EV Digest 5226
Topics covered in this issue include:
1) Re: Transformer cores
by "STEVE CLUNN" <[EMAIL PROTECTED]>
2) Re: Charging outlet - what is common?
by paul wiley <[EMAIL PROTECTED]>
3) Re: The Names have been Changed to Protect the Innocent!
by John Wayland <[EMAIL PROTECTED]>
4) Re: The Names have been Changed to Protect the Innocent!
by "Mike Ellis" <[EMAIL PROTECTED]>
5) Re: The Names have been Changed to Protect the Innocent!
by John Wayland <[EMAIL PROTECTED]>
6) Re: dc converter disconnect
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
7) Re: Tango Naysayers
by Eric Poulsen <[EMAIL PROTECTED]>
8) RE: EV digest 5225
by "Adams, Lynn" <[EMAIL PROTECTED]>
9) Re: Off-the-shelf multiple battery voltage display sought
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Electrathon controller selection
by "Tom Eberhard" <[EMAIL PROTECTED]>
11) RE: Bad cells/battery mainteneance
by "Mark Fisher" <[EMAIL PROTECTED]>
12) Re: dc converter disconnect
by Dave Cover <[EMAIL PROTECTED]>
13) RE: The Names have been Changed to Protect the Innocent!
by "Matthew D. Graham" <[EMAIL PROTECTED]>
14) good conversion candidate?
by Rod Hower <[EMAIL PROTECTED]>
15) Re: Electrathon controller selection
by "Peter VanDerWal" <[EMAIL PROTECTED]>
16) Re: Horsepower / Torque
by "Peter VanDerWal" <[EMAIL PROTECTED]>
17) Re: good conversion candidate?
by Doug Weathers <[EMAIL PROTECTED]>
18) Re: good conversion candidate?
by "David Roden" <[EMAIL PROTECTED]>
19) RE: Off-the-shelf multiple battery voltage display sought
by "Peter VanDerWal" <[EMAIL PROTECTED]>
20) RE: Off-the-shelf multiple battery voltage display sought
by "Myles Twete" <[EMAIL PROTECTED]>
21) RE: Off-the-shelf multiple battery voltage display sought
by "Don Cameron" <[EMAIL PROTECTED]>
22) Re: Transformer cores
by Lee Hart <[EMAIL PROTECTED]>
23) Re: Charging outlet - what is common?
by Rush <[EMAIL PROTECTED]>
24) RE: Off-the-shelf multiple battery voltage display sought
by "David Roden" <[EMAIL PROTECTED]>
25) Re: Charging outlet - what is common?
by "David Roden" <[EMAIL PROTECTED]>
26) RE: Off-the-shelf multiple battery voltage display sought
by [EMAIL PROTECTED]
27) GFCI again (Was: Re: Charging outlet - what is common?)
by Doug Weathers <[EMAIL PROTECTED]>
28) Re: Off-the-shelf multiple battery voltage display sought
by Doug Weathers <[EMAIL PROTECTED]>
29) Re: Transformer cores
by Victor Tikhonov <[EMAIL PROTECTED]>
30) Re: Off-the-shelf multiple battery voltage display sought
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Hi Justin , I've been thinking about the same thing, I was thinking of using
the transformer from a 12v to 120 ac converter , I find them from time to
time , and was thinking the turn ratio would be about right for a 156v car .
I saw another circuit where they had in series , transistor , coil , cap .
... the transistor comes on , power through the coil , cap charges , next
cycle , transistor 2 also hooked to coil same place as T1 but it goes to
ground , and when it comes on it pulls the current that is stored in the cap
, back through the coil to ground , ready for cycle 2 . The neat thing about
this is the cap keep the coil form saturatating and saves the transistor
from to much current . I played around with a lm3524 chip for a while , got
lots of stuff , two outputs , current limit , voltage sense . I see 555 in
the dc to ac converters , well easy to think of this stuff , but doing it is
another . www.mpja.com has some 15v 4 amp switching supplies for $33 ,
says 85 to 264v vac . I'm going to get one and try it out ,.. I saw a 800w
dc to ac converter for $50 less that 10 cents a watt , we just don't have
enough buying power yet :-) .
Steve Clunn
----- Original Message -----
From: "Justin Southam" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, March 02, 2006 1:38 AM
Subject: Transformer cores
Hi All, i've been thinking of building my own dc-dc convertor using a
variation of the old square-wave inverter design used in cheap ups's etc,
a
centre tapped primary with the centre tap at battery voltage and grounding
each end of the primary alternately. Because the output is rectified the
switching frequency no longer needs to be 50 or 60 hertz. Finally the
point
of this email, does anyone have a feel for the maximum frequency i can
reasonably run an ordinary soft iron laminated core transformer. I suspect
its dependent on the quality of the laminations but would be happy with a
ballpark figure.
Thanks,
Justin
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.375 / Virus Database: 268.1.1/272 - Release Date: 01-03-06
--- End Message ---
--- Begin Message ---
I use a 15 amp 120 volt outlet with it's own circuit. I found that the garage
circuit that i was using was tied in with the furnace blower. Whoops! The best
part is that i can usually find an outlet somewhere when i park!
---------------------------------
Brings words and photos together (easily) with
PhotoMail - it's free and works with Yahoo! Mail.
--- End Message ---
--- Begin Message ---
Hello to All,
A quick note....there's a new video up at the web page where White
Zombie lights up the tires in front of a cop! Special thanks to
Washington state's Clark County Sheriff Department.
See Ya...John Wayland
http://wwwplasmaboyracing,com
Jim Husted wrote:
Hey John all
Man I wish I could have been there!!! I had even practiced my "Dat's NOT Mine! , and We don't need NO stinking badges Lines, LMAO!!! I can't wait to see the pics and video. As soon as I get them I'll throw them up at the site for everyone, being John seems to have no time here lately having all the fun 8^ )
Cya
Jim Husted
Hi-Torque Electric
--- End Message ---
--- Begin Message ---
I think John had a little too much fun. =)
www.plasmaboyracing.com
On 3/2/06, John Wayland <[EMAIL PROTECTED]> wrote:
>
> Hello to All,
>
> A quick note....there's a new video up at the web page where White
> Zombie lights up the tires in front of a cop! Special thanks to
> Washington state's Clark County Sheriff Department.
>
> See Ya...John Wayland
>
> http://wwwplasmaboyracing,com
>
> Jim Husted wrote:
>
> >Hey John all
> >
> > Man I wish I could have been there!!! I had even practiced my "Dat's
> NOT Mine! , and We don't need NO stinking badges Lines, LMAO!!! I can't
> wait to see the pics and video. As soon as I get them I'll throw them up at
> the site for everyone, being John seems to have no time here lately having
> all the fun 8^ )
> > Cya
> > Jim Husted
> > Hi-Torque Electric
> >
> >
> >
> >
> >
>
>
--- End Message ---
--- Begin Message ---
John Wayland wrote:
Hello to All,
http://wwwplasmaboyracing,com
Oops. Try this link, it works better :-)
http://www.plasmaboyracing.com
See Ya....John Wayland
--- End Message ---
--- Begin Message ---
I meant to say:
This is just a safety step to keep the DC/DC from seeing the full pack
charging
voltage. Lawrence Rhodes........
----- Original Message -----
From: "Bill & Nancy" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, March 01, 2006 12:52 PM
Subject: Re: dc converter disconnect
Is it best to disconnect the dc to dc when charging the pack? Does the
repeated switching of power off and on harmful to the converter
components?
Thanks,
Bill
Lawrence Rhodes wrote:
I have a Magnacraft relay that can easily cut out the DC/DC when
charging. It could also do things like take out the precharge resistor.
It just depends on how you want to design your system. There are many
ways to do it. LR.........
--- End Message ---
--- Begin Message ---
My mistake. Clearly the blog posters were correct.
damon henry wrote:
Let's see...
One of the most prolific EV builders on this list is notorious for his
spelling errors. I guess his opinions must never be worth anything
either...
damon
--- End Message ---
--- Begin Message ---
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Electric Vehicle Discussion List
Sent: Thursday, March 02, 2006 6:32 AM
To: Electric Vehicle Discussion List
Subject: EV digest 5225
EV Digest 5225
Topics covered in this issue include:
1) Re: Portable Dyno Setup
by "Joe Smalley" <[EMAIL PROTECTED]>
2) Re: dc converter disconnect
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
3) Re: Looking for suggestions for converting 6054 type headlights to
HID
by Neon John <[EMAIL PROTECTED]>
4) The Names have been Changed to Protect the Innocent!
by John Wayland <[EMAIL PROTECTED]>
5) Re: GE EV2000 Controller
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
6) Re: Charging outlet - what is common?
by "Joe Smalley" <[EMAIL PROTECTED]>
7) Transformer cores
by Justin Southam <[EMAIL PROTECTED]>
8) Re: Portable Dyno Setup
by Neon John <[EMAIL PROTECTED]>
9) Re: Transformer cores
by Danny Miller <[EMAIL PROTECTED]>
10) Re: Off-the-shelf multiple battery voltage display sought
by "Paul G." <[EMAIL PROTECTED]>
11) Re: Horsepower / Torque
by "Paul G." <[EMAIL PROTECTED]>
12) RE: Horsepower / Torque
by "Pestka, Dennis J" <[EMAIL PROTECTED]>
13) Re: The Names have been Changed to Protect the Innocent!
by Jim Husted <[EMAIL PROTECTED]>
--- End Message ---
--- Begin Message ---
"Paul G." wrote:
> How about running the outputs to small audio transformers instead of
> speakers? The outputs can be wired together and provide an audio
> signal. A car EQ generally expects an audio signal input.
Yes, you could use transformers. However, now you have LOTS of wiring to
deal with. I was trying to avoid having two wires from every battery
monitor, with its attendant rat's nest of wires and connectors.
--
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 ---
Looking at past races, the top 3 cars are within a couple of % points,
so 1% is worth going after. I've never raced before, but I think that the
biggest challenge is getting the most out of the battery while still
finishing the race. Not sure what pulse driving would do to the
battery. I have to do more research on this Peukert concept.
(http://www.smartgauge.co.uk/peukert.html) seems like a good
place to start.
Still no word on the controllers? Anyone?
1. Navitas TPM400-48 (http://www.navitastechnologies.com/tpm400.html)
2. Sevcon MillipaK 4Q (
http://www.evparts.com/shopping/product_details.php?id=268&product_id=2116)
3. 4QD PRO-150 (http://www.4qd.co.uk/prod/Prog150/index.html)
4. Alltrax AXE 4844 (
http://www.golfcarcatalog.com/catalog/index.cfm?fuseaction=product&id=3541)
5. Curtis 1227-41XX (
http://www.curtisinst.com/index.cfm?fuseaction=cProducts.dspProductCategory&catID=10
)
Tom.
However, for Electrathon, I suppose any trick that gives you even a 1%
> gain might be worth doing! PM motors have full field losses all the
> time, so they might benefit the most from pulse driving. If you had to
> drive very slow (a parade, for example), this might be the only way to
> get really high efficiency.
>
--- End Message ---
--- Begin Message ---
All:
Haven't seen any responses, but here's what has developed. I may not have
ten Trojans in the trunk, but I've been fiddling...
Just got a "project" 700 watt EV scooter. As recieved, it is even more
gutless than I expected. It
uses four 20 AH AGM batteries in series, for a nominal 48V.
Checking the battery voltage, it looks like there are two batteries with
bad cells. I'm getting 11
volts on two batteries after a full night's charge, while the other two
batteries in the bank are 13.2 or so right off the charger.
Can I just swap out the two bad batteries and keep the two known good ones,
or should I replace all 4?
---from reading, it appears that I CAN just swap out batteries in a series
pack without too much worry. I'll monitor individual battery voltage to make
sure one cell isn't falling behind. I'll probably use Lee Hart's LED array,
perhaps brought up to the handlebars with a ribbon cable, since it is nearly
impossible to reach the battery terminals with out extensive panel removal.
---I put a Fluke inductive Ammeter on a battery cable, and saw 20+ amps
through the line, so I guess the three feet of ~14 ga. wires from the
controller to the hubmotor aren't choking it too much. Of course, if I'm
multiplying correctly, 20*48 is 960 watts, not the listed 700, but perhaps
the rating was conservative.
Can I "freshen up" an AGM battery by adding a ~little~ distilled water? The
"sealed" vents amount to a rubber cup over each cell.
I haven't tried this yet, but I don't see why not.
The EXTREMELY sketchy Chinese "user's manual" refers to a six-monthly
"maintenance." I suspect they are referring to an equalizing charge. Am I
right?
Wouldn't a six-monthly (or more frequent) individual charge to bring
"lagging" cells up to their neighbors be better than forcing too much
current through the good cells?
Mark
--- End Message ---
--- Begin Message ---
Ok, the dumb setting was still a little too high for me. How would you use the
circuit in the
diagram? What hooks to the 12v, 5v, etc?
How about the Kilovac relays with the glass top. I like the look of these
things and would like to
incorporate it in the car. I have one with a 12v coil with 8kvdc contact
rating, dpdt. What could
I use it for in an EV, dc-dc, ceramic heater, dome light?
Dave Cover
--- Eric Poulsen <[EMAIL PROTECTED]> wrote:
> David McWethy wrote:
> >> Why not use a mos fet and small relay to turn the mos fet on or off.
> >> Have the Mos fet on the negative end , a 10v zener for gate to
> >> source to keep gate voltage form going to hi and a 1 meg resistor
> >> form dc to dc input + to relay ( could even us opto coupler here)
> >> from other point of relay to fet gate. you could even put a cap in
> >> parallel with zener to give a slow start up ( save the caps in your
> >> dc to dc converter) .
> >
> > Steve - I don't question that all of this is good advice. What is it
> > in English? Just when I think I start to know the language you guys
> > come up with a "zener". I still don't know what a "mos fet" is , tho
> > the term is now familiar.
> >
> > I should have paid attention to this stuff 20 years ago!
> >
> > Dave
> >
> A zener diode is a simple shunt voltage regulator. It's a diode that's
> make to have a specific breakdown point for reverse voltages. Typically
> you connect a higher voltage to a current limiting resistor that's in
> series with the zener that's referenced to your ground, like this:
>
>
>
> +12V
> |
> /
> \
> / Current limiting resistor
> \
> |
> +-----------> 5V out
> |
> __|__/
> / /\
> / \ 5V Zener Diode
> ----
> |
> |
> |
> 0V (gnd)
>
>
> This is only suitable for very low power output.
>
> WRT to the MOSFET (Metal Oxide Semiconductor Field Effect Transistor)
> ... Well, that's a bit outside the scope of a simple email =) Suffice
> it to say it's something of an electrically controlled switch, much like
> a regular transistor.
>
>
--- End Message ---
--- Begin Message ---
Great video, John! Looks like you're going to need to break out the putty
knife to scrape all that tire slag off of White Zombie!
I hope you've got video of the runs down the track, too!
Matt Graham
-----Original Message-----
From: John Wayland [mailto:[EMAIL PROTECTED]
Sent: Thursday, March 02, 2006 10:23 AM
To: [email protected]
Subject: Re: The Names have been Changed to Protect the Innocent!
John Wayland wrote:
> Hello to All,
http://wwwplasmaboyracing,com
Oops. Try this link, it works better :-)
http://www.plasmaboyracing.com
See Ya....John Wayland
--- End Message ---
--- Begin Message ---
http://www.i4u.com/article5165.html
Very aerodynamic and lightweight.
Rod
--- End Message ---
--- Begin Message ---
I would think that the geometrically higher aero drag at the higher speeds
would more than eliminate any small gains in drive efficiency.
> Lawrence Rhodes asked:
>>> I wonder if Electrathoners use pulse driving technique?
>>> Going let's say 30 to 45mph and using the coast to extract
>>> extra distance.
>
> [EMAIL PROTECTED] wrote:
>> I think that technique is more useful in an ICE - peak efficiency
>> under heavy load, then turn off the engine, coast, and bump-start
>> when you're going too slow.
>
> It works any time you have a motor that has a rather narrow efficiency
> peak. Electric motors usually have a rather broad efficiency peak, so
> the technique should be less useful.
>
> However, for Electrathon, I suppose any trick that gives you even a 1%
> gain might be worth doing! PM motors have full field losses all the
> time, so they might benefit the most from pulse driving. If you had to
> drive very slow (a parade, for example), this might be the only way to
> get really high efficiency.
> --
> 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
>
>
--
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 ---
> Need some help determining if the transmission in my 1965 Datsun truck can
> handle the torque that I may subject it to.
> Maybe someone can help with a simple way to determine this.
>
> I have set up a spreadsheet to look at Horsepower and Torque based on
> different voltages/amperages/efficiencies.
> It gives me 173.73 HP based on a 144 volt setup @ 1000 Amps @ 90%
> efficiency.
> First, is this correct?
Without knowing what kind of motor, it's difficult to say....
However, I seriously doubt that you have (or can get) a motor that is 90%
efficient at 1000 amps.
Assuming it's a more or less standard ADC type series wound motor, it's
probably closer to 50% efficient at that current.
> It is also showing 9124 ft/lbs of Torque @ 100 RPM.
> Is this correct or am I "Way Out" in left field on this?
I'm going to guess WAY Out, as in out of the ball park and across the
other side of the k-mart parking lot.
--
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 ---
On Mar 2, 2006, at 10:04 AM, Rod Hower wrote:
http://www.i4u.com/article5165.html
Very aerodynamic and lightweight.
That's a sweet-looking car, especially at $13,000. There's more info
at Loreno's website:
<http://www.loremo.com/index_en.php>
It's way too little information for coming to a valid conclusion, but
there might be a problem converting one of these to an EV - gross
vehicle weight. The website makes a big deal about reducing weight to
the minimum. I wouldn't expect it to be able to hold a lot of lead.
On the other hand, it's so lightweight and aerodynamic that perhaps a
small pack will be sufficient. And of course there's lithium, which
might be more affordable in 2009.
We'll see.
Rod
--
Doug Weathers
Bend, OR, USA
<http://learn-something.blogsite.org/>
--- End Message ---
--- Begin Message ---
On 2 Mar 2006 at 10:04, Rod Hower wrote:
> http://www.i4u.com/article5165.html
>
And http://www.loremo.com/
There are plenty of specialty ICEs, vehicles with a very small potential
market, and somehow the builders find a way to make them reasonably
profitable and salable. It's rather a rhetorical question, but what's the
problem with specialty EVs? Is it just that potential financial supporters
are leery of EVs?
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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--- End Message ---
--- Begin Message ---
My goodness, you folks sure are coming up with complicated solutions to a
simple problem.
Why not just use a separate LED bar graph display for each battery and
then arrange them together like the previously mentioned graphic
equalizer?
It doesn't take much to build a bar graph display with a LM3914. Arrange
your batteries into roughly 12V modules and montior them using something
like this:
http://www.uoguelph.ca/~antoon/circ/batmon12.htm
It's not off the shelf, but it's still pretty simple and relatively cheap.
It's what I'm planning on bulding, I'm just trying to find a suitable 10
segment bar graph display.
> The source code will probably take input from a ADC,
> Send the information to a DSP that is programmed to
> Do a FFT transform on the signal, and then break the
> Frequency domain signal into discrete frequencies.
>
> Like was said earlier...it is much easlier to design
>>From the ground up than to reverse engineer and redesign
> Someone else's system...try it and let me know how it
> Goes, but I think you're wasting your time with a
> Spectrum analyzer...especially when they use off the
> Shelf components designed to do only that one thing
> As cheap as possible...
>
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Andre' Blanchard
> Sent: Wednesday, March 01, 2006 6:16 PM
> To: [email protected]
> Subject: RE: Off-the-shelf multiple battery voltage display sought
>
> At 03:38 PM 3/1/2006, you wrote:
>>Remember that an audio spectrum analyzer uses the Decibel and that is a
>
>>logrythmic base, Not Linear.
>>
>>-----Original Message-----
>>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>
>>Behalf Of Andre' Blanchard
>>Sent: Wednesday, March 01, 2006 3:20 PM
>>To: [email protected]
>>Subject: Re: Off-the-shelf multiple battery voltage display sought
>>
>><< snip >>
>>
>>
>>Is there any open source spectrum analyzer software available?
>>
>>Then all you need is a laptop with a mic. input, if you can modify the
>>software you can display the data anyway you want.
>>Not the most rugged but it may work for some.
>>
>>
>>__________
>>Andre' B. Clear Lake, Wi.
>
> But if you got the source code you can do anything you want with the
> data.
>
>
> __________
> Andre' B. Clear Lake, Wi.
>
>
--
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 ---
Lee mentione:
> Yes, you could use transformers. However, now you have LOTS
> of wiring to deal with.
> I was trying to avoid having two wires from every battery
> monitor, with its attendant rat's nest of wires and connectors.
Audio amps use capacitive coupling all the time.
Why couldn't you use HV capacitors to couple the outputs of all your little
tone outputs and combine them in a single audio op-amp stage?
Maybe on paper it gets nuts for the lowest frequency range...
-Myles
--- End Message ---
--- Begin Message ---
Hi Peter, will you do anything for isolation?
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Peter VanDerWal
Sent: March 2, 2006 1:13 PM
To: [email protected]
Subject: RE: Off-the-shelf multiple battery voltage display sought
My goodness, you folks sure are coming up with complicated solutions to a
simple problem.
Why not just use a separate LED bar graph display for each battery and then
arrange them together like the previously mentioned graphic equalizer?
It doesn't take much to build a bar graph display with a LM3914. Arrange
your batteries into roughly 12V modules and montior them using something
like this:
http://www.uoguelph.ca/~antoon/circ/batmon12.htm
It's not off the shelf, but it's still pretty simple and relatively cheap.
It's what I'm planning on bulding, I'm just trying to find a suitable 10
segment bar graph display.
> The source code will probably take input from a ADC, Send the
> information to a DSP that is programmed to Do a FFT transform on the
> signal, and then break the Frequency domain signal into discrete
> frequencies.
>
> Like was said earlier...it is much easlier to design
>>From the ground up than to reverse engineer and redesign
> Someone else's system...try it and let me know how it Goes, but I
> think you're wasting your time with a Spectrum analyzer...especially
> when they use off the Shelf components designed to do only that one
> thing As cheap as possible...
>
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> On Behalf Of Andre' Blanchard
> Sent: Wednesday, March 01, 2006 6:16 PM
> To: [email protected]
> Subject: RE: Off-the-shelf multiple battery voltage display sought
>
> At 03:38 PM 3/1/2006, you wrote:
>>Remember that an audio spectrum analyzer uses the Decibel and that is
>>a
>
>>logrythmic base, Not Linear.
>>
>>-----Original Message-----
>>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>>On
>
>>Behalf Of Andre' Blanchard
>>Sent: Wednesday, March 01, 2006 3:20 PM
>>To: [email protected]
>>Subject: Re: Off-the-shelf multiple battery voltage display sought
>>
>><< snip >>
>>
>>
>>Is there any open source spectrum analyzer software available?
>>
>>Then all you need is a laptop with a mic. input, if you can modify the
>>software you can display the data anyway you want.
>>Not the most rugged but it may work for some.
>>
>>
>>__________
>>Andre' B. Clear Lake, Wi.
>
> But if you got the source code you can do anything you want with the
> data.
>
>
> __________
> Andre' B. Clear Lake, Wi.
>
>
--
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Justin Southam wrote:
> I've been thinking of building my own dc-dc convertor using a
> variation of the old square-wave inverter design used in cheap
> ups's etc, a centre tapped primary with the centre tap at battery
> voltage and grounding each end of the primary alternately.
These normally used a regular 60hz transformer. They either varied the
on-time of the transistor for each half-cycle, or used a
constant-voltage transformer to regulate the output.
> Because the output is rectified, the switching frequency no longer
> needs to be 50 or 60 hertz. Finally the point of this email, does
> anyone have a feel for the maximum frequency I can reasonably run
> an ordinary soft iron laminated core transformer?
A cheap 60hz transformer uses the thickest and lowest-grade laminations
they can get away with without it burning up. You can tell because they
run hot even at no load (when all you have is core loss). You're not
likely to get anywhere trying to run them at higher frequencies, as they
would just get hotter still. The cheapest transformers will have 10% to
25% of their power input in core loss!
Higher quality transformers use thinner laminations and better materials
to get higher efficiency; you can recognize them because they run cool
with no load. You can run these cores at 100-1000 Hz if you like; all
that happens is that the core loss goes up proportional to frequency. If
it was 3% at 60hz, it's 30% at 600hz.
You could with a 12v 15amp battery charger; it already has the
transformer, rectifier, ammeter, and sometimes charge control circuitry.
The simplest circuit is probably a half-bridge, with 2 SCRs and 2
capacitors, like this:
F1 _
+96vdc_ / \____________________
\_/ _|_ _|_
SCR1 _\_/_ T1 ___ C1
/ |____ 120vac____|
| |_|_|_| |
_|_ _ _ _|_
SCR2 _\_/_ | | | ___ C2
/ | 12vac |
common___________|_______________|
C1+C2 are your input filter capacitor. They also block DC current from
flowing in the transformer primary, which would saturate the core and
seriously reduce efficiency.
Trigger SCR1 on. Current flows from the +96v pack, thru SCR1,
transformer T1's primary, and to common thru C2. This will be a
half-sinusoidal pulse of current, starting at zero (due to T1's
inductance), rising to a peak, and then falling back to zero when C2 is
fully charged. When the current falls to zero, SCR1 natually turns off.
Now trigger SCR2 on. Current flows from the +96v left on C2, back thru
T1's primary, SCR2, and to common. This is also a half-sinusoidal pulse
of current, starting at zero (due to T1's inductance), rising to a peak,
and then falling back to zero when C2 has discharged.
It turns out that the voltage on the capacitors will be *higher* than
96v. When C1 reaches +96v, there is zero volts across T1; but its
inductance keeps the current flowing a little longer, charging C1
*above* the supply voltage. At no load, the peak could be as much as
double the input voltage.
This peaking effect is useful; it means the transformer has a normal
120vac sinewave on its primary. Its secondary circuit thus works just as
it would when plugged into the AC line. If it's a battery charger, it
charges the battery, etc. (The transformer could even be an induction
motor or any other inductive 60hz load.)
The frequency of operation depends on the resonant frequency of T1's
inductance and C1 and C2. For a 60hz transformer, you would pick C1 and
C2 to resonate at 60hz. If the core losses are tolerable as described
above, you could run it at a higher frequency, by using lower values for
C1 and C2.
The control circuit is very simple; it just waits until the current in
one SCR reaches zero before triggering the other SCR. If you trigger the
next SCR immediately, the frequency changes with the transformer's
inductance (which changes depending on load current). For a fixed
frequency, use values for C1 and C2 to insure the SCRs always turn off
earlier than your fixed-frequency trigger pulses.
Fuse F1 is there in case the control circuit every screws up and
accidentally triggers both SCRs "on" at once.
The capacitors must be AC types (NOT ELECTROLYTICs!) because with no
load they can charge as high as DOUBLE the applied DC voltage.
This is a very old circuit; inexpensive, simple and rugged; but the
transformer and capacitor are large.
--
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
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Here in AZ you can get a tax credit of up to $75 for the installation of a
dedicated outlet for charging EV's
http://www.eere.energy.gov/afdc/progs/view_ind.cgi?afdc/5871/0
Also somebody, Nick Viera I think, put up a web site that had all the NEMA
plugs and specs. I thought I had it book marked, but haven't been able to find
it. He has also made a nice schematic of his modular plugs
http://go.driveev.com/jeepev/convpgs/charger.php, which I plan to copy...
Rush
Tucson AZ
www.ironandwood.org
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Many years ago I built a simple monitoring panel for my Comuta-Car. It had
eight edgewise panel meters with some arbitrary scale, bought surplus for a
buck or two each. I don't recall their specs any more, but I remember using
a zener diode (also surplus) and a voltage divider network for each. I
vaguely remember aiming for a range of about 1 volt from 0 to full scale,
with the nominal level-road driving voltage about in the middle.
I built the circuit on a piece of perfboard and put the whole mess in a
builder's box. I made the battery connections with #24 wire (surplus) and
fused each pair with a cheap surplus inline fuse and fuseholder. (Today I'd
put a fuse on each connection, and I'd also use proper fuses and
fuseholders, but in those days I didn't know any better.)
It was fairly easy to see the weak batteries with this setup. The main
problem I had was that I set too small a range. The meters stayed visible
at steady speeds, as I expected, but hill climbing and acceleration usually
sent all the meters to zero. Also, it was somewhat distracting trying to
watch the display while driving down the road. I found it was better to
have a passenger keep an eye on it.
If I were doing something similar today, I'd probably use Lee's glowing LED
approach instead. I think that would make it even easier to see the
weaklings. Besides, I don't see very many cheap surplus meter movements in
the catalogs any more.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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On 2 Mar 2006 at 10:29, Rush wrote:
> a web site that had all the NEMA
> plugs and specs.
Does this help?
http://www.leviton.com/sections/techsupp/nema.htm
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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<<<It doesn't take much to build a bar graph display with a LM3914. Arrange
your batteries into roughly 12V modules and montior them using something
like this:
http://www.uoguelph.ca/~antoon/circ/batmon12.htm
It's not off the shelf, but it's still pretty simple and relatively cheap.
It's what I'm planning on bulding, I'm just trying to find a suitable 10
segment bar graph display.>>>
http://www.allelectronics.com/cgi-bin/category/345/LED_Displays.html (a search
for bargraph also brings up LM3914) or a more linear one like
http://www.alltronics.com/images/22L007.jpg ?
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On Mar 2, 2006, at 9:29 AM, Rush wrote:
Also somebody, Nick Viera I think, put up a web site that had all the
NEMA plugs and specs. I thought I had it book marked, but haven't been
able to find it. He has also made a nice schematic of his modular
plugs
http://go.driveev.com/jeepev/convpgs/charger.php, which I plan to
copy...
Looks nice. I'm pondering the same thing at the moment.
I have a PFC-20 and want to be able to use it safely on either 120v or
240v. I know that there was a lot of discussion recently about GFCI
for the Manzanita Micro PFC chargers, but sadly, I don't think there
was ever a consensus on the best solution. So I'm reopening the
discussion again - sorry about that.
I haven't been able to find a dual-voltage GFCI (does anyone know of
one?), so I need two of them. One solution is to put two GFCI male
plugins inside the vehicle and wire them both to the charger. This
makes it necessary to prevent power being present on the unused pins,
so there would need to be safety interlocks and/or relays that
disconnect the unused outlet.
Another solution that just occurred to me would be two inline
waterproof GFCIs. Add them to Nick's adapters. Plus another one for
L6-30 outlets (the long extension cord doesn't have a GFCI in it).
So is this a stupid idea, or a waste of time? Should I just build the
dual outlets and interlocks? Or not worry about GFCI?
Rush
Tucson AZ
www.ironandwood.org
--
Doug Weathers
Bend, OR, USA
<http://learn-something.blogsite.org/>
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On Mar 2, 2006, at 1:13 PM, Peter VanDerWal wrote:
http://www.uoguelph.ca/~antoon/circ/batmon12.htm
It's not off the shelf, but it's still pretty simple and relatively
cheap.
It's what I'm planning on bulding, I'm just trying to find a suitable
10
segment bar graph display.
Google says:
<http://www.elexp.com/opt_0ida.htm>
Check out the last one on the page.
--
Doug Weathers
Bend, OR, USA
<http://learn-something.blogsite.org/>
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Lee Hart wrote:
...
The capacitors must be AC types (NOT ELECTROLYTICs!) because with no
load they can charge as high as DOUBLE the applied DC voltage.
Slight correction:
It doesn't matter how high the voltage gets. Normally you must
use AC caps types because of polarity on them gets reversed,
not because of magnitude of the voltage in them. Even if voltage
tenfolds you still can use electolytics *provided* they can handle
ripple current and rated for highest (+ some) voltage they will see.
Unlike AC (non-polarized) caps electrolytics are never rated for
reactive power handling, so it will be difficult to say. But again,
sized properly,
electrolytics will work just fine in any circuit which guarantees
the same voltage polarity on them.
Victor
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> It doesn't take much to build a bar graph display with a LM3914.
> http://www.uoguelph.ca/~antoon/circ/batmon12.htm
> It's not off the shelf, but it's still pretty simple and relatively
> cheap.
It's adequate. It has a scale adjustment, but no offset adjustment.
There's no temperature compensation (in fact, the reverse polarity
protection diode compensates the wrong way). There's no LED brightness
adjustment to deal with night vs. direct sunlight. Most of the supply
current powers the LM3914 itself, not the LEDs. No alarm outputs to do
anything if a battery voltage does get too high or too low. And of
course they are not isolated.
There are about 20 parts; with a PC board it's probably $10 or so per
battery. With packaging and labor, you'd have a product that has to sell
for $20 or so. And this is for one without many features.
Now build a couple dozen of them for each battery in your pack. Wiring
them up seems to take forever. It gets old fast! This illustrates the
classic problem; even a simple circuit gets complicated when you have to
do it so many times.
That's why it's so tempting to build a "one box monitors all" type of
monitor. This box is a lot more complicated, but you only have to build
one of them. You also only need one wire per battery, not two per
battery. But here too, you have to be careful a "simple" project doesn't
get so complicated that you never get it done.
--
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
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