EV Digest 5497
Topics covered in this issue include:
1) Re: Regen
by Christopher Zach <[EMAIL PROTECTED]>
2) Re: Other Hybrids Honda Insight
by Christopher Zach <[EMAIL PROTECTED]>
3) RE: Regen
by Cor van de Water <[EMAIL PROTECTED]>
4) Re: Regen
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
5) Re: Other Hybrids Honda Insight
by Ralph Merwin <[EMAIL PROTECTED]>
6) Re: Regen
by Ralph Merwin <[EMAIL PROTECTED]>
7) Re: Regen
by Chet Fields <[EMAIL PROTECTED]>
8) RE: Regen
by "Bill Dennis" <[EMAIL PROTECTED]>
9) Three-wheel Go-cart
by "Bill Dennis" <[EMAIL PROTECTED]>
10) cost of conversion WAS: Donor Car Recommendations for EV Conversion
by David Brandt <[EMAIL PROTECTED]>
11) Re: EV Copyright Infringement running rampant
by Chip Gribben <[EMAIL PROTECTED]>
12) Re: AC vs. DC [long, technical]
by Lee Hart <[EMAIL PROTECTED]>
13) Re: Regen
by "Evan Tuer" <[EMAIL PROTECTED]>
14) Re: Question about NIMH patent(s)
by Lee Hart <[EMAIL PROTECTED]>
15) Re: Front-Wheel or Rear-Wheel Drive
by jimevdl <[EMAIL PROTECTED]>
16) Re: Donor Car Recommendations for EV Conversion
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
17) Re: Three-wheel Go-cart
by "Peter VanDerWal" <[EMAIL PROTECTED]>
18) RE: Three-wheel Go-cart
by "Roger Stockton" <[EMAIL PROTECTED]>
19) Re: Regen
by David Dymaxion <[EMAIL PROTECTED]>
20) Re: Three-wheel Go-cart
by "Mark Grasser" <[EMAIL PROTECTED]>
21) Re: AC vs. DC [long, technical]
by "Arthur W. Matteson" <[EMAIL PROTECTED]>
--- Begin Message ---
Regen should be OFF until you are below 80% SOC and/or
configured to respect a max pack voltage and throttle back,
the Prius does it by reducing and eventually disabling
regeneration based on SOC.
*nod* The Prizm limits max pack voltage to 365 (14.7 volts per battery).
However I think that's still a bit high, as you're pumping 30 amps into
the pack. At that point the regs are kind of like little paper
parachutes :-)
On the other hand, this totally fits in with the Hawker "charge them
hard for a bit every once in awhile" thing. Nothing that's on the market
is going to beat a 50kw motor on full regen.
Chris
--- End Message ---
--- Begin Message ---
I don't see Keith's email address, so I'll reply here:
Keith: Badger Honda a bit. My dad has an insight, and Honda found a
secret warranty thing that allowed them to replace the pack free. He had
about 110k as well.
On a more EV related note: This is going to happen more and more as time
goes on. At some point people will start balking at replacing a 3k
battery and just sell the insight. Maybe it would be a good EV
conversion candidate...
Chris
--- End Message ---
--- Begin Message ---
I think it was Electro Automotive who said that
charging should be done at the bottom of the hill.
In your case, it would be best to charge at work,
if possible, not at home.
Do you need to equalize every single night?
I think it is Roland Wiench who charges to 80%
every time and only takes his pack to 100% once
every ten cycles or so.
But he has lead and you have Lithium, not sure
if that makes a difference.
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Bill Dennis
Sent: Thursday, May 18, 2006 7:42 AM
To: ev@listproc.sjsu.edu
Subject: RE: Regen
Ralph wrote:
>One problem I had with regen was with a fully charged pack and any downhill
>sections of the road.
This downhill dilemma will be my situation when I start using my EV. The
first part of my commute is 5 miles downhill, then the last part is 5 miles
back up at the end of the day.
I've got Li-ion cells, so I want to charge them all the way each night to
equalize them--therefore I won't be able to put any of the downhill energy
back into them.
One thing I had considered (in the future) was keeping some smaller voltage
string in the car for regen, perhaps BB600's. I could charge them
partially, then let the downhill morning commute regen into them. At night
I was thinking that when I got to the uphill part, I could be going at 30mph
or so with the Li-ions just before hitting the hill, then disengaging the
Curtis controller from the motor, and instead switching on a contactor that
connected the BB600's directly to the motor to get me back up the last 5
miles. This would save high-current draw on the Li-ions, too.
Are there any problems with this method?
Thanks.
Bill Dennis
--- End Message ---
--- Begin Message ---
Ralph,
(Seems strange ... as if I'm talking to myself ...) Would it be
pragmatic to redirect the fully charged regen state energy to a
resistive load of some sort, like a heating element (could prove useful
during the winter months) or an auxiliary battery? ... further would
seem like there would be some sort of over-voltage protection built in
to the controller.
Just the 2 cents of a newbie (unadjusted to inflation that make my
opinion worth about ... ummm ... absolutely nothing),
Ralph P.
Ralph Merwin wrote:
[EMAIL PROTECTED] writes:
Once again a question that may spark debate: Is the amount of energy
re-cooped from braking sufficient to off set the additional weight gain
of the regen itself?
Ralph,
There has been discussion in the past about regen, and the benefit is
claimed to be about 5% additional range with the right circumstances.
My Geo Prizm used to have a Zapi H2 controller with regen. The additional
weight consisted of a couple of contactors - hardly a penalty.
As for any real benefit, my commute at the time was 26 miles round trip,
with a long uphill climb on the freeway going to work (and the long coast
on the way home). The trip used about 66 amp hours. On a good day with
the traffic moving just right, I could coast all the way down the hill on
the freeway in the evening, and the pack would get about 2 amp hours put
back in. On most days though, traffic prevented me from coasting and I
didn't see much regen. I had no way to measure the regen during the
balance of the trip (stop-n-go traffic, etc).
One problem I had with regen was with a fully charged pack and any downhill
sections of the road. I had to keep my foot lightly on the pedal to keep
the controller out of regen mode or else the pack voltage would go too high.
Ralph
--- End Message ---
--- Begin Message ---
Christopher Zach writes:
>
> On a more EV related note: This is going to happen more and more as time
> goes on. At some point people will start balking at replacing a 3k
> battery and just sell the insight. Maybe it would be a good EV
> conversion candidate...
I'm actually counting on this for a future project - converting an Insight
or current model Prius into a Pure EV. The cost of replacement batteries
will lead to cheap Insights and Prius' (unless, of course, we are so lucky
as to have battery prices fall substantially).
Ralph
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] writes:
>
> (Seems strange ... as if I'm talking to myself ...) Would it be
> pragmatic to redirect the fully charged regen state energy to a
> resistive load of some sort, like a heating element (could prove useful
> during the winter months) or an auxiliary battery? ... further would
> seem like there would be some sort of over-voltage protection built in
> to the controller.
In my opinion, a vehicle with regen does need some alternative dump load
it can use when the batteries are full, and the controller should be smart
enough to switch from the pack to the dump load. Otherwise the controller
has no choice but to disable regen if the pack is full, which makes braking
action feel unpredictable. I can feel this on my wife's Prius - the feel
of the braking changes as the pack fills up.
Ralph M.
--- End Message ---
--- Begin Message ---
I join Ralph P. (chemcat9) in the puzzled category on Regen being a newbie
myself. I had brought up this topic the other day and hopefully it only got
swept under the rug because of all the excitement about the cross country trips
to the races and such.
But what is the issue with shunt wound motors. Are they more expensive, or
unobtainable? Are the controllers to allow regen more complicated and
expensive? (Otmar?)
My Soleq EVCort has the *DC* shunt wound motor with regen and (echoing someone
elses sentiments in a prior post) IMHO it is quite charming. I like that fact
that I don't have to rely on the brakes to stop 2 tons of vehicle and that at
least some of that energy is going back into the batteries. Saves brake pads,
increases range, probably contributes some to the life of the batteries as
well.
It seems rather overkill that you should need to add a completely redundant PM
motor and all of it's associated linkage both mechanical and electrical
exclusively for the regen.
Anteing up my inflation adjusted $.02 as well, ;)
Chet
--- "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote:
> Ralph, (Merwin)
>
> (Seems strange ... as if I'm talking to myself ...) Would it be
> pragmatic to redirect the fully charged regen state energy to a
> resistive load of some sort, like a heating element (could prove useful
> during the winter months) or an auxiliary battery? ... further would
> seem like there would be some sort of over-voltage protection built in
> to the controller.
>
> Just the 2 cents of a newbie (unadjusted to inflation that make my
> opinion worth about ... ummm ... absolutely nothing),
>
> Ralph P.
__________________________________________________
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--- End Message ---
--- Begin Message ---
I've thought of regenning to the 12V system's battery, too. You could even
use an alternator for the task.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Thursday, May 18, 2006 9:13 AM
To: ev@listproc.sjsu.edu
Subject: Re: Regen
Ralph,
(Seems strange ... as if I'm talking to myself ...) Would it be
pragmatic to redirect the fully charged regen state energy to a
resistive load of some sort, like a heating element (could prove useful
during the winter months) or an auxiliary battery? ... further would
seem like there would be some sort of over-voltage protection built in
to the controller.
Just the 2 cents of a newbie (unadjusted to inflation that make my
opinion worth about ... ummm ... absolutely nothing),
Ralph P.
Ralph Merwin wrote:
> [EMAIL PROTECTED] writes:
>
>> Once again a question that may spark debate: Is the amount of energy
>> re-cooped from braking sufficient to off set the additional weight gain
>> of the regen itself?
>>
>
> Ralph,
>
> There has been discussion in the past about regen, and the benefit is
> claimed to be about 5% additional range with the right circumstances.
>
> My Geo Prizm used to have a Zapi H2 controller with regen. The additional
> weight consisted of a couple of contactors - hardly a penalty.
>
> As for any real benefit, my commute at the time was 26 miles round trip,
> with a long uphill climb on the freeway going to work (and the long coast
> on the way home). The trip used about 66 amp hours. On a good day with
> the traffic moving just right, I could coast all the way down the hill on
> the freeway in the evening, and the pack would get about 2 amp hours put
> back in. On most days though, traffic prevented me from coasting and I
> didn't see much regen. I had no way to measure the regen during the
> balance of the trip (stop-n-go traffic, etc).
>
> One problem I had with regen was with a fully charged pack and any
downhill
> sections of the road. I had to keep my foot lightly on the pedal to keep
> the controller out of regen mode or else the pack voltage would go too
high.
>
> Ralph
>
>
>
--- End Message ---
--- Begin Message ---
A friend of my is building a three-wheel go-cart (two wheels rear, one wheel
front) and wants to make it electric. His current design has an electric
motor driving only one of the rear wheels. My initial thought is that this
will make the vehicle want to pull to one side.
1) How have you other go-cart EV builders out there hooked up the electric
motor to the wheels?
2) Do you have any experience/recommendations on motor size, battery back
voltage, Amphours?
3) What kind of controller are you using? Is a simple resistor, though
wasteful, good enough for this size vehicle, or is there a good, small
controller that works?
Thanks.
Bill Dennis
--- End Message ---
--- Begin Message ---
John Westlund wrote:
> But $12,000 is a lot to work with for a conversion. Most
> conversions cost $6,000-8,000.
I haven't been back on the list for too long (less than a year), so
maybe I missed something, and I don't mean to offend, but this seems
like the same estimate we have always quoted since the early '90's.
Prices have gone up. Let's see what it should be.
> -WarP 9'' series DC motor x1 $1,395
Try $1680 with advanced timing and delivery.
> -Exide Orbital battery x29 $2,784
That's $96 each. Mind sharing where you get them at that price and if
that includes delivery? Mine are PS-121000 power sonics were quoted at
$135 each (last week - includes recent lead and fuel price increases)
and $380 for delivery to my door. Total $3485 for 23 of them.
> -Godzilla Controller(72-348V DC, 1,000 amp max, hall effect
> pedal input) x1 $2,830
That's the Z1K-EHV. My Z1K-HV (same model but 'only' goes to 300V)
cost $2791.53 (with free shipping) including all the stuff that you
have to have to go with it such as the fuse, speed sensor (at that high
voltage you really want to use one), palm to talk to the Zilla and
program it, miscellaneous cables, etc. So this is close, but there is
a premium for those extra few volts.
> -PFC 20 Charger x1 $1,500
> -Rudman MkIIB Battery Regulators x29 $1,305
Haven't got to the point of ordering these yet, but I'm sure it will be
at least a bit higher due to shipping. And don't forget 58 fuses for
the regs! If you use KLKD fuses (rated for pack voltage), expect to
pay $3-4 each, and that doesn't include a holder. 12V fuses and inline
fuseholders will reduce that to $10 or so for the fuses and $25 or so
for inline fuseholders, but I don't think the low voltage fuses are
recommended.
> -Miscellaneous components(Heat shrink tubing, tools, adaptor
> plate, fuses, ect.) $2,000
That's about right for electrical components and tools only, but it
adds up fast.
> -Datsun 1200 in good condition $2,000
Really?!? Where?!?
> Total: $13,814
Thats significantly above the $8000 cap of the "typical" budget
estimate, and more than his $12000 estimated budget, but I believe if
you went to 300V and used the "HV" Zilla, you could meet the mark.
Looking at an actual ongoing conversion, we can get an idea of costs.
The prices I quote above are from my cost records. So far, my Fiero
conversion has cost $11,800 and I haven't bought DC-DC, batteries,
charger, or regs yet. Of that, I need to subtract $893.11 I spent on
repairs/upgrades to the car only that are not strictly required to do
the conversion.
> Doesn't include shipping costs and assumes you do your own
> work on the battery racks, adaptor plate, etc.
That's a big chunk. Adapter plate and vacuum pump (didn't mention that
item) were $1100.93 for my conversion from CANEV. I'll do my own
racks, but haven't started fabrication yet.
My projected total is $11800-$893.11 +$3485 for batts +$1035 for 23
regs +$1500 for charger +$300 (low estimate) for DC-DC = $17226.89.
Significantly over and above the $8000 cap in the "typical" quote.
This price estimate is based on a half finished car and does not
include the cost of rack materials or the parts to repair/upgrade the
car that were not required for the conversion (wouldn't want to include
those, as they will be different for every car). However, I also
haven't added any brake upgrades or suspension modifications, and those
are usually needed for a conversion. For my car, that adds $300 for
the brakes and I don't know how much yet for the springs/struts.
That's significantly higher, just considering the conversion-related
components.
> You could do a conversion with less performance and similar
> range(in theory) for much cheaper, if you are willing to
> sacrifice performance and sacrifice the zero maintenance
> that AGM batteries offer. Using cheaper but dramatically
> less powerful flooded batteries would make the car very
> cheap to operate and far cheaper to build at around $7,000.
> Even with flooded golf cart batteries, it would still be
> possible to achieve an 85-90 mph top speed in a Datsun 1200
> using a 120-144V pack, so 60 mph is not out of the question
> at all!
That still sounds a bit low, but OK (price-wise), going with floodies
and a curtis helps a lot, but for the money, Zillas are by far the best
value. What's a new Curtis 1221 (120V, 400A) running nowadays? $995
at evparts! A 1231 is $1495!
So perhaps we should be telling people that the standard run of the
mill conversion will cost $10,000-$12000 instead of $6000-$8000. (And
obviously I should edit the FAQ on this subject at evparts since it was
written way back when...)
Dave Brandt
__________________________________________________
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--- Begin Message ---
Hey guys,
I just checked the PDF file that Dan Hartman sent me and sure enough
this guy stole the complete "Build an EV" section just as it appears on
the EVA/DC website including all my illustrations, pictures (including
my brother in-law holding the hub/flywheel assembly for the motor) and
all the text I wrote word for word.
And he's selling it on Ebay for $4.99
Then he has the audacity to say in the opening page in big Red and
Black letters:
"Copyright Notice
This File is Protected By Copyright 2000-20006
No Part May Be Reproduced
No Part May Be Resold
No Part May Be Given Away or Transferred
Violators Will Be Prosecuted
This File is Encoded With Your Email Address AND Postal Address"
This is the part I can't believe. Someone steals your stuff and then
puts up a notice threatening to prosecute people for the stuff he
stole. Unbelievable.
I don't mind people using the information. That's why its on the EVA/DC
website for anyone to use so we can get more EVs on the road. But
taking it and trying to call it your own and profiting from it is going
over the top.
Dan sent me all the info to write a complaint to Ebay so I'm going to
report him.
Chip Gribben
EVA/DC Webmaster
http://www.evadc.org
NEDRA Webmaster
http://www.nedra.com
--- End Message ---
--- Begin Message ---
"Arthur W. Matteson" wrote:
>> You are assuming one particular inverter circuit (the 6-transistor,
>> 6-diode fullwave bridge). But there are *many* inverter circuits.
> But I was presuming you were talking about inverters like Victor's.
> In this circuit context, an inverter without diodes would almost
> certainly not survive.
Agreed. The particular circuit Siemens uses in their inverters requires
6 transistors and 6 diodes. Leave any one of them out and it fails. This
inverter circuit is optimized for driving induction motors.
But, there are lots of *other* inverter circuits that don't need all
these parts. It is a mistake to assume that one particular circuit is
the only way to do it, and that all others are automatically inferior.
The best circuit keeps changing, depending on the application, the parts
available, new inventions, and re-implementations of old ideas.
> many MOSFET/BJT/IGBT circuits need antiparallel diodes; the boost
> converter and series-motor controller are two exceptions.
Right! And there are others. They are very useful circuits, widely used
when the need arises.
>> Regen adds twice the power semiconductors, and doubles the amount
>> of control logic.
> Lee, in what practical context is this true for AC EVs?
Because you can build simpler, cheaper AC motor controllers if you don't
require regen. The AC equivalent of the series motor / PWM controller,
if you will. *Most* mass produced AC motor controllers don't have regen.
> Remember, the power factor not being 1.00 shows that the current isn't
> in phase with the voltage anyway. Even in normal operation, what could
> seem like regen occurs, except its due to inductive storage instead of
> mechanical input. That's what reactive power is - borrowing and giving
> back in one cycle.
This assumes sinusoidal drive waveforms, and that the motor is inductive
and so has a lagging power factor.
However, the waveforms don't have to be sinusoidal; they can be square
waves, trapezoidal, or something else. A PM or wound-field motor can
have a 1.0 or even a leading (capacitive) power factor.
Also, if all the antiparallel diodes have to deal with is the leakage
inductance and "snubbing" energy, they can be far smaller (they only
carry small current for very short times). Regen requires large diodes
(large currents for large amounts of time).
> The extra control logic needed for "vector control" is whatever it takes
> for "iq", the quadrature current, to go negative. The equations all
> remain the same. For the '241, I need to implement a negative-quotient
> division, but that's all (and this is fairly easy).
Again, this all assumes an induction motor.
> Many newer, lower-voltage parts have very good diodes inside.
Yes; but you pay more for a MOSFET with a better diode.
> A series-motor controller doesn't need a MOSFET/IGBT antiparallel
> diode, since current can't flow that way [for long]. But it needs
> a diode in another configuration instead. You've got "half" of a
> half-bridge, in a sense.
The antiparallel diode is missing because most series motor controllers
use the "buck" circuit. This circuit requires one transistor, one diode,
one inductor (often the motor), and one capacitor (often the battery).
If you wanted regen, the buck circuit won't do it. Regen adds a second
transistor and a second diode -- i.e. twice the parts again!
> AC motors are very tricky to control, especially when they involve
> magnets.
Perhaps you've been reading the wrong books :-)
You can replace the commutator of a DC motor with an electronic version,
and have a very simple AC motor that runs on DC. "Commutation" is
controlled by an opto-interruptor or hall effect pickup on the rotor.
With transistors having the same 1-2v on-state drop, your motor performs
exactly the same as it did with brushes, but without a commutator. Your
"control" logic is virtually non-existent.
A perfectly ordinary AC induction motor can be fed fixed-frequency,
fixed-voltage AC, and will automatically run at a predictable rpm (minus
slip). If the voltage is too high or low for the given load and
frequency, it just shifts its power factor to limit current. Its
efficiency will be a little worse, but it still works so well that this
is how virtually all AC induction motors are used.
> - A simple on-off, no-PWM three-phase-bridge design would have
> considerable torque ripple.
Yes. But so do ICEs. If you're building a conversion, the flywheel is
already there to take care of this.
> - A six-step design would work but would also have some ripple,
> much like a BLDC trapezoidal system. Three smooth sine waves
> would have no torque ripple, as mentioned above.
Yes again. Perfectly smooth torque matters for a tape or disk drive. But
is it a refinement without a purpose in an EV?
> - All three of "on-off", "six-step", and "V/Hz sine wave" suffer
> from extreme acceleration or deceleration when the speed command
> is changed even slightly.
As does an EV with a series motor, or even an ICE with a big engine!
The motor speed in a vehicle changes quite slowly. Fast transient
response is an asset for servomotors, but not needed for automobiles.
The accellerator can simply have an RC network that limits the rate of
change to something reasonable.
> A closed-loop, non-microprocessor design for a three-phase induction
> motor would be certainly possible. But it would be difficult, large,
> and impractical compared to software (and I think contrary to your
> point). And field-oriented control would almost certainly be
> prohibited and left to microprocessors or FPGAs only.
You're saying that a $5 brushless DC fan is impossible? That an
automotive alternator (a wound field AC synchrounous motor) can't work
without a computer? :-)
> (I'm well aware: closed loops are done all the time for power supply
> circuits.)
There you go! Computers are generally a poor solution for closed-loop
control; analog and discrete circuits are vastly faster and simpler. You
only go to computers when the problem becomes so intractible that it is
required.
>> Notice that *all* the successful applications where DC-powered AC
>> motors have replaced DC brushed motors have used *different*
>> topologies and motor types than the auto companies used! That
>> should be a hint!
> An example?
There are endless numbers of them. Brushed motors have been replaced by
AC motors and controllers in (in order of size)
- tape players
- disk drives
- CD players
- fans
- R/C models
- electric bikes
- auto alternators (replaced generators)
- hybrid vehicles (Prius, Insight, etc.)
- industrial applications
- railroad locomotives
- ships
Which of these used induction motors with sinewave inverters? NONE of
them!
> One of the "hints" I use to support my choice of the standard
> textbook-taught three-phase-bridge topology is the fact that power
> modules are built around this design.
Except that power modules are available for *every* topology.
Also, remember that semiconductor companies are in business to sell
semiconductors. The more the better! They natually tend to promote
designs that uses as many as possible.
--
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 ---
On 5/18/06, Cor van de Water <[EMAIL PROTECTED]> wrote:
True,
Regen should be OFF until you are below 80% SOC and/or
configured to respect a max pack voltage and throttle back,
the Prius does it by reducing and eventually disabling
regeneration based on SOC.
Regen is so nice to have that I'd prefer to have it always present. I
notice when driving the Insight that it is disabled once the battery
is full, and it's annoying since I'm used to my Berlingo EV which
doesn't do this.
All you need is a giant regulator and a large external resistor to
burn off the spare energy, if your batteries can't take it.
The advantages are that it's more consistent to drive, and is a
further reduction in brake pad wear.
--- End Message ---
--- Begin Message ---
>> One of these days their patent rights are gonna expire and then
>> it'll be open season on auto size NIMH battery packs!
> Sure, but by then, lithium will have long since eaten their lunch in
> the large capacity world. Forget NiMH for EVs; it's already history.
The nimh cell is really quite a nice design. It (mostly) uses abundant,
inexpensive materials (nickel, iron, potassium hydroxide, and water). It
is cheaper than lithium based cells. It is the most environmentally
friendly rechargeable battery; easy to recycle, and the least harmful
when idiots throw them in landfills. They've been practical to mass
produce, and have proven to have a very long life when not abused.
The main thing holding it back has been the patent and licensing
restrictions. If/when this goes away (patents expire), nimh could easily
have a rebirth!
--
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 converted (and drive daily) a '92 Celica. I do think front drive is more
efficient, but here's something else to think about: conversion complexity.
The right drive shaft of my Celica (probably true for other years and other
type FWD cars) mounts a bearing to the ICE. When you pull out the ICE- there
goes your convenient place to connect this bearing. I fabricated a mount that
"straps" to the Advanced DC motor, but building it, and getting it aligned was
tough.
If I had it to do over, I probably would have chosen a RWD car, or a different
front-drive that didn't have this drive shaft complication. (a Nissan 240 RWD
was the other body style I was considering- but the Celica donor was found
first).
Jim Seibert
-----Original Message-----
>From: Wayne <[EMAIL PROTECTED]>
>Sent: May 17, 2006 9:59 PM
>To: EV <ev@listproc.sjsu.edu>
>Subject: Front-Wheel or Rear-Wheel Drive
>
>Details! Argh! Details!
>
>I'm still puzzling over the donor vehicle...I've my eyes now loosely
>fixed on either a 1993 Mustang or 1990 Celica. I'm leaning towards
>the Mustang if only because of its boxy shape (less wasted space
>filling a box with boxes rather than filling a drum with boxes).
>
>Besides the Mustang outweighing the Celica by 325 lbs another
>immediate significant difference between the two is the drive train;
>the Mustang has a longitudinal front engine, rear-wheel drive whilst
>the Celica has a transverse front engine, front-wheel drive.
>
>I've long been under the impression that front wheel drive is more
>efficient in getting power to the wheels than its rear-wheel drive
>brethren. If this is true then the Celica gains favor.
>
>Any thoughts or preferences between FWD vs RWD in an EV sense?
>
>Wayne White
>
>If those of us who "can", "do" then those of us who "can't" won't
>suffer as much from the high prices of excess.
>
--- End Message ---
--- Begin Message ---
I'm thinking a Mazda B2000 cabplus from the late 80's and 156v of 6v
golfcart batteries might do it. Depending on if you use using 1800's or
145's etc... You can vary the range with the same size battery. Only the
weight changes. 1456(1800's) pounds to 1820.(145's). This is 26 batteries
and a K1 Zilla. It should accelerate like a stock Maxda with a 9" or larger
motor. It should have very good range. .John Wayland might have some ideas
like increasing the batteries even more and using the next Zilla up. Not
sure what the breaking point might be but it's possible that a 40 battery
system might work.at 240vdc Zilla system. 2240 pounds with 1800's. 2800
pounds with US 145 batteries. Lawrence Rhodes.....
----- Original Message -----
From: "John Westlund" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, May 18, 2006 3:29 AM
Subject: Re: Donor Car Recommendations for EV Conversion
Unless you're willing to sacrifice seating 4 adults and
instead compromise for 2 or 3 adults, meeting your range
goal on a $12,000 budget will be difficult.
But $12,000 is a lot to work with for a conversion. Most
conversions cost $6,000-8,000.
For the type of car you describe, I'd recommend looking for
something that is:
a) lightweight, under 2,000 pounds
b) seats 4
c) is aerodynamic
d) has a reasonable amount of room for batteries
Not many cars will meet this criteria. In fact, none
available in the U.S. might meet it at all. Finding the
right donor won't be easy.
But do some research.
Look into a Datsun 1200. Stock, they are 1,600 pounds and
have decent aerodynamics. John Wayland has a Datsun 1200
conversion named Blue Meanie. It will get about 35-40 miles
range at 60 mph with a battery pack of 17 Exide Orbitals.
This is a 697 pound battery pack, with an EV weighing 2,400
pounds, much of that being stereo equipment. It has an
Advanced DC 9" motor, Zilla 1k controller, does 0-60 mph
in under 6 seconds, and tops out at around 125 mph. It seats
4 adults.
However, you want more range than that.
The only way to get it is to add more batteries. You might
be able to do 80-100 miles range under gentle driving, *IF*
you can fit a 348V pack of Exide Orbital AGM batteries,
weighing in at 1,189 pounds or perhaps a 144V pack of Trojan
T105 flooded lead acid batteries weighing in at 1,464 pounds
if you're less concerned about performance and don't care
about acceleration. Both setups would handily exceed your
performance goals. $12,000 can get you acceleration like a
Ferrari or Porsche in an EV, use it wisely! Go with wet
cells, and the price will drop along with the acceleration.
There are no guarantees on range, as driving style is a big
factor. But in theory, it is possible, but difficult, to
meet your goals.
The following setup will get you 0-60 mph in 6 seconds, top
speed of 120+ mph, and an estimated range of 80+ miles at 60
mph in a Datsun 1200:
-WarP 9'' series DC motor x1 $1,395
-Exide Orbital battery x29 $2,784
-Godzilla Controller(72-348V DC, 1,000 amp max, hall effect
pedal input) x1 $2,830
-PFC 20 Charger x1 $1,500
-Miscellaneous components(Heat shrink tubing, tools, adaptor
plate, fuses, ect.) $2,000
-Rudman MkIIB Battery Regulators x29 $1,305
-Datsun 1200 in good condition $2,000
Total: $13,814
Doesn't include shipping costs and assumes you do your own
work on the battery racks, adaptor plate, ect.
You could do a conversion with less performance and similar
range(in theory) for much cheaper, if you are willing to
sacrifice performance and sacrifice the zero maintenance
that AGM batteries offer. Using cheaper but dramatically
less powerful flooded batteries would make the car very
cheap to operate and far cheaper to build at around $7,000.
Even with flooded golf cart batteries, it would still be
possible to achieve an 85-90 mph top speed in a Datsun 1200
using a 120-144V pack, so 60 mph is not out of the question
at all!
Further, low rolling resistance tires would be a must for
this range.
In theory, this car would get over 80 miles range, needing
only 25-30 amps to maintain 60 mph if you go with an AGM
setup of 348V. If you go lower speeds, range will improve.
Go faster, it will drop. Accelerate fast, range will suffer
greatly.
You also do not want to fully discharge your batteries, as
it will shorten their life and increase your operating
costs. You want to routinely discharge them 30-50% to
maximize life. So if your daily range is 50-75 miles, you
better have charging in between stops.
At 35 mph, you'd have no problem getting 100 miles range, on
the other hand. What speed do yuo need that range?
With such a conversion, you'd certainly be treading new
ground, and success cannot be guaranteed as it's
theoretical. Be careful.
It is possible to get 100+ miles range in an EV on a $7,000
budget or so. But this EV would be a small pickup, like an
80s model Chevy S10, and such a vehicle can usually only
seat 2 or 3 adults, not 4. Taking a small pickup and loading
it up with 2,500 pounds of batteries is proven and has been
demonstrated on a repeated basis to give 80+ mph top speed,
dreadfully slow acceleration, and range in excess of 100
miles per charge at 60 mph highway speeds. If you're willing
to sacrifice one or two seats, or can find a small pickup
with an extended cab in order to seat 4, this is the way to
go.
Further, if you're willing to alter your vehicle's
appearance by doing aerodynamic modifications, you can
dramatically increase your range.
Figure out what compromises you're willing to make. Are you
willing to drive a truck loaded with batteries, instead of a
small car? If you must have a small car, would you be happy
if it could only seat 2(ie. Sports car)? Or would you be
happy to drive at low speeds of 30-40 mph in order to get
your range?
--- End Message ---
--- Begin Message ---
Probably 90%(perhaps more) of the go-karts (gas and electric) out there
only drive one of the rear wheels.
I suppose that theoretically they might pull to one side, but you'd never
notice it when driving one.
How fast does he want it to go? How heavy is he and how heavy is the
go-kart? How long/far does he want to go?
You need to know the answers to these questions to figure out motor and
battery sizes.
A resistor is pretty much out of the question, the power levels for even a
low speed go-kart will make the resistor huge and wastefull and probably
more expensive than a controller.
However, he might be able to get away with a contactor controller
(basically just a bunch of relays or switches)
> A friend of my is building a three-wheel go-cart (two wheels rear, one
> wheel
> front) and wants to make it electric. His current design has an electric
> motor driving only one of the rear wheels. My initial thought is that
> this
> will make the vehicle want to pull to one side.
>
> 1) How have you other go-cart EV builders out there hooked up the
> electric
> motor to the wheels?
> 2) Do you have any experience/recommendations on motor size, battery back
> voltage, Amphours?
> 3) What kind of controller are you using? Is a simple resistor, though
> wasteful, good enough for this size vehicle, or is there a good, small
> controller that works?
>
> Thanks.
>
> Bill Dennis
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
Peter VanDerWal wrote:
> Probably 90%(perhaps more) of the go-karts (gas and electric)
> out there only drive one of the rear wheels.
I don't think this is correct. Every go kart I've seen has a solid rear
axle, so while there is only a single driven sproket on the rear axle,
both rear wheels are driven.
This is why go kart driving technique involves leaning in the corners;
you want to unload one rear wheel so it can spin because both are driven
and there is no differential.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Are there any new, off-the-shelf shunt motors suitable for EVs? I
think you'd have to order a custom wind from Warfield or Husted.
Likewise, I don't think there are any 100 to 200 kW sepex controllers
available.
So I think the barrier to shunt/sepex is that you are much more on
your own.
Just a random thought, a system using four golf cart sepex motors
(maybe one for each wheel) might work.
--- Chet Fields <[EMAIL PROTECTED]> wrote:
> ...
> But what is the issue with shunt wound motors. Are they more
> expensive, or
> unobtainable? Are the controllers to allow regen more complicated
> and
> expensive? (Otmar?)
>
> My Soleq EVCort has the *DC* shunt wound motor with regen and
> (echoing someone
> elses sentiments in a prior post) IMHO it is quite charming. I like
> that fact
> that I don't have to rely on the brakes to stop 2 tons of vehicle
> and that at
> least some of that energy is going back into the batteries. Saves
> brake pads,
> increases range, probably contributes some to the life of the
> batteries as
> well.
> ...
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Subject: Re: Three-wheel Go-cart
Probably 90%(perhaps more) of the go-karts (gas and electric) out there
only drive one of the rear wheels.
I don't think this is correct, at least on any go cart with any power, it
would be a solid shaft and both wheels getting drivin together.
I suppose that theoretically they might pull to one side, but you'd never
notice it when driving one.
Again I dissagree
How fast does he want it to go? How heavy is he and how heavy is the
go-kart? How long/far does he want to go?
You need to know the answers to these questions to figure out motor and
battery sizes.
A resistor is pretty much out of the question, the power levels for even a
low speed go-kart will make the resistor huge and wastefull and probably
more expensive than a controller.
However, he might be able to get away with a contactor controller
(basically just a bunch of relays or switches)
A friend of my is building a three-wheel go-cart (two wheels rear, one
wheel
front) and wants to make it electric. His current design has an electric
motor driving only one of the rear wheels. My initial thought is that
this
will make the vehicle want to pull to one side.
1) How have you other go-cart EV builders out there hooked up the
electric
motor to the wheels?
2) Do you have any experience/recommendations on motor size, battery
back
voltage, Amphours?
3) What kind of controller are you using? Is a simple resistor, though
wasteful, good enough for this size vehicle, or is there a good, small
controller that works?
Thanks.
Bill Dennis
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
I'm only considering 1HP or more EVs here. Brushless fans and disk
drives are out of the question, unless otherwise stated.
> Because you can build simpler, cheaper AC motor controllers if you don't
> require regen. The AC equivalent of the series motor / PWM controller,
> if you will. *Most* mass produced AC motor controllers don't have regen.
Most AC motor controllers don't have regen, because a good deal connect
to the 60Hz power line. Line rectifiers are involved. It takes a bunch
of extra circuitry to do regen there, whether you're controlling a DC or
AC motor. But they often come with a resistive "brake" function
instead, to limit the link voltage.
> This assumes sinusoidal drive waveforms, and that the motor is inductive
> and so has a lagging power factor.
Square waves are made up of sine waves. In fact the higher harmonics
make the load *seem* to have an even lower power factor - that's why PWM
works to start with. (In reality, the power factor is a complex
function - but higher frequencies get averaged better, and their
currents will be lagging.)
> Also, if all the antiparallel diodes have to deal with is the leakage
> inductance and "snubbing" energy, they can be far smaller (they only
> carry small current for very short times). Regen requires large diodes
> (large currents for large amounts of time).
This does not simply concern leakage inductance and snubbing energy.
The motor's mutual inductance is what makes the PWM work to start with.
Like in the buck converter, that current has to flow through somewhere
when the switch is off. That's why the current sine waves (or Fourier
combination thereof) have a slight triangular ripple on them. If you're
using IGBTs in the standard three-phase-bridge, the top diode and bottom
switch form a buck converter, as well as the bottom diode and top
switch. For a power factor of quite close to 1.00, nearly the full
switch current flows through the opposing diode each cycle. Other
motors may slightly vary, but not much.
Regen doesn't so much make a voltage increase on the motor wires, as
would be expected - it makes a phase shift. This is why PWM drives can
regenerate even if the full bus voltage isn't utilized - it's a matter
of timing (I'm not absolutely sure though).
> > The extra control logic needed for "vector control" is whatever it takes
> > for "iq", the quadrature current, to go negative. The equations all
> > remain the same. For the '241, I need to implement a negative-quotient
> > division, but that's all (and this is fairly easy).
>
> Again, this all assumes an induction motor.
A permanent-magnet AC (sinusoidal BLDC) fits into this category as well.
Except that "id", the direct current, is set to zero because the magnets
provide the field. That is basically the only change between the two
types. "Vector control" can also be applied to other types of
synchronous machines, quite easily.
> > A series-motor controller doesn't need an antiparallel diode...
>
> If you wanted regen, the buck circuit won't do it. Regen adds a second
> transistor and a second diode -- i.e. twice the parts again!
But this isn't really saying why AC controllers are inferior, because
we're talking about the common DC-series topology. True, AC has about
six times the parts on average, but each can be smaller since the
current is spread out (although the total is still higher).
> > AC motors are very tricky to control, especially when they involve
> > magnets.
>
> Perhaps you've been reading the wrong books :-)
But this is from first-hand experience, with both those with magnets and
without. My DC and AC success has taught me much, even more so than the
failures it took to get there.
Hall-sensors are an exception to what I said. They make BLDC control
much easier. But they increase the cost in another way, and many
companies are looking to get rid of them. I have a friend who worked
for GE to develop their constant-velocity sensorless BLDC blower, using
a similar technique to what I would do later for TI.
> A perfectly ordinary AC induction motor can be fed fixed-frequency,
> fixed-voltage AC, and will automatically run at a predictable rpm (minus
> slip).
I wouldn't really say that counts as "control."
> > - All three of "on-off", "six-step", and "V/Hz sine wave" suffer
> > from extreme acceleration or deceleration when the speed command
> > is changed even slightly.
>
> As does an EV with a series motor, or even an ICE with a big engine!
But almost all series-wound-EVs and ICEs use a *torque* command! This
is much different than a speed command. These problems do not happen
with a current/torque command. An approximate torque command is easy
for an ICE - just vary the fuel - but not as easy for an induction
motor.
Cruise control is one exception, but it usually has a fairly low loop
gain, so oscillations are damped.
Integrating a torque step gives a speed ramp - but differentiating a
speed step gives a torque impulse. There's the sore neck again.
> The motor speed in a vehicle changes quite slowly. Fast transient
> response is an asset for servomotors, but not needed for automobiles.
> The accellerator can simply have an RC network that limits the rate of
> change to something reasonable.
It still might be nice to be able to let off on the throttle suddenly
without having the car jerk, in a dangerous situation.
> > A closed-loop, non-microprocessor design for a three-phase induction
> > motor would be certainly possible. But it would be difficult, large,
> > and impractical compared to software (and I think contrary to your
> > point). And field-oriented control would almost certainly be
> > prohibited and left to microprocessors or FPGAs only.
>
> You're saying that a $5 brushless DC fan is impossible?
An induction BLDC fan is indeed impossible. Note my first line - "for a
three-phase induction motor."
> And an automotive alternator (a wound field AC synchrounous motor)
> can't work without a computer? :-)
That's not an induction motor. True, you could rectify an induction
motor's output, but that still leaves you "out of control" for defining
the output voltage at a varying ICE RPM. Baseball-sized zener diodes
excluded.
> Which of these used induction motors with sinewave inverters? NONE of
> them!
Things like a disk drive have a greater need to be synchronous and
compact. The cost of the magnets is negligible, there.
I'm fairly certain the Prius has at least one sinewave inverter.
I just got an E-mail that I'll be working in a lab, which I had toured a
few months ago, this summer. The professor is doing work for Toyota -
he has two Prius controllers and a battery pack sitting in his room. He
tells me that there are three inverters inside - certainly not an
example of something simple. It doesn't seem particularly compact to
me, even though he said it's the industry's best.
"Successful" is subjective, anyway.
> Also, remember that semiconductor companies are in business to sell
> semiconductors. The more the better! They naturally tend to promote
> designs that uses as many as possible.
I don't think that everyone's motivation always has to be something evil
or greedy. Why would they sell individual MOSFETs, in that case?
I wish they sold 1.5-pin MOSFETs. :-/
- Arthur
--- End Message ---
