EV Digest 4002
Topics covered in this issue include:
1) Re: Follow-up on Valence Li-Ion batteries in 12V size
by Victor Tikhonov <[EMAIL PROTECTED]>
2) Re: Refining Hybrid truck ideas
by Martin Klingensmith <[EMAIL PROTECTED]>
3) Re: Jeep EV (Battery LED, Raptor controller questions)
by Nick Viera <[EMAIL PROTECTED]>
4) Re: DIY Controller? (DIY Motor)
by Victor Tikhonov <[EMAIL PROTECTED]>
5) Etek & hybrid
by [EMAIL PROTECTED]
6) Re: Follow-up on Valence Li-Ion batteries in 12V size
by "Philippe Borges" <[EMAIL PROTECTED]>
7) Re: Jeep EV (Battery LED, Raptor controller questions)
by Nick Viera <[EMAIL PROTECTED]>
8) Re: DIY Controller? (DIY Motor)
by [EMAIL PROTECTED]
9) Re: Sundancer whereabouts?
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Motors in series? Torque vs. power?
by Lee Hart <[EMAIL PROTECTED]>
11) Re: Jeep EV (Battery LED, Raptor controller questions)
by Lee Hart <[EMAIL PROTECTED]>
12) Re: DIY Controller
by Jeff Shanab <[EMAIL PROTECTED]>
13) Re: DIY Controller? (DIY Motor) - AC Motor - AC5DC - listening?
by Rod Hower <[EMAIL PROTECTED]>
14) Re: High Current Li-ions from Sony
by Jeff Shanab <[EMAIL PROTECTED]>
15) More on AC
by Jeff Shanab <[EMAIL PROTECTED]>
16) Re: Jeep EV (Battery LED, Raptor controller questions)
by "Richard Furniss" <[EMAIL PROTECTED]>
17) Re: Refining Hybrid truck ideas
by "Ryan Stotts" <[EMAIL PROTECTED]>
18) Re: Refining Hybrid truck ideas
by Chris Zach <[EMAIL PROTECTED]>
19) Re: DIY Controller? (DIY Motor)
by Lee Hart <[EMAIL PROTECTED]>
20) Re: DIY Controller
by Seth Allen <[EMAIL PROTECTED]>
21) Re: DIY Controller
by Lee Hart <[EMAIL PROTECTED]>
22) Re: DIY Controller? (DIY Motor)
by Lee Hart <[EMAIL PROTECTED]>
23) Re: More on AC
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Philippe Borges wrote:
That actually applies to any battery - it must match the
intended application to get decent results.
Ok Victor I will tell it obvious way:
imho TS li-ion cells are UPS batteries, period.
they sag a lot upper C/2 and doesn't like either to be cycled to 80%.
You can think of them as of UPS batteries, but they are not.
They are made with EV use in mind. Now, they may sag just as
UPS batteries do. On the other hand, occasionally people use
UPS batteries in their EVs.
Now, if they sag at C/2 more than you'd like, pick larger C.
Cycling to 80% is no problem unless you have data to prove
otherwise. This is the word from the battery creator I spoke
to personally. Take it at face value (e.g. if you choose not
to believe it, no one can convince you otherwise).
I talk about a $500 test pack not $5000 and not everbody has an automatic
batterie cycler with data log.
Yes. the battery may be $500 but the test rig is $5000.
Ask Gary or Joe.
Define "good" batteries". That depends on your application
and appetite.
"good" EV batteries:
The right horse to put money in and promote EV :^)
By that definition TS batteries are good. I put money
in it and drive to work every day, promoting EV.
Define "Expensive". That depends on how much money one is
able and willing to commit to your hobby.
My "expensive" definition is more like:
something you put lots of money in and nothing usable back.
Fuzzy logic. Did I put lots of money in? my pack was $8.9k
Did I get anything usable back? Oh, yes, compared to 28
Optimas [which, I'm surprised, did not fold my Honda in half],
I got very peppy and light EV, daily driver, object to learn
stuff, test bed for BMS development, pride of ownership,
bragging rights to be among first ones to inject LiIon
waves in quiet ocean of PbA batteries. Was it worth $8.9k?
Every penny to me.
i agree, an assumption is...an assumption, always right to someone and wrong
to other...
In fact i just use Saft definition of discharge rate:
"a traction battery is better quoted at his 1C discharge level"
understandable when you are used to work with 100Ah Saft ni-cad :^)
Saft is special case - there is no other manufacturer like that.
You're lucky to live near by and have access to them.
Otherwise you are trying to juice an electric Humwee with AA cells,
needs a
lot of them in serie and/or parallel to keep voltage high and current
low...though well done it will work for sure, the gain/cost ?
No, it will not be practical even if works for one off demo,
like for t-zero.
ok TS 200Ah, let's choose... your car exemple and compare 326V Optima pack
with say about 300V TS pack.
pack price:
$3 500 | $30 000
who will pay that to a company which itself don't know how to charge their
cells ?
First, 28 Optimas didn't really fit in my car (I had to remove
right seat) and too heavy for safe driving.
Second, you show the price difference, but don't point out
advantages gained, so one can decide if advantages worth
the money.
If you think $30k TS pack is priced too high, quote
me SAFT's, I'd love to hear how much that would be.
Other choice - Kokam cells. 4x price of TS, but may be
8x of performance. Worth it?
Not for me. But did for Cliff Rassweiler from ProEv.
I applaud his choice.
so you have immediate range ok,
Not just OK, about 3x better than it was.
weight gain ok,
Not only gain (you mean loss), but handling, safety,
fun factor, utility (right seat is back).
usable power ok (less than
Optima but usable)
I could not take advantage of Optima's power anyway
since the system is rated to 280A. So Optima was way
overkill power wise and lower power but higher capacity
TS cells are far better match *for my vehicle*.
BUT it need a lot and BIG TS cells to make it just drive
ok !
No, my cells are small, and it drives *better* now than
with Optimas. Lack of power is taken care of by capacitor bank.
Yes, extra expense but *for me* worth the gain - caps last forever
(in EV terms), not consumable item as batteries, don't care
if they are cold or hot, no special charging needed.
look at the price, at the waranty and still unknown life, where is the
real gain here ?
See all above - to me it is real gain overall.
To me means to *my* understanding and sense of improvement
and available *to me* money to pay for it.
Everyone else's circumstances are different.
i don't have enough money to bet $30 000 or even half this
in batteries !
I do.
Talking about money is dangerous. Spend little and
someone will lave you a cheap stake. Spend a bit more
and Jerry will tell you that you have more money
than brains. So my advice - avoid looking at other's
pockets and stick to technical. Everyone will decide
for themselves about worthiness for them; dealer
cost means little as it is relative to the one's income
(and ambitions).
I don't know for USA but in europe, importator/distributor generaly test
product he sell, because he has to warrant it.
In the USA it can be either way. I doubt Roderick
personally tests every component he cells on EV Parts
site. In general, manufacturer's warranty apply and distributor
will help you to exchange under performing product, but
distributor is not responsible for quality manufacturer
provides. Distributor also uses manufacturer's data sheets.
He can conduct own tests, but the value depends on the
reputation and experience.
If you tomorrow will distribute SAFT's batteries will
you conduct your tests? you might, but would I
believe Philippe's documents more than SAFT's own?
Even if SAFT doesn't have something you measure.
So YES i'm disappointed that you or jukka don't make that test, it's not
customer job.
We do tests to the best of out abilities within resources
available. If some one pays me to do the tests, I'd do it
8 hrs a day. Until then, I'll keep my day time job
which pays bills and do the tests if I have free time.
imagine GM selling you a van which had a sticker:
"once you have tested the body resistance in an accident please return the
car to us, we will inspect results and maybe improve the car"
imagine TS cells with a sticker:
"once you have find better way to charge this cell and make them last,
please let we know, we are still looking for it"
I'm not a GM or TS. I have no right to dictate them how to
do business; if I don't like it, I just vote with my dollar
by going somewhere else. It is up to them to change if they
want my money.
Same applies to me - if you don't like the service - suggest
improvements, but it is up to me to implement them or even to
listen. You, in turn, are free to turn around and shop elsewhere,
like at SAFT, no problem.
Sheer wanted to test NiZn, so he bought it. No time to do it,
Joe helped out.
Lee wanted to test TS LiIons, so he bought few to answer his
own questions.
As far as I know, none of them are too rich or wasteful.
thank much to them because their experience make lots of people not loosing
big bucks for nothing.
Yes, thank them, but you can't be *frustrated* at them if they
wouldn't volunteer to do it.
I CRY it here: customer don't have to be a beta tester !
I agree. I am also a TS customer myself, haven't you noticed?
How old are you Philippe, may I ask?
no problem Victor,
i'm 30, one 8 old boy and too much EV sitting around (my wife opinion)
though my english should give me near 8 years old :^)
Merci beaucoup, your English is far better than my French,
so don't worry about it. Reason I asked, I'm 45 (BTW today
is my birth day :-) ) and I want to enjoy EV and all the
technology associated with it while I'm alive. Based on
what I've learned in this country, despite quickest pace
of technological advances than anywhere else (simply
because USA sucks in the best brains from all over the
world) waiting time and broken promises may well be longer
than one expects. So while at the age of most engineering
productivity, I want and produce results now. At 30,
I perhaps could afford to "wait and see" some more.
As Gary Graunke will tell you, FC cars were promised
to him while he was in high school; roughly 30
years ago. GM said then "it is around the corner".
Well, we all may retire and die from old age and this
still be around the corner.
Perhaps the room or building with *that* corner,
GM was talking about, is round after all...
Victor
--
'91 ACRX - something different.
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
Jeff Shanab wrote:
With todays newer fuel injected car can we plug a datalogger into
the diagnostic port to capture fuel injector and rpm data? Would
that provide us with a good fuel usage numbers. What about using
In theory it should. But, I've seen precious few products that actually
make fuel consumption data available. If it were easy, I would expect to
see "miles per gallon computers" on the market that do it.
Nuts and Volts magazine had a contest recently, the winning contestant
made an OBDII mileage gauge.
My internet connection is horribly slow right now otherwise I would try
to find a web page for you. It used an Atmel MCU and had an analog gauge
as I recall.
--
Martin K
http://wwia.org/sgroup/biofuel/
--- End Message ---
--- Begin Message ---
Hi,
> The resistors limit the current no matter which LEDs are lit. So,
> if the 10ma or so current drain doesn't bother you, you can leave
> it on.
My only concern is that the resistors get hot to the touch after awhile.
I measured them with a temp. probe, and were around 60 degrees C. Maybe
this is a perfectly reasonable operating temp. though? I used 3-watt
resistors.
Thanks
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
---------------------------------------------
On Tue, 2005-01-04 at 16:15, Lee Hart wrote:
> Nick Viera wrote:
> > Thanks. I did test it, and all of the LEDs work. I wired the most
> > positive and most negative sensing wires to the switched side of
> > my contactors, so when the ignition switch is off, the two center
> > red LEDs light (because the other three wires go straight to
> > batteries). For now I'm just removing the glass fuses on those
> > 3 wires so I can turn it off.
>
> The resistors limit the current no matter which LEDs are lit. So, if the
> 10ma or so current drain doesn't bother you, you can leave it on. I like
> to use it to tell me if my pack really *is* off!
--- End Message ---
--- Begin Message ---
Lee, are you joking or seriously suggest someone to try
to perform these "not strictly nesessary improvements"?
Victor
Lee Hart wrote:
...
The EV-grade AC motors produced for the auto companies are at least 10x
the price of normal AC motors because they are hand-made, low
production, and have lots of "fiddly" little improvements that are nice
if cost is no object, but not strictly necessary. You could "blueprint"
a stock AC motor and make these changes yourself (or just the ones you
felt were justified). Here is a typical list:
- change to liquid cooling
Drill holes, add cooling lines, hoses, fittings, etc.
Auto companies do this "because we always liquid-cooled
our motors". Or, just add an external blower and keep it
air cooled.
- precision balanced rotor, better bearings
Inverter-grade motors can run to 13,000 rpm and above.
Stock motors are only made "good enough" for 3600 rpm.
Balancing and bearings for 8000 rpm is pretty easy.
- better insulation
Inverters don't deliver nice clean sinewaves; they produce
spiky waveforms with larger peak voltages. The auto
environment is also likely to be dirty and wet. So, they
add insulation to prevent voltage breakdowns. You can epoxy
or re-varnish the windings and add insulation. Or, have the
motor rewound with extra insulation.
- higher temperature materials
An EV motor is likely to be overloaded more (hill climbing,
drag racing), so they use the highest-class insulation and
materials. But normal motors are usually class 180 (class H)
anyway. If yours is not, rewind it with class 180 materials.
- rewound to suit the actual application
Motors can be wound for any voltage. The auto company motors
are custom-wound for whatever weird voltage worked out best.
("You want it wound for 163v? Ok, but it will cost extra!")
But you can also just reconnect the coils that are already
there for different voltages, and then pick your pack voltage
to match.
- lower-resistance rotor
EV-grade motors use the lowest rotor resistance possible,
to maximize efficiency. Normal induction motors deliberately
have extra rotor resistance, so they can start at 60hz and
full voltage (but lose efficiency in the bargain). But
rotors are easy to change. You can get low-resistance rotors
or modify an existing rotor to be lower resistance. Or, just
accept a few percent efficiency hit and use a standard rotor.
--- End Message ---
--- Begin Message ---
Lee,
I think it was you that suggested using an Etek as a kind of turbo
booster for a homemade hybrid but I lost the e-mail so I'm hoping I'm
responding to the right person. The more I think about all the compromises
and complexity involved with how I wanted to design a parrallel hybrid the
more I think I'm just going to wind up having to make a series hybrid. With
a parrallel hybrid I'll have to do a lot of welding/fabricating and would
need pobably two motors, minimmum 6.7". Plus it's something I can afford to
do within about 6 months. Is it possible to integrate an Etek with a
MillipaK to boost the engine when I hit the accelerator and then
automatically switch to regen when I hit a certain speed to act as the
truck's alternator/pack charger. Is it possible to get the motor RPM to
match the engine rpms to give the perfect amount of boost every time I hit
the gas pedal and not have to mess with trying to coordinate two
accelerators? The Etek would be mounted like the alternator is now with a
toothed belt to the engine. Thanks for the expertise.
John Shelton
--- End Message ---
--- Begin Message ---
After AC vs DC there is now TS vs Saft :^)
i'm still understanding (or thinking i understand) your opinion about TS
products, we still disagree and won't convince each other, no matter.
I'm, like many, still waiting next EV batterie, for me it will be soon SAFT
(oups sorry) NIMH because i think li-ion is and will be kept too expensive.
(and because since 1/1/2005 Ni-cad based new EV car or trucks
importation/construction is prohibited)
Kokam or similar perf. lithium cells at $500 kwh would significate quick ICE
car market death, Batterie power should became next petrol for
tranportation, china don't bother too much about petrol so why not ?
My son knows about ICE cars and EV, maybe when it will be father, his son
will know only EV... perhaps TS cells high powered at abordable for
everybody costs ;^)
Philippe
Et si le pot d'échappement sortait au centre du volant ?
quel carburant choisiriez-vous ?
http://vehiculeselectriques.free.fr
Forum de discussion sur les véhicules électriques
http://vehiculeselectriques.free.fr/Forum/index.php
--- End Message ---
--- Begin Message ---
Hi,
> That will tell you how much voltage the controller is dropping. It
> should be under 3 volts at full on.
It has always been a good 20 volt drop. It makes no difference if the
WOT LED on the controller is on or not, the voltage difference is still
large at WOT.
BUT, something interesting happened on a drive I just took. Yesterday I
was playing around with the Max Current pot on the Raptor, and I found
out after today's drive that I left the pot turned just slightly down
from the "max current" (most clockwise) position. During the drive
today, I actually DID see 132 volts at the motor side at WOT. This is
what the pack voltage was sagging to as well (I was flooring it while
going up a grade). So, I *DID* see pack voltage across the controller's
output. Also, I saw that I was pulling almost 400 amps from the
batteries, whereas yesterday I *couldn't* draw more than 300 amps in 1st
gear under the same conditions and with the "max current" pot set to
full. Another difference was that the WOT LED didn't come on above 4300
motor rpms like it usually does, in fact I don't recall seeing it on at
all during my drive today.
So, it seems that a slight change in the position of the "max current"
potentiometer on the Raptor affected the output voltage, input current,
and controller current limit state during WOT. The performance of the
Jeep did not change though.
I don't know if this info is significant in any way, but I found it odd
that *decreasing* the "max current" setting would cause me to see an
*increase* in the amount of current I could draw from the batteries, and
cause me to actually see pack voltage in the motor loop during WOT.
Thanks
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
------------------------------------------
On Tue, 2005-01-04 at 13:01, Otmar wrote:
> >Hi,
> >
> >> Good job! That looks great to me.
> >> Have you tested it? It doesn't work well if the LED's are in
> >> backwards.
> >
> >Thanks. I did test it, and all of the LEDs work. I wired the most
> >positive and most negative sensing wires to the switched side of my
> >contactors, so when the ignition switch is off, the two center red LEDs
> >light (because the other three wires go straight to batteries). For now
> >I'm just removing the glass fuses on those 3 wires so I can turn it off.
>
> Ah, but they will still do that if the red LEDs are in backwards.
> I found that the threshold for them to turn on was 4V instead of 2V
> when they were in backwards.
> You might want to try just moving one end by 3V to insure it is as
> sensitive as you want.
> This is not to say that I expect your battery to have problems, only
> that it's good to fully test anything that you build and rely on.
>
> >I think it means 100% duty cycle based on what the manual says:
> >
> >"The Yellow LED illuminates when the throttle is wide open or "Floored".
> >This indicates that the controller is no longer switching and is
> >delivering maximum power to the motor. Should the LED not come on during
> >a full throttle condition, this indicates that the controller is in peak
> >current limit. Your trying to pull more amps through it than it can
> >deliver"
>
> Yes that sounds right.
>
> I wonder why you are getting different readings at full throttle?
>
> You might check the voltage drop at the controller by putting the
> analog meter from the B+ terminal to the M- terminal and checking
> while the LED is on.
> That will tell you how much voltage the controller is dropping. It
> should be under 3 volts at full on.
--- End Message ---
--- Begin Message ---
> Don't be fooled by the the stock ratings of a standard off-the-shelf AC
> motor -- that's only what it can do on ordinary 60hz power. On an
> inverter, its ratings are considerably better. First, the nameplate
> gives continuous-duty ratings; you can double the HP for EV use since
> you won't run at this power level for even 1 hour. Second, the inverter
> can double the frequency; this doubles the HP again. Third, you can
> improve the cooling with an external blower, to double it yet again.
> That means you can get 8 times the nameplate HP out of a motor for EV
> use. That's why a "100 HP" AC EV motor is the size of a 12 HP
> conventional AC motor.
In order to double the velocity and get the torque to remain the same, the
voltage input must be doubled from normal. Unfortunately, like any
transformer, this will saturate the core. The motor *will* put out the power
but it will get *very* hot and be inefficient. Also, breakdown torque is
typically
3.5x steady-state torque.
My friend who used to work for GE, and was on the University of Illinois
FutureCar team a few years ago, got 80HP out of a Magnetek which was 10" in
diameter and about as long. It powered the school's Dodge Intrepid hybrid
very well.
> - change to liquid cooling
> Drill holes, add cooling lines, hoses, fittings, etc.
> Auto companies do this "because we always liquid-cooled
> our motors". Or, just add an external blower and keep it
> air cooled.
I recommend the air-cooled method. Most motors already have holes for this,
and you will simply be boosting the small fans already in it.
> - precision balanced rotor, better bearings
> Inverter-grade motors can run to 13,000 rpm and above.
> Stock motors are only made "good enough" for 3600 rpm.
> Balancing and bearings for 8000 rpm is pretty easy.
My off-the-shelf 3600RPM motor is good to about 4500RPM. This was one of the
things the Baldor representative I called was quite sure of.
> - better insulation
> Inverters don't deliver nice clean sinewaves; they produce
> spiky waveforms with larger peak voltages. The auto
> environment is also likely to be dirty and wet. So, they
> add insulation to prevent voltage breakdowns. You can epoxy
> or re-varnish the windings and add insulation. Or, have the
> motor rewound with extra insulation.
My Super-E already has insulation for this purpose (ISR wire), and it only
cost me $750.
> - rewound to suit the actual application
> Motors can be wound for any voltage. The auto company motors
> are custom-wound for whatever weird voltage worked out best.
> ("You want it wound for 163v? Ok, but it will cost extra!")
> But you can also just reconnect the coils that are already
> there for different voltages, and then pick your pack voltage
> to match.
My motor can't be configured for less than 230V line-line, and I don't think
many can. There's nothing wrong with a DC-DC converter for this purpose.
Having a 96-144V battery pack is easier to charge, safer, and cheaper (not to
mention easier to transistion from DC). The DC-DC converter doesn't have to
take the full power if it's isolated - just "add" it to the battery pack. It
can support regenerative braking (can even turn off to come to a better stop)
and will interface to a PFC charger frontend. I've got at least 200A through
my DC-DC.
> - lower-resistance rotor
> EV-grade motors use the lowest rotor resistance possible,
> to maximize efficiency. Normal induction motors deliberately
> have extra rotor resistance, so they can start at 60hz and
> full voltage (but lose efficiency in the bargain). But
> rotors are easy to change. You can get low-resistance rotors
> or modify an existing rotor to be lower resistance. Or, just
> accept a few percent efficiency hit and use a standard rotor.
This is a good idea...where would one go to find a new rotor?
Arthur Matteson
- Custom Auto Electronics, East Lansing, MI
- 1980 Renault LeCar, "Little Homebrew AC"
http://mywebpages.comcast.net/awmatt
--- End Message ---
--- Begin Message ---
Ryan Stotts wrote:
> Is this vehicle still around?
> http://motortrend.com/roadtests/classic/112_0405_archive/
The yellow car in the MotorTrend article looks like Sundancer #1, built
in 1970, which was sold to Exide. It had twelve golf cart batteries, a
contactor controller, 8HP series motor, and solid rear axle with the
motor mounted to it "golf-cart" fashion.
> http://www.mclellansautomotive.com/sales-lit/bysub/electricvehicles/sundancer/index.shtml
The SAE report #720188 covers Sundancer #1 and #2. #2 was built in 1971
and also went to Exide. It had an SCR controller and was red, but was
otherwise much like #1.
More Sundancers were subsequently built, and the design evolved as McKee
learned and experimented. They had various names, depending on who it
was sold to (ESB, Autodynamics, McCulloch, Copper Development
Association, etc.). You can also find it called the Mk-16 Commuter Car.
The Feb 1972 issue of Mechanix Illustrated had a test report on a third
one (Tom McCahill Report -- We Test A _Practical_ Electric Car) which
had a much nicer, more finished interior.
The 17 Oct 1974 issue of "Machine Design" had a later Sundancer which
had the motor mounted transversely to the frame, with a shaft on each
end, driving each rear wheel independently with a variable-speed belt. A
13th battery was added, and the rear suspension went from a solid axle
to independent swing axles.
"Road Test" magazine for July 1974 describes one built for McCulloch
Enterprises. It was expanded to 18 golf cart batteries, a 15hp series
motor, and SCR controller. It was also rear wheel drive, with a central
chassis-mounted 2-speed transaxle/differential. It had a fiberglass body
from a Studebaker Avanti.
In 1975, another one appeared as the Copper Electric Town Car. It had 18
golf cart batteries in the central backbone like all Sundancers, but
this one rolls out the rear. A compound-wound DC motor drives the front
wheels thru a transaxle. Hydrocaps reduced watering. The steel body was
very streamlined, and had the interesting feature of sliding doors.
I don't know where any of the Sundancers are today. I tried hard to buy
one, but failed. I did find the one built for Autodynamics in an
amusement park in Rhode Island, but it had been butchered to use as a
ride.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
>> We don't normally switch series fields in series/parallel because
>> their resistance is so low that the switches used have as much
>> (or more) resistance. So, variations in the switch resistance
>> cause the current in the different field coils to divide unequally.
>> This causes efficiency and arcing problems.
David Chapman wrote:
> Lee, would some kind of solid state switching device be practical
> and not have the problems that I assume is caused by contactor use?
No; it would make it worse. The field windings have a *very* low
resistance; like 0.003 ohms (0.3v at 100 amps). No (practical)
semiconductor has a low enough "on" resistance to compete with a
contactor.
--
"Wisdom is not a product of schooling, but of the lifelong attempt to
acquire it." -- Albert Einstein
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Nick Viera wrote:
>
> Hi,
>
> > The resistors limit the current no matter which LEDs are lit. So,
> > if the 10ma or so current drain doesn't bother you, you can leave
> > it on.
>
> My only concern is that the resistors get hot to the touch after awhile.
> I measured them with a temp. probe, and were around 60 degrees C. Maybe
> this is a perfectly reasonable operating temp. though? I used 3-watt
> resistors.
That's normal for resistors. Most can happily tolerate temperatures so
hot they will unsolder themselves and fry the PC board before the
resistor itself is harmed.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
I think there is one thing we can't change in the off the shelf 60hz
motor, the choices of lamination material.
Won't there will be higher losses and more heating?
I don't know how big of a factor this is but I would want to start with
a "high eff" motor.
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The Baldor Super E inverter rated motor has
all of the things Lee mentioned about upgrading
an AC motor for EV use. There are two things that are
not optimized, weight and liquid cooling. I don't
think there is a big weight penalty for the Baldor
motor even though it is designed for industrial use
(maybe 30lbs extra max? probably 10). Cooling can be
easily accomplished with a good blower (like Ametek
blowers!).
The super E motors have nice sized bearings, class H
insulation and are balanced for high RPM. They are
also built in the USA (not that this makes it better,
just unusual in todays economy).
Maybe a Baldor engineer like Ed can chime in with
advantages.
--- [EMAIL PROTECTED] wrote:
> > Don't be fooled by the the stock ratings of a
> standard off-the-shelf AC
> > motor -- that's only what it can do on ordinary
> 60hz power. On an
> > inverter, its ratings are considerably better.
> First, the nameplate
> > gives continuous-duty ratings; you can double the
> HP for EV use since
> > you won't run at this power level for even 1 hour.
> Second, the inverter
> > can double the frequency; this doubles the HP
> again. Third, you can
> > improve the cooling with an external blower, to
> double it yet again.
> > That means you can get 8 times the nameplate HP
> out of a motor for EV
> > use. That's why a "100 HP" AC EV motor is the size
> of a 12 HP
> > conventional AC motor.
>
> In order to double the velocity and get the torque
> to remain the same, the
> voltage input must be doubled from normal.
> Unfortunately, like any
> transformer, this will saturate the core. The motor
> *will* put out the power
> but it will get *very* hot and be inefficient.
> Also, breakdown torque is typically
> 3.5x steady-state torque.
>
> My friend who used to work for GE, and was on the
> University of Illinois
> FutureCar team a few years ago, got 80HP out of a
> Magnetek which was 10" in
> diameter and about as long. It powered the school's
> Dodge Intrepid hybrid
> very well.
>
> > - change to liquid cooling
> > Drill holes, add cooling lines, hoses, fittings,
> etc.
> > Auto companies do this "because we always
> liquid-cooled
> > our motors". Or, just add an external blower and
> keep it
> > air cooled.
>
> I recommend the air-cooled method. Most motors
> already have holes for this,
> and you will simply be boosting the small fans
> already in it.
>
> > - precision balanced rotor, better bearings
> > Inverter-grade motors can run to 13,000 rpm and
> above.
> > Stock motors are only made "good enough" for 3600
> rpm.
> > Balancing and bearings for 8000 rpm is pretty
> easy.
>
> My off-the-shelf 3600RPM motor is good to about
> 4500RPM. This was one of the things the Baldor
> representative I called was quite sure of.
>
> > - better insulation
> > Inverters don't deliver nice clean sinewaves;
> they produce
> > spiky waveforms with larger peak voltages. The
> auto
> > environment is also likely to be dirty and wet.
> So, they
> > add insulation to prevent voltage breakdowns. You
> can epoxy
> > or re-varnish the windings and add insulation.
> Or, have the
> > motor rewound with extra insulation.
>
> My Super-E already has insulation for this purpose
> (ISR wire), and it only
> cost me $750.
>
> > - rewound to suit the actual application
> > Motors can be wound for any voltage. The auto
> company motors
> > are custom-wound for whatever weird voltage
> worked out best.
> > ("You want it wound for 163v? Ok, but it will
> cost extra!")
> > But you can also just reconnect the coils that
> are already
> > there for different voltages, and then pick your
> pack voltage
> > to match.
>
> My motor can't be configured for less than 230V
> line-line, and I don't think
> many can. There's nothing wrong with a DC-DC
> converter for this purpose.
> Having a 96-144V battery pack is easier to charge,
> safer, and cheaper (not to
> mention easier to transistion from DC). The DC-DC
> converter doesn't have to
> take the full power if it's isolated - just "add" it
> to the battery pack. It
> can support regenerative braking (can even turn off
> to come to a better stop)
> and will interface to a PFC charger frontend. I've
> got at least 200A through
> my DC-DC.
>
> > - lower-resistance rotor
> > EV-grade motors use the lowest rotor resistance
> possible,
> > to maximize efficiency. Normal induction motors
> deliberately
> > have extra rotor resistance, so they can start at
> 60hz and
> > full voltage (but lose efficiency in the
> bargain). But
> > rotors are easy to change. You can get
> low-resistance rotors
> > or modify an existing rotor to be lower
> resistance. Or, just
> > accept a few percent efficiency hit and use a
> standard rotor.
>
> This is a good idea...where would one go to find a
> new rotor?
>
> Arthur Matteson
> - Custom Auto Electronics, East Lansing, MI
> - 1980 Renault LeCar, "Little Homebrew AC"
> http://mywebpages.comcast.net/awmatt
>
>
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Batteries are made from a pair of half reactions, one at the anode and
one at the cathode. The voltage potential of the two reactions is added
togather to create the cell potential.
changes to the anode could also vary the cell voltage.
Look here
http://www.sud-chemie.com/scmcms/web/content.jsp?nodeId=4855&lang=en
The exm 1037 at first glance is less desirable because of lower voltage,
but it looks like it would increase cycle life and decrease self
discharge tremendously.
Since it is compatible with liPF4 and LipF6 i don't see why it can't be
used with LiMn2O4. I have emailed them for even more info
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A few years back the automanuf started to look at improving the AC as a
source of better fuel milage and emmisions.
They went to alum to reduce weight on exchangers and started using
scroll compressors.
The other thing they did was put a coating in the glass that reduces
heat gain by something like 12%. It is a big enough detail to make sure
when you have your windshield replaced, that the glass shop knows and
gets the coated, or your AC won't keep up in some regions of the US.
This was also done to prevent the max interior temp of a car in a
parkinglot from damaging dash materials, upholstry and, lower
temp(cheaper) plastics.
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Nick,
My T-Rex had a problem with the pot also, if I slammed the hood to hard I
would loose my throttle adjustment (could not get WOT). This might not be
your problem but it's starting to sound familiar.
>
> So, it seems that a slight change in the position of the "max current"
> potentiometer on the Raptor affected the output voltage, input current,
> and controller current limit state during WOT. The performance of the
> Jeep did not change though.
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RE: MPG Gauge
Don't know how it works...
http://www.jcwhitney.com/autoparts/CatalogOrderSearch?sku=wa735800p&storeId=10101&catalogId=10101
If it doesn't, looks like you have up to 6 months to get a
refund if I read their warranty right..
Maybe it's just a "fancy" engine vacuum gauge?
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Vacuum gauge.
Chris
Ryan Stotts wrote:
RE: MPG Gauge
Don't know how it works...
http://www.jcwhitney.com/autoparts/CatalogOrderSearch?sku=wa735800p&storeId=10101&catalogId=10101
If it doesn't, looks like you have up to 6 months to get a
refund if I read their warranty right..
Maybe it's just a "fancy" engine vacuum gauge?
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[EMAIL PROTECTED] wrote:
Arthur Matteson wrote:
> In order to double the velocity and get the torque to remain the
> same, the voltage input must be doubled from normal. Unfortunately,
> like any transformer, this will saturate the core.
No. You double the voltage *and* frequency. The current will remain the
same, the core won't saturate, and motor heating is basically unchanged.
Actually, it runs a little hotter because core loss increases, but runs
a little cooler because the higher rpm improves cooling -- so you wind
up just about where you started.
> The motor *will* put out the power but it will get *very* hot
> and be inefficient.
No again; Since current is the same but we doubled voltage, we doubled
power in, so output power doubles. Core loss is only a few percent;
doubling it to 6% is only a minor amount of efficiency loss.
> Also, breakdown torque is typically 3.5x steady-state torque.
That's for a normal-resistance rotor, and changes depending on rotor
resistance.
> I recommend the air-cooled method. Most motors already have holes
> for this, and you will simply be boosting the small fans already
> in it.
I agree. It is a lot easier to improve the cooling of an air-cooled
motor than to retrofit liquid cooling (without a machine shop).
> My Super-E already has insulation for this purpose (ISR wire),
> and it only cost me $750.
Excellent.
>> - rewound to suit the actual application
> My motor can't be configured for less than 230V line-line, and
> I don't think many can.
That's if you leave the stock number of turns. But if you are willing to
rewind it, you can have just about any voltage (down to the point where
a coil is just a single turn).
> There's nothing wrong with a DC-DC converter for this purpose.
> Having a 96-144V battery pack is easier to charge, safer, and
> cheaper (not to mention easier to transistion from DC).
I agree. It is cheaper and easier to have a pack made from a few large
batteries rather than many small ones.
But with AC, there is a tendency to use high-voltage, low-current
transistors and motors. Designers usually give in, and use a high
voltage pack.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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Yes. Now there are some people on the list who tell me that high
efficiency inverter rated motors have steel that is still not so great.
But like Lee said, that is splitting hairs. The elctrical frequency is
not that high, on average maybe 200Hz, so you don't get penalized
badly, especially if the motor is decent sized.
If I needed an AC motor and couldn't get one cheaply, then I would get
an inverter rated motor rewound with fewer turns with nice insulation
like he said. Make sure they stuff the slots so you get the same mass
of copper in the motor. A high speed balance and you are most of the
way there. Even some EV 1 rotors are poured aluminum into the lams,
just like commercial motors.
Or you could get one pretty cheaply, probably with an encoder, from
electro Automotive, if you can fit a Solectria AC 55.
disclosure- I used to work for Solectria
Seth
On Jan 4, 2005, at 8:11 PM, Jeff Shanab wrote:
I think there is one thing we can't change in the off the shelf 60hz
motor, the choices of lamination material.
Won't there will be higher losses and more heating?
I don't know how big of a factor this is but I would want to start
with a "high eff" motor.
--- End Message ---
--- Begin Message ---
Jeff Shanab wrote:
> I think there is one thing we can't change in the off the shelf 60hz
> motor, the choices of lamination material.
Right; if you did, you'd be throwing out most of the motor!
> Won't there will be higher losses and more heating?
Yes, but core losses are only a few percent. Doubling them (at 120 Hz
for example) is still only 6% loss, or a 3% reduction in overall
efficiency. Most inverter drives will run completely stock 60 Hz motors
at up to 120 Hz without problems (and produce twice the speed and HP in
the process).
> I don't know how big of a factor this is but I would want to start
> with a "high eff" motor.
Right. For an induction motor, one way to spot high efficiency is to
look at the rated rpm. For a 2-pole motor, a 3450 rpm motor is
"standard" slip and efficiency, 3500 rpm is low slip, and 3550 rpm is
high efficiency low slip.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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Victor Tikhonov wrote:
> Lee, are you joking or seriously suggest someone to try
> to perform these "not strictly nesessary improvements"?
I am quite serious. People spend a lot of time "blueprinting" normal
ICEs to squeeze out just a little more power. The same thing works for
electric motors.
You can improve cooling, install better bearings, precision balance the
rotor, superinsulate the windings, etc. all to get more power. These are
the same things the factory does, but they charge a lot.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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--- Begin Message ---
Jeff Shanab wrote:
> A few years back the automanuf started to look at improving the AC
> as a source of better fuel milage and emmisions... They went to alum
> to reduce weight on exchangers and started using scroll compressors.
> The other thing they did was put a coating in the glass that reduces
> heat gain by something like 12%. It is a big enough detail to make
> sure when you have your windshield replaced, that the glass shop
> knows and gets the coated, or your AC won't keep up in some regions
> of the US. This was also done to prevent the max interior temp of a
> car in a parking lot from damaging dash materials, upholstery and,
> lower temp (cheaper) plastics.
This is a good example of how penny-wise and pound-foolish the auto
companies can get.
A 12% improvement is trivial compared to the 50% improvement we get in
our homes with double-glazed windows.
Even 1/4" of styrafoam insulation in the metal walls and ceiling of a
car would cut heat penetration by 4:1.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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