EV Digest 6805
Topics covered in this issue include:
1) RE: Watt-hour semantics question
by Tom Gocze <[EMAIL PROTECTED]>
2) Watt hours per mile
by JS <[EMAIL PROTECTED]>
3) Re: Triangle wave generator
by Danny Miller <[EMAIL PROTECTED]>
4) Re: PIR June 29-30 EV drag racing?
by Jim Husted <[EMAIL PROTECTED]>
5) RE: Watt-hour semantics question
by "Roger Stockton" <[EMAIL PROTECTED]>
6) Re: Triangle wave generator
by Danny Miller <[EMAIL PROTECTED]>
7) Zilla cooling
by Dave Cover <[EMAIL PROTECTED]>
8) Re: Please help, Aircraft Generator starting torque issue.
by Michael Barkley <[EMAIL PROTECTED]>
9) Re: Triangle wave generator
by Lee Hart <[EMAIL PROTECTED]>
10) Best paint for Battery racks
by Chip Gribben <[EMAIL PROTECTED]>
11) sombody to do conversion in Houston, TX.
by <[EMAIL PROTECTED]>
12) Re: Please help, Aircraft Generator starting torque issue.
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
13) Re: 15k DIY Porsche. 20k Installed.
by "Ted C." <[EMAIL PROTECTED]>
14) Re: 10,0000 cycles (was: Battery chart for a hand-out...)
by Bill Dube <[EMAIL PROTECTED]>
15) Re: Triangle wave generator
by Lee Hart <[EMAIL PROTECTED]>
16) Re: Best paint for Battery racks
by Lee Hart <[EMAIL PROTECTED]>
17) Re: Using Audio Capacitors for Dragsters
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Hi Roger,
Thanks for the answer, but I guess I am wondering which number are we
considering when we talk about an "average" vehicle running
300 or whatever wh/mile. That seems low if you are considering the AC
input energy, but typical for the reading off an E meter.
Tom
--- End Message ---
--- Begin Message ---
My car is a 1981 Jet Electrica - Ford Escort.
Controller is Curtis 1231C. DC/DC Curtis 1400E.
Charger is ZIVAN NG3 240 volt AC.
16 T105 batteries - 10 months old - 3650 miles. Watered twice. Weakest
cell S.G. shows ~ 70% SOC after 16 miles. 100 volts after 5 minutes rest.
Watt-hour meter Westinghouse type CA probably from the 1930's or 40's on
solar power.
240 volt 15 amp 60 Hz calibrated with 2 100 watt light bulbs for 10 hours.
The usual car trip is 16 miles morning, then fully charged, 16 miles in
the afternoon and again fully charged.
Normal city traffic, going with the flow. Battery Amps usually between
50 - 200 Amps. Longest trip without charging = 39 miles.
Mostly below 40 miles per hour. Driver plus 1 adult passenger and a 6
year old granddaughter.
Never driven in the rain or after dark. Elevation change - gradual,
about 1000 feet.
Battery temperatures varied between 60 and 105 Fahrenheit. (No heat or A/C).
Total miles since watt hour meter installed = 1362
Total kWh = 370
Or 3.68 miles per kWh
270 watt hours per mile. This seems low as it includes charging losses.
Estimated speedometer error 2%
Estimated watthour meter error 5%
Estimated thinking error 100%
John in Sylmar, CA
--- End Message ---
--- Begin Message ---
Watchdog timers are a hardware feature to defend against things like
code bugs or state errors due to electrical surges or dropouts, or even
crystal/oscillator failure. The timer runs independently from the core
and if the code doesn't send a "clear" command by the expected interval,
the processor will reset itself entirely.
This is different that latch-up though. Latch-up is an electrical
failure, usually from applying too much voltage to the Vdd rail.
Returning the voltage to normal does not made the condition go away (it
latches), only removing power will fix it. The Watchdog timer cannot
resolve the situation, nor can any other hardware or software feature.
Fortunately, latchup is hardly a "normal" problem in a properly designed
circuit.
The MOSFET driver chip is a good idea. The one thing to note is this is
a somewhat "extreme" situation, usually not driving one or two MOSFETs
but many. The total gate capacitance is quite high. Not all "off the
shelf" MOSFET drivers will do an acceptable job. You can always design
your own driver with discrete components. An expert could probably do a
better job that the off-the-shelf driver chip, but it requires special
education and experience to do that.
Danny
(-Phil-) wrote:
Most microcontrollers have watchdogs. Lockups just don't happen
unless you subject them to electrically hostile environments.
(provided you don't have buggy software, that is!)
Best advice is to use an off-the-shelf MOSFET driver chip. Many of
them do all the dirty work for you, and if you are building a
T-Bridge, then they have protection from accidental shoot-through, and
the needed dead-band gap.
--- End Message ---
--- Begin Message ---
Hey Chuck
White Zombies motors are actually sitting at the shop
right now under a morge sheet. John and Tim gave the
back half a good fry earlier this year so she's down
for repair. I wasn't able to pop it apart today but
the back armature looks really pissed so they got it
good.
While it's down we're gonna upgrade it with some added
changes. At this point I'm thinking I'm gonna be
popping the Ka-Bobs off that shaft and replacing the
rear one. In as much as it sucks I'll be able to
glean some data as to how everythings been holding up,
like the middle bearing etc.
I'd like to send this out to the paint shop and have
them airbrush some cool peeled paint revealing a
Zombie textured motor or something. What you say John
you up for a little artisic touch on this build Mr.
magizine?
Anyway at this point all I can say is I'll get it back
to John as fast as I can. The biggest plus is I got
the shaft 8^o so now it's a bit of how much more does
Wayland want to change.
Anyway Chuck, sorry to be the one to tell you but
those evil bastards killed my motor 8..^(
Good thing it's a Zombie though cause they just keep
rising from the dead 8^) hehe.
Had fun
I'll keep you all posted.
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________Pinpoint
customers who are looking for what you sell.
http://searchmarketing.yahoo.com/
--- End Message ---
--- Begin Message ---
Tom Gocze wrote:
> Thanks for the answer, but I guess I am wondering which
> number are we considering when we talk about an "average"
> vehicle running 300 or whatever wh/mile. That seems low
> if you are considering the AC input energy, but typical
> for the reading off an E meter.
I think 90%+ of the time we are talking of battery Wh/mi on an E-Meter,
perhaps 5% of the time it is Wh/mi at the battery pulled out of the air
with a bit of wishful thinking and knowledge of the typical discharge
current and nominal pack voltage (i.e. conversions with nothing but an
ammeter and voltmeter for instrumentation), and perhaps the other 5% is
people with some form of AC meter (but perhaps no E-meter).
The Wh/mi from the battery is of greater interest on this list, I
believe, since we are generally concerned with how well/poorly our
vehicle is performing, and/or figuring out how much battery capacity is
required for a particular range.
The Wh/mi from the AC outlet is only really of value for comparing per
mile operating costs with ICE vehicles, so its value is of less
practical interest.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Yes, the power stage includes that- and the power transistors
themselves, of course.
A driver is necessary for several reasons. The 5V/0V from a PIC is not
high enough to fully turn on a MOSFET gate. 7v-10v or so is much better.
Second, the PIC output pin cannot put out enough current to turn on
large MOSFETs quickly, the gate has too much capacitance. Higher
transition times result in much greater heat in the transistors (heat
originating from this cause is called "switching losses").
Third, to do the best job, some tuning the to driver's waveform is
sometimes needed to minimize switching losses. The sharpest square wave
from low-to-high may not be the best choice. Perfecting this requires
some detailed knowledge of transistors and usually we model the
transistor and driver in SPICE and observe the predicted behavior, saves
a lot over trial-and-error tweaking especially when you need to test a
circuit running on hundreds of amps.
Danny
tt2tjw wrote:
Danny,
by power stage do you mean busbars , cooling, mountings ?
by driver do you mean the IGBT driver? If a driver board such as BG2A
from powerex is used does that solve the "driver" problem or is the
"driver" problem more than just this?
Tom Ward
Danny Miller wrote:
You can design a lot of great features into a uC-driven motor
controller too. It's simple and easy to make them effective.
Still, a reminder- additional features are of limited use. The
primary problem is still the power stage and its driver. Having a
PWM generator 10x more advanced than an analog one won't do much to
reduce the problem. Well, advanced thermal shutdown procedures,
testing the ON-state voltage drop, and overcurrent detection can
reduce the demands on the transistors, but generally not a remarkably
high reduction, if any.
Danny
tt2tjw wrote:
Danny Miller wrote:
> It is far easier to design a system- and do it right- with a uC.
That was the impression I came to after reading many application
notes and reference designs (from IR, POWEREX, SEMIKRON, FAIRCHILD
etc) for intelligent IGBT modules, and IGBT drivers, they all seem
to be designed around a microcontroller.
Chet Fields wrote:
> it may not be a good idea as it may lock up and cause the MOSFETs
to be stuck on
the IGBT drivers I have looked at have integrated protection to deal
with this situation, I was assuming that in a mass produced driver
this function would be implemented correctly and reliably.
Danny Miller wrote:
That's pretty close to nonsense. IIRC the person claiming this has
no experience with microcontrollers.
A uC is a fine way to generate a PWM signal. It is far easier to
design a system- and do it right- with a uC. There's an awful lot
to designing an analog controller. The analog controller has a lot
more that can go wrong with it. You need a lot of inside
information on how each type of component may fail to start to work
the problems out.
It's important to understand however that being able to generate a
PWM is only a small part of the design problem for an EV
controller. The output transistors are large and expensive to
obtain and very tricky to mount where you can meet their extreme
thermal, mechanical, and electrical needs. The transistor driver,
where we take 0 to 5v or whatever PWM and turn it into a transistor
drive with the appropriate voltage level and best waveform shape is
tricky too.
Danny
Chet Fields wrote:
I had thought first of using a microcontroller, but then good
advice from the list suggested that
it may not be a good idea as it may lock up and cause the MOSFETs
to be stuck on. I don't really
know of a good way to protect from that happening except for maybe
some fuses or something.
I did think that a microcontroller like a PIC would give me alot
of flexibility though. I am a
programmer professionally so I would definitely be more in my
element instead of designing these
discrete analog circuits, although I have to admit it has been and
still looks like a lot of fun
if I can get it working.
I thought of starting with the analog and then moving later
(perhaps) into the PIC if I can come
up with the proper scheme to protect against a dangerous situation
with a lock up.
Chet
--- tt2tjw <[EMAIL PROTECTED]> wrote:
Chet,
is there any reason not to use a microcontroller with PWM outputs?
Chet Fields wrote:
I am trying to generate the triangle wave for the PWM circuit
and I am using the good ol' 741
Op
____________________________________________________________________________________
Looking for earth-friendly autos? Browse Top Cars by "Green
Rating" at Yahoo! Autos' Green Center.
http://autos.yahoo.com/green_center/
--- End Message ---
--- Begin Message ---
I just wanted to pass along some info on how I addressed the cooling for my
Z1k. In searching for
pumps I kept coming across parts used for cooling PCs, overclocking supplies. I
finally found a
nice kit by Thermaltake, the AquaBay M5. I picked it up on eBay for less than
$69 delivered.
It includes a quiet brushless pump, a medium/small reservoir and an inline
temps sensor with a
display. The pump flows 500 l/h. The fittings are very good quality chrome in
both 1/2" and 3/8".
The 1/2" work perfect with the fittings Otmar supplies. I have it set up to
monitor the coolant
temp immediately after the Zilla. You can set an alarm in the temp sensor if it
get's too hot. The
reservoir even has a level indicator that will warn you if you are running out
of coolant.
It looks good and works good so far. Time will tell if it can hold up in the
car. I'll try and
post my experiences over time, good and bad.
Dave Cover
--- End Message ---
--- Begin Message ---
I ran a wire from a 36 volt tap from my main battery
bank to the smaller field (A) Terminal, that had been
originally tied to the 72vdc main armature
(B)terminal. The motor ran, but backwards? I was
afraid to put a ground on the other smaller (D)
terminal, not knowing where it's connected in the
motor/generator.
Should I just get another 36volt battery bank, and
wire it to the small terminals A & D?
Do all controllers pulse the negative side of the
battery bank to the motor? Is this why when I tapped
off with 36 volts from the main battery bank, the
motor ran backwards for some reason? You can see the
terminals referenced mentioned above with the wiring
diagrams at the website: www.texomaev.com , under the
"94' Mitsubishi Conversion Project" link.
--- "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
wrote:
> HI- I don't recognize the # J-29, but if it is like
> the G-29 and the G-32
> it will have 2 large terminals (about 3/8" ) and on
> a raised block on the
> side
> two more smaller ones (about 3/16"). If so the
> Alltrax controller will not
> work
> by it's self. The small terminals require between
> 24-36 volts independent of
> the Altrax. for a quick test tap 36v off the main
> pack (10 gage wire),
> through
> a contactor opperated by the key switch, to the
> small terminals. Connect the
> Altrax to the large terminals. This way the small
> gage field coils will be
> energised
> before the throttle pedal is depressed. They should
> not see more than 36
> volts or
> less than24volts.
> If this field is not enegerised, the Altrax will go
> immediately into
> current overload.
> This system should be used only as a test, as long
> term use will unbalance
> the
> battery pack.
> Rember to check rotation, reversing the leads on the
> small feild will
> reverse rotation.
> Father Time
>
>
> > [Original Message]
> > From: Michael Barkley <[EMAIL PROTECTED]>
> > To: <ev@listproc.sjsu.edu>
> > Date: 5/21/2007 4:53:34 PM
> > Subject: Re: Please help, Aircraft Generator
> starting torque issue.
> >
> > Phil, thanks for your support in this matter - I
> have
> > produced controller data for Alltrax by attempting
> to
> > drive up on auto service ramps and logging the
> data.
> >
> > Alltrax came back, telling me that the controller
> was
> > immediately going into current limit. If anyone
> wants
> > that data, I'd be happy to send it to them. I
> believe
> > it was pulling 400+ amps at the motor, and the
> 72vdc
> > pack voltage was sagging down to around 66vdc. As
> > long as I stop on level grade, the car takes off
> fine,
> > and will climb inclined grades.
> >
> > Alltrax, hasn't offered a resolution, I asked
> about a
> > controller bypass, (at say 24vdc) at least for the
> > initial boost to get the car rolling, and then
> switch
> > back to the controller, but haven't heard anything
> > from them on that idea. Some of the seasoned
> EV'rs
> > might know of a way to make something like that
> work.
> >
> >
> >
> >
> > --- "(-Phil-)" <[EMAIL PROTECTED]> wrote:
> >
> > > I for one think this kind of discussion is
> > > interesting and definitely
> > > on-topic. Having this kind of thing discussed
> and
> > > in the archives will help
> > > people in the future!
> > >
> > > Do you have any volt/amp readings from your
> setup?
> > > When you are trying to
> > > go up the incline it would be very informative
> to
> > > read the controller
> > > amps/volts. On the alltrax I believe all you
> need
> > > is a laptop and a serial
> > > cable (plus their software, which you can
> download)
> > >
> > > -Phil
> > > ----- Original Message -----
> > > From: "Michael Barkley" <[EMAIL PROTECTED]>
> > > To: "EVDL.ORG EVDL.org" <ev@listproc.sjsu.edu>
> > > Sent: Monday, May 21, 2007 1:17 PM
> > > Subject: Please help, Aircraft Generator
> starting
> > > torque issue.
> > >
> > >
> > > > Please, if anyone can help me with a solution,
> to
> > > my
> > > > torque problem from a deadstop, I sure would
> like
> > > to,
> > > > off list talk with you. I don't want to
> bother
> > > the
> > > > list with an ongoing discussion, as I know
> using
> > > an
> > > > aircraft generator as a motor, isn't the
> smartest
> > > way
> > > > to go (Dang you "MotherEarthFarce" for hooking
> me
> > > with
> > > > that 75mpg article) before I found this EV'r
> list.
> > > >
> > > > That disclaimer aside, here's my problem, I
> think:
> > > > I'm using an Aircraft Generator J29 to be
> exact,
> > > it's
> > > > not a combo, starter/generator and therefore
> it
> > > seems
> > > > to be lacking in starting torque as a motor.
> > > >
> > > > Is there anyway to salvage my EV and still use
> > > this
> > > > motor somehow? It has plenty of pep and speed
> > > once it
> > > > gets going, but the EV will not go if it's on
> an
> > > > incline using an AXE 7245 controller @ 72vdc.
> I
> > > just
> > > > purchased brand new batteries, and although
> it's
> > > > better, the car will not overcome an incline
> from
> > > a
> > > > deadstop.
> > > >
> > > > Please, if you have any ideas - send them to
> me
> > > off
> > > > list, as I don't want to fill up email boxes
> of
> > > the
> > > > others that aren't interested in this issue.
> > > >
> > > > Thanks in advance - Mike
> > > >
> > > > Michael Barkley
> > > >
> > > > www.texomaev.com
> > > >
> > > >
> > >
> > >
> >
> >
> > Michael Barkley
> >
> > www.texomaev.com
> >
>
>
>
--- End Message ---
--- Begin Message ---
Chet Fields wrote:
[a micro] may not be a good idea as it may lock up and cause the
MOSFETs to be stuck...
Danny Miller wrote:
It is far easier to design a system- and do it right- with a uC.
This is one of those questions where the best answer depends on your
skill level.
If you happen to be a skilled programmer and an expert in microcomputer
based design, then this is the best approach (for you).
If you happen to be a skilled analog design engineer and an expert with
opamps, then that's the best approach (for you).
Heck, if you are skilled with vacuum tubes and have a bunch of them
lying around, even they would be a satisfactory approach.
You can build a great design with *any* of these technologies. Or, if
you don't know what you're doing, you can build a lousy design with any
of them, too!
My usual concern with microcomputers is that it's so easy to build
really flaky designs with them. Do a shoddy job designing the hardware,
and it crashes from static electricity or noise. Do a shoddy job on the
software, and it's buggy and crashes.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
I had my battery racks powder coated. That was like 8 years ago and
they still look good. No peeling paint or corrosion.
Powder coating can take all kinds of abuse.
Chip
On May 22, 2007, at 4:39 PM, Electric Vehicle Discussion List wrote:
From: Joe Buford <[EMAIL PROTECTED]>
Date: May 22, 2007 2:01:03 PM EDT
To: ev@listproc.sjsu.edu
Subject: Best paint for Battery racks
What would be the best paint to paint the battery
racks after cleaning and striping them?
Thanks
Joe
--- End Message ---
--- Begin Message ---
I got a call from Dominick Hawkins and he is looking for sombody to do or help
with a conversion . He is in Houston, TX. And would greatly appreciate any
assistance in finding someone who could help him there . Contact him directly
Dominick Hawkins (713) 480-1648 or e mail him at
[EMAIL PROTECTED]
P. O. Box 2601 Houston, TX.
77252-2601, Thanx again
Steve Clunn
--- End Message ---
--- Begin Message ---
HI-
You need to make sure that the shunt field is disconnected from the series
field
With your motor wired the way I believe it is, you should have continuity
between
at least one small terminal and one large terminal. If so, remove the brush
cover
and disconnect the small wire I mentioned in the prevous post,and tape it
off
back out of the way. You should no longer have continuity between the small
and
large terminals.You should now be able to apply 36 volts to the small
terminals.
If needed the rotation can be reversed by switching the small leads.
> [Original Message]
> From: Michael Barkley <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Date: 5/22/2007 7:16:09 PM
> Subject: Re: Please help, Aircraft Generator starting torque issue.
>
> I ran a wire from a 36 volt tap from my main battery
> bank to the smaller field (A) Terminal, that had been
> originally tied to the 72vdc main armature
> (B)terminal. The motor ran, but backwards? I was
> afraid to put a ground on the other smaller (D)
> terminal, not knowing where it's connected in the
> motor/generator.
>
> Should I just get another 36volt battery bank, and
> wire it to the small terminals A & D?
>
> Do all controllers pulse the negative side of the
> battery bank to the motor? Is this why when I tapped
> off with 36 volts from the main battery bank, the
> motor ran backwards for some reason? You can see the
> terminals referenced mentioned above with the wiring
> diagrams at the website: www.texomaev.com , under the
> "94' Mitsubishi Conversion Project" link.
>
>
> --- "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> wrote:
>
> > HI- I don't recognize the # J-29, but if it is like
> > the G-29 and the G-32
> > it will have 2 large terminals (about 3/8" ) and on
> > a raised block on the
> > side
> > two more smaller ones (about 3/16"). If so the
> > Alltrax controller will not
> > work
> > by it's self. The small terminals require between
> > 24-36 volts independent of
> > the Altrax. for a quick test tap 36v off the main
> > pack (10 gage wire),
> > through
> > a contactor opperated by the key switch, to the
> > small terminals. Connect the
> > Altrax to the large terminals. This way the small
> > gage field coils will be
> > energised
> > before the throttle pedal is depressed. They should
> > not see more than 36
> > volts or
> > less than24volts.
> > If this field is not enegerised, the Altrax will go
> > immediately into
> > current overload.
> > This system should be used only as a test, as long
> > term use will unbalance
> > the
> > battery pack.
> > Rember to check rotation, reversing the leads on the
> > small feild will
> > reverse rotation.
> > Father Time
> >
> >
> > > [Original Message]
> > > From: Michael Barkley <[EMAIL PROTECTED]>
> > > To: <ev@listproc.sjsu.edu>
> > > Date: 5/21/2007 4:53:34 PM
> > > Subject: Re: Please help, Aircraft Generator
> > starting torque issue.
> > >
> > > Phil, thanks for your support in this matter - I
> > have
> > > produced controller data for Alltrax by attempting
> > to
> > > drive up on auto service ramps and logging the
> > data.
> > >
> > > Alltrax came back, telling me that the controller
> > was
> > > immediately going into current limit. If anyone
> > wants
> > > that data, I'd be happy to send it to them. I
> > believe
> > > it was pulling 400+ amps at the motor, and the
> > 72vdc
> > > pack voltage was sagging down to around 66vdc. As
> > > long as I stop on level grade, the car takes off
> > fine,
> > > and will climb inclined grades.
> > >
> > > Alltrax, hasn't offered a resolution, I asked
> > about a
> > > controller bypass, (at say 24vdc) at least for the
> > > initial boost to get the car rolling, and then
> > switch
> > > back to the controller, but haven't heard anything
> > > from them on that idea. Some of the seasoned
> > EV'rs
> > > might know of a way to make something like that
> > work.
> > >
> > >
> > >
> > >
> > > --- "(-Phil-)" <[EMAIL PROTECTED]> wrote:
> > >
> > > > I for one think this kind of discussion is
> > > > interesting and definitely
> > > > on-topic. Having this kind of thing discussed
> > and
> > > > in the archives will help
> > > > people in the future!
> > > >
> > > > Do you have any volt/amp readings from your
> > setup?
> > > > When you are trying to
> > > > go up the incline it would be very informative
> > to
> > > > read the controller
> > > > amps/volts. On the alltrax I believe all you
> > need
> > > > is a laptop and a serial
> > > > cable (plus their software, which you can
> > download)
> > > >
> > > > -Phil
> > > > ----- Original Message -----
> > > > From: "Michael Barkley" <[EMAIL PROTECTED]>
> > > > To: "EVDL.ORG EVDL.org" <ev@listproc.sjsu.edu>
> > > > Sent: Monday, May 21, 2007 1:17 PM
> > > > Subject: Please help, Aircraft Generator
> > starting
> > > > torque issue.
> > > >
> > > >
> > > > > Please, if anyone can help me with a solution,
> > to
> > > > my
> > > > > torque problem from a deadstop, I sure would
> > like
> > > > to,
> > > > > off list talk with you. I don't want to
> > bother
> > > > the
> > > > > list with an ongoing discussion, as I know
> > using
> > > > an
> > > > > aircraft generator as a motor, isn't the
> > smartest
> > > > way
> > > > > to go (Dang you "MotherEarthFarce" for hooking
> > me
> > > > with
> > > > > that 75mpg article) before I found this EV'r
> > list.
> > > > >
> > > > > That disclaimer aside, here's my problem, I
> > think:
> > > > > I'm using an Aircraft Generator J29 to be
> > exact,
> > > > it's
> > > > > not a combo, starter/generator and therefore
> > it
> > > > seems
> > > > > to be lacking in starting torque as a motor.
> > > > >
> > > > > Is there anyway to salvage my EV and still use
> > > > this
> > > > > motor somehow? It has plenty of pep and speed
> > > > once it
> > > > > gets going, but the EV will not go if it's on
> > an
> > > > > incline using an AXE 7245 controller @ 72vdc.
> > I
> > > > just
> > > > > purchased brand new batteries, and although
> > it's
> > > > > better, the car will not overcome an incline
> > from
> > > > a
> > > > > deadstop.
> > > > >
> > > > > Please, if you have any ideas - send them to
> > me
> > > > off
> > > > > list, as I don't want to fill up email boxes
> > of
> > > > the
> > > > > others that aren't interested in this issue.
> > > > >
> > > > > Thanks in advance - Mike
> > > > >
> > > > > Michael Barkley
> > > > >
> > > > > www.texomaev.com
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> > > Michael Barkley
> > >
> > > www.texomaev.com
> > >
> >
> >
> >
>
--- End Message ---
--- Begin Message ---
I would have to agree that 150 mile range is a little bit optimistic. I do
own a 914 and use it daily for around town errands. I keep the range of my
trips under 20 miles total. But I don't use the best batteries for EV
driving. I do have the rear truck completely useable. Just tonight my wife
and I did our grocery shopping. You get about six full bags in the back
trunk. I agree that without the trunk space the car would be good for just a
work commuter car and not much else. For me my car is great for the around
town trips that I am always doing so the range is not much of an issue. One
really needs to build the car for the intended purpose. If you don't need
the trunk, then beef up the car and load it up with batteries. But I
wouldn't expect 150 mile range to be normal or at least till a better
battery technology comes around that the average Joe can get off the shelf
at a reasonable price. Till then I will live within the range of my car and
pay THE MAN when I need to go outside that range. At least now I have some
choice.
http://www.austinev.org/evalbum/915
Ted
Olympia, WA
N47 03.442 W122 49.108
Thank GOD for Thomas Edison. Without him we would all be watching TV by
candle light.
----- Original Message -----
From: "(-Phil-)" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, May 22, 2007 2:06 PM
Subject: Re: 15k DIY Porsche. 20k Installed.
IMHO the 914 makes a great electric commuter. Good for one plus anything
you'd ever carry to work, etc.
Most Electric 914's I've seen have batteries where the 18gal tank used to
be
in the front between the wheels, and also some in about half the rest of
the
front space. In the rear, only the engine bay is usually used for
batteries
since the motor is down low and doesn't take up near as much space as the
ICE+gear. Most of the rear trunk and some the front one is open for some
storage still!
Unless you are going to fully load it up on batteries, you will have
plenty
for groceries, etc. If you DID load it up, you'd probably have an
awfully
heavy and overloaded car! The car is a unibody, but without a roof, so
if
you go crazy with weight you are likely going to have to seriously
reinforce
the belly!
It will only seat 2 however...
(I've owned three 914's)
-Phil
----- Original Message -----
From: "GWMobile" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Cc: <[EMAIL PROTECTED]>
Sent: Tuesday, May 22, 2007 11:24 AM
Subject: Re: 15k DIY Porsche. 20k Installed.
I used to own a 914 and they are great fun however there is one serious
consideration to think about with them.
Remember unless the goal is a science experiment you probably want a
USEABLE electric car in the end. That means some storage space and maybe
more than two seats.
Alfter all is said and done you want a car that is functional. The only
saving grace for a gas powered 914 which has NO back or space at all
behind the front seats is the front and rear trunk (because the engine is
right behind the seats so you have both a big front and back trunk)
but when you add batteries in those trunks you no longer have that space.
If you want an electric go cart for fun then a 914 is a great electric
car.
If you want a functional car that you can even put a few grocery bags in
then an electric 914 is useless.
It will have NO storage space. And only one other seat.
It will seriously have NO Storage space. People really don't understand
it until they use one for a while. There are NO nooks and crannies behind
the seat - just a sheer firewall.
Something to keep in mind.
You would hate to spend all the time and money to make an electric only
to realize you don't have a very day to day functional vehicle when you
are finished.
You won't save gas or the environement if it is a car you really won't
drive.
On Tue, 22 May 2007 11:05 am, Michael Wendell wrote:
I was just looking at the www.electroautomotive.com site
that link is http://www.electroauto.com
...and their AC kit is around 15k with batteries. After all
the talk of what's available I'm begining to think that is a
bargain. If you are a miser it will go 150 miles on the flat.
i'm a lurker, still in the dreaming stage with this, but i didn't
realize
their kits had that kind of range. i'm hoping to have the time to
seriously
begin tinkering this fall.
the 914 seems to be a somewhat popular conversion, and electro's kit may
have something to do with that.
while i like the 914, i've been wondering if the boxster might be a
better,
more modern equivalent. what does the list think, too heavy? i've seen
beat
up boxsters selling for reasonable prices on ebay, and i'd imagine that
parting out the ICE equipment would yield a nice payback.
thanks, i'll go back to lurking.
m.
Michael Wendell
Web/Graphics Guy
Speedgoat Bicycles
724.238.7181
[EMAIL PROTECTED]
www.GlobalBoiling.com for daily images about hurricanes, globalwarming
and the melting poles.
www.ElectricQuakes.com daily solar and earthquake images.
--- End Message ---
--- Begin Message ---
I'll ask and find out for sure.
I get the impression that because of the stable chemistry, and the
laser-welded seal, calendar aging is not an issue.
Bill Dube'
At 08:40 AM 5/22/2007, you wrote:
Bill,
Can you answer the question of whether or not the A123 cells have a
time dependent degrading factor, like the old Lithium chem does?
Thanks muchly,
--T
On 5/19/07, Bill Dube <[EMAIL PROTECTED]> wrote:
Here is the cycle life info on their new website:
http://www.a123systems.com/newsite/index.php#/applications/phev/pchart2/
Notice that it is a straight line for % capacity remaining versus
cycles. As I mentioned earlier, if 50% remaining capacity is OK with
you, then the cycle life is 10,000 cycles.
Like I said, I don't just make this stuff up. :-)
Many (perhaps most) of the battery manufacturers use 50% remaining
capacity for the "end" of the cycle life.
Bill Dube'
At 07:53 PM 5/17/2007, you wrote:
>You need to dust off your calculator and actually do the math.
>
>At 50% capacity loss (10 times 5%) you will get 10,000 cycles (10
>times 1,000.) This is direct quote from the engineers a A123
>Systems. I don't make this stuff up.
>
>By the way, can you find another brand of battery that lists the
>cycle life for 10 C discharge?
>
>At 08:33 PM 5/17/2007, you wrote:
>>What that chart shows:
>>
>> 1C the loss is 5% at 25C after 1000 cycles
>> 2C the loss is 10% at 45C
>> 2C the loss is 20% at 60C
>>
>>All I can really say is you are now Bill the Battery Salesman
>>to say expect 10,000 cycles for an EV.
>>
>>Jack Murray
>>
>>Bill Dube wrote:
>>>As I mentioned in a post yesterday, (in answer to YOUR post) the
>>>temperature is what really matters in the cycle life. The
>>>high-current cycle tests makes the cells run at high temperatures,
>>>and thus shorten cycle life.
>>>If you look at the chart
>>>http://www.a123systems.com/newsite/pdf/ANR26650M1_Datasheet_FEB2007-1.pdf
>>>you will notice that the 25 C curve indicates a 5% capacity loss
>>>after 1,000 cycles. (This is what you would expect in the typical
>>>EV environment.)
>>>Looking at the 60 C curve, you see that the capacity loss is about
>>>25%. after 1,000 cycles. At the same current, but at 45 C, the
>>>curve shows about 12% loss after 1,000 cycles.
>>>EVs typically discharge batteries at 1C, sometimes less, sometimes
>>>a bit more. Low internal resistance keeps the cell temperature at
>>>30 C or below. Thus, in an EV, you can expect the cycle life of
>>>about 10,000 cycles to 50% capacity.
>>> Why don't you dig up the cycle life of an Optima at 10 C
>>> discharge at 60 C? You can't find this chart because the battery
>>> would be a puddle of smoking molten goo at this temperature.
>>>Bill Dube'
>>>
>>>At 06:49 PM 5/17/2007, you wrote:
>>>
>>>>So the chart that A123 publishes that shows 20% loss at 1000
>>>>cycles at 10C discharge is not correct?
>>>>
>>>>
>>>>Bill Dube wrote:
>>>>
>>>>>The cycle life on A123 Systems cells is actually much more than
>>>>>1,000 cycles, if you rate it the same way other manufacturers'
>>>>>do. The 1,000 rating is for just 5% loss of capacity. If you
>>>>>rate it to 50% loss of capacity, (like lead-acid AGMs are rated)
>>>>>the cycle life is 10,000 cycles.
>>>>>I don't think Li-Ion FePo has a calender capacity loss like
>>>>>conventional Li-Ion does. The chemistry is much more stable.
>>>>>Bill Dube'
>>>>>
>>>>>At 05:35 PM 5/17/2007, you wrote:
>>>>>
>>>>>>I'm manning a booth at the Maker Faire (San Mateo County
Fairgrounds, May
>>>>>>19-20, http://www.makerfaire.com ) over the weekend and
wanted to give a
>>>>>>hand-out regarding EVs. In addition to some white papers by
>>>>>>Tesla, I wanted
>>>>>>to put together two charts.
>>>>>>
>>>>>>The first one, I was hoping to put gas price over time, vs
>>>>>>battery cost over
>>>>>>time. Does anyone know where I'd get data for battery
>>>>>>cost? Say, for NiMH
>>>>>>and LiIon, over the past 10 years or so?
>>>>>>
>>>>>>The second one was inspired by
>>>>>>http://www.madkatz.com/ev/batteryTechnologyComparison.html
>>>>>>and it's a chart of battery specs, with an added emphasis on
>>>>>>total cost of
>>>>>>the battery, per kilowatt-hour, over the lifetime of the battery.
>>>>>>Here it
>>>>>>is so far... does anyone have good info on what a modern NiCad
>>>>>>would be to
>>>>>>use? Anyone had experience (and pricing) with Valence's U-Charge?
>>>>>>Also,
>>>>>>what's the realistic peak power out of a flooded lead-acid or hawker
>>>>>>Genesis? (I figure the racers on this list would know for real...)
>>>>>>
>>>>>>Tech Density #Cycles Discharge Cost
>>>>>> Wh/kg W/kg (per month) $/kWh $/kW
>>>>>> $/LifeTimekWh
>>>>>>Est Range
>>>>>>Flooded
lead-acid 47 600 20%? $85 $0.14
>>>>>>"AGM" lead-acid 35 412? 500 5%? $145 $12?
>>>>>>$0.29 ~60
>>>>>>NiCad 50? 2000? 100%? $300?
$0.15
>>>>>>NiMH (Nilar) 55 385 4000 $960 $137
>>>>>>$0.24 ~110
>>>>>>LiIon (18650) 176 631 500 ??% $535 $149
>>>>>>$1.07 ~250
>>>>>>LiPho (A123) 110 3000 1000* $1300 $47
>>>>>>$1.30 ~180
>>>>>>
>>>>>>Notes:
>>>>>>LiIon loses 5% of capacity per year, regardless of whether you
>>>>>>use it. See
>>>>>>http://www.buchmann.ca/Article5-Page1.asp
>>>>>>NiCads have severe memory effects.
>>>>>>
>>>>>>W/kg is max possible "peak" rate.
>>>>>>Wh/kg is "average" or "nominal" discharge rate.
>>>>>>Range is affected by how much extra packaging must surround the
>>>>>>battery, for
>>>>>>example extra temperature monitoring that affects 18650 cells.
>>>>>>18650 cells est. at $5 each
>>>>>>* - cycles claimed by A123
>>>>>>
>>>>>>Sources:
>>>>>>
>>>>>>http://www.nilar.com/index.php?pageID=33&languageID=1
>>>>>>NiMH based on Nilar 24V 9AHr=216WHr @3.9kg $208 each
>>>>>>
>>>>>>http://www.madkatz.com/ev/batteryTechnologyComparison.html
>>>>>>
>>>>>>http://www.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf
>>>>>> => 56kWH, 200kW, 200 miles, 375V, 450kg (317kg batt weight est)
>>>>>>6,831 cells, 46.5g each at $5 each would be $34,150 for 56kWHr
>>>>>>
>>>>>>http://libattery.ustc.edu.cn/english/introduction%203.htm
>>>>>>
>>>>>>Flooded specs based on US Battery US185 spec 195AHr=2340WHr @49kg $200
>>>>>>
>>>>>>AGM Specs based on Hawker G70EP 72AHr=864WHr @24.9kg $125
>>>>>>
>>>>>>A123 specs based on 3.3V, 2.3Ah, 7.6WHr @70g $10.00 (dev kits
>>>>>>are $20 each
>>>>>>in much smaller quantity)
--- End Message ---
--- Begin Message ---
(-Phil-) wrote:
Most microcontrollers have watchdogs.
Yes; and some of them actually work! But most are a band-aid; they only
matter *after* something has gone wrong.
You have to know a lot about the micro, what triggers its watchdog, and
what sorts of thing can defeat it. Usually, it works by resetting the
micro if the software fails to do something every so often. But reset
won't work if the chip is damaged, is latched up from noise, if its
clock oscillator has stopped, etc.
Lockups just don't happen unless you subject them to electrically
hostile environments.
And an electric car is one of the most hostile environments there is!
(provided you don't have buggy software, that is!)
Software bugs are a fact of life. *Every* program has bugs. One-off
programs written by amateurs or beginners are especially likely to have
them.
Best advice is to use an off-the-shelf MOSFET driver chip.
You'll find that off-the-shelf driver chips don't have sufficient gate
drive for the very large MOSFETs or IGBTs. They are made mainly for much
smaller mass-produced controllers.
When you start out, build a test bed with a small motor and a
current-limited supply. Run the MCU off a totally separate power
supply. Then get your software right. Once that's done, you can
scale up the design by adding more MOSFETs in parallel. Remember
to make sure your gate drive circuitry is up to the task. MOSFET
gates have high relative capacitance, so to switch them fast enough
to not be a problem, sometimes that involves several peak amps!
(don't switch TOO fast though!)
Good advice! PS: you'll find that even a small controller needs several
amps of gate drive. A large controller needs 10's of amps of peak gate
drive current.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Michael Barkley wrote:
Do you recall what particular product you used in
this test?
At the time we tested the bedliner material, it was
some that NAPA was selling in gallon containers. Now
they along with others have the bedliner material in a
spray can, which is much easier to use. Put at least
two coats of it on the area or item, you want to
protect.
I'm sure this was a good expedient solution. But, do you actually know
what that bedliner material is? Sulfuric battery acid can be very hard
on materials. It might be worth contacting the manufacturer to find out
if it really will withstand battery acid for any length of time.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Bill Dennis wrote:
Interesting concept, Lee. You mention a freewheel diode. Is a
freewheel still necessary in this setup? If I'm understanding your
description correctly, the field winding will be sending its current
either through the armature winding, or through the MOSFET to ground,
and the armatue will always be getting its current from either the
battery (through the field winding) or from the capacitors. If a
freewheel diode is necessary, then why, and where does it go?
This type of boost controller uses exactly the same parts as a buck
controller; one switch, one diode, one capacitor, and one inductor. The
boost version is arranged like this (view with a fixed width font):
_ _ _
battery+____| | | |________|\|____________
motor | |/| | |
field | diode | _|_
| _|_ / \ motor
switch / capacitor ___ \___/ armature
| | |
battery-______________|____________|______|
The "switch" can be an SCR, transistor, MOSFET, IGBT, etc. The diode is
still necessary; it acts as a freewheel diode for the field inductance,
so current can flow continuously in it whether the switch is on or off.
Note that this type of controller has an advantage over a conventional
buck converter; if the transistors fail on (their normal failure mode),
it STOPS the motor and shorts the input power source (and hopefully
blows a fuse).
But, it has the drawback that the motor voltage can't be less than the
pack voltage, i.e. you need a contactor (not shown) to turn the motor
completely off.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
