EV Digest 2852
Topics covered in this issue include:
1) Re: Lowest frequency (was Re: AC vs DC)
by Victor Tikhonov <[EMAIL PROTECTED]>
2) Re: EV1 vs Prizm...
by "Christopher Zach" <[EMAIL PROTECTED]>
3) Re: 1958 Chevy Truck Conversion
by Rich Rudman <[EMAIL PROTECTED]>
4) Re: DC to AC
by Rich Rudman <[EMAIL PROTECTED]>
5) Re: Lowest frequency (was Re: AC vs DC)
by Rich Rudman <[EMAIL PROTECTED]>
6) Re: EV1 vs Prizm...
by "Ralph Merwin" <[EMAIL PROTECTED]>
7) Re: EV1 vs Prizm...
by "Christopher Zach" <[EMAIL PROTECTED]>
8) ADDING FUEL CELLS TO THE FIRE
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
9) RE: Troubleshooting help needed!
by "Chris Tromley" <[EMAIL PROTECTED]>
10) Re: Sparrow handling
by Lee Hart <[EMAIL PROTECTED]>
11) Re: Troubleshooting help needed!
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
12) Re: Ampabout
by Keith Richtman <[EMAIL PROTECTED]>
13) RE: EV1 vs Prizm...
by "Chris Tromley" <[EMAIL PROTECTED]>
14) Re: Sparrow handling
by "John G. Lussmyer" <[EMAIL PROTECTED]>
15) RE: EV1 vs Prizm...
by "Park, Youngchul" <[EMAIL PROTECTED]>
16) Re: DC to AC
by "Jon \"Sheer\" Pullen" <[EMAIL PROTECTED]>
17) RE: DC to AC
by "Andre Blanchard" <[EMAIL PROTECTED]>
18) Re: Amps and amp hours
by "Jon \"Sheer\" Pullen" <[EMAIL PROTECTED]>
19) Basic STAMP and PIC book recommendations?
by "Chuck Hursch" <[EMAIL PROTECTED]>
20) Re: Troubleshooting help needed!
by Peter VanDerWal <[EMAIL PROTECTED]>
21) Re: Lowest frequency (was Re: AC vs DC)
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Basic STAMP and PIC book recommendations?
by "John G. Lussmyer" <[EMAIL PROTECTED]>
23) Re: EV1 vs Prizm...
by Chris Zach <[EMAIL PROTECTED]>
24) Re: Crimp connectors
by "BORTEL" <[EMAIL PROTECTED]>
25) Li Ion Charge Curve
by "Chris Brune" <[EMAIL PROTECTED]>
26) Re: Need US 2200's
by [EMAIL PROTECTED]
--- Begin Message ---
Yes, thanks Lee.
After additional comments from my partner I realized what I
have known but failed to describe - as the rotor freq approach 0,
inverter freq once approached minimum, stay about the same just
slip allowed to increase, supporting about the same torque as
for normal operation. Carrier frequency derating (6kHz to 2 kHz)
with temp raising is taken care of by the software.
Concept is rather simple; the modeling hardware (motor and IGBTs
and implementing it in software, is complex and that's where
the value of the modern inverters is (and is proprietary valuable
info of manufacturer).
This is why [while silicon is cheap and getting cheaper]
high end inverters unlikely will get cheaper. Sophistication and
so the cost of the software allows them to reliably work in any
conditions and monitor hardware very well.
Victor
Lee Hart wrote:
>
> Lee Hart wrote:
> >> Under these conditions you have DC flowing in the motor windings.
>
> Victor Tikhonov wrote:
> > It's not DC, it's PWM pulses. Even though they're in one direction
> > (DC in that sense), the most powered phase gets continuously less than
> > 100% duty, perhaps at stall even less than 30%, so it won't overheat.
>
> Think a little more about it. The motor is stalled (brushless DC, or
> synchronous AC), or rotating slowly backwards (if an induction motor).
> The "correct" frequency to apply to the stator windings is 0 Hz. To get
> high torque, you need high current. Since voltage is roughly
> proportional to rpm, and rpm is zero, the applied voltage is nearly
> zero. So, the inverter must apply a high DC current at very low voltage.
>
> The inverter is really just six PWM controllers; each one works like the
> one PWM controller for driving a DC motor. To deliver high current at
> low voltage, it switches at a very low duty cycle. The transistor
> switches on; the current ramps up; the transistor switches off, the
> current ramps down. The motor winding's inductance acts as a filter to
> limit the rate of change in current.
>
> Suppose you want to apply 100amps at 3v to the winding with a 300v
> battery pack. That takes a 3v/300v = 1% duty cycle. You want to switch
> at 15 KHz, so it is inaudible. The on-time is thus 1% of 1/15KHz = 0.66
> microseconds. If you're using IGBTs, they can't turn on and off that
> fast; they spend the first 0.33us starting to turn on, and the last
> 0.33us turning back off. Your switching losses are huge, because it is
> in its linear region throughout this interval.
>
> If the motor winding isn't saturated, its inductance limits the rate of
> rise of current. For example, suppose the motor has 100uH of inductance.
> V = L x di/dt. We apply 300v for 0.66us; the current rise is di = V x dt
> / L = 300v x 0.66us / 100uH = 2 amps. So, to get 100a average, the
> current is really ramping up from 99a to 101a during the on-time, and
> ramping down from 101a to 99a during the off time. That's essentially
> DC.
>
> But, DC tends to saturate the iron. When this happens, the inductance
> fall drastically. Suppose it falls to 1uH. Now instead of 2a ripple, we
> have 200a of ripple! The current is rising from 0 to 200a during each
> on-time, and falling from 200a to 0 in each off-time. In effect, the
> inverter has lost control of the current. It can't produce a short
> enough on-time to limit current, at a time when its transistors are
> being hit with unusually high switching losses.
>
> > I can roll backwards with shaft speed -1 RPM all day long, the
> > inverter (just one phase's IGBT's really) will be cooler than at
> > high speed.
>
> I'll bet what the inverter software does is to deliberately raise the
> frequency and voltage, but reduce the stator current. The inverter
> transistors and stator windings now run cooler, but the motor is now
> running at high slip, and the rotor windings are getting hot.
>
> > The question was - to have smooth transition from neg to pos
> > freq it must be able to generate <1Hz freq, infinitely close to 0.
>
> No; remember that with an induction motor, there are MANY frequencies
> and voltages that will produce the same torque and rpm! One is the most
> efficient from the motor's perspective, but that may NOT be the most
> efficient from the inverter's perspective!
>
> > Yet the spec says 0.7 Hz min. Any clues?
>
> I think induction motor inverter designers try to avoid the 0 frequency
> (DC output) case. It is dangerous to the inverter and motor, and you
> don't need it to produce a smooth transition thru 0 rpm.
>
> Brushless DC and PM synchronous motor designers don't have this luxury
> -- they *must* generate 0 frequency to get torque at 0 rpm.
> --
> 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 ---
> I forget what the range of the Gen1 EV1s was when they were new. Could
> this be a case of 5-6 year old batteries wearing thin? There are also
> possible differences in how the respective cars' electronics decide what
> is the max DOD, basic lead/total weight ratios, etc. And your
> off-the-shelf Hawkers are really high quality batteries, probably just
> as good or better than the EV1's Panasonics.
That's true. And expensive as well.
> To really do an electric car right, you have to start from scratch and
> build it as electric. The EV1 got most everything right. If it had
> been designed around the same DC components most of us use it would have
> been a substantially better car than a typical conversion. The
> optimization was very well executed. My guess is that such a car would
> have ~95% of the original's range, much better than a conversion. But
> there was little magic in the drive system itself. Replacing it with
> one of Victor's Siemens systems or your Dolphin would probably bring it
> about even with the original's performance.
Perhaps, but my wonder is are the engineering expenses put forth in making
the EV1 20-30% better than the Prizm "worth" it? Especially when considering
that a better type of pack will totally blow away engineering improvements.
I'm curious now as to how much money GM/Geo/Toyota burned in modifying the
Prizms for electric. Not the cost of the drive system, but the
frame/research.
Chris
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] wrote:
>
> Steve,
>
> Also, Jeff Bradley drove his Sparrow several years ago at Woodburn, and did
> 1/4 mile in 14.932 seconds, top speed of 83.48 mph. That means he finished
> the 1/4 mile with the 8" ADC motor spinning at about 7400+ rpm.
>
> -Ed Thorpe
>
This is what a 8" will do with the brushes timed right and broken in.
Well kinda broken in, my levels of "brushes broken in" have increased
since then.
7400 is Way more that I would recomend for average Ev use. I have my Rev
limiter set to 5500 for Street and 6500 for race. My motor goes to sleep
at about 5000. I am sure the Sparrow motor is not pulling full amps at
7400 either. But... hey it lives through it.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
1sclunn wrote:
>
>
> Jon has been asking me this but I haven't given it a lot of though, I see
> crews all day building houses with gen's going ,next time I'm out cutting
> grass /tomorrow :-( I'll ask what would it be worth to have all the
> 120 ac you need on the job with know noise ..
> Steve Clunn
>
> ----- Original Message -----
I have a 2500 watt inverter, runs off of 12 volts. or a Good sized
Diesel truck starter battery.
It would do just fine. Take it home and plug it in for recharge or just
make sure you can crank the oil burner with what is left.
It costs about $2500, and a good 5Kw Gen set is about $1000, no battery,
no massive cables.
Any Highschool drop out can get a Genset running. A inverter in grunt
service may suffer from the dreded "reverse Polarity test"
It can be done , it's getting cheaper, but still is about 3x the cost
that a Job Crew needs to live with.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>
Well now it's been a while since I have had technical Issues with Lee,
but there are some with this post.
Lots of editing here,
> Lee Hart wrote:
> >> Under these conditions you have DC flowing in the motor windings.
With Dc in the windings you have a very good brake!! Try it some time.
12 volts across two phases of a 3 phase motor. It don't turn very good!!
>
> Victor Tikhonov wrote:
> > It's not DC, it's PWM pulses. Even though they're in one direction
> > (DC in that sense), the most powered phase gets continuously less than
> > 100% duty, perhaps at stall even less than 30%, so it won't overheat.
>
> Think a little more about it. The motor is stalled (brushless DC, or
> synchronous AC), or rotating slowly backwards (if an induction motor).
> The "correct" frequency to apply to the stator windings is 0 Hz. To get
> high torque, you need high current. Since voltage is roughly
> proportional to rpm, and rpm is zero, the applied voltage is nearly
> zero. So, the inverter must apply a high DC current at very low voltage.
This is self evident. But you still need the voltage to push the amps. A
240 volt motor seeing 100 amps is going to need Quite a bit of volts to
make this happen, Say 12to 24 volts. It's a e=IR problem.
>
> The inverter is really just six PWM controllers; each one works like the
> one PWM controller for driving a DC motor. To deliver high current at
> low voltage, it switches at a very low duty cycle. The transistor
> switches on; the current ramps up; the transistor switches off, the
> current ramps down. The motor winding's inductance acts as a filter to
> limit the rate of change in current.
Six switces yes, but the low side switches can be locked full on with NO
switching losses. Just conduction. You don't have to PWM Both sides of
the bridge. One is enough for current control. Of course the other
phases are off. And Yes you see some nice DC type wave forms, When read
on the motor leads. Just like a Dc Buck converter controller.
>
> Suppose you want to apply 100amps at 3v to the winding with a 300v
> battery pack. That takes a 3v/300v = 1% duty cycle. You want to switch
> at 15 KHz, so it is inaudible. The on-time is thus 1% of 1/15KHz = 0.66
> microseconds. If you're using IGBTs, they can't turn on and off that
> fast; they spend the first 0.33us starting to turn on, and the last
> 0.33us turning back off. Your switching losses are huge, because it is
> in its linear region throughout this interval.
This is where you are rather wrong. A power module now a days can be run
at 50 to 100Khz. Stay under 25Khz and the switching losses are minimal.
Stay over 20Khz since Sheer can hear it!!! I run the PFC modules at 20K,
and the PFC20 ThunderBolts at 40Khz. The switching losses go non linear
over about 55Khz. This is painful test data!
>
> If the motor winding isn't saturated, its inductance limits the rate of
> rise of current. For example, suppose the motor has 100uH of inductance.
> V = L x di/dt. We apply 300v for 0.66us; the current rise is di = V x dt
> / L = 300v x 0.66us / 100uH = 2 amps. So, to get 100a average, the
> current is really ramping up from 99a to 101a during the on-time, and
> ramping down from 101a to 99a during the off time. That's essentially
> DC.
Yup I concur.
>
> But, DC tends to saturate the iron. When this happens, the inductance
> fall drastically. Suppose it falls to 1uH. Now instead of 2a ripple, we
> have 200a of ripple! The current is rising from 0 to 200a during each
> on-time, and falling from 200a to 0 in each off-time. In effect, the
> inverter has lost control of the current. It can't produce a short
> enough on-time to limit current, at a time when its transistors are
> being hit with unusually high switching losses.
As you get to higher and higher amps the saturation effects "Drop off a
cliff" They get Very dangerous. We can see it at 80s amp and it gets to
be catastrophic at about 100 amps of inductor current. Same thing
happens in a Ac or DC drives. It's important to design you current limit
controls to be as fast as your load can saturate. In our world the Vsats
get hit, control loop is then reprogrammed so that we don't go there. In
the AC drive, your Vsats get hit, and the current control loop needs to
Wait a few cycles for the amps to come back into control. This is what
ate the T-REX 1200 controllers with 360 volt and stiff Inspiras, and
multiple motors. The current would wind up, then the motors would
saturate or arc dropping the effective inductance to just about nothing.
In the chargers If you run it up against the Vsats, you get a nasty
scream sizzle. At 12 Kw it scares the Crap out of ya!! The whole test
bench sounds like Hell has come for your Lunch. I don't like this test
point, but You have to know where it is to check that it is active and
healthy.
There is some thing that says a DC series wound will saturate a lot
slower than a AC drive. The line goes that the field and Armature fields
confine themselves. And saturation becomes a soft limit. BLDC is rather
abrupt, torrid inductors are abrupt also , but with a predictable roll
off. Induction, well it will saturate, but how fast I don't really have
data on.
Clearly a 100 amp charger needs a different inductor recipe. This is
not too hard to do.
A good Ac power stage can hold the curents in line, frequency shift if
nessasary, or just give up and flag a Error. But you have to remember
that a Stalled AC drive is no worse than a Stalled DC drive. The DC
locked rotor is definatley a more abusive event. Having your AC power
stage able to handle DC locked rotor conditions, ensures that the
nornmal AC issues can't hurt the switches. I test my AC stages by
running all 6 inverter states DC. I vary the PWM on the high side while
holding the low side at full on. Then adjust the Gate Vsats, to the peak
amps. This is with the AC motor in line, and air cooled. This is the
worse possible DC event on the power stage.
There are other AC control nightmares that are beyond this thread right
now.
>
> > I can roll backwards with shaft speed -1 RPM all day long, the
> > inverter (just one phase's IGBT's really) will be cooler than at
> > high speed.
>
> I'll bet what the inverter software does is to deliberately raise the
> frequency and voltage, but reduce the stator current. The inverter
> transistors and stator windings now run cooler, but the motor is now
> running at high slip, and the rotor windings are getting hot.
>
> > The question was - to have smooth transition from neg to pos
> > freq it must be able to generate <1Hz freq, infinitely close to 0.
>
> No; remember that with an induction motor, there are MANY frequencies
> and voltages that will produce the same torque and rpm! One is the most
> efficient from the motor's perspective, but that may NOT be the most
> efficient from the inverter's perspective!
>
> > Yet the spec says 0.7 Hz min. Any clues?
>
> I think induction motor inverter designers try to avoid the 0 frequency
> (DC output) case. It is dangerous to the inverter and motor, and you
> don't need it to produce a smooth transition thru 0 rpm.
Actually you do if you are doing AC servo or traction work. Fork trucks
need to go from full forward to full reverse all the time. Ac quality Ac
drive has this well written and enginered. I didn't get to this point.
>
> Brushless DC and PM synchronous motor designers don't have this luxury
> -- they *must* generate 0 frequency to get torque at 0 rpm.
Yea if you don't, you don't have much of a product!! You also need
encoders to do this on BLDC, but not really on induction, well that's
still being argued.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Christopher Zach writes:
>
> I'm curious now as to how much money GM/Geo/Toyota burned in modifying the
> Prizms for electric. Not the cost of the drive system, but the
> frame/research.
To my knowledge, they didn't spend a dime. The conversions were done
by US Electricar using stock vehicles.
Ralph
--- End Message ---
--- Begin Message ---
> To my knowledge, they didn't spend a dime. The conversions were done
> by US Electricar using stock vehicles.
Ok, someone must have. Not only researched it but crashed a bunch into walls
to recertify the modifications for a DOT sticker.
Chris
--- End Message ---
--- Begin Message ---
5.
ADDING FUEL CELLS TO THE FIRE
The Bush administration has been busily touting fuel-cell cars as a
critical component of its energy plan and the solution to many an
environmental woe. But what if the solution turns out to cause its
own problems? According to new research published in this week's
issue of Science, the technology used in hydrogen fuel cells could
contribute to the destruction of the ozone layer, which protects the
Earth from excessive doses of ultraviolet light. If fuel cells were
used to power everything from cars to utilities, the researchers
found, large amounts of hydrogen would drift into the stratosphere
and increase the depletion of the ozone layer. The technology could
be refined to mitigate the problem, but the scientists emphasized
that the likely impact on the ozone layer must be taken into account
when planning the shift to a hydrogen-based economy.
straight to the source: Boston Globe, Associated Press, H. Josef
Hebert, 13 Jun 2003
<http://www.gristmagazine.com/forward.pl?forward_id=1234>
only in Grist: Tough cell -- what can we learn from Bush's
FreedomCAR hydrogen plan? -- by Amanda Griscom in Powers That Be
<http://www.gristmagazine.com/powers/powers022603.asp?source=daily>
----------------------------------------------------
This mailbox protected from junk email by Matador
from MailFrontier, Inc. http://info.mailfrontier.com
--- End Message ---
--- Begin Message ---
Mark Dodrill wrote:
> .... Just to review I have a 1985 Nissan Pulsar
> 120v DC, 20 buddy-paired Optima YTs, Curtis 1231 controller,
> Sevcon Gen II DC/DC, and Link10 (Emeter).
>
> I charged it per normal last night, and was on my way up the
> hill by my house to take my son to school. It's a pretty
> steep hill, so I always take it in first gear, and go easy on
> it, never more than 15 mph or 120 or so amps. When I got to
> the top of the hill, I heard a slight click or thump (not
> very loud), and then I didn't have power anymore. Pressing
> on the gas resulted in the start of the whine noise that the
> Curtis always makes, but then no noise and no power. I tried
> it several more times with the same effect. Link10 reports
> correct voltage, so I know there is an electrical circut. I
> checked the batteries and none were disconnected or smelling
> or melted. I tried turning off and on the ignition several
> times, and turning off and on the main disconnect. Link10
> doesn't seem to show any amps flowing when I'm trying to go.
> I looked at the controller and it looks normal--all wires are
> connected, no burning or charing. The motor seemed to be
> connected just fine from what I could see of it. I even
> checked my contactor and it looks fine too.
Hi Mark,
I'm only venturing a guess here, but it might be a blown controller. A
Curtis 1231 is a bit marginal for a car that weighs a bit over 3000
lbs.(?) unless it's very well heatsinked. Especially with frequent
steep hill climbs. 500 motor amps isn't a lot, so you're probably at
its limit a lot. That "click or thump" might have been some silicon
going pop.
Try disconnecting your motor and doing the light bulb test. No light,
blown controller. If you do need a controller, take a look at KTA.
They still have some Raptors, which would be a much better controller
for your car. I think EVA also has some rebuilt Curtii.
Chris
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] wrote:
>> The speed sensing is based on a halls sensor on the motor shaft,
>> so it's based on the rear/power wheel.
John G. Lussmyer wrote:
> Depends on which variation you have. On older DCP equiped Sparrows,
> the speedometer sensor is a magnetic pickup off the right front
> brake disc.
Aha, this means there is a way to sense if the rear wheel is spinning.
Put *both* the rear wheel hall sensor, and front wheel speedometer
sensor on. Compare their speeds, and limit the controller or braking
accordingly.
> That's for sure. I'm tempted to look into 1 (or maybe 3) BMW
> Motorcycle ABS units.
How do they do ABS on a motorcycle?
--
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 ---
Sounds like the controller blew. Shouldn't have at that amp draw but it
sounds suspictious. Lawrence Rhodes....
never more than 15 mph or 120 or so
> amps. When I got to the top of the hill, I heard a slight click or thump
> (not very loud), and then I didn't have power anymore. Pressing on the
> gas resulted in the start of the whine noise that the Curtis always makes,
--- End Message ---
--- Begin Message ---
Bruce, the GEM cars were not designed to be CARB cars. They were
designed and built for years by Global Electric Motorcars before
DChrysler bought the company. The SOC meter is the same one used by
thousands of forklifts all over the world, it works fine, but it is
voltage based so it won't tell you anything under load.
Keith
At 12:55 PM -0700 6/13/03, Bruce EVangel Parmenter wrote:
<snip>
GEMs, like other cheap nEVs for cheap CARB credits, aren't
designed to last even with maintenance. The group 27
batteries they use have a two piece flat cell cover which
does not lend itself to easy watering of the cells. With a
cheap inaccurate SOC meter, the nEV newbie will run the
batteries flat and prematurely kill the pack. Then all of us
will hear their @#$%&ing about how bad EVs are.
--- End Message ---
--- Begin Message ---
Christopher Zach wrote:
> Perhaps, but my wonder is are the engineering expenses put
> forth in making the EV1 20-30% better than the Prizm "worth"
> it? Especially when considering that a better type of pack
> will totally blow away engineering improvements.
>
> I'm curious now as to how much money GM/Geo/Toyota burned in
> modifying the Prizms for electric. Not the cost of the drive
> system, but the frame/research.
Engineers in a wide variety of fields would kill for 20-30%
improvements. Sure it's worth it, when you consider a new car takes a
lot of upfront costs anyway, and the incremental cost for the EV1s
improvements weren't that big. Aero testing, sure. But reconfiguring
the chassis to hold batteries in the right place isn't that big a deal,
and any unusual construction features had been done on other vehicles
already. All the really new stuff they did could (and should) apply to
GM's other product lines.
EVs need high efficiency, so there was a valid incentive to maximize it.
Unfortunately, the automakers don't see much incentive in optimizing ICE
vehicles. What GM learned will be useful if/when someone puts an EV on
the market.
Most of us are used to conversions. Your Prizm is a big step up. You
should try renting an EV1 before they disappear to see how much better
it really is. I think you'll be impressed. As well as most of us do
with our conversions, it's just not the same as a purpose-built EV.
That's where the future is.
Chris
--- End Message ---
--- Begin Message ---
At 03:39 PM 6/13/2003 -0700, Lee Hart wrote:
> That's for sure. I'm tempted to look into 1 (or maybe 3) BMW
> Motorcycle ABS units.
How do they do ABS on a motorcycle?
I don't know, but my 85 K100 has front Antilock Brakes. You can feel (and
hear) it buzzing as you apply the front brakes.
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream.... http://www.CasaDelGato.com
--- End Message ---
--- Begin Message ---
50 mile range is with "defective" Delco batteries. With Panasonic
Lead Acid batteries, some people saw 110 mile range.
Young
-----Original Message-----
From: Christopher Zach [mailto:[EMAIL PROTECTED]
Sent: Friday, June 13, 2003 11:37 AM
To: [EMAIL PROTECTED]
Subject: EV1 vs Prizm...
I was looking at the EV1 owner's group and found something interesting.
One person was saying the range of his 97 EV1 on a Lead-Acid pack was only
in the 38-44 mile range between charges. Another was pulling a max of 50
miles with a SOC of under 10% at the end of the run.
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, June 13, 2003 10:21 AM
Subject: Re: DC to AC
> 1sclunn wrote:
> >
>
> >
> > Jon has been asking me this but I haven't given it a lot of though, I
see
> > crews all day building houses with gen's going ,next time I'm out
cutting
> > grass /tomorrow :-( I'll ask what would it be worth to have all
the
> > 120 ac you need on the job with know noise ..
> > Steve Clunn
> >
> > ----- Original Message -----
> I have a 2500 watt inverter, runs off of 12 volts. or a Good sized
> Diesel truck starter battery.
> It would do just fine. Take it home and plug it in for recharge or just
> make sure you can crank the oil burner with what is left.
>
> It costs about $2500, and a good 5Kw Gen set is about $1000, no battery,
> no massive cables.
> Any Highschool drop out can get a Genset running. A inverter in grunt
> service may suffer from the dreded "reverse Polarity test"
>
> It can be done , it's getting cheaper, but still is about 3x the cost
> that a Job Crew needs to live with.
I should mention that the $600 truck stop special 3kW inverters also work
just great. They aren't nearly as programmable as the one Rich has - they
can't be taught to, for example, match up with a power line - but they will
run everything from refrigerators to microwaves to skil saws to power
amplifiers (I've tried all of the above).
You do, however, need massive cables. They draw about 10X the current on
their 12V side that they'r eputting out on their 120V side (imagine that
;-)) so, if you're running a pair of 15A power amplifiers at your rave (or,
for you normal people, a pair of 10A lawnmowers), expect 300A battery
currents. Peukert can really eat into your running time here - I'd suggest
parallelling many, many 12V batteries if you want to try this.
One upside of the more expensive ones is they often use 48V as a battery
voltage instead of 12V, which lowers the operating current considerably.
Oh: one warning: Don't try and run them at their 'Peak' rating for very long
at all. While I've not personally seen this, I have a friend who blew up a
$600 special trying to use it for a minute at it's peak rating - and then
the mfgr refused to refund or repair because they claim the 'peak' rating is
only for motor-starting and that kind of thing, and running it for longer
than a few seconds at that rating voids the warentee.
Since I've never tried running more than one big motor off mine, I can't say
if you'd get into trouble running 2+ electric lawnmowers off of one. They're
supposed to have current limits, but I get the feeling they're often rather
shoddily built.
S.
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--- Begin Message ---
You also want to be careful about ground and neutral connections on the
cheap ones. The one I had did not have a neutral, there was about 60 volts
RMS between its ground and each side of the power outlet.
It died when I tried a temp connection to the house breaker panel, so I
could have a few lights while the power was out.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Jon "Sheer" Pullen
Sent: Friday, June 13, 2003 4:45 PM
To: [EMAIL PROTECTED]
Subject: Re: DC to AC
>> snip <<
Oh: one warning: Don't try and run them at their 'Peak' rating for very long
at all. While I've not personally seen this, I have a friend who blew up a
$600 special trying to use it for a minute at it's peak rating - and then
the mfgr refused to refund or repair because they claim the 'peak' rating is
only for motor-starting and that kind of thing, and running it for longer
than a few seconds at that rating voids the warentee.
Since I've never tried running more than one big motor off mine, I can't say
if you'd get into trouble running 2+ electric lawnmowers off of one. They're
supposed to have current limits, but I get the feeling they're often rather
shoddily built.
S.
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--- Begin Message ---
> Right now I am drawing 1 amp. If I continue this for 1 hour I will
> have drawn 1 amp-hour.
>
> If I draw 60 amps for 1 min, I will have drawn 1 amp-hour.
> (ignoring peukert).
>
> If I draw 3600 amps for 1 sec, there goes 1 amp-hour.
No, there go your battery terminals.
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--- Begin Message ---
Does anybody have any favorite texts for Basic STAMP or PIC
micros that they have found especially useful in helping them
design EV controllers (like battery management systems)? I'm
starting to get the urge to actually get into reading and playing
with these devices. My background is software engineering at the
workstation level (C, C++, Unix), so the low-level micros are
probably going to be a little different. Just want to get
started with books/info that are useful for this kind of project,
rather than being way off in left field.
Thanks,
Chuck Hursch
Larkspur, CA
NBEAA treasurer and webmaster
www.geocities.com/nbeaa
http://www.austinev.org/evalbum/339.html
www.geocities.com/chursch/bizcard.bmp
--- End Message ---
--- Begin Message ---
Did you check fuses/ckt breakers?
I'm with the others, sounds like a blown controller, but I'd want to
check and make sure there wasn't a blown fuse somewhere first.
P.S. as has been mentioned recently; going up a hill slowly might reduce
battery current, but it does NOT reduce motor loop current. As Otmar
said, going up the hill slowly is actually HARDER on the
controller/motor because you give them more time to heat up.
By all means shift down, but hit the hill going fast and go up as
quickly as possible (in 1st gear).
On Fri, 2003-06-13 at 13:02, Mark Dodrill wrote:
> Hello all. My electric Pulsar has been working well up until now, and I
> need some troubleshooting help with a problem it has. I think I know what
> is wrong, but I'd like to find out what you think. Just to review I have
> a 1985 Nissan Pulsar 120v DC, 20 buddy-paired Optima YTs, Curtis 1231 controller,
> Sevcon Gen II DC/DC, and Link10 (Emeter).
>
> I charged it per normal last night, and was on my way up the hill by my
> house to take my son to school. It's a pretty steep hill, so I always take
> it in first gear, and go easy on it, never more than 15 mph or 120 or so
> amps. When I got to the top of the hill, I heard a slight click or thump
> (not very loud), and then I didn't have power anymore. Pressing on the
> gas resulted in the start of the whine noise that the Curtis always makes,
> but then no noise and no power. I tried it several more times with the
> same effect. Link10 reports correct voltage, so I know there is an electrical
> circut. I checked the batteries and none were disconnected or smelling
> or melted. I tried turning off and on the ignition several times, and turning
> off and on the main disconnect. Link10 doesn't seem to show any amps flowing
> when I'm trying to go. I looked at the controller and it looks normal--all
> wires are connected, no burning or charing. The motor seemed to be connected
> just fine from what I could see of it. I even checked my contactor and
> it looks fine too.
>
> So, what is the problem? One of my buddy pairs needs to be replaced (which
> I was going to do today), but that's all that I know about that might be
> awry, and I don't see how this would effect it.
>
> Any ideas or thoughts would be greatly appreciated.
> Mark Dodrill
>
>
--
EVDL
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--- Begin Message ---
Lee Hart wrote:
>> Under these conditions you have DC flowing in the motor windings.
Rich Rudman wrote:
> With DC in the windings you have a very good brake! It don't turn
> very good!
Exactly! The situation being discussed was a synchronous AC or brushless
DC motor at stall (0 rpm), or an induction motor that is rotating
backwards when you want it to go forwards (for which 0 rpm would be the
"correct" way to produce torque in the opposite direction that it is
rotating, i.e. brake it).
> But you still need the voltage to push the amps. A 240 volt motor
> seeing 100 amps is going to need quite a bit of volts to make this
> happen, say 12 to 24 volts.
Check the DC resistance of a large AC motor. It is VERY low! It *has* to
be, or its efficiency would be terrible.
For example, I just measured a 15 HP 240vac 3-phase motor at 0.12 ohms
phase-phase. It would draw 100 amps at just 12vdc. And this is too small
a motor for a traction drive. Victor can probably tell you the DC
resistance of his Siemens traction motors, and I'll bet it is even lower
than this.
> Six switches yes, but the low side switches can be locked full
> on with NO switching losses. Just conduction. You don't have to
> PWM both sides of the bridge. One is enough for current control.
True, but the ones that *are* switching are having the problem I
mentioned; not enough time to fully switch on/off due to the extremely
low duty cycle, and thus very high switching losses.
>> Suppose you want to apply 100amps at 3v to the winding with a
>> 300v battery pack. That takes a 3v/300v = 1% duty cycle. You want
>> to switch at 15 KHz, so it is inaudible. The on-time is thus 1%
>> of 1/15KHz = 0.66 microseconds. If you're using IGBTs, they can't
>> turn on and off that fast.
> This is where you are rather wrong. A power module now a days can
> be run at 50 to 100Khz.
This was just an example.
Sure, MOSFETs can run faster; but who is using MOSFETs in an AC drive?
Just about all of them use IGBTs. Give me the specs for a real IGBT
module used in a real AC induction motor drive. Look at its turn-on,
turn-off, and storage times.
--
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 ---
At 12:55 PM 6/13/2003 -0700, Chuck Hursch wrote:
Does anybody have any favorite texts for Basic STAMP or PIC
micros that they have found especially useful in helping them
design EV controllers (like battery management systems)? I'm
Not really books, but I did find a lot of good info about the Atmel AVR
micro-controllers at the AVRFreaks.Net site.
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream.... http://www.CasaDelGato.com
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--- Begin Message ---
Engineers in a wide variety of fields would kill for 20-30%
improvements. Sure it's worth it, when you consider a new car takes a
lot of upfront costs anyway, and the incremental cost for the EV1s
improvements weren't that big. Aero testing, sure. But reconfiguring
the chassis to hold batteries in the right place isn't that big a deal,
and any unusual construction features had been done on other vehicles
already. All the really new stuff they did could (and should) apply to
GM's other product lines.
Hm. So their "it cost us a billion to develop it" line really doesn't
hold water.
EVs need high efficiency, so there was a valid incentive to maximize it.
Unfortunately, the automakers don't see much incentive in optimizing ICE
vehicles. What GM learned will be useful if/when someone puts an EV on
the market.
True they do need good efficiency; however what they wound up with was a
very expensive shell coupled to a two-seater which was not going to be
much of a family type of car.
Maybe my thought here is that a manufacturer (say... Toyota) should take
something that they have now (say an Echo/Prius) and implement an AC
motor solution that goes in place of the ICE. Same mounts/instruments.
The only trick of course is where to put the batteries...
Most of us are used to conversions. Your Prizm is a big step up. You
should try renting an EV1 before they disappear to see how much better
it really is. I think you'll be impressed. As well as most of us do
with our conversions, it's just not the same as a purpose-built EV.
That's where the future is.
When do the EV1's go away if I might ask? Does anyone in the LA basin
rent them now? Any on the East coast?
Fly out to LAX to try out a EV1, then fly out to NYC to ride on the
Concorde. Both beautiful technologies that are to vanish beneath the
waves...
Chris
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John,
The cheapest place to get larger size crimp connectors is on eBay. I buy a
lot of connectors there and always am able to get them for less than half of
retail. The other great thing is UPS will deliver them, so you don't need to
live in town.
Dan
----- Original Message -----
From: "John G. Lussmyer" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, June 12, 2003 9:50 PM
Subject: Re: Crimp connectors
> At 08:12 PM 6/12/2003 -0700, Lee Hart wrote:
> >Are you sure? Even my local Ace Hardware and Autozone stores carry them.
> >The selection is limited, though.
>
> 8 miles to the ACE, smallish store, few terminals.
> Rat Shack parts/hobbiest corner isn't much bigger than a closet, even
> fewer...
> I'll probably have to go to the mainland to find something. (Or maybe at
> NAPA 30 miles north of me.)
>
> >All the major electronics distributors carry them; Digikey, Mouser, etc.
> >For my temperature sensors I'm using terminals I got from Waytek
> >(www.waytekwire.com, 800-328-2724). They are tinned copper "standard
> >eyelet" terminals, 5/16" bolt hole, #6 wire, #36472, $0.27 each.
>
> Thanks, I may try those.
>
> --
> John G. Lussmyer mailto:[EMAIL PROTECTED]
> Dragons soar and Tigers prowl while I dream.... http://www.CasaDelGato.com
>
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I have sent another curve to Gary Graunke for him to post on his web site.
This time I decided to do things a bit differently. I wanted to charge the
4 cells in series like they would be installed in a normal vehicle. I also
reduced the current to better simulate the charge current that these
batteries are likely to see.
Charge profile was constant current @ 12A to start, and then constant
voltage of 17.1V till the current droped to 1A.
The cells were not fully discharged when this cycle was started. Charge
time was about 9 hours.
Very interesting to note how balanced the cells were at the end of charge.
Cell voltage were 4.270, 4.282, 4.278, and 4.282. The low cell was Cell 90,
which if this were my pack would probably be removed from service (at least
from the data I have to this point). Even so, the cell voltages are very
close at end of charge. And NO cell equalization was done.
I hope the self-balancing trend continues. Would be nice to not have to
worry about balancing.
Chris Brune
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--- Begin Message ---
Thanks,
But I managed to get 12 US battery 145's (much better than the 2200) delivered
to my door for less than the "generic" golf cart bats at the store!!
Thanks to all who helped me arrange this.
James
Quoting Bruce EVangel Parmenter <[EMAIL PROTECTED]>:
>
> I see your domain is charlotte.nc.us
> so your USbattery dealer is:
>
> Classic Auto Supply
> 200 West 24th. St.
> Charlotte NC 28206
> (704) 331-0695
> Fax (704) 250-3596
>
> According to the http://usbattery.com site, US2200
> specs are:
>
> 115 [EMAIL PROTECTED] L: 10-1/4", W: 7-1/8", H: 11-1/8", 63lbs
>
> Lee is right that a trainer pack would get you by.
> A typical 'golf cart' battery from a non-
> USbattery or Trojan manufacturer is a 105 to 108
> (Minutes @ 75 Amp) battery, and what you wanted
> was a US2200 which is a 115 (Minutes @ 75 Amp).
>
> So, you will get ~10% less range using a
> generic 'golf cart' battery. Make sure the
> battery's POSTs fit your cables.
>
> So if you can get a battery that fits, connects,
> and the price is right, then its a plan.
>
> P.S. -If it were my EV, and I had as good a
> USbattery dealer as I have here, I would move
> up to US-125s. A little electrolyte starved, but
> the best range bang for the buck in your size.
>
>
> : sent via Redhat9 Linux:
>
>
> =====
> ' ____
> ~/__|o\__
> '@----- @'---(=
> . http://geocities.com/brucedp/
> . EV List Editor & RE newswires
> . (originator of the above ASCII art)
> =====
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
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>
>
--- End Message ---
