EV Digest 5079
Topics covered in this issue include:
1) Re: Mk3 Regs
by "Rich Rudman" <[EMAIL PROTECTED]>
2) RE: Tire Ignition Sequence Photos of White Zombie???
by "Roger Stockton" <[EMAIL PROTECTED]>
3) Re: Pack voltage switches for peripheral devices?
by "John Luck Home" <[EMAIL PROTECTED]>
4) Re: Cube power supplies (was Re: Neg supply for E-meter )
by Lee Hart <[EMAIL PROTECTED]>
5) Re: "Posicharge" item on eBay
by Neon John <[EMAIL PROTECTED]>
6) Re: Announcement: New NEDRA Class Rules
by "Roderick Wilde" <[EMAIL PROTECTED]>
7) Re: "Posicharge" item on eBay
by Andrew Letton <[EMAIL PROTECTED]>
8) Re: I want to build a PWM DC motor controller
by "Stefan T. Peters" <[EMAIL PROTECTED]>
9) RE: I want to build a PWM DC motor controller
by "Roger Stockton" <[EMAIL PROTECTED]>
10) Where can I get a high voltage switch? 48+
by Mark Hastings <[EMAIL PROTECTED]>
11) Re: 5 votes to top for Wayland !! RE: Electric Car just 44 Votes
away from Grabbing the #10 Spot!
by Victor Tikhonov <[EMAIL PROTECTED]>
12) Re: Cube power supplies (was Re: Neg supply for E-meter )
by Neon John <[EMAIL PROTECTED]>
13) Re: Pack voltage switches for peripheral devices?
by Lee Hart <[EMAIL PROTECTED]>
14) Re: I want to build a PWM DC motor controller
by Lee Hart <[EMAIL PROTECTED]>
15) Re: Geo Metro EV on a budget
by Lee Hart <[EMAIL PROTECTED]>
16) RE: White Zombie is now #1
by "Pestka, Dennis J" <[EMAIL PROTECTED]>
17) RE: 5 votes to top for Wayland !! RE: Electric Car just 44 Votes
away from Grabbing the #10 Spot!
by Randall Prentice <[EMAIL PROTECTED]>
18) Re: I want to build a PWM DC motor controller
by "Stefan T. Peters" <[EMAIL PROTECTED]>
--- Begin Message ---
Hey Chris and listers..
I have been busy all weekend building up my Fiero and shoveling Weeks of
charger repairs and orders, so..
I have not been sitting here playing "EV lister".
What I have been hounding all my Evil buss supports for is simple and
robust. We don't need a Evil Buss that can play MP3 sounds..
Bruce finally got the time to get code cut that works, but... we need some
work on it still.
The bridge is a special loaded MK3 board that has the 232 drivers and Evil
buss terminators on it.
We could cut a speical pcb just for this function, but I insisted that all
the Regs be the same. This idea may be taken any way.... Dropping the 232
stuff could cut the normal Reg's Realestate by quite a bit. Having any Reg
be just the one you need is also a good idea in the real world of BMS field
support.
I gotta go.... more appointments to make..
Rich Rudman
Manzanita Micro
----- Original Message -----
From: "Chris Brune" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, January 08, 2006 8:44 PM
Subject: Re: Mk3 Regs
> Rich,
> I can't believe a day and half and not one response to this... I'll bite,
> bring on the details!!!
> I'm very excited to see what you guys have put together. There's been a
lot
> of talk about doing this by a number of people nice to see some action by
> somebody. I know that Ralph and I have been working on and off (mostly
off)
> for more than a year on this. I suspect that if what Bruce and Sheer have
> put together works it will make all the recent EVILbus protocol
discussions
> mute.
>
> Is the "bridge" reg a bus master?
>
> Details???
>
> Regards,
> Chris Brune Tigard, OR
> 93 Honda Del Sol
>
--- End Message ---
--- Begin Message ---
Victor Tikhonov [mailto:[EMAIL PROTECTED] wrote:
> 'Course I meant film scanner, usually 2400 lpi resolution
> in average (not a generic flat bed scanner attempting to scan
> negatives as any other paper).
I'm talking about 14,000dpi drum scanners used professionally to convert
analog images to digital, not consumer grade junk. 2400dpi is nowhere
near sufficient to read all the information available on an analog
negative/positive and is representative of a flatbed scanner attampting
to scan film with an attachment; even dedicated consumer film scanners
are higher resolution than this.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Thanks Lee - I think the 10 Ohm and the 1uF are in series with each other
then across the contacts. As I am going to be breaking 10 amps should I
increase to say 20ohm and 4.7uF ? Is it CxR seconds that I am trying to
make large ?
Thanks
John
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, January 10, 2006 3:53 PM
Subject: Re: Pack voltage switches for peripheral devices?
John Luck Home wrote:
I have a similar problem trying to switch my ceramic heater core. The
pack
voltage is 220v and the current for the heater is aprox 10 amps. I have
tried regular relay (AC) arcing, I have tried series connecting a 30v
25
amp DC relay that had 3 poles and it still arcs - so I am stuck. Next
step
I think is a mag blowout contactor to stop the arcing.
220vdc is "up there" where you have serious arcing to contend with! You'll
need enough AC contacts to handle at least 880vac to break this reliably.
The
simplest solution is to get a small Kilovac contactor rated for these
voltages.
Failing that, you'll need at least a couple normal relays to get at least
4
contacts in series. And, use an RC or RCD snubber across them (see my
earlier
post).
--- End Message ---
--- Begin Message ---
Neon John wrote:
> I've bought several hundred of these power supplies surplus, usually
> by the box full at hamfests and have yet to run into a regulated one
> that doesn't have current limit. Though unregulated switchers were
> used somewhat in the beginning of the laptop age, they're few and far
> between. Mfrs want to keep that heat out of the laptop.
If you're dealing with supplies that came with a $2000 laptop, they are
intended to charge batteries and probably are built to higher quality
standards. I was thinking more of the garden-variety "wall wart" types you
get with many consumer products, and that sell for $20 new. These are the
ones that have one-time thermal fuses, or will shutdown and not restart if
overloaded.
> I'm thinking about the SMPS chips I have experience with and I having
> trouble imagining designing a PS without regulation.
It depends on the application. A camcorder or electric drill is pretty
undemanding. Switchers are always at least semi-regulated, though their
accuracy may not be all that good and they won't be temperature compensated.
There will be a largish voltage drop in the long wire, so the voltage will
vary a fair amount as the load current changes. The cheaper ones regulate on
the *primary* side, and don't sense output voltage at all.
Heat can be another challenge. They don't expect you to use it outdoors, over
a wide temperature range. Current limit is higher than the normal "rated"
load current, so it may run hotter than usual. They may not have enough
safety factor in the design to handle it continuously.
None of this says it will never work; just that you need to know what you are
getting, and do some testing yourself to be sure it will work.
> I've been kicking around the idea of using some of these as a pack
> charger. I recently picked up a large box of fairly large bricks with
> 28 volt, 8 amp output. One of these across sets of 4 cart batteries
> would make dandy chargers if the input PF isn't too bad. I need to
> measure that before I think about it too much longer.
It's been 0.7 or so for the ones I've measured. The real killer with operating
a bunch of them in parallel is inrush. Each supply will draw 10-20 amps peak
inrush when turned on. Put a few in parallel, and you're likely to trip a
fuse or blow a breaker.
You may have to rig up some way to turn them on in sequence. For example, turn
on the first one, whose output powers a relay to turn on the second, whose
output switches on the third, etc.
> I've reverse-engineered the Progressive Dynamics Charge Wizard, a cute
> little PIC-based wafer that turns their RV converters into intelligent
> 3 stage chargers. I've figured out how to apply the Wizard to any DC
> supply that has either an accessible reference voltage, an accessible
> feedback terminal or an adjustable output voltage. The wizard not
> only does the smart charge algorithm, it also has a maintenance mode
> that does a periodic equalization charge. All without user input.
> Since this wizard can be had in single piece quantities for a little
> over $15, one can easily and cheaply turn a power cube into a smart
> charger.
Sounds cute! Let us know more about how it works out. How does it throttle the
charger?
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 [EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
On Tue, 10 Jan 2006 08:25:47 -0800, [EMAIL PROTECTED] wrote:
>Any idea what this was used on:
>http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4603646892
>
Looks like a homemade charge/discharge datalogger to me. Given that
it's 24 volts and has "aero" in the name, I imagine it either has
something do do with charging aircraft batteries or perhaps
self-propelled luggage carts.
Nifty setup but the guy's smokin' dope on the price. IMO :-)
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
--- End Message ---
--- Begin Message ---
Hi Jerry, You would definitely NOT be in funny car class. The "Spirit of the
Rules" would tell you that. You are setting up for a production vehicle.
Your car is a great example of why we set up the CV "Concept Vehicle" class.
This is direct from the NEDRA page: "Concept vehicles are used for
prototypes and vehicles that are one of a kind and do not fall easily under
the other categories. As soon as there are two or more of the vehicle, then
it is no longer a concept vehicle." You should know that we haven't
addressed updating this class yet but the only major change may be in the
number produced before a vehicle is considered a production vehicle. After
you reached that number then your cars would be in SP "Street Production"
class. I hope this clarifies your concerns.
Roderick Wilde
NEDRA Rules Committee
----- Original Message -----
From: "jerryd" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, January 10, 2006 2:15 AM
Subject: Re: Announcement: New NEDRA Class Rules
Hi Rod and All,
I too am wondeing where my Freedom EV
composite body/chassis will fit? Certianly not in thr Funny
car class I'd hope.
Thanks,
Jerry Dycus
----- Original Message Follows -----
From: [EMAIL PROTECTED]
To: [email protected]
Subject: Re: Announcement: New NEDRA Class Rules
Date: Mon, 9 Jan 2006 20:06:44 -0500
Hi all,
I think you missed the mark on the new rules. This is
because I just ended up in
"Pro Street" class. It has been a daily drive. If I take
my carbon fiber hood off and my after market air dam off of
81 VW Rabbit pickup, I guess I am back in Street Conversion
?
I think the two or more motors should have been in the new
specs.
If you look look at the fastest cars (John, Otmar,the new
240 Nisson, the old 280 Z, Hall chevy) they are all two
motors. I liked to say that I had the fastest single motor
"SC/b"( That might not be true, but it made me feel good.)
Also this spring I bought a 820I TVR (1987). It was a
production British sports car and the last year imported.
It construction is Fiber glass body on a tube frame. If I
convert it, what class is it in ?
Robert Salem
81 VW pickup 240volts,11" Kostov, Z2K - (14.9 91 mph)
Hi All,
Roderick Wilde here from NEDRA, the National Electric
Drag Racing Association. We have been toiling tirelessly
on a new set of class rules since late September (yes
over three months), and we are now ready to announce the
new class definitions.
This effort came about as a direct result of discussions
on this list of the vagueness of our very brief class
descriptions (hey, they worked for much longer than I
thought they would). NEDRA has adopted the NHRA (National
Hot Rod Association) rules and we try to follow the
guidelines and examples they set. If you take a look at
the NHRA rules you'll see that they are quite long and
very detailed. Our new NEDRA class definitions, though
far more detailed than in the past, are still much simpler
and briefer than the NHRA's. This was an intentional
decision to keep the class descriptions very easy to
understand and the requirements easy to comply with.
The really good news is that we have created two
entirely new classes! Our original "Street Conversion"
class encompassed many different types of cars, yet it
has been dominated by professional racers (such as Plasma
Boy for instance), so we decided to subdivide the class
into two new ones. We formed a new class called "Pro
Street Conversion" for the "hopped up" type cars. This
reopens the original "Street Conversion" class back up
for the average "daily driver" type cars. This will open up
the availability for daily drivers to set new World
Records during the exciting and expanded 2006 racing
season. Former "Street Conversion" record holders that
no longer fit in the new criteria of "Street Conversion"
will be moved up to "Pro Street".
IMPORTANT NOTE: No one loses any World Records! Your
record may simply be reclassified to a different class.
We hope that does not hurt too many people's feelings
out there.
The other new class is on the other end of the spectrum
and is called "Extreme Street" (XS) for excessive of
course. This is basically an "anything goes within NHRA
regulations" class designed for street bodied, ground up
, purpose built race cars with plastic/carbon/fiberglass
bodies and a custom chassis. This is basically the
"funny car" class. John and I first discussed the
formation of this class over six years ago
Please note the "Spirit of the Class" definitions listed
before each class. This is a plain English paragraph
describing what the class is all about and was included
to assist you in understanding our intent for the class
and categorizing your vehicle within the new class
structure.
Check all the new NEDRA class rules here:
http://www.nedra.com/class_rules.html
Feel free to contact the rules committee with your
comments. The rules committee consisted of::
Brian Hall, John Wayland, Ken Trough, and Roderick
Wilde.
I thank all of the rules committee members for their
tireless work on what sometimes seemed to be an endless
nightmare!
Roderick Wilde
NEDRA President
-------------------------------------------------
*The Spirit of the Street Conversion Class*
The Street Conversion (SC) class is for basic street
legal and licensed conversions that have not been
modified for racing. "Conversions" are vehicles that
have been mass-produced but were NOT originally
manufactured as electric vehicles. This is the class for
the "daily driver" and DOT tires are required.
*The Spirit of the Pro Street Class*
The Pro Street Conversion class (PS) is for street legal
and licensed conversions that have been modified for
racing use while still maintaining their street
appearance and drivability. "Conversions" are vehicles
that have been mass-produced but were NOT originally
manufactured as electric vehicles. Racing slicks are
allowed.
*The Spirit of the Modified Conversion Class*
Class MC: (Modified Street Conversion) The intent of
this class is for street bodied and chassised vehicles
that are heavily modified for racing. This class does
not require vehicles to be licensed for street use and
racing slicks are allowed.
*The Spirit of the Xtreme Street Class*
Class XS: (Xtreme Street) The intent of this class is
for street bodied vehicles that are built as all out
race vehicles and differ from SC, PS and MC classes, all
of which require stock production bodies and frames.
This is the class for custom tube chassis or other highly
modified chassis vehicles. This class does not require
vehicles to be licensed for street use and racing slicks
are allowed.
--
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--- End Message ---
--- Begin Message ---
Google Aerovironment.
They have done extensive work on fast charging.
Evidently they've spun off a separate charger company:
http://www.posicharge.com/index.html
I'd guess that this thing was some prototype test device, though I
wouldn't put anything built by Aerovironment and "homemade" in the same
category.
I do have to agree on the price though...
cheers,
Andrew
Neon John wrote:
On Tue, 10 Jan 2006 08:25:47 -0800, [EMAIL PROTECTED] wrote:
Any idea what this was used on:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4603646892
Looks like a homemade charge/discharge datalogger to me. Given that
it's 24 volts and has "aero" in the name, I imagine it either has
something do do with charging aircraft batteries or perhaps
self-propelled luggage carts.
Nifty setup but the guy's smokin' dope on the price. IMO :-)
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
Stefan Peters wrote:
The MOSFET package specifies a "time to final Rds" of 15uS given the
recommended 1uS rise time on the gate.
15us would be rather slow for a MOSFET. Perhaps this is just where they
measure it, to avoid ringing and noise problems in their test setup.
That is with a 1uS input rise time. This is a "MOSFET Switch" with a
current/temp limiter and active voltage clamping built in and designed
to be driven with a logic-level input. It employs soft switching of a
International Rectifier HEXFET Power MOSFET. I might have to add a
snubber circuit though...
If I smoke the MOSFETs, I'll move up to the faster one.
If the problem is diode reverse recovery energy, a faster MOSFET makes the
problem *worse*!
Oops! I meant the faster diode ;)
Thanks for the other points to research!
--
Stefan T. Peters
--- End Message ---
--- Begin Message ---
Stefan Peters [mailto:[EMAIL PROTECTED] wrote:
> > Except that if you need multiple subnet switches stacked up
> > to allow sereis parallel switching of 4-6 strings, and each
> > switch needs close to the same amount of silicon as the
> > single monolithic PWM controller, then what's the point?
>
> Who said multiple? If a Motor Controller was equipped with PWM, you
> wouldn't need multiple strings to spread the current draw
> around, would you?
Somewhere along the line we have lost track of what we are talking
about. ;^>
I am specifically trying to understand what (if any) benefit
your/Redrock EV's scheme of switching individual batteries into/out of
the traction string has when compared to a normal single series string
PWM controller situation.
If I have a 120V set of batteries connected in a single series string
with a plain Curtis controller, I get a known efficiency and
performance.
If I have the same set of batteries and just use the Redrock EV scheme
of switching batteries in/out (no PWM), I get 2.8x the losses of the
Curtis system *in the best case*, even using your figure of 1.2 milliohm
per Battery Controller (or whatever you are calling it now). At any
lower voltages the losses skyrocket due to the 1.35V drop across each
battery module that is pulled out of the string. And, this is based on
using 24V modules, not even one module per 6V or 12V battery. So, your
scheme is *way* less efficient than the status quo and needs to have
some really redeeming features to counter that.
If I allow for series/parallel switching of the 24V modules, then I need
one or more subnet switches to perform this switching. Your system
diagrams show the subnet switch as having 2 inputs and one output, which
leads me to conclude that I would require 4 such switches stacked in
series to allow 5 24V modules to be combined to provide voltages from
24V to 120V. Still no PWM at all, but at least one of these subnet
switches needs to be able to handle switching 96V and full current (i.e.
whatever maximum you want to allow at the lowest voltage step). In
addition, this switch must be able to connect its two inputs in either
series or parallel to its output, and ideally needs to be able to
connect either of its inputs to its output. All in all, this suggests
to me that even with no PWM capabilities at all this single subnet
switch ends up containing as much or more silicon as the single 120V
Curtis controller, and I need 4 switches! Admittedly, I could build
each switch with just enough silicon to handle whatever switching it
needs to do, they don't all have to handle 96V at full current.
However, the point remains the same: cost wise your system appears to be
at a disadvantage to the status quo, even without the individual battery
modules that hold the promise of providing some additional value in the
form of BMS functionality.
> I mean monolithic as you can't rearrange or reassemble the
> stuff to make other stuff. Modular means you can. Modular
> means shared design and testing. Less hours, more benefit.
> Are you sure you actaully played with LEGOs for a
> considerable time before? ;)
Yep. And now that I've grown up I am an EE who develops embedded
software professionally and am quite familiar with the concepts of
modularity and reuse. And, I haven't stopped playing with LEGOs either.
;^>
> It appears that you still see this as a single "product"
> and not a system or framework. It is a collection of parts
> that can be combined (or customized) in various ways to
> give you various types of functionality.
I understand this, however, to evaluate what merit this approach has we
must consider a collection/combination that approximates the features,
etc. available from conventional alternatives and see if that collection
actually offers a benefit that would encourage a user to choose it over
the alternative.
I have not yet been able to identify a single advantage to the end user
of your system over the status quo.
At best, we have the possibility of your system offering built-in BMS
functionality. However, to do so it must include a full complement of
battery management modules, with their accompanying efficiency penalty
(2.8x the loss of a plain PWM controller in the best case). Then to
provide the performance of a plain PWM controller we must include
module(s) to allow series parallel switching (more loss, and most
notably more cost). We now have a system that provides similar
performance to a plain PWM controller but costs more and is less
efficient, but includes BMS functionality. Is this better value than a
plain PWM controller and a stand-alone BMS system? Hard to say, but my
gut feel is that so far we really haven't been able to make much of a
case for why this new approach makes any sense as a replacement for
available motor controller alternatives.
Now, if it could offer the same performance as available controllers and
provide BMS functionality for little or no additional cost (over a
conventional controller), it would have great potential. Or, if it
offered similar enough performance (e.g. modern contactor controller) at
much less cost than available motor controllers (no mention of BMS
functionality this time), again I think it would have great potential.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Can anyone point me to a switch that is on-off-on, on-on-off or just on-off
that will handle a 48volt contactor that is listed at 450 ohms? I saw and
on/off at $100+ but that is a little much.
It is for my tractor that has a 48 volt pack. I switch on and off by a set of
contactors. Off - On with a starting resistor - On no resistor.
There is no auxilery battery or relay right now I actually tap the pack for
12 volts to switch a 12 vdc ->120vdc relay to then power the 48vdc relay for
each on position.
I'd like to get rid of the tap and the 12vdc relays that go with it but I
can't find a suitable on-off-on swith or even just an on-off switch
Thanks,
Mark Hastings
--- End Message ---
--- Begin Message ---
Voted #1529. Looks like 3 out of first 10 are EVs. 30% - not bad.
Victor
Roderick Wilde wrote:
I just got to my computer this morning and actually Wayland is Number
One and still moving upward. The EV movement may be small but it sure
packs a punch! Way to go all you EV supporters! It is you that have made
this happen. Thank you all so much!
--- End Message ---
--- Begin Message ---
On Tue, 10 Jan 2006 12:10:45 -0500, Lee Hart <[EMAIL PROTECTED]>
wrote:
>Neon John wrote:
>> I've bought several hundred of these power supplies surplus, usually
>> by the box full at hamfests and have yet to run into a regulated one
>> that doesn't have current limit. Though unregulated switchers were
>> used somewhat in the beginning of the laptop age, they're few and far
>> between. Mfrs want to keep that heat out of the laptop.
>
>If you're dealing with supplies that came with a $2000 laptop, they are
>intended to charge batteries and probably are built to higher quality
>standards. I was thinking more of the garden-variety "wall wart" types you
>get with many consumer products, and that sell for $20 new. These are the
>ones that have one-time thermal fuses, or will shutdown and not restart if
>overloaded.
These power cubes sell in the same price range new. I recently bought
a lot of 12 volt, 5 amp cubes from a surplus outlet for less than $5
ea. They were advertising $5 for single pieces but discounted the
quantity purchase. I got all they had, about 35 of 'em. These were
new in the OEM packaging. $5 is about the most I'll pay for them
unless they've something special.
there seems to be two generic classes of power cubes for laptops. One
type, such as this Dell has, has two outputs, one for charging and the
other for operation. The other class is a single output and the
various voltage are developed internal to the laptop. This latter
kind is also used on power speakers, some of the cheap ChiCom neon
that's flooding the market and stuff like that. This is the type I
look for.
>
>> I'm thinking about the SMPS chips I have experience with and I having
>> trouble imagining designing a PS without regulation.
>
>It depends on the application. A camcorder or electric drill is pretty
>undemanding. Switchers are always at least semi-regulated, though their
>accuracy may not be all that good and they won't be temperature compensated.
>There will be a largish voltage drop in the long wire, so the voltage will
>vary a fair amount as the load current changes. The cheaper ones regulate on
>the *primary* side, and don't sense output voltage at all.
You might be surprised at some of these chargers. I was recently
given a DeWalt 18 volt 1 hour NiCad charger. The electronics were OK
but a bad battery had melted the case. I was absolutely amazed at
what I found on the inside. A Z8 microprocessor, some other LSI chips
with the numbers ground off, dozens of smaller chips and transistors
and a double bucketfull of discrete surface mount components. Turns
out this thing can charge anything from 9 to 18 volts and is
temperature compensated. there is a thermistor on one of the battery
contacts that infers battery temperature via conducted heat along the
heavy contact.
This thing promptly got mounted in a project box along with a GFI
(non-line isolated) and has become my universal NiCad charger. It
appears to do a good job on NiMH too.
I mentioned this on my private mailing list and it turns out that one
of the members wrote the exemplar code for this application when he
worked for Zilog. If someone would design in the Z8 chip, Zilog would
customize the code to the application at no charge. Slick...
>> I've reverse-engineered the Progressive Dynamics Charge Wizard, a cute
>> little PIC-based wafer that turns their RV converters into intelligent
>> 3 stage chargers. I've figured out how to apply the Wizard to any DC
>> supply that has either an accessible reference voltage, an accessible
>> feedback terminal or an adjustable output voltage. The wizard not
>> only does the smart charge algorithm, it also has a maintenance mode
>> that does a periodic equalization charge. All without user input.
>> Since this wizard can be had in single piece quantities for a little
>> over $15, one can easily and cheaply turn a power cube into a smart
>> charger.
>
>Sounds cute! Let us know more about how it works out. How does it throttle the
>charger?
Quite clever, actually. The Charge Wizard (CW) has a 3 wire interface
to the converter - 12 volts, ground and output control. The output is
generated from a simple 2 bit D/A converter. One bit is high for
bulk/absorption charge, the other is high for float and both go high
for equalize. The converter itself is current limited so the CW only
has to specify the voltage setpoint. The converter scales this D/A
current to the correct voltage setpoint.
The couple of supplies that I've converted so far have not had remote
sense so I rigged up a couple of reed relays, one to each bit, that
switches in the appropriate setpoint pot. Rather than try to get the
two pots to add up to the correct equalize voltage, I used a third
reed relay operated by both bits being high. This relay switches in
yet another pot.
The CW can be used with just about any battery voltage by separating
the Vcc and sense voltages and scaling the sense appropriately. There
is a 78L05 chip on the board to regulate the PIC's Vcc so the supply
voltage needn't be regulated.
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
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John Luck Home wrote:
> Thanks Lee - I think the 10 Ohm and the 1uF are in series with each other
> then across the contacts.
Correct.
> As I am going to be breaking 10 amps should I increase to say 20ohm and
> 4.7uF? Is it CxR seconds that I am trying to make large?
It takes about 1 msec for the contact to go from its closed to its fully open
position. The value of C is to limit the rate of rise in voltage when the
switch contact opens. This C is being charged by you load current, so it
needs to go up proportionately as the load current increases.
The R is there for two reasons. First, it limits the peak current when the
contact closes (and has to both power the load *and* discharge the
capacitor). Second, it provides damping to prevent oscillations and ringing
if the load is inductive.
If the R and C values get unreasonable, you can add a diode across the R.
Orient it to conduct when the capacitor is charging (i.e. it shorts the R). C
can now be smaller, and R larger.
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 [EMAIL PROTECTED]
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Danny Miller wrote:
> The other thing that comes to mind is that motor insulation is more
> stressed not only as a factor of voltage but also frequency...
> However people don't seem to be mentioning frequent problems with
> insulation failure so this might not be a practical issue.
Motors normally come with sufficient insulation to pass hipot, which is
1250vac or more. But it is possible to break it down if you subject it to
very fast, square wave switching, as inductive spikes can easily be in the
thousands of volts. Extra reinforced insulation gets used in very high
voltage motors, especially those driven by inverters.
A related problem is capacitance to ground. The windings and the case of the
motor form capacitors. Generally this capacitance is uncontrolled, so you
don't know what it will be, and whether different terminals have the same
value. This capacitance can cause problems with GFCIs, or can mess up the
waveform you are trying to apply to a winding. This capacitance is another
thing they tend to control in inverter-grade motors.
> Resistance appears greater with PWM. Say the load requires an average
> voltage of half the pack voltage at 50 amps average current and thus we
> use a 50% duty cycle. So the batteries put out basically 100 amps half
> the time, whereas a single pack would deliver 50 amps all the time.
Except that the motor's inductance tends to filter the current spikes. A
(properly) designed PWM has relatively low battery and motor current ripple.
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 [EMAIL PROTECTED]
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First, thanks to everyone for lots of comments on this thread! I know; a "good
cheap EV" is an oxymoron. If it's cheap, it's likely to be a piece of crap.
If it's good, it's going to be expensive (in dollars and/or time).
However, I think back lovingly to my first EV. It was cheap; and didn't take a
lot of time or money to build. And it was "good" in my eyes, because it
worked and I didn't know any better!
But of course it had lots of safety and reliability problems. I murdered my
first set of batteries from abuse and carelessness. There was almost no
instrumentation, so I didn't know what I was doing. I burned up things from
excessive current, and had "stuck on" incidents from using parts beyond their
ratings. And no amenities; not even a heater.
Most of my problems stemmed from ignorance. I didn't know any better. Like any
first car, it looked good to me! If I knew then what I know today, I could
have made FAR fewer mistakes. It would have been a lot safer, more reliable,
and would have worked a lot better, without necessarily costing any more or
taking any more time to build.
But, here's the paradox. Now that I know a lot more, my standards are a lot
higher, too. The same EV that I thought was wonderful back then would now
impress me as crude, slow, pile of crap!
But, I'm thinking about this project, anyway. It gives me a chance to build
the EV that I should have built back then, but today; when I *do* know how it
should have been done. And... it's not for me! I don't have to please myself;
I have to please my cousin's kid, who is, just like I was, looking for a
cheap simple first EV. I'm thinking that *he'll* be satisfied with it even if
I'm not!
Now you might say, "Kids today have higher standards." Baloney! If you saw the
junker he's driving today, you'd understand. As kids, we all dream of owning
a Porsche or Ferrari. But reality intrudes; so we drive clapped-out Geo
Metros with 100k miles. Our first car is a typically terrible; but we love it
anyway.
There are 3 basic problems to deal with:
1. Technical
- what parts to use (batteries? motor? controller?)
- what's available (used? surplus? deals?)
- what can we make ourselves to save money (battery boxes? charger?)
- what do we have to buy? (adapter? coupler?)
2. Logistics
- he lives 500 miles away; I have to help by remote control
- I have tons of stuff that could be used, but might be too
hard for a beginner to use/modify without care
3. Human factors
- as a kid, would *I* have listened to "experts"?
- how do I phrase/arrange things so he doesn't just repeat all
the same mistakes I did?
- how do I encourage him not to "cheap out" on important stuff,
and blow his budget on stuff he doesn't need?
Roderick Wilde wrote:
> Tell him if he's really interested in EVs find out the true cost by going
> to the EV Classifieds.
He has looked there. Nothing really jumped out as something he'd want to buy,
but it gave him a great idea of the range of vehicles that can be converted.
But the prices put him in the mindset of "I can do it cheaper myself." He
drives an electric forklift at his job, and the maintenance guys are
encouraging him with surplus parts.
Tom Shay wrote:
> This situation looks hopeless to me. Joe Sixpack doesn't like to pay
> $3.00 for gasoline and wants to covert his Metro to an EV for less than
> $1000. His advisor lives 500 miles away. Lee Hart is asking the rest
> of us what to do... A beginner not familiar with EVs or the conversion
> process can't successfully build an EV with second hand and second
> rate parts.
Exactly. It's a "minefield" to build an inexpensive EV that works well,
because any mistakes have a tremendous cost in time and money. One big
mistake, and you've blown the whole budget. And beginners make lots of
mistakes!
The challenge is to see if we can devise a "formula" for building a good cheap
EV, one that if followed by Joe Sixpack will result in a usable EV.
I'll try to respond more specifically to how we might achieve this in
subsequent posts.
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 [EMAIL PROTECTED]
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I got #1550 for John and I also voted for Rod and Matt.
Looks like the electrics have the 1st 5th and 7th spot.
Let's get 1st 2nd and 3rd.
Dennis
-----Original Message-----
From: Christopher Robison [mailto:[EMAIL PROTECTED]
Sent: Tuesday, January 10, 2006 9:21 AM
To: [email protected]
Subject: White Zombie is now #1
This is really poor form, but I can't resist posting ... I got vote number
1490 :o)
--chris
On Tue, 2006-01-10 at 10:10 -0500, jerryd wrote:
> Hi Wayland, Hump and All,
> Wayland is just a few votes, 5, from taking the top
> spot!! Way to go everyone!! Now lets get Matt who is in 5th place and
> Rod in 8th up there for a 1-2-3 finish this month !! Voting URLs
> below.
> Thanks,
> Jerry Dycus
>
> >Stay Charged!
> >
> >Hump
> >
> >http://www.dragtimes.com/Mazda-RX-7-Timeslip-7519.html
> >http://www.dragtimes.com/Datsun-1200-Timeslip-7484.html
> >http://www.dragtimes.com/Nissan-240SX-Timeslip-7382.html
> >
> >
> >
>
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It is equally good to see the comments and replies that are happening on the
side.
Way to go you guys on good answers.
Regards
Randall Prentice
> Victor Tikhonov wrote:
> Sent: Wednesday, 11 January 2006 7:12 a.m.
> To: [email protected]
> Subject: Re: 5 votes to top for Wayland !! RE: Electric Car
> just 44 Votes away from Grabbing the #10 Spot!
>
> Voted #1529. Looks like 3 out of first 10 are EVs. 30% - not bad.
>
> Victor
>
> Roderick Wilde wrote:
> > I just got to my computer this morning and actually Wayland
> is Number
> > One and still moving upward. The EV movement may be small
> but it sure
> > packs a punch! Way to go all you EV supporters! It is you
> that have made
> > this happen. Thank you all so much!
>
>
>
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Roger Stockton wrote:
Somewhere along the line we have lost track of what we are talking
about. ;^>
I am specifically trying to understand what (if any) benefit
your/Redrock EV's scheme of switching individual batteries into/out of
the traction string has when compared to a normal single series string
PWM controller situation.
Just the ability to control each battery separately. This allows for
automatic mix-and-match, battery fail over/replacement, and gradual
system upgrades to a very high limit.
Which given how many messages on this list just in the last week that
have been about those very things, must be somewhat everyday concerns
for the community.
Yep. And now that I've grown up I am an EE who develops embedded
software professionally and am quite familiar with the concepts of
modularity and reuse. And, I haven't stopped playing with LEGOs either.
;^>
Sorry about the snappiness. I'm trying to promote a "shared" way of
making all of the various "open-source" projects people have asked for.
I think you can make one set of circuits that can be reused in various
ways to perform all operation aspects of a EV. I am just *experimenting*
with the BatPack setup. The prototype will of course be way less
efficient then anything currently being used. Who knows what kind of
changes or refinements can occur if people spend some time with it.
But, when I started ordering parts for my own, private BatPack
experiments, I thought: "Since I need many of the same basic subsystems
- micro and it's support circuits, isolation circuits, high power
switching circuits, even series/parallel capabilities - that a PWM or
contactor style controller will use, how about trying to make it in such
a way that the pieces can be used with little or no modification in
various other configurations"
I am *personally* assembling them in such a way to make a BatPack/simple
contactor style combo setup. Because that is where my interest lies.
That's all. Plus you have to test the primary components (System
Controller, various Motor Controllers) somehow. It makes sense to make
this setup first, because then you can programmatically vary the voltage
going to different styles of Motor Controllers during testing. So with a
working set of Battery Controllers, you can simulate different pack
sizes and voltage sags realtime while developing a PWM-based or other
style of Motor Controller. Plus I then have one half of a remote
programmable Battery Sensor for BMS use.
The fact that you can have one set of components that can support
everything from a contactor controller-style setup (and I would actually
use contactors, myself - for the reason pointed out) to a traditional
PWM-based system, to a BatPack-style setup (which I agree is not for
everyone), is what demonstrates this. Even with basic BMS functionality
included. ;)
I understand this, however, to evaluate what merit this approach has we
must consider a collection/combination that approximates the features,
etc. available from conventional alternatives and see if that collection
actually offers a benefit that would encourage a user to choose it over
the alternative.
Ah-ha! Now we have it. To evaluate the system structured in such a way
as to give the same features and benefits as a retail PWM controller,
you would configure it as such:
Data Bus:
System Controller -> PWM-based Motor Controller
HV Bus:
Batteries (series) -> PWM-based Motor Controller -> Motor
This would give you a bone-fide DIY programmable PWM-based speed
controller. It should have about the same specs as any other PWM
controller, except you can replace part of it without replacing the
other. And if you decide to switch control styles, you can reuse many of
the parts.
I have not yet been able to identify a single advantage to the end user
of your system over the status quo.
Modularity. Component reuse. Less waste with many parallel open-source
EV projects. I guess EE and NE/SE are much further apart in their
practices then I originally thought. Which is why perhaps those two
diverged many moons ago. Those reasons alone can save a software company
thousands a month, which is why it is a cornerstone of modern
large-scale software design practices. It can save us the "DIY EV
development" community months or years in duplicated efforts. Seems like
something of a major advantage to me...
At best, we have the possibility of your system offering built-in BMS
functionality. However, to do so it must include a full complement of
battery management modules, with their accompanying efficiency penalty
(2.8x the loss of a plain PWM controller in the best case). Then to
provide the performance of a plain PWM controller we must include
module(s) to allow series parallel switching (more loss, and most
notably more cost). We now have a system that provides similar
performance to a plain PWM controller but costs more and is less
efficient, but includes BMS functionality. Is this better value than a
plain PWM controller and a stand-alone BMS system? Hard to say, but my
gut feel is that so far we really haven't been able to make much of a
case for why this new approach makes any sense as a replacement for
available motor controller alternatives.
Now, if it could offer the same performance as available controllers and
provide BMS functionality for little or no additional cost (over a
conventional controller), it would have great potential.
OK, the micro board for the Motor Controllers and the Battery Controller
are the exact same. And if you build a micro board and attach it to a
current sensor with amplifier instead of a power switch with a bypass,
you have a Battery Sensor.
Data Bus:
System Controller -> PWM-based Motor Controller -> Battery Sensors
HV Bus:
Batteries (series) -> PWM-based Motor Controller -> Motor
This gives you the system you are looking for. Why do it that way
instead of individually designing, testing, and building circuits that
fit in one or two big boxes? Because then you have *one* small and *one*
tiny micro circuit and one HV circuit and one sensor circuit to test and
become familiar with. For 20 components. So fewer PCB patterns to get
etched. Less variety of electronic parts to source (quantity discounts
on both points). But most importantly, when you want to change something
later (even radically), you can reuse many of the little boxes you
already built, tested, and know are good.
Or, if it
offered similar enough performance (e.g. modern contactor controller) at
much less cost than available motor controllers (no mention of BMS
functionality this time), again I think it would have great potential.
Data Bus:
System Controller -> multi-stage series/parallel Motor Controller
HV Bus:
Batteries (many strings) -> multi-stage series/parallel Motor Controller
-> Motor
Depending on how the Motor Controller is built, you can that system as
well. You are asking me how that particular Motor Controller is going to
be designed. I haven't the foggiest. I'm someone who knows how to get
many (thousands) of computers talking to each other all at once at very
high speeds in noisy environments (with advance compression and
encryption if needed) without messing anything up.
If one person did all the parts of a "open-source" community project,
what would be the point? Plus I really have no idea how to make one that
is cheaper then a PWM-based one and can handle the currents/voltages
required. I couldn't even make a good PWM-based one right now. You had
some ideas for those, right? Sounds like you can be a great part of
this, if you want to contribute. Heck, post a better System Controller
schematic even. You're the EE, I'm just the crazy computer guy who
thinks we can make high power control electronics with the same level of
modularity as a bunch of C++ objects, that's all. That way wwaaayyy more
people then just the engineers and advanced hobbyists can contribute to
such a project. How? Data - we always need more data.
--
Stefan T. Peters
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