some weaker field to start with. Most
times you would need to limit field weakening to when
the controller applies full voltage or is in by-pass.
So your throttle would be floored and vehicle speed
would vary depending on wind and grade.
Field weakening increases motor speed for a given load
and also the current. It may change the commutation
so arcing may occur. This depends on the motor,
voltage, load, etc. One rule does not apply for all.
The resistor used does dissipate heat, but overall,
reduces the field circuit loss.
The best way to use field weakening with a series
motor is get one with 4 field terminals so the fields
can be switched from series (full field) to series
parallel (weak field). Some even have 3 field
terminals where 4 coils are used for full field and 2
coils for half field. Without the diverter resistor,
PWM can be used in the weak field mode.
But after all said and done, I would not count on this
for much more than 10 to 15 percent speed increase,
unless you have an oversized motor.
Jeff
--- Steve Condie <[EMAIL PROTECTED]> wrote:
> Okay, in my ongoing search for enlightenment, I've
> been trying to understand field weakening (FW). As
> best I understand, the purpose of FW is to cause a
> series wound motor to spin at a higher speed than it
> otherwise would, by altering the "back EMF". The
> mechanism is to add a parallel circuit to the wires
> in the field winding, lessening the current in those
> windings (because some bypasses it through the FW
> circuit.) Jerry Dycus has provided real world data
> - a 12 inch, 12 gauge wire in parallel with the
> field bypasses an appropriate amount of current to
> provide a speed boost in a (smallish?) motor drawing
> 100 amps at its top speed at full voltage, I think
> is what he posted. I think that means that the
> inherent resistance in such a shorting wire is such
> that the current left for the field is about right
> for his purposes.
>
> [By the way, part of my problem is that since Bruce
> Parmenter terminated the Yahoo individual post
> archive all of my bookmarks to posts explaining this
> stuff have become useless, so I'm mostly going by
> memory.]
>
> I think this also implies that while the motor will
> spin faster with the field weakened, available
> torque will be less. Yes? What's not clear to me
> is if there's any **other** adverse consequence of
> field weakening on a regular basis as opposed to
> short term for a burst of speed. To put it into a
> "real world" situation, most current road going (and
> certainly freeway-capable) vehicles are designed
> with higher voltage systems because higher voltage
> will allow a motor to spin faster (among other
> things. It also allows the delivery of more watts
> with less current and thus smaller wires - but I
> digress.) Could the same RPM range be accomplished
> with a lower voltage-based system by going without
> FW during the first half of the motor speed range,
> then shifting to FW - and keeping it activated - all
> the while the motor is in its upper RPM range? Is
> there a hidden downside? Losses through the FW
> circuit, perhaps?
>
>
>
> ---------------------------------
> Ahhh...imagining that irresistible "new car" smell?
> Check outnew cars at Yahoo! Autos.
____________________________________________________________________________________
TV dinner still cooling?
Check out "Tonight's Picks" on Yahoo! TV.
http://tv.yahoo.com/
--- End Message ---
--- Begin Message ---
There is a PDF that John Lussmeyer's wrote with all the info:
http://www.casadelgato.com/EV/EVILbusSpecification.pdf
Shawn Waggoner
Florida EAA
561-543-9223
www.floridaeaa.org
-----Original Message-----
From: Eidson, Mark [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 09, 2007 1:33 PM
To: ev@listproc.sjsu.edu
Subject: Evil Bus Spec
I've spent some time in the archive's but was unable to find a link to
the EVil spec. Does such a link exist? me
--- End Message ---
--- Begin Message ---
It's probably already been stated, but fan horsepower goes up as the cube of
RPM
--- End Message ---
--- Begin Message ---
Every Sparrow on the road pushes its ADC 8" faster than your racing
speed. At 75mph, a Sparrow's motor is turning something like 7800rpm.
While that's a reasonable argument not to drive your Sparrow so fast,
most owners do.
- Jake Oshins
Sparrow owner
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Rich Rudman
Sent: Tuesday, May 01, 2007 10:06 AM
To: ev@listproc.sjsu.edu
Subject: Re: ADC 8" red line...
That's a bit too high for me!!
Stone cold maybe... But not hot.
I set my rev limter for 6500 racing and 5500 street.
some say 8000 is oK.. I don't go there
Madman
Racing.
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, May 01, 2007 9:19 AM
Subject: ADC 8" red line...
> Just how safe is it to spin a bone stock ADC 8" 6900 RPM?
>
> Just curious.
>
> Ken
>
________________________________________________________________________
> AOL now offers free email to everyone. Find out more about what's
free
> from AOL at AOL.com.
>
--- End Message ---
--- Begin Message ---
Hi Guys,
Speaking of these curves, correct me if I'm wrong, before I do something
stupid and expensive.
The way these curves are generated is?
Apply the specified voltage to the motor while
Applying physical load until a given current is reached at the specified
voltage
Measure Torque
Measure RPM
Calculate HP based on torque and RPM?
Or measure HP and RPM and calculate torque?
Calculate efficiency based on watts in and HP out?
This appears to be abstract to use because in practice, we tend to limit
current and let volts rise with RPM until we can't achieve the chosen
current? So we're really operating in a straight up and down line at
constant torque and increasing HP beneath our chosen current point until we
hit the point where we're back EMF limited and the current drops with
further RPM increase? So we will only see the HP listed on the graph for a
moment as we hit pack voltage = motor voltage before current drops?
TIA,
Marty
----- Original Message -----
From: "Steve Peterson" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, May 09, 2007 11:17 AM
Subject: Re: Motor equations
Yup, that helps me understand how the concepts relate to the curves. Now
all I have to do is figure out how to model the curves. Many thanks.
--Steve
On Wed, 2007-05-09 at 08:32 -0700, Jeff Major wrote:
Hi Steve,
Good question.
The plots you refer to are amps vs torque and RPM vs
torque. So this makes it a combination of the two
basic equations. Plus the fact that the torque in the
equation is the *electromagnetic torque* and not the
output torque. The plots use output torque which
accounts for losses (friction, windage and core).
These losses are significant at light loads on the
series motor where RPM is high. This tends to
straighten out the amp vs torque curve, but it still
bends down somewhat at light loads.
Also, the Eg in the equation is the generated voltage
or back EMF and not the applied voltage. So one has
to account for the resistance and brush drop. These
are low at light loads so affect the RPM vs torque in
the opposite manner.
Hopes that helps.
Jeff
--- Steve Peterson <[EMAIL PROTECTED]>
wrote:
> Thanks, Jeff...
>
> Your explanation makes sense, but leaves me with a
> new question:
>
> If Torque is proportional to Flux, and Flux varies
> with the current, why
> is the ADC torque vs. amps curve darned near linear
> while the rpm vs
> torque curves have a "deep" bend in them?
>
> --Steve
>
> On Wed, 2007-05-09 at 07:15 -0700, Jeff Major wrote:
> > Steve,
> >
> > RPM = Ks * Eg / Flux
> >
> > where Ks = machine constant (including units
> > conversion), Eg = generated voltage.
> >
> > Torque = Kt * Ia * Flux
> >
> > where Kt = machine constant (including units
> > conversion), Ia = armature current.
> >
> > Although equations appear linear, the Flux is not
> a
> > linear function of current for the series motor
> due to
> > saturation, so the Torque vs RPM characteristic is
> > curved.
> >
> > Jeff
> >
>
>
__________________________________________________
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--- End Message ---
--- Begin Message ---
Thanks, me.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Shawn Waggoner, FLEAA
Sent: Wednesday, May 09, 2007 10:44 AM
To: ev@listproc.sjsu.edu
Subject: RE: Evil Bus Spec
There is a PDF that John Lussmeyer's wrote with all the info:
http://www.casadelgato.com/EV/EVILbusSpecification.pdf
Shawn Waggoner
Florida EAA
561-543-9223
www.floridaeaa.org
-----Original Message-----
From: Eidson, Mark [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 09, 2007 1:33 PM
To: ev@listproc.sjsu.edu
Subject: Evil Bus Spec
I've spent some time in the archive's but was unable to find a link to
the EVil spec. Does such a link exist? me
--- End Message ---
--- Begin Message ---
The Zilla on our 2006 NmG is set for an RPM limit of 6400 RPM. That
occurs at just a smidge over 75 MPH.
Ken
-----Original Message-----
From: [EMAIL PROTECTED]
To: ev@listproc.sjsu.edu
Sent: Wed, 9 May 2007 12:56 PM
Subject: RE: ADC 8" red line...
Every Sparrow on the road pushes its ADC 8" faster than your racing
speed. At 75mph, a Sparrow's motor is turning something like 7800rpm.
While that's a reasonable argument not to drive your Sparrow so fast,
most owners do.
- Jake Oshins
Sparrow owner
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Rich Rudman
Sent: Tuesday, May 01, 2007 10:06 AM
To: ev@listproc.sjsu.edu
Subject: Re: ADC 8" red line...
That's a bit too high for me!!
Stone cold maybe... But not hot.
I set my rev limter for 6500 racing and 5500 street.
some say 8000 is oK.. I don't go there
Madman
Racing.
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, May 01, 2007 9:19 AM
Subject: ADC 8" red line...
Just how safe is it to spin a bone stock ADC 8" 6900 RPM?
Just curious.
Ken
________________________________________________________________________
AOL now offers free email to everyone. Find out more about what's
free
from AOL at AOL.com.
________________________________________________________________________
AOL now offers free email to everyone. Find out more about what's free
from AOL at AOL.com.
--- End Message ---
--- Begin Message ---
On Wed, May 9, 2007 5:30 am, Deanne Mott wrote:
> Was it here that I read a statistic something like, it takes more
> electricity to refine a gallon of gas than it takes to propel an EV the
> equivalent number of miles down the road? If that's true, that's a
> statistic I'd like to throw around - gets you around the whole dirty
> electricity arguement.
That is close to a 'fact' published on the Gizmo website. It was later
pulled, after someone pointed out it was "not quite true". There are many
other products produced in refining than just gas.
Still, if the EV is very efficient (tiny), and the car it replaces is not,
and the oil doesn't need to be refined (stays in the ground), then the
argument holds.
--- End Message ---
--- Begin Message ---
But you also have to consider too that to make the electricity, some amount of
fuel had to be refined to power the generators too. To be more accurate you'd
have to do a complete "Well-to-Wheels" analysis going down both paths.
I am making my demarcation however at the pump and the plug in my house. My
dollars go directly to those two sources. The only difference is that my
emissions are directly from the ICE or in the case of the EV from the upstream
source of electricity. My presumption (and maybe a wrong one) is that the fuel
to the pump and the fuel to the power company's tanks is a wash as far as net
energy (and carbon production) to get it there. My point is that, once the
fuel is produced and distributed, the power company can burn it cheaper and
cleaner than I can in my ICE car.
Mike
----- Original Message -----
From: Deanne Mott <[EMAIL PROTECTED]>
Date: Wednesday, May 9, 2007 4:36 am
Subject: Re: EV's on Local Talk Radio
To: ev@listproc.sjsu.edu
> Was it here that I read a statistic something like, it takes more
> electricity to refine a gallon of gas than it takes to propel an EV
> the equivalent number of miles down the road? If that's true, that's
> a statistic I'd like to throw around - gets you around the whole dirty
> electricity arguement.
>
> Good luck, have fun on the radio show...
>
> > They way I figure it, if my 15mpg car made 19 lbs of CO2 for
> each gallon of gasoline then the ICE I had made 0.8 lbs CO2 per mile.
> >
> > My EV that gets ~333 Wh/Mi would only make 0.33 lbs CO2 per mile
> (electricity produced from Natural Gas here in Anchorage)
> >
> > To me that looks like a 2-1/2 times cleaner Carbon footprint.
>
>
--- End Message ---
--- Begin Message ---
You may want to mention that in cases like here in Illinois, over half of
our electricity production is nuke, and therefore likely has a much reduced
carbon footprint. Of course it may just open the door to a nuclear waste
argument. Maybe I can claim that I'm driving an atomic car?
Marty
----- Original Message -----
From: "MIKE WILLMON" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, May 09, 2007 2:57 PM
Subject: Re: EV's on Local Talk Radio
But you also have to consider too that to make the electricity, some
amount of fuel had to be refined to power the generators too. To be more
accurate you'd have to do a complete "Well-to-Wheels" analysis going down
both paths.
I am making my demarcation however at the pump and the plug in my house.
My dollars go directly to those two sources. The only difference is that
my emissions are directly from the ICE or in the case of the EV from the
upstream source of electricity. My presumption (and maybe a wrong one) is
that the fuel to the pump and the fuel to the power company's tanks is a
wash as far as net energy (and carbon production) to get it there. My
point is that, once the fuel is produced and distributed, the power
company can burn it cheaper and cleaner than I can in my ICE car.
Mike
--- End Message ---
--- Begin Message ---
I was under the impression that their LFP line of cells are LiFePO4?
http://www.thunder-sky.com/products_en.asp?fid=66&fid2=70
On 5/9/07, Timothy Balcer <[EMAIL PROTECTED]> wrote:
No.. I wasn't referring to Thundersky cells, which are not LiFePO4,
they are standard chemistry.
Here is the link: http://tinyurl.com/226qwo
On 5/9/07, Ian Hooper <[EMAIL PROTECTED]> wrote:
> Valence Saphions are Lithium batteries including BMS designed for EV
> use. Great idea, but overpriced: http://www.valence.com
>
> The 54c/Wh cells mentioned was probably referring to ThunderSky
> (http://www.thunder-sky.com), but there's a real shortage of easy-to-
> use BMSs available for EV-sized lithiums. Definitely a big hole in
> the market there for some entrepreneurial soul to fill. Hmm... *gears
> turning*..
>
>
--
www.electric-lemon.com
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To add to Evan's comments, I've seen flame arrestors used on the watering
system overflow outlets - but not in every case, so I don't know when they're
required. I get the impression that the watering system is the only route for
hydrogen to escape. That's certainly the case on the MR range, where there
are no removeable cell caps.
I don't think that the separator problem which plagued the MR range of Safts
prior to 2000 - and killed at least one European EV demo project - was a
problem with the conventional (high maintenance ;-) nicad range. Certainly
the old bubbly boiler orange-cap STMs lived long and prospered. I'm not
100% sure of that though.
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Jack Murray wrote:
Who sells an EV-ready pack?
Scroll all the way to the bottom of the page:
http://ev-battery.com/Batteries/PricesDoc.html
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interesting article on softpedia
New Materials For Twice as Powerful Lithium Batteries
- A layered material doubles the life of a lithium-ion batteries
By: Lucian Dorneanu, Science Editor
http://news.softpedia.com/news/New-Materials-For-Twice-as-Powerful-Lithium-Batteries-54139.shtml
Diagram of a lithium battery
Enlarge picture
The biggest drawback of most portable electronic devices, such as
notebooks, cellphones, PDAs and many others is the
fact that they become useless after the rechargeable batteries
completely discharge.
Unfortunately, the devices themselves have known huge developments,
while their batteries remain a source of discontent among users. Even
the most advanced laptop can only last for three hours if relying only
on the most advanced lithium batteries.
Now, researchers at the Department of Energy's Argonne National
Laboratory have developed a new approach to increasing the capacity and
stability of rechargeable lithium-ion batteries.
It's based on a new material that the positive electrode will be made
of. The material itself has a multi-layered nano-crystalline composite
structure.
The new approach of the Argonne laboratories focused on a two-component
structure, an active component responsible for the charge storage that
is embedded in another, inactive component that has a stabilizing role
in the structure.
The first tests are promising, as the new composite materials showed
exceptionally high charge-storage capacities, in excess of 250 mAh/g,
which is more than twice the capacity of materials in conventional
rechargeable lithium batteries.
Furthermore, the stability of the new batteries has also increased, even
though few people know that conventional lithium batteries can be
dangerous if mistreated and unless care is taken their lifespan may be
reduced.
For now, the most advanced lithium-ion battery design is the lithium
polymer cell.
Another advantage of the new technology is that the overall cost of the
lithium batteries will be lowered by focusing on manganese-rich systems,
instead of the more expensive cobalt and nickel versions.
Here's another thing that most consumers don't know and that the
producers don't ever mention: the lifespan of the lithium-ion battery
depends largely on the manufacturing time (shelf life) regardless of
whether it was charged and not just on the number of charge/discharge
cycles.
In other words, if you buy a new Li-ion battery that has been produced
in the same lot as your used battery and has never been used, the unused
one, (that stayed on a shelf for the same period of time when you were
using yours), is, in fact, not much better than your old one!
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another of interest perhaps from softpedia
Solar Powered Scooters Soon on the Streets
- "Surprisingly", a student designed the recharging system
By: Lucian Dorneanu, Science Editor
Enlarge picture
Scooters and mopeds are the favorite means of transportation for the
youngster, especially students,
due to the ease of mobility, the low purchase and maintenance price and
to the fact that it's an easy way to get through heavy traffic in the
big cities.
Some municipalities have even banned car access in certain areas within
the city center, so there's yet another reason why young people love
this miniature bike.
Now, the scooters will get even more love from the youth, thanks to the
work of a student at The University of Nottingham, Matt Alvey, who is
studying Architecture and Environmental Design.
He just designed a brand new recharging system for photovoltaic cells
(solar energy converter cells) that he mounted on a scooter. It all
began when a company making electrical storage sheds for scooters
approached the university about integrating solar power to recharge the
vehicle.
Caroline Moore, Director of Security GB, the Chesterfield based company
that sells the storage sheds, says "We wanted a solar panel system that
would reduce the electric costs for disabled users and cut costs on
getting a power supply connected to the shed."
The first results are good and seem to overcome problems often
associated with connecting mains power to the shed. The new gadget can
prove costly as it requires a qualified electrician to do the work, but
it would also prevent the possibility of the charger overloading the
owner's mains electricity supply to their home.
"The other big advantage is that it will generate electricity by a
renewable means and therefore has no harmful emissions," said Alvey.
"Increasingly more and more people are becoming aware of their own
impact on the environment. Renewable energy technologies are becoming
extremely popular with the general public and this project is one
example of how demand for a green solution was sought by the consumer,"
said Dr Mark Gillott, Co-Director of the Institute for Sustainable
Energy Technology at the School of the Built Environment.
Future applications will be very profitable, since there is a growing
market for electric bikes, so the student has every reason to find a way
of making them 100% sustainable.
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--- Marty Hewes <[EMAIL PROTECTED]> wrote:
> argument. Maybe I can claim that I'm driving an atomic car?
> Marty
I do. Absolutely. Well, nuke-powered scoot... about +-50% nuke in
Ontario,Cda. plus coal, but it runs just fine on hydro, and wind and
solar too... bring it on. If and as the mix of electricity sources
shifts towards renewables in the future, your nuke car will just get
"greener and greener" as it gets older.
Gassers can't do that. After they are new, the exploding combusting
bits just get older and dirtier. leakier. less efficient. less green.
So yeah, it's OK to mention the nuke thing. But string it into that
one sentence, that the car is already plugged into the future. There'll
never be a better "flexi-fuel system" vehicle built than the EV <smile>
`Cept the hybrid EVs... the human-electrics ;->
tks
Lock
kickin'in Toronto
hybrid ped
Get a sneak peak at messages with a handy reading pane with All new
Yahoo! Mail: http://mrd.mail.yahoo.com/try_beta?.intl=ca
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Marty> You may want to mention that in cases like here in Illinois, over
Marty> half of our electricity production is nuke, and therefore likely
Marty> has a much reduced carbon footprint.
According to this EPA site:
http://www.epa.gov/cleanenergy/powerprofiler.htm
my fuel mix (ComEd - I live in Evanston) is 52% coal, 44% nuclear and 2%
natural gas. Maybe you're downstate? The nation as a whole has somewhat
less nuclear (20%), 3% oil, 7% hydro, 16% natural gas and 2% non-hydro
renewables. I know my regional mix doesn't add up to 100%. Those are the
numbers EPA provides.
--
Skip Montanaro - [EMAIL PROTECTED] - http://www.webfast.com/~skip/
"The hippies and the hipsters did some great stuff in the sixties,
but the geeks pulled their weight too." -- Billy Bragg
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nope, no spacers
----- Original Message -----
From: mike golub <[EMAIL PROTECTED]>
Date: Wednesday, May 9, 2007 2:07 am
Subject: Re: Batteries or Charger funny?
To: ev@listproc.sjsu.edu
> do you have spacers between your batteries?
> --- Mike Willmon <[EMAIL PROTECTED]> wrote:
>
> > Been running twenty Crown CR-225's in the truck now
> > for 5 months.
> > Over the winter the batteries have been kept around
> > 75*F to 80*F by keeping the lid propped open
> > appropriatley to regulate the
> > temp. Recently outside temps started to rise for
> > the summer and I came out and they were 104*F and
> > the charger did not shut off.
> > It was still running full open at just under my
> > regulation voltage of 145V. OK so a little thermal
> > runaway. I pulled the
> > insulation out of the lid, let the truck sit outside
> > without the lid for the weekend. Battery temps back
> > down to 75*F. A few more
> > days running without the insulation in the lid and
> > temps are normal; I still prop the lid open at work
> > to cool. Because its
> > warmer out and the likelyhood of the batteries
> > running over 80*F I've dropped the Reg voltage to
> > 143V. But the last few days as
> > I've watch the end of charge the voltage gets up to
> > 143V, the blue Reg light (1500 "Mega"candella ;-)
> > flashes on the PFC-20 and
> > an hour later voltage drops to 141V, Reg light goes
> > off, charger continues full tilt until I shut it
> > off. Battery temps barely
> > 80*F. Its time for a water check and Equalize anyway
> > so I refill all the cells (all of them need a
> > little). It hits 143V and drops
> > to 141V a couple more times, then it hits Reg and
> > times out normally a couple times. The last 3 days
> > though it will not reach
> > 143V at all. I'd like to run an equalize charge but
> > I cannot get them over 143V. I'm only running
> > 110VAC so I can only charge at
> > ~10.5 amps. The last 3 days I've just shut it off
> > manually when the KillaWatt meter says I've returned
> > 120% of what I calculate I
> > use during the day. The calculation is verified by
> > a couple data pulls from the Zilla. At 380 Wh/mi
> > its slightly higher I figure
> > because I have the summer treads on that run 35psi,
> > while my winter treads were 44psi (I notice steering
> > is a little harder with
> > the summer tires too, but thats expected). I don't
> > seem to be using more power than I expect. I don't
> > seem to be losing any
> > range. It doesn't seem to be losing any steam after
> > 15 miles of driving. All the driving seems normal.
> > Battery temps seem
> > normal. All batteries when at the top of charge are
> > average 7.11V with one highest at 7.2V and two
> > lowest at 7.02V (all other run
> > 7.08V to 7.15V).
> >
> > What am I doing wrong?
> >
> > Mike,
> > Anchorage, Ak.
> >
> >
>
>
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