All the electric car discussion of late has gotten me all geeked up. It's a
thought that I've had on and off over the years. But I don't think that I
was even prepared to pull the trigger because of the huge cost of
conversion.
Until I met Greg Coleman's Yugo electric conversion:
With a free doner and scrounged parts he was able to get a working
conversion done for under $1000. This perked up my interest.
So I was thinking with all of this brainpower out on the list and with
nearly half of the items needed for an electric car conversion right in our
wheelhouse, how feasible would it be to design a low cast electric car
conversion? I don't know but I'm starting this thread to find out.
An electric car conversion requires seven essential elements:
1. Donor car
2. Electric motor
3. Batteries.
4. Custom transmission coupling
5. Controller
6. Battery pack monitoring
7. Charger.
While clearly some of these items are not a custom job, I'm interested in
discussing whether or not any of the electronics items are in fact doable.
So let's get started:
1. Donor car. I'm already there. I have a 1993 Toyota Tercel with a bad
engine that consuming a ton of oil. It functions well otherwise. So a
conversion is a logical choice. So the donor car is essentially free.
2. The Yugo started with a 5 HP motor, and now has a 8 HP motor. I found
this 10 HP motor on Ebay:
A couple of hundred bucks isn't a bad start for a motor replacement.
3. Batteries are always a challenge. You need to manage cost, weight, and
charging. While LiPo may be great, you're talking about a $20k pricetag.
So to keep it simple and use flooded lead acid to keep the costs down. One
site I read stated that for reasonable range that batteries should weigh at
least 30% of the gross weight of the car. Since the Tercel clocks in at
about 2000 pounds, then at least 700 pounds of battery bank is needed.
6V golf cart batteries are decently priced. However, batteries like the
Trojan T105 only clock in at 61 lbs each. So there seems to be a fit
problem in terms of getting the right number of batteries (at least 12) and
the right voltage (48V for the given motor).
4. Custom coupling is either a buy one or make nice at a machine shop.
5. Controller. While not that complicated, they are costly. Check out this
page with a ton of controllers:
Except for the high power electronics, this is in our wheelhouse.
Fundamentally it's a PWMed high power driver that's controlled by a
resistive input that connects to an ADC.
IIRC MOSFETs parallel OK because they self balance the load. But they need
really stiff drivers on the gate right? What about IGBTs? What is the price
point of the high power electronics as compared to the controllers on the
page above?
This page: evworld.com/archives/hobbyists/hartsbeat001.html
has a discussion about rheostat-contactor controllers but no details.
6. Battery pack monitoring. Another PIC doable task. Read the voltage
across a shunt using ADC to get the amps for the motor. Read the voltage of
the pack to get its Depth of Discharge. I'm wondering if it's possible to interface
that to the gas gauge to get a quick idea of the DoD using existing
instrumentation?
7. Charging is another possible PIC project. Again the primary item is
power electronics. It seems like a hefty isolation transformer, a honking
huge full bridge and a high powered buck converter could easily charge a
bank. And the typical bulk, absorption, trickle cycle can be managed by
either a PIC or by any number of these custom charger chips.
So I'd be interested in hearing your thoughts. Any leads on an inexpensive
battery bank would also be welcome.
> All the electric car discussion of late has gotten
> me all geeked up.
Hi Byron,
I used to (early to mid 1990's) be involved in that
sort of thing, and even designed a few controllers.
I'm happy to provide input. Hopefully you will be the
group leader, because I hate group projects where
there's nobody in charge.
The most important thing about electric cars is
weight. You really need to keep it as light as
possible. The choice of donor car is critical. Don't
take something sub-optimal because it's free. Can you
live without power brakes? Good, you don't need a
vacuum pump. Use a tiny 12v battery for accessories
and keep it charged from the main pack with a
converter. etc. etc.
> -----Original Message-----
> From: .....piclist-bouncesKILLspam@spam@mit.edu [piclist-bouncesKILLspammit.edu] On
Behalf
> Of Byron Jeff
> Sent: 04 December 2007 18:57
> To: .....piclistKILLspam.....mit.edu
> Subject: [OT][EE] Let's design a PICLIST electric car conversion.
>
> All the electric car discussion of late has gotten me all geeked up.
It's
> a
> thought that I've had on and off over the years. But I don't think
that I
> was even prepared to pull the trigger because of the huge cost of
> conversion.
>
> Until I met Greg Coleman's Yugo electric conversion:
>
> http://www.austinev.org/evalbum/762
>
> With a free doner and scrounged parts he was able to get a working
> conversion done for under $1000. This perked up my interest.
That's certainly an interesting conversion, but the 15mile range is
surely a huge limitation if you don't live next door to your shops and
workplace?
Regards
Mike
=======================================================================
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=======================================================================
> All the electric car discussion of late has gotten me all geeked up. It's a
> thought that I've had on and off over the years. But I don't think that I
> was even prepared to pull the trigger because of the huge cost of
> conversion.
>
> Until I met Greg Coleman's Yugo electric conversion:
>
> http://www.austinev.org/evalbum/762
>
> With a free doner and scrounged parts he was able to get a working
> conversion done for under $1000. This perked up my interest.
>
> So I was thinking with all of this brainpower out on the list and with
> nearly half of the items needed for an electric car conversion right in our
> wheelhouse, how feasible would it be to design a low cast electric car
> conversion? I don't know but I'm starting this thread to find out.
>
> An electric car conversion requires seven essential elements:
>
> 1. Donor car
> 2. Electric motor
> 3. Batteries.
> 4. Custom transmission coupling
> 5. Controller
> 6. Battery pack monitoring
> 7. Charger.
>
> While clearly some of these items are not a custom job, I'm interested in
> discussing whether or not any of the electronics items are in fact doable.
>
> So let's get started:
>
> 1. Donor car. I'm already there. I have a 1993 Toyota Tercel with a bad
> engine that consuming a ton of oil. It functions well otherwise. So a
> conversion is a logical choice. So the donor car is essentially free.
>
> 2. The Yugo started with a 5 HP motor, and now has a 8 HP motor. I found
> this 10 HP motor on Ebay:
>
> http://cgi.ebay.com/10-HP-48V-DC-VEHICLE-ELECTRIC-MOTOR_W0QQitemZ310003961541QQihZ021QQcategoryZ67008QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
>
> A couple of hundred bucks isn't a bad start for a motor replacement.
>
> 3. Batteries are always a challenge. You need to manage cost, weight, and
> charging. While LiPo may be great, you're talking about a $20k pricetag.
> So to keep it simple and use flooded lead acid to keep the costs down. One
> site I read stated that for reasonable range that batteries should weigh at
> least 30% of the gross weight of the car. Since the Tercel clocks in at
> about 2000 pounds, then at least 700 pounds of battery bank is needed.
>
> 6V golf cart batteries are decently priced. However, batteries like the
> Trojan T105 only clock in at 61 lbs each. So there seems to be a fit
> problem in terms of getting the right number of batteries (at least 12) and
> the right voltage (48V for the given motor).
>
> 4. Custom coupling is either a buy one or make nice at a machine shop.
>
> 5. Controller. While not that complicated, they are costly. Check out this
> page with a ton of controllers:
>
> http://www.electricvehiclesusa.com/category_s/48.htm
>
> Except for the high power electronics, this is in our wheelhouse.
> Fundamentally it's a PWMed high power driver that's controlled by a
> resistive input that connects to an ADC.
>
> IIRC MOSFETs parallel OK because they self balance the load. But they need
> really stiff drivers on the gate right? What about IGBTs? What is the price
> point of the high power electronics as compared to the controllers on the
> page above?
>
> This page: evworld.com/archives/hobbyists/hartsbeat001.html
> has a discussion about rheostat-contactor controllers but no details.
>
> 6. Battery pack monitoring. Another PIC doable task. Read the voltage
> across a shunt using ADC to get the amps for the motor. Read the voltage of
> the pack to get its Depth of Discharge. I'm wondering if it's possible to interface
> that to the gas gauge to get a quick idea of the DoD using existing
> instrumentation?
>
> 7. Charging is another possible PIC project. Again the primary item is
> power electronics. It seems like a hefty isolation transformer, a honking
> huge full bridge and a high powered buck converter could easily charge a
> bank. And the typical bulk, absorption, trickle cycle can be managed by
> either a PIC or by any number of these custom charger chips.
>
> So I'd be interested in hearing your thoughts. Any leads on an inexpensive
> battery bank would also be welcome.
>
> BAJ
>
I'd be very interested. I'd like to use NiMH cells.
If you complete the project and document it with massive photos and some
text, or if you FAIL and document exactly WHY, I will pay for the right to
publish it on the site.
>> -----Original Message-----
>> From: EraseMEpiclist-bouncesspam_OUTTakeThisOuTmit.edu [piclist-bouncesspam_OUTmit.edu] On
>>
> Behalf
>
>> Of Byron Jeff
>> Sent: 04 December 2007 18:57
>> To: @spam@piclistKILLspammit.edu
>> Subject: [OT][EE] Let's design a PICLIST electric car conversion.
>>
>> All the electric car discussion of late has gotten me all geeked up.
>>
> It's
>
>> a
>> thought that I've had on and off over the years. But I don't think
>>
> that I
>
>> was even prepared to pull the trigger because of the huge cost of
>> conversion.
>>
>> Until I met Greg Coleman's Yugo electric conversion:
>>
>> http://www.austinev.org/evalbum/762
>>
>> With a free doner and scrounged parts he was able to get a working
>> conversion done for under $1000. This perked up my interest.
>>
>
> That's certainly an interesting conversion, but the 15mile range is
> surely a huge limitation if you don't live next door to your shops and
> workplace?
>
> Regards
>
> Mike
>
> =======================================================================
> This e-mail is intended for the person it is addressed to only. The
> information contained in it may be confidential and/or protected by
> law. If you are not the intended recipient of this message, you must
> not make any use of this information, or copy or show it to any
> person. Please contact us immediately to tell us that you have
> received this e-mail, and return the original to us. Any use,
> forwarding, printing or copying of this message is strictly prohibited.
> No part of this message can be considered a request for goods or
> services.
> =======================================================================
>
>
Yes, I need 50 mile round-trip at 80MPH, to keep from being swept off
the road...
There's a guy on the Team Swift website doing a conversion using a Geo
Metro/Suzuki Swift and an electric forklift that he bought cheap.
Regarding lightweight, keep in mind that not all light cars are suitable
for electric conversion since their payload carrying capacity can be
quite low.
Dave
Dave Schmidt wrote:
> There's a guy on the Team Swift website doing a conversion using a Geo
> Metro/Suzuki Swift and an electric forklift that he bought cheap.
>
> Regarding lightweight, keep in mind that not all light cars are suitable
> for electric conversion since their payload carrying capacity can be
> quite low.
> Dave
>
>
I could become involved in charging and control. My goal is to
eventually run it from solar
power...
Is that a series motor? It doesn't look large enough for a road worthy EV.
The single most popular motor for electrical vehicle conversions is the
Advanced DC 9". Almost everyone uses a series motor because it can
provide the torque needed without saturating.
Is there a specific reason why you want to do this as a piclist project?
The electric vehicle discussion list does this kind of thing as it's
defined mission. I'm not saying it's a bad idea, but there is much more
collective experience over there.
> Regarding lightweight, keep in mind that not all
> light cars are suitable
> for electric conversion since their payload carrying
> capacity can be
> quite low.
Hi Dave,
But having a car with limited payload is good because
it forces you to limit the payload. I've seen too many
people convert pickup trucks, and they are
disappointed because of the lousy range. However if
you start with something efficient, you're likely to
end up with something efficient rather than a "faster
forklift".
>All the electric car discussion of late has gotten me all geeked up. It's a
>thought that I've had on and off over the years. But I don't think that I
>was even prepared to pull the trigger because of the huge cost of
>conversion.
>
>Until I met Greg Coleman's Yugo electric conversion:
>
>http://www.austinev.org/evalbum/762
>
>With a free doner and scrounged parts he was able to get a working
>conversion done for under $1000. This perked up my interest.
>
>So I was thinking with all of this brainpower out on the list and with
>nearly half of the items needed for an electric car conversion right in our
>wheelhouse, how feasible would it be to design a low cast electric car
>conversion? I don't know but I'm starting this thread to find out.
>
>An electric car conversion requires seven essential elements:
>
>1. Donor car
>2. Electric motor
>3. Batteries.
>4. Custom transmission coupling
>5. Controller
>6. Battery pack monitoring
>7. Charger.
>
>While clearly some of these items are not a custom job, I'm interested in
>discussing whether or not any of the electronics items are in fact doable.
>
>
>
>http://cgi.ebay.com/10-HP-48V-DC-VEHICLE-ELECTRIC-MOTOR_W0QQitemZ310003961541QQihZ021QQcategoryZ67008QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
>
>
>
If you look close at the specs for the above motor you will notice it
says INT. DUTY (intermitent Duty). In other words, for those not aware,
it is like a car starter motor. ON for a minute or less let cool for 5
minute.
You need to get a motor built for CONT. DUTY. (continuous duty)
See if you can find an old electric fork lift. The motors in those were
made to work almost 24 hours a day. Most I worked on were 48VDC. In
fact one version of CLARKE forklift I worked on mounted the motor
direct to the differential. I think they used some type of sun gear
to drop the RPM.
Or if you use a front wheel drive, why not just pull the motor leave the
trans axle. if you get a manual transmission just make a plate to match
the bellhousing and mount the motor to that and the frame. The
transmission may be useful for different types of driving (city, high
speed highway or hilly driving).
It may make it easier to connect the electric motor to the drive train
with out alot of machining and engineering work.
Probably best to take the thread to a more specific forum, and drop a
note occasionally here to keep the group informed of developments. Seems
like the thread is going to generate a lot of traffic over a long period
of time, as opposed to the temporary threads where someone is helping or
being helped. Sometimes it would be nice to be able to start a thread
and take it to a temporary list while it has a lot of traffic for a few
days, and then closes. :)
> Is that a series motor? It doesn't look large enough for a road worthy EV.
> The single most popular motor for electrical vehicle conversions is the
> Advanced DC 9". Almost everyone uses a series motor because it can
> provide the torque needed without saturating.
>
> Is there a specific reason why you want to do this as a piclist project?
> The electric vehicle discussion list does this kind of thing as it's
> defined mission. I'm not saying it's a bad idea, but there is much more
> collective experience over there.
>
> -
> Martin K
>
>
>
> If you look close at the specs for the above motor you will notice it
> says INT. DUTY (intermitent Duty). In other words, for those not aware,
> it is like a car starter motor. ON for a minute or less let cool for 5
> minute.
Ouch! Great catch!
>
>
> You need to get a motor built for CONT. DUTY. (continuous duty)
>
> See if you can find an old electric fork lift. The motors in those were
> made to work almost 24 hours a day. Most I worked on were 48VDC. In
> fact one version of CLARKE forklift I worked on mounted the motor
> direct to the differential. I think they used some type of sun gear
> to drop the RPM.
>
> Or if you use a front wheel drive, why not just pull the motor leave the
> trans axle.
> if you get a manual transmission just make a plate to match
> the bellhousing and mount the motor to that and the frame.
That's the plan.
> The
> transmission may be useful for different types of driving (city, high
> speed highway or hilly driving).
I don't see high speed highway driving with a sub 20 HP motor.
> It may make it easier to connect the electric motor to the drive train
> with out alot of machining and engineering work.
That's how conversions are usually done. I've already snipped my list but I
believe I alluded to a custom coupling to the existing transmission.
On Tue, Dec 04, 2007 at 04:00:12PM -0500, Martin wrote:
> Is that a series motor? It doesn't look large enough for a road worthy EV.
> The single most popular motor for electrical vehicle conversions is the
> Advanced DC 9". Almost everyone uses a series motor because it can
> provide the torque needed without saturating.
>
> Is there a specific reason why you want to do this as a piclist project?
> The electric vehicle discussion list does this kind of thing as it's
> defined mission. I'm not saying it's a bad idea, but there is much more
> collective experience over there.
There is a specific reason. Over there is virutally always buying a
collection of premade components and assembling them. The reason being that
there isn't enough electronics expertise (either low power or high power)
to consider otherwise.
Here we have the expertise to at least discuss the pros and cons of custom
electronics for the project. Especially when trying to be cost effective,
this is an invaluable resource.
The key thing is trying to do it in a very cost effective manner. And from
all of my reading, the EV folks seem to be quite proud of the tons of cash
that they sink into their craft. So I'm asking here because I believe that
I'll get a more realistic perspective on how to do it.
On Tue, Dec 04, 2007 at 03:13:03PM -0500, Michael Rigby-Jones wrote: {Quote hidden}
>
>
> > -----Original Message-----
> > From: RemoveMEpiclist-bouncesTakeThisOuTmit.edu [spamBeGonepiclist-bouncesspamBeGonemit.edu] On
> Behalf
> > Of Byron Jeff
> > Sent: 04 December 2007 18:57
> > To: TakeThisOuTpiclistEraseMEspam_OUTmit.edu
> > Subject: [OT][EE] Let's design a PICLIST electric car conversion.
> >
> > All the electric car discussion of late has gotten me all geeked up.
> It's
> > a
> > thought that I've had on and off over the years. But I don't think
> that I
> > was even prepared to pull the trigger because of the huge cost of
> > conversion.
> >
> > Until I met Greg Coleman's Yugo electric conversion:
> >
> > http://www.austinev.org/evalbum/762
> >
> > With a free doner and scrounged parts he was able to get a working
> > conversion done for under $1000. This perked up my interest.
>
> That's certainly an interesting conversion, but the 15mile range is
> surely a huge limitation if you don't live next door to your shops and
> workplace?
Absolutely. As a test yesterday I clock my typical evening run for a
Monday. It came in at just under 40 miles.
I'm still researching the weight, battery power, and the like effect on
range. I know that more battery and less frame weight along with
aerodynamics all affect the performance.
> On Tue, Dec 04, 2007 at 04:00:12PM -0500, Martin
> wrote:
> > Advanced DC 9". Almost everyone uses a series
> motor because it can
> > provide the torque needed without saturating.
This is an important point. In an electric car you
need bursts of power, which is why motors with
permanent magnets are usually unsuitable. Series wound
motors can produce gobs of torque for short periods of
time.
On Tue, Dec 04, 2007 at 02:50:08PM -0500, Bob Blick wrote:
>
> --- Byron Jeff <RemoveMEbyronjeffTakeThisOuTclayton.edu> wrote:
>
> > All the electric car discussion of late has gotten
> > me all geeked up.
>
> Hi Byron,
>
> I used to (early to mid 1990's) be involved in that
> sort of thing, and even designed a few controllers.
> I'm happy to provide input. Hopefully you will be the
> group leader, because I hate group projects where
> there's nobody in charge.
I can do that. Any suggestions of where to start in terms of getting up to
speed on power electronics?
> The most important thing about electric cars is
> weight. You really need to keep it as light as
> possible. The choice of donor car is critical. Don't
> take something sub-optimal because it's free.
OK. Will re-evaluate the car I have in that light. I think I read that it's
close to 2000 lbs with the engine removed.
> Can you live without power brakes?
Unsure. I can't think of the last time I drove a car without power brakes.
Since I'm not planning on using a high end DC or AC motor, regenerative braking probably
won't be an option.
> Good, you don't need a
> vacuum pump. Use a tiny 12v battery for accessories
> and keep it charged from the main pack with a
> converter. etc. etc.
>
> High battery voltage keeps your losses down.
Losses change against the square of the current...
> Pump the tires to 65 psi.
Lowers the rolling resistance.
>
> When driving, accelerate quickly and then coast.
I actually practiced coasting today just to see what it's like. It's an
interesting experience.
> I can do that. Any suggestions of where to start in terms of getting up to
> speed on power electronics?
I haven't got any ready references. I did teach a short unit on motor
control but that was many years ago and I don't have anything saved. The
controllers I am familiar with have all used paralleled MOSFETs for the
switch and fast recovery rectifiers for the freewheel diodes. Curtis PMC
and Zapi are the two I'm most familiar with. Ones I have designed have
the same topology. You do cycle-by-cycle current limiting because
economics force you to design with little headroom. Operating frequency
is typically 16KHz.
> OK. Will re-evaluate the car I have in that light. I think I read that it's
> close to 2000 lbs with the engine removed.
Pre-1995 Geo Metro hatchback is good for economy, but has poor handling.
1995-2001 Metro hatchback has much better handling and is still a light
car. But the Metros require a fairly short motor because underhood space
is limited. You pretty much need to retain the clutch. Only a skilled
driver can drive without one, and an electric motor doesn't spin down
when you take your foot off the pedal like a gas engine would.
> Since I'm not planning on using a high end DC or AC motor, regenerative braking probably
> won't be an option.
You can do regenerative braking with almost any motor, but in practice a
skilled driver will outperform it!
> > When driving, accelerate quickly and then coast.
>
> I actually practiced coasting today just to see what it's like. It's an
> interesting experience.
Does this requirement still applies to series-wound motor? Doesn't
it's current naturally drop low when it does not have to accelerate?
>Is there a specific reason why you want to do this as a piclist project?
If it is done as a PICList thing, perhaps a [Projects] tag could be added
for any such project related traffic, rather than intersperse it among other
tags - I guess a portion would be [PIC], mostly [EE], and possibly some [OT]
within the project, but if the directly project related stuff had its own
tag, that would keep the info together.
> That's certainly an interesting conversion, but the 15mile range is
> surely a huge limitation if you don't live next door to your shops and
> workplace?
Would be (almost) enough for me. My commute is around 7 miles each way, but
getting to work does involve going up a significant hill, and some other
undulations. There is a slightly more indirect route with easier grade than
the 20-30% that I normally take, which would ease the load on the motor, and
probably add only about 1/2 mile, but I still think I would like a rooftop
of solar cells to provide a topup while parked during the day.
> -----Original Message-----
> From: piclist-bouncesEraseME.....mit.edu [EraseMEpiclist-bouncesmit.edu] On
Behalf
> Of Byron Jeff
> Sent: 04 December 2007 18:57
> To: RemoveMEpiclistEraseMEEraseMEmit.edu
> Subject: [OT][EE] Let's design a PICLIST electric car conversion.
>
> All the electric car discussion of late has gotten me all geeked up.
It's
> a
> thought that I've had on and off over the years. But I don't think
that I
> was even prepared to pull the trigger because of the huge cost of
> conversion.
For inner city commuting it makes sense, especially in London where it
is exempt from the congestion charge (Then again, military tanks and
APCs are also exempt!).
Regards
Mike
=======================================================================
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=======================================================================
On Wed, Dec 05, 2007 at 04:34:53AM -0500, KPL wrote:
> > > When driving, accelerate quickly and then coast.
> >
> > I actually practiced coasting today just to see what it's like. It's an
> > interesting experience.
>
> Does this requirement still applies to series-wound motor? Doesn't
> it's current naturally drop low when it does not have to accelerate?
Drops to 0 amps. If you release the accelerator on an electric car, the
motor stops completely. So if you use the motor to accelerate the car, then
let it coast, you're consuming no power while coasting. Different than an
ICE, which will idle during coasting.
It was interesting to see how far a car, which isn't tuned for this
activity, will coast at reasonable speed.
> > Does this requirement still applies to series-wound motor? Doesn't
> > it's current naturally drop low when it does not have to accelerate?
>
> Drops to 0 amps. If you release the accelerator on an electric car, the
> motor stops completely. So if you use the motor to accelerate the car, then
> let it coast, you're consuming no power while coasting. Different than an
> ICE, which will idle during coasting.
I mean, current should be low even if the motor is left running, since
it has just to hold the speed, not accelerate.
Anyway, that should be function of controller, not the driver, to
manage lowest possible consumption.
>
> It was interesting to see how far a car, which isn't tuned for this
> activity, will coast at reasonable speed.
>
>
> BAJ
> -
> Drops to 0 amps. If you release the accelerator on an electric car, the
> motor stops completely. So if you use the motor to accelerate the car,
> then
> let it coast, you're consuming no power while coasting. Different than an
> ICE, which will idle during coasting.
>
> It was interesting to see how far a car, which isn't tuned for this
> activity, will coast at reasonable speed.
>
I've seen a design for a "bidirectional DC to DC converter" that one might
visualize as a "DC Variac." With the right kind of motor (what kind?),
mechanically forcing the motor past its no-load speed would dump power
back into the batteries. The "accelerator" becomes a speed control. If the
motor is going slower than the set point, power goes from the battery to
the motor. If the motor is going faster than the set point, power goes
from the motor to the battery.
On Tue, Dec 04, 2007 at 09:30:40PM -0500, Bob Blick wrote:
> Byron Jeff wrote:
>
> > I can do that. Any suggestions of where to start in terms of getting up to
> > speed on power electronics?
>
> I haven't got any ready references. I did teach a short unit on motor
> control but that was many years ago and I don't have anything saved. The
> controllers I am familiar with have all used paralleled MOSFETs for the
> switch and fast recovery rectifiers for the freewheel diodes. Curtis PMC
> and Zapi are the two I'm most familiar with. Ones I have designed have
> the same topology. You do cycle-by-cycle current limiting because
> economics force you to design with little headroom. Operating frequency
> is typically 16KHz.
Any ideas about the economics? If it isn't cost effective to hand build,
then I probably won't waste time doing so. Say if the target is something
like 160V, 300A, 16 KHz. What would be a sample MOSFET that could be
paralleled to deliver that type of power? If it's going to be $500 in power
electronics, then buying a controller would be the right move. However if
the electronics are cheaper and you pay the rest with sweat equity, then it
may be worth looking at.
> > OK. Will re-evaluate the car I have in that light. I think I read that it's
> > close to 2000 lbs with the engine removed.
>
> Pre-1995 Geo Metro hatchback is good for economy, but has poor handling.
> 1995-2001 Metro hatchback has much better handling and is still a light
> car. But the Metros require a fairly short motor because underhood space
> is limited.
There's about a 125 lbs difference in the curb weights of the two vehicles
(1993 Tercel (2002 lbs) vs. the Metro (1874 lbs for the 1997 hatchback)).
While I understand that every pound counts, from a cost standpoint it
simply doesn't make sense to me to get rid of a car that I already bought
and paid for in order to buy a car that's a little over 100 lbs lighter.
I must reiterate that cost is my primary concern. I'm not looking to invest
$15K, $10K, or even $5K into this project. Even more than trying to
minimize weight, I'm trying to minimize costs. And that's the costs of
everything. I need to find something other than an Advance 9 motor because
they run $1000 each for the low end model. I want to locate a cheap used
battery pack, even if half of its lifetime is gone. I plan to use the car
that I have. It's not a ultralight, but it isn't a boat anchor either. Like
I said above I'd be willing to put sweat equity into a controller because
commercial controllers are expensive.
Say I have a free donor car and a $1K budget. Should I forget about it? I
know this is a beg, borrow, scrounge project. I'm OK with foregoing pretty
much everything except for cost and performance adequate enough to be safe
on the roads. A vehicle that tops out at 10MPH, takes 20 minutes to
accelerate to top speed, and has a range of 1 mile doesn't work. However, a
bettery pack that'll only last for a year, a simple cheap controller, or an
adapted lower voltage motor because it's cheap is doable.
> You pretty much need to retain the clutch. Only a skilled
> driver can drive without one, and an electric motor doesn't spin down
> when you take your foot off the pedal like a gas engine would.
Now I'm confused. From what I've been reading I got the impression that it
was the exact opposite. Releasing the accelerator stops the motor and that
gears could be shifted without clutching. I absolutely don't mind retaining
the clutch and I planned to do so. But I'd like to be clear about the
situation you outline above.
>
>> Since I'm not planning on using a high end DC or AC motor, regenerative braking
>> probably won't be an option.
>
> You can do regenerative braking with almost any motor,
I thought that it was simple with AC motors but that the controller had to
do a lot of work on series DC motors. High end Zapis do DC braking but that
the low end Curtis' didn't.
> but in practice a skilled driver will outperform it!
Good to know. Like I said I wasn't planning on it.
Thanks for the information. Hope to hear more soon.
> On Tue, Dec 04, 2007 at 02:50:08PM -0500, Bob Blick wrote:
>
>> --- Byron Jeff <RemoveMEbyronjeffspam_OUTKILLspamclayton.edu> wrote:
>>
>>
>>> All the electric car discussion of late has gotten
>>> me all geeked up.
>>>
>> Hi Byron,
>>
>> I used to (early to mid 1990's) be involved in that
>> sort of thing, and even designed a few controllers.
>> I'm happy to provide input. Hopefully you will be the
>> group leader, because I hate group projects where
>> there's nobody in charge.
>>
>
> I can do that. Any suggestions of where to start in terms of getting up to
> speed on power electronics?
>
>
I have nothing specific, except that I am involved with a major solar
project at the same time. I have learned
a LOT about high currents and batteries; My new experience is with NiMH
batteries, so I think I can help
there...
On the vehicle.. I had a friend that made a conversion some years ago.
He told me that he drained the rear axle
grease and replaced it with much thinner silicon lubricant. He also
replaced the actual wheel bearing grease with
a high-performance version, all to reduce rolling friction. He went
further, replacing even slightly worn wheelbearings.
Finally, the smaller the tire the better, i.e. "working" rubber loses a
lot of energy.
I believe you're in the realm of a Curtis 1220, but that is actually a
120v (nominal) controller.
There are no samples that are going to do what you want. If you're going
to build a high power controller on your own you should seriously
consider using ISOTOP (TO227A?) packages. Then "all you have to do" is
cut out some copper bus bars. You can use copper as a current measuring
shunt if you use a 4-wire connection and have a tempco adjustment. I
can't stress enough the need for very quick overcurrent sensing and
protection. In my opinion current measurement is the most difficult part
of designing high power motor controllers.
Cafe electric uses high-side drivers and IGBTs for their 1 and 2kA
controllers. For 160v you're still in a good realm for MOSFETs I
believe. I don't think you're looking at nearly $500 in parts for a 300A
controller, but it will quickly add up the first time you blow up your
expensive ISOTOP FETs and diodes. You'll certainly learn a lot. I'm
interested now! I want to convert a motorcycle but the controller can be
the same.
-
Martin
> Any ideas about the economics? If it isn't cost effective to hand build,
> then I probably won't waste time doing so. Say if the target is something
> like 160V, 300A, 16 KHz. What would be a sample MOSFET that could be
> paralleled to deliver that type of power? If it's going to be $500 in power
> electronics, then buying a controller would be the right move. However if
> the electronics are cheaper and you pay the rest with sweat equity, then it
> may be worth looking at.
>
>
>>> OK. Will re-evaluate the car I have in that light. I think I read that it's
>>> close to 2000 lbs with the engine removed.
>>>
>> Pre-1995 Geo Metro hatchback is good for economy, but has poor handling.
>> 1995-2001 Metro hatchback has much better handling and is still a light
>> car. But the Metros require a fairly short motor because underhood space
>> is limited.
>>
>
> There's about a 125 lbs difference in the curb weights of the two vehicles
> (1993 Tercel (2002 lbs) vs. the Metro (1874 lbs for the 1997 hatchback)).
> While I understand that every pound counts, from a cost standpoint it
> simply doesn't make sense to me to get rid of a car that I already bought
> and paid for in order to buy a car that's a little over 100 lbs lighter.
>
> I must reiterate that cost is my primary concern. I'm not looking to invest
> $15K, $10K, or even $5K into this project. Even more than trying to
> minimize weight, I'm trying to minimize costs. And that's the costs of
> everything. I need to find something other than an Advance 9 motor because
> they run $1000 each for the low end model. I want to locate a cheap used
> battery pack, even if half of its lifetime is gone. I plan to use the car
> that I have. It's not a ultralight, but it isn't a boat anchor either. Like
> I said above I'd be willing to put sweat equity into a controller because
> commercial controllers are expensive.
>
> Say I have a free donor car and a $1K budget. Should I forget about it? I
> know this is a beg, borrow, scrounge project. I'm OK with foregoing pretty
> much everything except for cost and performance adequate enough to be safe
> on the roads. A vehicle that tops out at 10MPH, takes 20 minutes to
> accelerate to top speed, and has a range of 1 mile doesn't work. However, a
> bettery pack that'll only last for a year, a simple cheap controller, or an
> adapted lower voltage motor because it's cheap is doable.
>
>
>> You pretty much need to retain the clutch. Only a skilled
>> driver can drive without one, and an electric motor doesn't spin down
>> when you take your foot off the pedal like a gas engine would.
>>
>
> Now I'm confused. From what I've been reading I got the impression that it
> was the exact opposite. Releasing the accelerator stops the motor and that
> gears could be shifted without clutching. I absolutely don't mind retaining
> the clutch and I planned to do so. But I'd like to be clear about the
> situation you outline above.
>
>
>>> Since I'm not planning on using a high end DC or AC motor, regenerative braking
>>> probably won't be an option.
>>>
>
>
>> You can do regenerative braking with almost any motor,
>>
>
> I thought that it was simple with AC motors but that the controller had to
> do a lot of work on series DC motors. High end Zapis do DC braking but that
> the low end Curtis' didn't.
>
>
>> but in practice a skilled driver will outperform it!
>>
>
> Good to know. Like I said I wasn't planning on it.
>
> Thanks for the information. Hope to hear more soon.
>
> BAJ
>
The overall pollution of electric/hybrid cars probably is many times higher than regular vehicles.
I knew the national lab and GM did this study 7 years ago. They found that the conventional vehicle achieved the least pollution on overall pollution "from well to wheel", it is not fuel cell vehicle, not electric/hybrid vehicles. The US EPA probably still has this report on the web somewhere.
Toyota hybrids might save end-user the cost of fuel, but is creating the largest scale of heavy-metal pollution on this planet in the human history. It will take 10-20 years for mankind to realize this kind of mistake.
(Also, please don't forget Japan is just an island country, they exported/shipped most of their garbage to the third world country just like we did here in USA. We send our pollution out of this country to keep it clean and quite here. Our TV and Radio seem cannot see/care about any of this. They might just think this is somebody else's problem. BTW, it is true exporting pollution cost much less than handling pollution locally from most business point of view.)
If the national lab study is right, we are making a big mistake.
The diesel can also achieve higher efficiency than gasoline engines, and make less pollution (zero emission on 2013 per US EPA regulation) with today's technology. Also it cost less than the hybrid. That's why we saw some Europe and Asia country decided putting more diesel vehicle on the road instead the hybrid/electric vehicle.
>
> On Tue, Dec 04, 2007 at 04:00:12PM -0500, Martin wrote:
> > Is there a specific reason why you want to do this as a piclist project?
> > The electric vehicle discussion list does this kind of thing as it's
> > defined mission. I'm not saying it's a bad idea, but there is much more
> > collective experience over there.
>
> There is a specific reason. Over there is virutally always buying a
> collection of premade components and assembling them. The reason being
> that
> there isn't enough electronics expertise (either low power or high power)
> to consider otherwise.
>
> Here we have the expertise to at least discuss the pros and cons of custom
> electronics for the project. Especially when trying to be cost effective,
> this is an invaluable resource.
>
> The key thing is trying to do it in a very cost effective manner. And from
> all of my reading, the EV folks seem to be quite proud of the tons of cash
> that they sink into their craft. So I'm asking here because I believe that
> I'll get a more realistic perspective on how to do it.
>
> BAJ
So, why not collaborate with them? Why not go to them and say:
"Hey, you folks are pretty good with cars, but you kinda suck at
electronics. We think we can help with the electronics portion. We have
some pretty efficient (power consumption / processing capability) [PIC]
microcontrollers that we understand really well. Beyond that, we're
generally good with electronics, and think we can design better control
modules. You're using a bunch of expensive off-the-shelf equipment, that
might not have a design tailored to your needs. Maybe if we can
collaborate, get a feel for what you guys want/do/need, we can design (or at
least toy with) some subsystems to better manage the electronics, from drive
to regenerative braking to battery monitoring and charge controlling, to
basic in-dash reporting (charge level, estimated remaining miles before
charge, fuel consumption rate, drivetrain warnings (overtemp, etc))."
I guess if they're really stuck on seeing who can spend the most on a
project you'll never get through to them. Still, I bet there are enough of
them that are:
a) cheap
b) poor (relative)
c) green
that they will have a strong desire to make a more efficient beast, while
keeping cost down. There could still be a pic-list group effort on the
electronics design side. Collaborate with the EV folks, get their
needs/wants/desires. Bring requirements back into pic-list for
design/build, hand it over for testing, get feedback, redesign. Still gives
a pic-list based project, just not quite as all-encompassing, but certainly
more inline with what 80% of folks here are probably better at doing
(electronics instead of mechanics).
Ever think of bringing the idea to a local high school auto shop? They tend
to be poor, but have kids who are quite adept with the mechanical things,
and they get a surplus of vehicles donated to them. I remember my high
school having an electric car project in the mid 90's, somewhat sponsored by
Virginia Power and GE IIRC, and a bunch of schools in the surrounding area
sent their contraptions to Richmond International Raceway to "compete."
Maybe, being that it's a bit over a decade later, more schools are being
invited to similar projects. The short lifecycle of highschool projects
might do well too. Design one control system the first year, and get it
deployed into a variety of vehicles (each school will likely use a different
make/model of car). Get feedback on how it does in each, and use the
feedback to tune the system, as well as begin to realize what vehicles make
better candidates, and retest next year.
In the end, do you want to do it so you can have a converted car for
yourself, or do you want to do it for the engineering challenge?
On Wed, Dec 05, 2007 at 11:58:46AM -0500, Martin wrote:
> I believe you're in the realm of a Curtis 1220, but that is actually a
> 120v (nominal) controller.
Somewhere in that ballpark.
> There are no samples that are going to do what you want.
It doesn't need to be samples. I just need to understand a ballpark on the
costs of the parts.
> If you're going
> to build a high power controller on your own you should seriously
> consider using ISOTOP (TO227A?) packages. Then "all you have to do" is
> cut out some copper bus bars.
A quick look shows that this is feasible then from a cost standpoint.
Digikey shows a 200V 110A part here:
runs $35 apiece. So even if you use 4 of them you're under $150.
> You can use copper as a current measuring
> shunt if you use a 4-wire connection and have a tempco adjustment. I
> can't stress enough the need for very quick overcurrent sensing and
> protection. In my opinion current measurement is the most difficult part
> of designing high power motor controllers.
I welcome ideas in this area.
> Cafe electric uses high-side drivers and IGBTs for their 1 and 2kA
> controllers. For 160v you're still in a good realm for MOSFETs I
> believe. I don't think you're looking at nearly $500 in parts for a 300A
> controller, but it will quickly add up the first time you blow up your
> expensive ISOTOP FETs and diodes. You'll certainly learn a lot. I'm
> interested now! I want to convert a motorcycle but the controller can be
> the same.
So where do I go to checkout freewheeling diodes? What specs do they need
to have?
Also any ideas about creating a stiff driver to drive the gates? The Vgs is
20V so there's going to need to be a lower voltage driver for the parts.
On Wed, Dec 05, 2007 at 12:49:56PM -0500, Martin wrote:
>
>
> Byron Jeff wrote:
> > Nice. But it runs $100K. I'd like to spend less than 1% of that cost.
> >
> > BAJ
> >
>
>
> How are you planning to get batteries for that cost? They're going to
> cost you around $100 a piece.
Good question. I'm hoping to scrounge up a used pack.
Also I've read reports that the Sams batteries are running $30 cheaper.
Please change the topic if you want to talk about the pros/cons of
hybrids. We're talking about electric cars, which are quite well proven
more efficient than gasoline cars.
Funny NYPD wrote:
> The overall pollution of electric/hybrid cars probably is many times higher than regular vehicles.
>
KPL wrote:
>>> When driving, accelerate quickly and then coast.
>> I actually practiced coasting today just to see what it's like. It's an
>> interesting experience.
>
> Does this requirement still applies to series-wound motor? Doesn't
> it's current naturally drop low when it does not have to accelerate?
>
Martin wrote:
> I believe you're in the realm of a Curtis 1220, but that is actually a
> 120v (nominal) controller.
> There are no samples that are going to do what you want. If you're going
> to build a high power controller on your own you should seriously
> consider using ISOTOP (TO227A?) packages. Then "all you have to do" is
> cut out some copper bus bars. You can use copper as a current measuring
> shunt if you use a 4-wire connection and have a tempco adjustment. I
> can't stress enough the need for very quick overcurrent sensing and
> protection. In my opinion current measurement is the most difficult part
> of designing high power motor controllers.
> Cafe electric uses high-side drivers and IGBTs for their 1 and 2kA
> controllers. For 160v you're still in a good realm for MOSFETs I
> believe. I don't think you're looking at nearly $500 in parts for a 300A
> controller, but it will quickly add up the first time you blow up your
> expensive ISOTOP FETs and diodes. You'll certainly learn a lot. I'm
> interested now! I want to convert a motorcycle but the controller can be
> the same.
> -
> Martin
>
I owned an electric motorcycle when I was a young engineer. I drove it
2miles each way to work
at Datapoint Corp in San Antonio, TX. It was great fun, but was only
1HP PM motor. To adjust
speed, it switched in 12V or 24V batteries. Very primitive.
One could do wonderful things today with the idea...
Bob Axtell wrote:
> I owned an electric motorcycle when I was a young engineer. I drove it
> 2miles each way to work
> at Datapoint Corp in San Antonio, TX. It was great fun, but was only
> 1HP PM motor. To adjust
> speed, it switched in 12V or 24V batteries. Very primitive.
>
> One could do wonderful things today with the idea...
>
> --Bob A
>
I have a 6.7" Advanced DC series motor and 275 amp Curtis controller
sitting in my basement. All I need is a motorcycle with a dead engine. I
was thinking an 80s Honda standard might work well.
-
Martin
> I owned an electric motorcycle when I was a young engineer. I drove it
> 2miles each way to work
> at Datapoint Corp in San Antonio, TX. It was great fun, but was only
> 1HP PM motor. To adjust
> speed, it switched in 12V or 24V batteries. Very primitive.
>
> One could do wonderful things today with the idea...
>
> --Bob A
Not to hijack the thread... but Bob, were you there at the time of the
8008 beginning?
> On Wed, Dec 05, 2007 at 12:49:56PM -0500, Martin wrote:
>
>> Byron Jeff wrote:
>>
>>> Nice. But it runs $100K. I'd like to spend less than 1% of that cost.
>>>
>>> BAJ
>>>
>>>
>> How are you planning to get batteries for that cost? They're going to
>> cost you around $100 a piece.
>>
>
> Good question. I'm hoping to scrounge up a used pack.
>
> Also I've read reports that the Sams batteries are running $30 cheaper.
>
> That's another part of the research.
>
> BAJ
>
I recommend that you create your battery system as increments of 12V
packs; that way, you can identify
a defective pack easily. Look at the 10 MAH RC Racing packs made by
OnlyBatteryPacks.Com. They
are VERY strong, made with 10 10MAH "D" Cells. Being charged
individually at 12V (15.5V charge
voltage applied) provides a capable, strong, reliable system if strung
into 48V, 96V, or 120V DC systems.
The weight is less than HALF of lead-acid with more power.
After weeks of research, I determined that pulse-charging (applying full
voltage, but keeping the on-time
very limited until the cell has recovered to 25% charge, then applying a
duration equivalent to 1/2C), ensures
a solid, repeatable, reliable charge for many cycle durations. I use a
series of isolated 15V 5A power supplies
as the charger basis.
> Please change the topic if you want to talk about the pros/cons of
> hybrids. We're talking about electric cars, which are quite well proven
> more efficient than gasoline cars.
No, they are NOT. They only move the pollution to another location.
e.g. Coal or gas fired power plants still pollute.
And their UNgreen cost of production (heavy metals in batteries, etc.)
probably make them LESS green than today's gasoline powered vehicles.
You have to look at TOTAL picture to be able to say EV's are 'better'
than gasoline powered, and they are NOT!
Kinda like the stampede to ethanol fuels.
The TOTAL cost of producing such fuels in North America (corn based) is
MUCH more than the gasoline they save.
You have to INCLUDE the cost of fertilizer, subsidies, fuel for
cultivation and shipping and all the OTHER 'hidden' costs before you can
make a meaningful comparison.
ca.today.reuters.com/stocks/FinanceArticle.aspx?view=PR&symbol=CM.TO&storyID=116533+22-Oct-2007+PRN
"America's efforts to add more corn-based ethanol to the nation's gas
tanks will fuel little more than inflation: CIBC World Markets
Report finds going yellow to send food prices soaring while delivering
dubious energy benefits"
and dozens more objective reports can be found with google.
> Funny NYPD wrote:
>
>>The overall pollution of electric/hybrid cars probably is
many times higher than regular vehicles.
Key word there is 'overall'. Include EVERYTHING used in
making and running EVs vs. gas/diesel in order to draw a
meaningful conclusion.
It's just another 'big lie' to make some people very rich.
Marcel Duchamp wrote:
> Bob Axtell wrote:
>
>
>> I owned an electric motorcycle when I was a young engineer. I drove it
>> 2miles each way to work
>> at Datapoint Corp in San Antonio, TX. It was great fun, but was only
>> 1HP PM motor. To adjust
>> speed, it switched in 12V or 24V batteries. Very primitive.
>>
>> One could do wonderful things today with the idea...
>>
>> --Bob A
>>
>
> Not to hijack the thread... but Bob, were you there at the time of the
> 8008 beginning?
>
I was. I knew the person who spec'd the opcodes, Gary Asbell. Datapoint
(then Computer Terminal
Corp, I think) was full of very clever people, er... myself included,
of course...<grin>
> Martin wrote:
>
>
>> Please change the topic if you want to talk about the pros/cons of
>> hybrids. We're talking about electric cars, which are quite well proven
>> more efficient than gasoline cars.
>>
>
> No, they are NOT. They only move the pollution to another location.
> e.g. Coal or gas fired power plants still pollute.
>
> And their UNgreen cost of production (heavy metals in batteries, etc.)
> probably make them LESS green than today's gasoline powered vehicles.
>
> You have to look at TOTAL picture to be able to say EV's are 'better'
> than gasoline powered, and they are NOT!
>
> Kinda like the stampede to ethanol fuels.
>
> The TOTAL cost of producing such fuels in North America (corn based) is
> MUCH more than the gasoline they save.
> You have to INCLUDE the cost of fertilizer, subsidies, fuel for
> cultivation and shipping and all the OTHER 'hidden' costs before you can
> make a meaningful comparison.
>
> http://www.factsaboutethanol.org/?p=234
>
> ca.today.reuters.com/stocks/FinanceArticle.aspx?view=PR&symbol=CM.TO&storyID=116533+22-Oct-2007+PRN
> "America's efforts to add more corn-based ethanol to the nation's gas
> tanks will fuel little more than inflation: CIBC World Markets
> Report finds going yellow to send food prices soaring while delivering
> dubious energy benefits"
>
> and dozens more objective reports can be found with google.
>
>
>> Funny NYPD wrote:
>>
>>
>>> The overall pollution of electric/hybrid cars probably is
>>>
> many times higher than regular vehicles.
>
> Key word there is 'overall'. Include EVERYTHING used in
> making and running EVs vs. gas/diesel in order to draw a
> meaningful conclusion.
>
> It's just another 'big lie' to make some people very rich.
>
> Robert
>
>
While I am generally not very "green", my ultimate plan is to use cheap
solar
cells to charge the electric car.
Funny NYPD wrote:
> The overall pollution of electric/hybrid cars probably is many times higher than regular vehicles.
>
> I knew the national lab and GM did this study 7 years ago.
That last sentence had an acronym in it, "GM". Where have I heard that
before? Oh yes, "Who Killed The Electric Car" :)
That's some great information on ethanol, Robert, but we're talking
about electric cars. Ethanol is not used to produce electricity in the
US. Try the EIA if you want some generation statistics. It's either
coal, hydroelectric, or nuclear (sum=95%+)
I'm going to consider this politics and not respond to this thread anymore.
-
Martin
> Martin wrote:
>
>
>> Please change the topic if you want to talk about the pros/cons of
>> hybrids. We're talking about electric cars, which are quite well proven
>> more efficient than gasoline cars.
>>
>
> No, they are NOT. They only move the pollution to another location.
> e.g. Coal or gas fired power plants still pollute.
>
> And their UNgreen cost of production (heavy metals in batteries, etc.)
> probably make them LESS green than today's gasoline powered vehicles.
>
> You have to look at TOTAL picture to be able to say EV's are 'better'
> than gasoline powered, and they are NOT!
>
> Kinda like the stampede to ethanol fuels.
>
> The TOTAL cost of producing such fuels in North America (corn based) is
> MUCH more than the gasoline they save.
> You have to INCLUDE the cost of fertilizer, subsidies, fuel for
> cultivation and shipping and all the OTHER 'hidden' costs before you can
> make a meaningful comparison.
>
> http://www.factsaboutethanol.org/?p=234
>
> ca.today.reuters.com/stocks/FinanceArticle.aspx?view=PR&symbol=CM.TO&storyID=116533+22-Oct-2007+PRN
> "America's efforts to add more corn-based ethanol to the nation's gas
> tanks will fuel little more than inflation: CIBC World Markets
> Report finds going yellow to send food prices soaring while delivering
> dubious energy benefits"
>
> and dozens more objective reports can be found with google.
>
>
> Bob Axtell wrote:
>
>
>> I owned an electric motorcycle when I was a young engineer. I drove it
>> 2miles each way to work
>> at Datapoint Corp in San Antonio, TX. It was great fun, but was only
>> 1HP PM motor. To adjust
>> speed, it switched in 12V or 24V batteries. Very primitive.
>>
>> One could do wonderful things today with the idea...
>>
>> --Bob A
>>
>
> Not to hijack the thread... but Bob, were you there at the time of the
> 8008 beginning?
>
Robert Rolf wrote:
> Martin wrote:
>
>> Please change the topic if you want to talk about the pros/cons of
>> hybrids. We're talking about electric cars, which are quite well proven
>> more efficient than gasoline cars.
>
> No, they are NOT. They only move the pollution to another location.
> e.g. Coal or gas fired power plants still pollute.
Sure, if you're talking gas Hummer vs electric Hummer. But one of the
things batteries force you to do is make a more efficient vehicle in the
first place.
>Martin wrote:
>
>
>
>>Please change the topic if you want to talk about the pros/cons of
>>hybrids. We're talking about electric cars, which are quite well proven
>>more efficient than gasoline cars.
>>
>>
>
>No, they are NOT. They only move the pollution to another location.
>e.g. Coal or gas fired power plants still pollute.
>
>And their UNgreen cost of production (heavy metals in batteries, etc.)
>probably make them LESS green than today's gasoline powered vehicles.
>
>You have to look at TOTAL picture to be able to say EV's are 'better'
>than gasoline powered, and they are NOT!
>
>Kinda like the stampede to ethanol fuels.
>
>The TOTAL cost of producing such fuels in North America (corn based) is
>MUCH more than the gasoline they save.
>You have to INCLUDE the cost of fertilizer, subsidies, fuel for
>cultivation and shipping and all the OTHER 'hidden' costs before you can
>make a meaningful comparison.
>
>
Thats the mistake a lot of people make.. You just use the cost per
bushel that they pay the farmer for the corn. the cost for
"fertilizer, subsidies, fuel for cultivation and shipping and all the
OTHER 'hidden' costs" are covered by the farmer who sells the corn.
> That's some great information on ethanol, Robert, but we're talking
> about electric cars. Ethanol is not used to produce electricity in the
> US. Try the EIA if you want some generation statistics. It's either
> coal, hydroelectric, or nuclear (sum=95%+)
> I'm going to consider this politics and not respond to this thread anymore.
> -
> Martin
My point was that people are arguing that EV's are more efficient
without considering ALL the input costs.
Just like the ethanol folks.
Solar panels are great, except that producing them uses huge
amounts of electricity and produces very toxic wastes (arsene
gas, arsenic, volatile organics, etc.).
EV's are great, except that charging them with polluting plants
is 'false' green thinking.
In the early 50's it was GM that teamed with Standard Oil Co. to get rid
of electric mass transportation and move it to oil (mainly gasoline back
then). The electric PCC street cars from Cleveland can be found still
running in Toronto, and Spain I think.Within a few years the streetcars
and trackless trolleys (rubber tired street buses with overhead electric
supply from 2 street car type trolley poles.) The equipment ran
frequently and was used heavily.
> Funny NYPD wrote:
>
>> The overall pollution of electric/hybrid cars probably is many times higher than regular vehicles.
>>
>> I knew the national lab and GM did this study 7 years ago.
>>
>
> That last sentence had an acronym in it, "GM". Where have I heard that
> before? Oh yes, "Who Killed The Electric Car" :)
>
> -Bob
>
Got the car - an 80-something Ford Ranger pickup. Unpowered brakes and
steering. Standard transmission. One of the on-line parts places
already has a conversion/motor mounting plate for this model
transmission (and lots of others). I don't think this would be
overweight, it's a small truck, nothing to it.
My commute would need about a 25 mile roundtrip range, which could
either be done at ~65 freeway speed, or about the same distance at ~35 +
stop&go. Only a couple of hundred feet in elevation change.
I've looked at the over-the-counter drop-in components, which would
probably add up to $5K. I might be able to do that if I spread it out,
but I'd really be interested in some DIY alternatives.
> Any ideas about the economics? If it isn't cost effective to hand build,
> then I probably won't waste time doing so. Say if the target is something
> like 160V, 300A, 16 KHz. What would be a sample MOSFET that could be
> paralleled to deliver that type of power? If it's going to be $500 in power
> electronics, then buying a controller would be the right move. However if
> the electronics are cheaper and you pay the rest with sweat equity, then it
> may be worth looking at.
A GNU controller would be a good idea. I designed one for 24-36V 200A
use that was modular, used PC board traces for current sensing. It was
quite a bit cheaper than commercial units. The biggest investment was
time. A >100V controller is a little less forgiving during development,
and a motor-generator dyno setup on the cheap is harder to do safely.
> There's about a 125 lbs difference in the curb weights of the two vehicles
> (1993 Tercel (2002 lbs) vs. the Metro (1874 lbs for the 1997 hatchback)).
> While I understand that every pound counts, from a cost standpoint it
> simply doesn't make sense to me to get rid of a car that I already bought
> and paid for in order to buy a car that's a little over 100 lbs lighter.
That's a couple of batteries worth of weight. Or a passenger. I get your
point, of course, bird in the hand, but you're already on that slippery
slope that leads to a vehicle with a 15 mile range, a used battery pack
that loses more energy than it stores, etc.
> I must reiterate that cost is my primary concern. I'm not looking to invest
> $15K, $10K, or even $5K into this project. Even more than trying to
> minimize weight, I'm trying to minimize costs. And that's the costs of
> everything. I need to find something other than an Advance 9 motor because
> they run $1000 each for the low end model. I want to locate a cheap used
> battery pack, even if half of its lifetime is gone. I plan to use the car
> that I have. It's not a ultralight, but it isn't a boat anchor either. Like
> I said above I'd be willing to put sweat equity into a controller because
> commercial controllers are expensive.
>
> Say I have a free donor car and a $1K budget. Should I forget about it? I
> know this is a beg, borrow, scrounge project. I'm OK with foregoing pretty
> much everything except for cost and performance adequate enough to be safe
> on the roads. A vehicle that tops out at 10MPH, takes 20 minutes to
> accelerate to top speed, and has a range of 1 mile doesn't work. However, a
> bettery pack that'll only last for a year, a simple cheap controller, or an
> adapted lower voltage motor because it's cheap is doable.
If you have plenty of free time and merely want to learn, sure. But I
heartily recommend that you fight for every pound as if it were solid
gold. And used batteries are awful. Nobody sells used batteries that are
any good. Why woud they sell a good battery? You will have to buy new
batteries, there's no way around it.
Lead-acid batteries are a real disappointment. So if that's all you can
afford, prepare to be underwhelmed. You'll have a vehicle you sweated a
thousand hours over but you saved a few bucks. On the other hand,
spending more money on a lighter car and lighter batteries, you'll still
put a thousand hours into it, but it will be something fun to drive.
>> You pretty much need to retain the clutch. Only a skilled
>> driver can drive without one, and an electric motor doesn't spin down
>> when you take your foot off the pedal like a gas engine would.
>
> Now I'm confused. From what I've been reading I got the impression that it
> was the exact opposite. Releasing the accelerator stops the motor and that
> gears could be shifted without clutching. I absolutely don't mind retaining
> the clutch and I planned to do so. But I'd like to be clear about the
> situation you outline above.
OK, here's the scenario. Upshifting. You pull it out of first, the motor
is spinning 2000 rpm too high for the next gear. Taking your foot off
the accelerator doesn't stop a DC motor so you grind into second. If you
have machined a lightweight coupling between motor and transmission with
no flywheel it's OK, but you do need to be the kind of person who has a
good feel for driving.
>> You can do regenerative braking with almost any motor,
>
> I thought that it was simple with AC motors but that the controller had to
> do a lot of work on series DC motors. High end Zapis do DC braking but that
> the low end Curtis' didn't.
It triples the complexity of the controller, and more than doubles the cost.
>
>> but in practice a skilled driver will outperform it!
>
> Good to know. Like I said I wasn't planning on it.
> Martin wrote:
>
>
>> That's some great information on ethanol, Robert, but we're talking
>> about electric cars. Ethanol is not used to produce electricity in the
>> US. Try the EIA if you want some generation statistics. It's either
>> coal, hydroelectric, or nuclear (sum=95%+)
>> I'm going to consider this politics and not respond to this thread anymore.
>> -
>> Martin
>>
>
> My point was that people are arguing that EV's are more efficient
> without considering ALL the input costs.
> Just like the ethanol folks.
>
> Solar panels are great, except that producing them uses huge
> amounts of electricity and produces very toxic wastes (arsene
> gas, arsenic, volatile organics, etc.).
>
> EV's are great, except that charging them with polluting plants
> is 'false' green thinking.
>
> R
>
And I've already said that when charging from the electricity grid of
the continental US, most of your energy is from coal, nuclear, or
hydroelectric. The "but the electricity comes from somewhere!" argument
is NOT new.
My car gets an average 40 miles per gallon. The energy content of 1
gallon of gas is about 36 kilowatt hours (131 megajoules). That's 1.1
miles per kilowatt hour. A Honda Civic conversion might get around 300
watt*hours per mile. That's 3 miles per kWh. Now I know you're not going
to accept my hypothesis based on "tank" to wheel efficiency, but if you
make reasonable estimations the numbers are still in favor of electric
cars.
Others have hypothesized that you can "follow the money" to estimate how
efficient something is. If we assumed that gasoline wasn't an expensive,
(HIGHLY SUBSIDIZED) commodity, this would even more in favor of electrics:
100 miles in my Civic would take about 2.5 gallons of gas. That's 90 kWh
of energy. The electric conversion would take 33 kWh. Electricity cost
varies, but it is averaged to $0.106 a kWh (per EIA). The electricity
costs $3.30. The gasoline costs about $10.50.
The electric car also uses/leaks no oil, antifreeze, has half (if that)
as many moving parts, is quiet, etc.
I'm not trying to sell you a car here.
Bob Blick wrote:
> KPL wrote:
>
>>>> When driving, accelerate quickly and then coast.
>>>>
>>> I actually practiced coasting today just to see what it's like. It's an
>>> interesting experience.
>>>
>> Does this requirement still applies to series-wound motor? Doesn't
>> it's current naturally drop low when it does not have to accelerate?
>>
>>
>
> Low is not zero. Zero current is better.
>
but presumably it takes more energy to get up to speed.
IE you will pull lots of power accelerating to a higher speed (with more
aero losses) then decelerate at 0 power, then pull lots of power again
to maintain a speed.
You would be best off accelerating at the peak efficiency of the motor.
Then perhaps optimize the motor selection to have an efficient cruse
speed. Your batteries etc will provide much more energy at lower current
draw to boot. Especially with lead acids.
> Ah! They want use to go back to cavemen, no Pics, no cars, no bicycles,
> no shoes - ouch, there is a couple of inches of snow on the ground. ~:
>
> Marcel Duchamp wrote:
>> Bob Axtell wrote:
>>
>>
>>> I owned an electric motorcycle when I was a young engineer. I drove it
>>> 2miles each way to work
>>> at Datapoint Corp in San Antonio, TX. It was great fun, but was only
>>> 1HP PM motor. To adjust
>>> speed, it switched in 12V or 24V batteries. Very primitive.
>>>
>>> One could do wonderful things today with the idea...
>>>
>>> --Bob A
>>>
>>
>> Not to hijack the thread... but Bob, were you there at the time of the
>> 8008 beginning?
A friend has an electric bicycle conversion. It has friction drive on the
front wheel. A small permanent magnet motor is on each side of the wheel.
For fast, the motors are in parallel. For slow, they are in series. This
also does regenerative braking if you put it in "slow" when going down a
hill.
As a kid, I built an "electric car" out of wood with wagon wheels. It had
chain drive from a car starter to one of the wagon wheels. I ended up
having to double the wheels on the back due to the weight of the battery
and the torque of the motor. My speed control consisted of reaching behind
to clip a big jumper cable type clip on the battery or remove it.
> Bob Blick wrote:
>> KPL wrote:
>>
>>>>> When driving, accelerate quickly and then coast.
>>>>>
>>>> I actually practiced coasting today just to see what it's like. It's an
>>>> interesting experience.
>>>>
>>> Does this requirement still applies to series-wound motor? Doesn't
>>> it's current naturally drop low when it does not have to accelerate?
>>>
>>>
>> Low is not zero. Zero current is better.
>>
> but presumably it takes more energy to get up to speed.
> IE you will pull lots of power accelerating to a higher speed (with more
> aero losses) then decelerate at 0 power, then pull lots of power again
> to maintain a speed.
> You would be best off accelerating at the peak efficiency of the motor.
> Then perhaps optimize the motor selection to have an efficient cruse
> speed. Your batteries etc will provide much more energy at lower current
> draw to boot. Especially with lead acids.
What I'm saying is that looking at the different places where loss
occurs, and discharge characteristics of batteries, it's hard to say
what driving style will work best. I could use the same data as you are
drawing from and make the opposite argument. For instance, lead-acid
batteries like to have recovery time. My method gives them that time,
yours doesn't. How important is that? The data available from the
manufacturers isn't going to give you anything you can calculate from.
But when it comes to talking about practical experience, I can say
without a doubt, accelerating quickly and then coasting is the most
efficient method for electric cars. It's also the method that works best
for a Honda Insight hybrid. I can't speak about other hybrids.
I agree with the anti Hybrid/electric stance in most cases, but not all.
The difference is that electricity CAN be produced via sustainable (green)
means and petrol can NOT. The fact that most electricity is still produced
with coal does invalidate the advantage for most drivers, but there are some
who have PV systems and spend little enough time on the road to be able to
make it worth while.
Batteries can be recycled.
Electricity can be produced without damaging the environment.
There is hope... for the future, if not for today.
In the mean time, I drive an old gas car...
...and I strongly support research and development, including that by
PICListers, into electric vehicle and alternative power generation
technology.
I'm still ready to offer $500 to anyone who will build one of these
techref.massmind.org/techref/member/plp-actcom-f00/sun-turbo-1.htm
and document the experience. I have also offered to pay for the right to
publish the experience, successful or not, of doing an eCar conversion.
On Dec 5, 2007 4:00 PM, Robert Rolf <EraseMERobert.RolfspamspamBeGoneualberta.ca> wrote:
> Martin wrote:
>
> > Please change the topic if you want to talk about the pros/cons of
> > hybrids. We're talking about electric cars, which are quite well proven
> > more efficient than gasoline cars.
>
> No, they are NOT. They only move the pollution to another location.
> e.g. Coal or gas fired power plants still pollute.
Of course it needs to be said that at the beginning of each new
technology, generally speaking, it is far less efficient, cheap,
powerful than the previous (incumbent) technology.
Over time this will change.
Further, moving the cost to another polution source, especially
centralized even considering line losses, etc still gives great
benefits in terms of pollution per kWH generated from a fossil fuel.
Cars are atrocious compared to new power plants being built today
(IIRC), though old plants are still pretty bad.
So for right now, yes, hybrid and electric cars actually do more
overall harm to the environment than their siblings, but keep in mind
that part of this is a not-in-my-backyard situation. Of course people
in smog filled cities would rather make China's skyline darker if
it'll improve their hometown's own air, and China is all too happy to
oblige.
>
> But when it comes to talking about practical experience, I can say
> without a doubt, accelerating quickly and then coasting is the most
> efficient method for electric cars. It's also the method that works best
> for a Honda Insight hybrid. I can't speak about other hybrids.
>
> Cheerful regards,
>
> Bob
That should be a function of controller, kind of cruise control, so
driver does not have to think about it.
Just to maintain speed with preset precision, by turning the motor on and off.
> While I am generally not very "green", my ultimate plan is
> to use cheap
> solar cells to charge the electric car.
I may (or may not) be able to help there.
The factory in China that I visited recently (and may visit
again before Christmas) buys in raw finished crystalline
photovoltaic cells and slices, dices, glues, bonds,
encapsulates, laminates, hammers, laser trims and more to
produce all sorts of end user PV products. They have
impressive stacks of larger PV panels than I've ever seen
before - and they make very small domestic market panels as
well.
They MAY be amenable to reselling either whole raw cells or
sliced portions. No doubt you can get these directly from
the maker but the MOQs are liable to be horrendous. I don't
know how happy they would be with this idea, but I can ask.
By replacing almost free Chinese labour with free personal
labour one may (or may not) be able to produce PV arrays
economically to ones own spec.
> Thats the mistake a lot of people make.. You just use the
> cost per
> bushel that they pay the farmer for the corn. the cost
> for
> "fertilizer, subsidies, fuel for cultivation and shipping
> and all the
> OTHER 'hidden' costs" are covered by the farmer who sells
> the corn.
Subsidies are a negative cost that falsely reduce the cost
reflected by the sale price. Subsidies MUST be factored out
for meaningful comparisons to be made.
Also, as I have commented on at length before, with little
apparent effect :-), the invisible hand is a known thief
that steals resource at such cost as it may be had,
regardless of its value. Thus, the cost of a product often
does not reflect its value in the wider order of things but
only the cost at which it may be obtained giving applicable
circumstances. Factors relating to long term value of a
resource to society or free access to a resource that is in
fact costing the system as a whole in real long term terms
are blithely ignored by the hand.
The obvious fallacy of "what you don't know won't hurt you"
is exploited to the full by the hand which will take
advantage of anything that others don't know that it can
turn to its advantage.
So Real cost = (market cost + subsidies) x K.
Where 1 < K < enormous (for most values of 1).
>
> The electric car also uses/leaks no oil, antifreeze, has half (if that)
> as many moving parts, is quiet, etc.
> I'm not trying to sell you a car here.
>
> -
> Martin
and those moving parts that are present, are much less stressed, since
electric motor works much more smoothly.
> The difference is that electricity CAN be produced via
> sustainable (green)
> means and petrol can NOT.
In fact, fwiw, although the fact seems to have little worth
to people for reasons which are obscure, it can.
Miscellaneous organic matter, including some pretty foul
garbage, can be converted to very nice long chain
hydrocarbon.
I know a man in Texas who is working on this technology at
present.
> The fact that most electricity is still produced
> with coal does invalidate the advantage for most drivers,
Coal can be a very clean fuel if properly burned. The fact
that it enthusiastically produces CO2 is 'more likely than
not' a bit of a problem in the current 'climate'.
> > But when it comes to talking about practical
> experience, I can say
> > without a doubt, accelerating quickly and then
> coasting is the most
> > efficient method for electric cars. It's also the
> method that works best
> > for a Honda Insight hybrid. I can't speak about
> other hybrids.
> >
> > Cheerful regards,
> >
> > Bob
>
> That should be a function of controller, kind of
> cruise control, so
> driver does not have to think about it.
> Just to maintain speed with preset precision, by
> turning the motor on and off.
>
> --
> KPL
Or have the ability to upload your own programming
into some sort of java-space.
On Tuesday 04 December 2007, Martin wrote:
> Is there a specific reason why you want to do this as a piclist
> project? The electric vehicle discussion list does this kind of thing
> as it's
Bryan Bishop wrote:
> On Tuesday 04 December 2007, Martin wrote:
>
>> Is there a specific reason why you want to do this as a piclist
>> project? The electric vehicle discussion list does this kind of thing
>> as it's
>>
>
> Can you link us to the EV discussion list?
>
> - Bryan
> http://evdl.org/
-
Martin
clayton.edu> wrote:
