EV Digest 5940
Topics covered in this issue include:
1) Re: Ranger doner
by "Rush" <[EMAIL PROTECTED]>
2) RE: emeter power supply
by Cor van de Water <[EMAIL PROTECTED]>
3) Re: Floodies/Batt. murder mystery/Thanks to Roger & Roland
by "Chuck Hursch" <[EMAIL PROTECTED]>
4) Re: AC vs DC?
by Lee Hart <[EMAIL PROTECTED]>
5) Re: AC vs DC
by Lee Hart <[EMAIL PROTECTED]>
6) Re: AC vs DC
by Lee Hart <[EMAIL PROTECTED]>
7) Re: air conditioning for ev's
by Lee Hart <[EMAIL PROTECTED]>
8) DC-DC Converter not working
by "Chris Sutton" <[EMAIL PROTECTED]>
9) Re: 3 wheelers in NJ?
by Lee Hart <[EMAIL PROTECTED]>
10) Reliability vs. Repairability... Re: AC vs DC
by Nick <[EMAIL PROTECTED]>
11) Re: AC vs DC
by Nick Austin <[EMAIL PROTECTED]>
12) RE: Floodies/Batt. murder mystery/Thanks to Roger & Roland
by "Roger Stockton" <[EMAIL PROTECTED]>
13) Re: AC vs DC? Wound Rotor motors?
by Lee Hart <[EMAIL PROTECTED]>
14) RE: DC-DC Converter not working
by "Roger Stockton" <[EMAIL PROTECTED]>
15) Re: AC vs DC
by "Paul G." <[EMAIL PROTECTED]>
16) Re: (was: CE on TV)
by "Paul G." <[EMAIL PROTECTED]>
17) Re: Engine swap for removal labor
by John <[EMAIL PROTECTED]>
18) RE: Reliability vs. Repairability... Re: AC vs DC
by "David Sharpe" <[EMAIL PROTECTED]>
19) Re: Electric assisted bicycle
by "Edward Ang" <[EMAIL PROTECTED]>
20) Re: Engine swap for removal labor
by Storm Connors <[EMAIL PROTECTED]>
21) BB600 update 473 miles
by Mike Phillips <[EMAIL PROTECTED]>
--- Begin Message ---
If you go to our website, www.TEVA2.com , clik on the projects link on the
left, and scoll down to
"Mark Brueggemann's S-10 Bed Lift Details", you'll see one way of making a tilt
bed work.
Rush
Tucson AZ
www.ironandwood.org
----- Original Message -----
From: "bruce parmenter" <[EMAIL PROTECTED]>
To: "evlist" <[email protected]>
Sent: Thursday, September 28, 2006 10:01 AM
Subject: Re: Ranger doner
> See http://www.coate.org/jim/ev/et/tilt_bed.html
> and ask them how they did it.
>
> Bruce {EVangel} Parmenter
>
>
--- End Message ---
--- Begin Message ---
Agree on laptop supplies (15V 4A or so) and two remarks on DC/DC:
1. Make very sure that the input and output of the DC/DC is
really good isolated, because you rely on it to prevent
your pack from being connected to frame ground, which can
cause your GFCI to blow as soon as you start charging, or
it can cause a short circuit on your charger output, dependent
how your charger works. Some cheap DC/DC have common ground
so make sure you check. I doubt that any of them will be
"Hi-pot" certified as required for every wall brick.
2. Efficiency of the 12V 1A switching power supply is just as
good as a DC/DC because that is what it essentially is:
Every small switching power supply is a diode bridge,
capacitor and isolated DC/DC.
First thing it does is recify the AC into DC.
Running it from DC means only two diode drops (1.2V) is
added, so efficiency is 1% lower than direct DC/DC.
My guess is that my switchers draw about 10mA when not
loaded - I would need to measure, but it is not a draw
that you should be concerned about. Certainly not when
comparing it to the loss in an DC/AC inverter.
Hope this clarifies,
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 Roger Stockton
Sent: Friday, September 29, 2006 2:18 PM
To: [email protected]
Subject: RE: emeter power supply
Cor van de Water wrote:
> My suggestion to look at a "wall-box" supply directly powered from
> your pack is to avoid the inefficiency of the series of conversions:
> 120V DC => 12V DC => 110V AC => 12V DC
> My suggestion is to hook up a switching power brick to your
> pack to get: 120V DC => 12V DC
I rather suspect that if efficiency is a consideration, then the better
approach is to use either an isolated 12V->12V DC/DC such as EV Parts
supplies for the E-Meter:
<http://www.evparts.com/shopping/product_details.php?id=434&product_id=1
540>
(it really isn't very pricey; certainly not in the >$100 range that the
original poster implied he would be looking at for an isolated DC/DC to
run his E-Meter).
Or, better still, look for a small 120VDC->12VDC isolated DC/DC, such as
Astrodyne's PWB series (5W, universal 85-265VAC input, $34):
<http://datasheet.astrodyne.com/PWB.pdf>
While running a notebook-type switching supply directly from the pack is
more efficient than running it from a 12V->110VAC inverter, the notebook
supply is far larger in output capability than an E-Meter requires, and
so will be running very lightly loaded and so at a fraction of its peak
efficiency.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
I guess I don't understand. We have Roland here advising 7.4V/6V
battery, looks to be constant voltage charging with no constant
current, so IU rather than IUI. I don't know how long the final
U is suppose to go, or down to what amps.
Bruce Parmenter seems to have been following an IU charging
regime on his US125s, going to about 2.57V/cell, which is about
7.7V/6V battery. I guess his batteries are going ok, this pack.
I, on the other hand, everytime I discharge the batteries fairly
deeply seem to get a new layer of sugarcoating white sulfate
crystals on top of my negative plates. My 1.25-year old
batteries (US125) were delivered with rather low electrolyte
levels and low specific gravity readings. I worked to get the
electrolyte levels up by adding water over several months. I had
one rather deep discharge in Oct 2005 that started the sugar
crystal layering. In the meantime, I have been following Roger's
advice of moving the constant voltage up towards 14.4V/12V and
then after reading further posts and US Batteries' page (+ Bruce
Parmenter's postings) final U went to the 2.57V/cell (15.6V/12V).
I also had a final 3-hr constant I phase for awhile at 4A, then
on advice of Greg McCrea moved it to 5.5A. I finally got the
average of the pack to 1257sg.
Then earlier (9/2) this month I ran a 75A load test to 5.25V, and
the batteries did better than I expected. But then last weekend
I was rather floored during my battery maint. / hydrometer
readings. Lots more sugar coating on the plates. sg readings
way down (I haven't finished the spreadsheet). Now my batteries
will no longer taper off into final I, resulting in the
hot/stinky battery post of a few days / week ago.
All that I'm reading leaves me to wonder, can these batteries be
charged and last? Most everybody seems to have problems with
batteries, and they ain't cheap. I've never seen this sugar
coating on my previous two packs. Appears Bob Bath has lost his
pack, Bruce had one fail after only a year, etc., etc. I am
definitely having my doubts...
I'll post my data (spreadsheets - jpg capture I think) in the
next few days. I hope someone can help me pull my pack out of
the hole. I can't see replacing a pack that is only 5K and 1.25
years old. That's 24 cents/mile, not to speak of the gas hauling
around a set and time installing them.
Chuck
PS: What's the red goo, Bob?
----- Original Message -----
From: "Bob Bath" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, September 23, 2006 5:02 PM
Subject: Re: Floodies/Batt. murder mystery/Thanks to Roger &
Roland
> That's what's such a bummer: I followed US Battery's
> advice (see website), and wound up murdering the pack.
> Yes, I do believe this was a case of EQ'ing the pack
> on practically every charge...
> Trojan, meanwhile, sticks more to your regimen.
> Now I'm curious to try the red goo that you've sworn
> by before!
>
> --- Roland Wiench <[EMAIL PROTECTED]> wrote:
>
> > Hello Bob,
> >
> > On your next pack of 144 volts. Try to not charge
> > over 177.6 volts when the
> > batteries are at 80 degrees F. This is 7.4 volts per
> > 6 volts or 14.8 per 12
> > volts. If the battery temperature is lower, than
> > the maximum I charge at is
> > 7.5 volts per 6 volt or 15 volts per 12 volt.
> >
> > Any time I see any one of the batteries have more
> > than a 0.04 volt
> > difference from the highest battery to the lowest
> > battery, than I will do a
> > equalization charge which is 7.73 volts per 6 volts
> > or 15.46 volts per 12
> > volt. I only do this equalization charge now every
> > three or more months.
> >
> > 15.46 x 12 = 185.52 volts! Its look like you were
> > doing balance or
> > equalization charging everytime which really cooks
> > the batteries, instead of
> > doing bulk charging which would be between 177 to
> > 180 volts.
> >
> > Roland
> >
> >
> > ----- Original Message -----
> > From: "Bob Bath" <[EMAIL PROTECTED]>
> > To: <[email protected]>
> > Sent: Saturday, September 23, 2006 1:15 PM
> > Subject: Floodies/Batt. murder mystery/Thanks to
> > Roger & Roland
> >
> >
> > > Well about a year ago, I started writing as I was
> > > frustrated that my batteries were no longer
> > hitting
> > > 186-189V.
> > >
> > > Battery experts got me to understand that while
> > 186
> > > may have been satisfactory for brand new, they
> > were
> > > not so anymore. The mystery, was why wouldn't the
> > > batteries taper down?
> > >
> > > Over time, I cut the charger to a rate that would
> > > gently bubble, (but not heat) the batteries. This
> > is
> > > around 173-175V for my 144V pack. Sure enough,
> > the
> > > charger tapers down to 6-7A.
> > >
> > > At this point (2 yrs. on the pack), I have 3
> > batteries
> > > that each have a cell that won't go past 1200 SG.
> > >
> > > It is my perception that with active material
> > flaked
> > > around the cell, I am faced with that favorite
> > > dilemma; replace whole pack, or replace the poor
> > > cells.
> > >
> > > I am leaning toward replacing the pack at this
> > point.
> > > Interstate is 90x18 or $1620 for the pack. I will
> > go
> > > with 165Ah, not 178Ah. Just don't think it's
> > worth
> > > the extra money; can use the extra weight, too.
> > >
> > > I will do a load test on a satisfactory battery
> > (ie,
> > > one where all of the cells are leaning to 1265
> > SG),
> > > and make a final decision.
> > >
> > > So despite having 6 years experience with EVs
> > under my
> > > belt, my understanding of EVs has been unmatched
> > with
> > > my understanding of batteries. Bummer.
> > >
> > > To those who responded then to my post, I continue
> > to
> > > be grateful to you for contributing to this list.
> > > Let's see if I can get more mileage/years under my
> > > belt next time/next pack...
> > > peace,
> > >
> > >
> > > Converting a gen. 5 Honda Civic? My $20 video/DVD
> > > has my '92 sedan, as well as a del Sol and hatch
> > too!
> > > Learn more at:
> > > www.budget.net/~bbath/CivicWithACord.html
> > > ____
> > > __/__|__\ __
> > > =D-------/ - - \
> > > 'O'-----'O'-'
> > > Would you still drive your car if the tailpipe
> > came out of the steering
> > > wheel? Are you saving any gas for your kids?
> > >
> > > __________________________________________________
> > > Do You Yahoo!?
> > > Tired of spam? Yahoo! Mail has the best spam
> > protection around
> > > http://mail.yahoo.com
> > >
> > >
> >
> >
>
>
> Converting a gen. 5 Honda Civic? My $20 video/DVD
> has my '92 sedan, as well as a del Sol and hatch too!
> Learn more at:
> www.budget.net/~bbath/CivicWithACord.html
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the
steering wheel? Are you saving any gas for your kids?
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
--- End Message ---
--- Begin Message ---
Andre' Blanchard wrote:
Have you ever seen how Edison did the windings on the armatures of his
Jumbo DC generators.
Great stuff. Thank you Andre'!
--
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 ---
[EMAIL PROTECTED] wrote:
Is not working in a higher voltage overall more efficient? If so would not
this give an edge for efficiency to AC systems? With most AC EV systems being
around 300 volts and DC in the 120 range for most full size 70 mph vehicles?
No; voltage has (almost) nothing to do with efficiency. A 48v or 480v
motor or controller have the same efficiency. Both packs typically built
whit the same type batteries (just wired differently), so there is no
difference there either. Voltage doesn't affect efficiency until you get
to extremes like 1 volt at 10,000 amps, or 10,000 volts at 1 amp.
You might think that higher voltages will lower the current, and that
must reduce the voltage drops in the wiring and improve efficiency,
right? But when you go through this, you find it doesn't work out that way.
In a motor, they fill the available winding space with as much wire as
will fit. A 240v motor needs twice as many turns as a 120v motor; so the
wire must be half the cross-sectional area to fit. Twice the length and
half the cross-section means a 240v motor has 4 times the winding
resistance as a 120v motor. Yes, it draws half the current for the same
horsepower, but power = I^2 R. 1/2 the current times 4x the resistance
means the power loss is the *same*!
For the batteries, suppose you have 20 12v batteries. You can wire them
all in series for 240v, or as two groups of 120v in parallel. You'll
find you have the same total number of connectors, same total wire
length, and same current in every wire for either the 120v or 240v case.
So again, the efficiency of both packs is exactly the same.
Suppose you used different sized batteries for the 120v and 240v case;
like ten 12v 100ah for 120v, and twenty 12v 50ah for 240v (so he the two
packs are the same size, weight, and watthour capacities so you have a
fair comparison). Now your 240v pack has twice the number of batteries,
so 2x the number of connectors and wire length as the 120v case. The
120v case has twice the current per wire and per battery; so you have to
use twice the wire size (assuming you size it for a particular
temperature rise). Just like the motor, the 240v case has 4x the
resistance (half the wire size, and twice the length). It runs at half
the current; P = I^2 R, so again, you're right back where you started,
with identical losses for both 120v and 240v packs.
Now look at the controller. When you look at the specs for MOSFETs, you
notice that their resistance is proportional to the *square* of their
voltage ratings. The really low resistance MOSFETs are also low voltage.
So again, a 120v controller will have less resistance, and so less
on-state voltage drop than a 240v controller. The power loss in both is
the same!
Yes, there are special cases where changing the voltage *does* change
the efficiency. They occur because you changed only *part* of the
system, or used parts intended for one voltage/current at the wrong
level. For instance a "72-144v" controller is more efficient at 144v
than it is at 72v, because it's obviously built with high-voltage MOSFETs.
Or, you could blindly wire both your 120v and 240v EVs with the same
size wire, ignoring the current change. Then the 240v version would have
less voltage drop -- due to oversizing the wire, not from the voltage.
--
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 ---
Cor van de Water wrote:
Due to brush limitations, the DC implementations tend to
use a voltage below 200V
Most EV DC motors are derived from fork lift motors. Fork lifts use low
voltage packs. So, their motors are always built low voltage (like
38-72vdc). EVers routinely use them at 2x rated voltage without
significant problems. But not surprisingly, trying to use them at 3x or
4x rated voltage starts to cause problems.
There are certainly no problems designing brushed motors over 200v.
There are millions of mass-produced 240v DC motors in use all over the
world. Many are built in both 120v and 240v versions (to satisfy US and
European markets), and there is no indication that the 240v version
costs more or is less reliable (or has any efficiency difference, for
that matter).
If you are going to run at 240vdc, you need a motor that is *designed*
for that voltage -- not a 72v forklift motor! There are plenty of
railway, bus, and large industrial DC motors built for high voltages;
they just don't happen to be as easy to get surplus.
Another reason for production EVs to use AC may be the
absence of brushes, or simply because they expected that in
high volume the simpler AC motors would result in an overall
lower cost solution, as prices of electronics tend to decrease.
Or because they were already familiar with AC, as in the AC
alternator - no car has a DC alternator.
I think you're correct. If you don't know anything about DC motors, you
assume brushes are unreliable; so you try to design them out. If you
only look at list prices for AC vs. DC motors of a given horsepower, the
AC ones are cheaper (because they are built in higher volumes). If you
don't know much about electronics, you'll assume that it always gets
cheaper (PCs did, didn't they?)
These are all naive assumptions. But, they are probably what led the
inexperienced auto company engineers to favor AC.
PS: *100%* of the motors in automobiles have brushes. Even the
alternators have slip rings! If brushes are so bad, why do the auto
companies use them universally? Why have they never used a brushless DC
or AC motor with inverter anywhere in any car (except their EVs)?
Also the perceived risk of a "full on" DC control may have
caused them to sway to AC
Perhaps; but no real DC EV has this problem with "full on" failure
modes; it's always designed out of any production EV. You only find it
in hobby projects or EVs designed by tiny inexperienced companies.
or because the professional suppliers were more in the AC camp
than the DC suppliers.
That's possible. If you go to a company that specializes in AC motors,
of course that is what you will get. To a man with a hammer, every
problem looks like a nail.
NOTE that in the Prius, the AC motor is entirely in a splash-
lubrication oil bath to remove heat from the motor as well as
to provide lubrication and removal of wear products.
That may be difficult with a DC motor's commutator & brushes.
Starter motors and alternators have brushes, and they are used under the
hoods of cars, and have no particular problems with their brushes.
--
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 ---
How many Btu's per watt does a peltier move?
These are incompatible units; like asking how many gallons are in a foot.
You can convert BTUs in to watthours; 1 BTU = 0.293 watthours
Or BTUs per hour into watts: 1 BTU/hour = 0.293 watts
I think you are looking for an efficiency factor. The ones used for
heating and cooling devices are the COP (Coefficient of Performance;
thermal watts pumped divided by electrical watts input), or the Carnot
efficiency (percent of ideal, i.e. a resistor is a 100% efficient heater).
The Carnot efficiency of Peltier devices is around 5-8%, and their COP
is typically 0.4-0.7.
For comparison, a compressor-based heat pump has a Carnot efficiency
around 30-45%, and a COP of 2-5.
--
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'm not sure my DC to DC Converter is working.
I had a small 12v battery I was using for a couple of months and last
week when driving, my 12v meter was showing the voltage slowly
dropping as I went home. When my vacuum pump went on it would blip
down to 10v, but when the voltage came back it was a little less each
time.
Also, when the main relay was engaged to let power flow to the
controller, I would notice about a 1/2v drop.
I put the 12v battery on a charger overnight, but the next day it
performed about the same.
I almost did not make it home one day as the voltage in the battery
was down to about 10v and the vacuum pump was barely working and
without vacuum stopping was much harder.
So, I replaced that battery and got a little bigger one just to start
over, but this new battery is doing similar things, just not dropping
as much.
With no load on the battery and the key on (which is turnning on the
DC-DC Converter, because the red light is light on the converter), the
12v guage says 12.0. Turning on the parking lights brings it down to
about 11.5. Turning on the headlights down to 11.25. Vacuum pump
goes on we blip down to 10ish.
The voltage going into the DC to DC is reading at full pack voltage (120v ish).
If I unhook the output from the 12v battery, the light on the
controller fades out and there is no voltage reading on the output
from the controller. If I hook up the output to the battery, I show
the battery voltage on the output of the controller.
How can I test to make sure the DC-DC is working, and shouldn't it be
able to keep up with the demands of the car?
--- End Message ---
--- Begin Message ---
Mark Hastings wrote:
*sigh*
Well I might be moving again. I was wondering if anyone on the list in
NJ or knows of anyone in NJ that has been able to register an enclosed
three wheeler?
I know I couldn't in CT but never intended on living in NJ. I was just
all settled down in TX too.
The old Gogomobile was a 3-wheeled car; except that the ones imported to
the USA had "dualies" fitted on the rear wheel so it technically was a
4-wheeled "car". This was done, I understand, to get around the special
motorcycle licensing and registration laws at the time.
So, could you retrofit dual wheels onto your 3-wheeler to make it into a
car? You can license a home-built car in every state.
--
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 ---
Just fishing around for opinions and experiences here...
In my observations, DC powered conversions tend to have more reliability
issues than AC powered (more frequent break-downs), but AC powered
vehicles seem to be MUCH more difficult to repair when they do break
down. I guess it is sort of six of one, half a dozen of another, but
what's the opinion/experiences of others on the list?
Nick
Lee Hart wrote:
Cor van de Water wrote:
Due to brush limitations, the DC implementations tend to
use a voltage below 200V
Most EV DC motors are derived from fork lift motors. Fork lifts use low
voltage packs. So, their motors are always built low voltage (like
38-72vdc). EVers routinely use them at 2x rated voltage without
significant problems. But not surprisingly, trying to use them at 3x or
4x rated voltage starts to cause problems.
There are certainly no problems designing brushed motors over 200v.
There are millions of mass-produced 240v DC motors in use all over the
world. Many are built in both 120v and 240v versions (to satisfy US and
European markets), and there is no indication that the 240v version
costs more or is less reliable (or has any efficiency difference, for
that matter).
If you are going to run at 240vdc, you need a motor that is *designed*
for that voltage -- not a 72v forklift motor! There are plenty of
railway, bus, and large industrial DC motors built for high voltages;
they just don't happen to be as easy to get surplus.
Another reason for production EVs to use AC may be the
absence of brushes, or simply because they expected that in
high volume the simpler AC motors would result in an overall
lower cost solution, as prices of electronics tend to decrease.
Or because they were already familiar with AC, as in the AC alternator
- no car has a DC alternator.
I think you're correct. If you don't know anything about DC motors, you
assume brushes are unreliable; so you try to design them out. If you
only look at list prices for AC vs. DC motors of a given horsepower, the
AC ones are cheaper (because they are built in higher volumes). If you
don't know much about electronics, you'll assume that it always gets
cheaper (PCs did, didn't they?)
These are all naive assumptions. But, they are probably what led the
inexperienced auto company engineers to favor AC.
PS: *100%* of the motors in automobiles have brushes. Even the
alternators have slip rings! If brushes are so bad, why do the auto
companies use them universally? Why have they never used a brushless DC
or AC motor with inverter anywhere in any car (except their EVs)?
Also the perceived risk of a "full on" DC control may have
caused them to sway to AC
Perhaps; but no real DC EV has this problem with "full on" failure
modes; it's always designed out of any production EV. You only find it
in hobby projects or EVs designed by tiny inexperienced companies.
or because the professional suppliers were more in the AC camp
than the DC suppliers.
That's possible. If you go to a company that specializes in AC motors,
of course that is what you will get. To a man with a hammer, every
problem looks like a nail.
NOTE that in the Prius, the AC motor is entirely in a splash-
lubrication oil bath to remove heat from the motor as well as
to provide lubrication and removal of wear products.
That may be difficult with a DC motor's commutator & brushes.
Starter motors and alternators have brushes, and they are used under the
hoods of cars, and have no particular problems with their brushes.
--- End Message ---
--- Begin Message ---
On Fri, Sep 29, 2006 at 05:05:03PM -0500, Lee Hart wrote:
>
> Starter motors and alternators have brushes, and they are used under the
> hoods of cars, and have no particular problems with their brushes.
On the Dodge TEVan they used brushed blower motors for pack and motor
cooling. The service manual indicates that you need to replace these
every 15'000 miles. They really quit working ~18K :-/
I also had an ICE Caravan when I was a teenager, and the brushes ware
down to the point that they are not touching the comm after about 150K
miles. Fortunately, these end up in the junk yard all the time, and so
there are tons of used blower motors to be had.
Also, aren't starter motors and alternators notorious for failing? I've seen
many dead starter motors. I though that the auto manufactures just made them
so cheap, because they only needed to last to the end of the warranty.
I don't know if they die due to brush problems or not, but they seem like
bad examples for low failure automotive brushed DC motors.
I guess they do seem to generally last for 100K miles, which is something.
--- End Message ---
--- Begin Message ---
Chuck Hursch wrote:
> In the meantime, I have been following Roger's
> advice of moving the constant voltage up towards 14.4V/12V and
I sure hope I didn't suggest 14.4V/12V battery (2.40V/cell) for US125s;
I'm one of the oddballs on the list who consistently recommends using
the 2.583V/cell (15.5V/12V or 7.75V/6V battery) value recommended by
USBMC for their product.
I will add the caution, however, that if you do use this value, you
really need to keep an eye on the battery temperature and adjust the
charge voltage accordingly because if you use just a bit higher charge
voltage than appropriate you could find that the current is unable to
taper off as it should. (The 2.583V/cell value is for 26.7C.)
> then after reading further posts and US Batteries' page (+ Bruce
> Parmenter's postings) final U went to the 2.57V/cell (15.6V/12V).
> I also had a final 3-hr constant I phase for awhile at 4A, then
> on advice of Greg McCrea moved it to 5.5A. I finally got the
> average of the pack to 1257sg.
4A might be a bit too low for these batteries, although they might well
taper to that level or below when new. USBMC recommends a finish rate
of C/40 (5.9A for your US125s), and suggests not exceeding this level.
> Lots more sugar coating on the plates.
Is it possible that you topped the batteries up with something other
than distilled water at some point?
> Appears Bob Bath has lost his pack,
Nope; I didn't see an on-list follow up from Bob, but he did an
equalising charge on his pack and those 2 stragglers popped right back
in line with the others.
> Bruce had one fail after only a year
Keep in mind that Bruce subjects his batteries to fairly extreme duty as
a result of his penchant for quick charging. Driving some distance in a
heavy vehicle such as his and then hooking up multiple chargers and
pumping 50-100A or more into the pack pretty much ensures an elevated
internal battery temperature, and with non-temperature compensated
chargers...
> I'll post my data (spreadsheets - jpg capture I think) in the
> next few days.
Looking forward to it!
If you get yourself of a copy of pdf995 <http://www.pdf995.com/> (free),
then you can print your spreadsheet plots, etc. to it just as you would
to any printer and have a nice .pdf format document to share. Printing
Excel plots, etc. to pdf995 results in compact files that you can zoom
in on to see data without the image falling apart like a jpg or other
capture will.
> I hope someone can help me pull my pack out of the hole.
I suspect the first (and perhaps only) remedial option you have is to
try an equalise charge; fully charge the pack, top up the water, and
then let it simmer away at 5-6A until the voltage quits rising (2 or 3
measurements taken 1hr apart remain essentially unchanged), or until the
s.g. quits rising over a similar observation interval. Bear in mind
that your s.g. will drop as the batteries age, and it also varies with
electrolyte temperature, so you may want to place more emphasis on the
observed capacity at 75A discharge rate than on the absolute s.g. values
you observe.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Steven Ciciora wrote:
Lee,
What would be the advantages and disadvantages of
exciting the wound rotor directly, through the
slip-rings? My thinking is that it would become a
synchronous AC motor. But would that be a "good"
thing? I imagine there is some optimum exciting
level; what would hapen if you over-excited the rotor?
Under-excited the rotor? ... You see, I have this
400 Hz aircraft alternator...
Funny you should say that! :-) I built an EV with an aircraft 15kw
3-phase 120/208vac alternator years ago.
Yes, if you apply DC power to the wound rotor, it makes it a synchronous
motor. Synchronous motors have a number of advantages over induction motors:
- more efficient (by eliminating slip)
- more torque (because you can get a stronger field)
- lower starting current (with external resistance or inductance
in series with the rotor windings)
- precise speed control (a natural for synchronous motors)
- perfect 1.0 power factor (by controlling field excitation)
- simpler inverter (fixed stator voltage; just adjust frequency)
- trivially easy to use as a generator (regenerative braking)
The DC field excitation voltage directly controls the stator AC voltage.
More field current = more AC stator voltage. If you're running on a
fixed voltage AC supply (like the AC powerline), the "right" field
excitation produces a perfect 1.0 power factor and peak efficiency. If
you under-excite it, the power factor becomes lagging (like an induction
motor); and current goes up, efficiency goes down. If you OVER-excite
it, power factor becomes leading; and again current goes up and
efficiency goes down. Synchronous motors are sometimes used this way
deliberately to do power factor correction.
In my case, I used an SCR inverter. They are cheap and simple, but have
the shortcoming of requiring commutation circuitry. This circuit
momentarily interrupts the SCR current flow to get it to turn off.
But here, I deliberately over-excited the synchronous wound-rotor motor
(aircraft alternator) so it had a leading power factor. This makes the
AC current automatically pass thru zero BEFORE the voltage; thus the
inverter SCRs automatically turned off with no commutation circuitry!
All I needed was a much smaller commutation circuit to get it started.
The idea worked, but the aircraft alternator was less than ideal. Like
the aircraft generators, it was light and powerful; but inefficient and
noisy. My main problem was low starting torque; without the big
commutation circuits, I couldn't get high starting current; thus low
starting torque.
--
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 ---
Chris Sutton wrote:
> I'm not sure my DC to DC Converter is working.
It sounds like you are pretty sure it isn't working! ;^>
If the DC/DC is working, it should be holding the 12V battery at 13.x
volts or higher with the DC/DC on and little or no load on the 12V
system. In a setup like yours, where the DC/DC comes on only with the
key, it should be adjusted to hold the battery at 14.x volts, otherwise
it will be unable to keep the battery charged in the short time it is
running each time you drive the vehicle.
Is there a fuse between the DC/DC output and the 12V battery?
What size/type of DC/DC is it?
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Question:
If you place the oscilloscope across only the armature what do you see?
The field winding *is* an inductor. The commutator is something that
needs (may need?) to be protected from excess voltage. I'm suspect it
may be receiving HV protection.
Paul "neon" G.
On Sep 28, 2006, at 4:33 PM, Cor van de Water wrote:
Your reasoning would be valid if there was an inductor or
transformer in the DC controller.
However, the DC controllers we know only limit the
AVERAGE output voltage.
They still send the full battery voltage to the motor, only
not the whole time. They switch it on and off to achieve an
average that is lower and because the motor has both self-
inductance as well as (rotational) mass, the result is a
smoothly controller motor, even though the voltage is
switching on/off very quickly.
you can easily see this effect by attaching an oscilloscope
to the motor connectors - you will see a "square wave" of
the full battery voltage, where the "on" time varies from
zero to (almost) continuously on, dependent on the throttle.
--- End Message ---
--- Begin Message ---
You really don't need to air your kill files to the list. That is both
immature *and* off topic.
Paul "neon" G.
On Sep 29, 2006, at 2:39 PM, Cor van de Water wrote:
/delete noconfirm message_subject contains "Why lie"
You are no longer being heard, fellows. Take it some place else.
--- End Message ---
--- Begin Message ---
I would say it is not a bad idea. I knew nothing about cars when I
started my conversion. I rented an engine hoist and invited over a
friend that does a lot of work on cars to pull the engine/tranny. I
tried to sell the engine at a place that specialized in nissans parts
and was told I had a boat anchor. (V6 from an 86 Nissan pickup) In the
end I put the engine up for free on craig's list and someone came and
took it away. I had a bunch of other stuff (muffler, exhaust pipes and
various other things) that I eventually rented a truck for so I could
take them to the transfer station. It would be nice to have the donor
stripped by someone with the appropriate tools and equipment and have
all the ICE parts out of my garage.
That said, given the fact I did not plan on reinstalling stuff, getting
it off the truck was not that bad.
I learned 2 lessons from my experience 1) selling a used engine may not
be so easy, and 2) I should have bought the collapsable engine hoist I
now own at the beginning of the process. During removal it cost be
about $40 to rent one for a weekend which wasn't bad, but as I've been
working on my motor mount I don't know what I would have done if I did
not have long term access to the hoist. Some of the more experienced on
the list may be able to design and fabricate a motor mount without a
hoist but not I.
John
On Friday, September 29, 2006, at 10:09 AM, Steve Kobb wrote:
I had AN idea... but I'm a newbie, so I don't know if it's a GOOD
idea. Perhaps the EVDL can give me some insight.
Here's the concept:
What if go to a neighborhood mechanic or engine re-builder and make
him this offer: I will go out and buy a running, decent, not-too-old
Ford Ranger...
...and then GIVE him for FREE the entire engine and all associated ICE
hardware, IF...
...he does the labor to remove all that stuff from the vehicle. In
other words, he gets an engine; I get his time.
The attraction to me, of course, is that it would get me to a
completed conversion much faster than if I removed the equipment
myself.
Now here's my question to you: If this IS a good idea, who is it good
FOR? Both me and the mechanic? Or just him? Or just me?
Let's say that it's just good for him. That would mean that I'm giving
away something MUCH more valuable than what he's giving me.
Or maybe it's the reverse. I just don't know.
Your comments are welcome.
Steve Kobb
--- End Message ---
--- Begin Message ---
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Nick
Sent: Saturday, 30 September 2006 9:02 AM
To: [email protected]
Subject: Reliability vs. Repairability... Re: AC vs DC
snipped
> PS: *100%* of the motors in automobiles have brushes. Even the
> alternators have slip rings! If brushes are so bad, why do the auto
> companies use them universally? Why have they never used a brushless DC
> or AC motor with inverter anywhere in any car (except their EVs)?
>
Id like to correct something here. If would consider truck electrical
systems as automotive, there are brushless 24V alternators around. They are
larger & heavier than brushless ones because they need additional windings.
You can get them in ratings of 100A plus. I have converted them to 48V
(delta to star) for use in homepower systems. They are not very efficient
however. David Sharpe
--- End Message ---
--- Begin Message ---
Or buy this
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2666
I have personally tested this "hybrid" bicycle. I describe the
experience as "superman". The harder you try to pedal, the more
electric assist you get. No extra control or throttle to twist. It
is a very satisfying experience.
The bicycle is surprisingly light also at 50lb including batteries
(24V Nimh). It is foldable. And, it is relatively low cost at $600.
On 9/29/06, Ryan Bohm <[EMAIL PROTECTED]> wrote:
Hi everyone,
I had a voicemail from a lady wanted to electrify her bicycle. If any
of you know of people doing this type of project, or would be willing to
help her, let me know. I'll call the lady back and relay the information.
-Ryan
--
- EV Source <http://www.evsource.com> -
Professional grade electric vehicle parts and resources
E-mail: mailto:[EMAIL PROTECTED]
Toll-free: 1-877-215-6781
--
Edward Ang
President
AIR Lab Corp
--- End Message ---
--- Begin Message ---
If you are going to sell a used engine, you have to
sell it before you remove it. That way the buyer knows
how it runs.
--- John <[EMAIL PROTECTED]> wrote:
> I would say it is not a bad idea. I knew nothing
> about cars when I
> started my conversion. I rented an engine hoist and
> invited over a
> friend that does a lot of work on cars to pull the
> engine/tranny. I
> tried to sell the engine at a place that specialized
> in nissans parts
> and was told I had a boat anchor. (V6 from an 86
> Nissan pickup) In the
> end I put the engine up for free on craig's list and
> someone came and
> took it away. I had a bunch of other stuff (muffler,
> exhaust pipes and
> various other things) that I eventually rented a
> truck for so I could
> take them to the transfer station. It would be nice
> to have the donor
> stripped by someone with the appropriate tools and
> equipment and have
> all the ICE parts out of my garage.
>
> That said, given the fact I did not plan on
> reinstalling stuff, getting
> it off the truck was not that bad.
>
> I learned 2 lessons from my experience 1) selling a
> used engine may not
> be so easy, and 2) I should have bought the
> collapsable engine hoist I
> now own at the beginning of the process. During
> removal it cost be
> about $40 to rent one for a weekend which wasn't
> bad, but as I've been
> working on my motor mount I don't know what I would
> have done if I did
> not have long term access to the hoist. Some of the
> more experienced on
> the list may be able to design and fabricate a
> motor mount without a
> hoist but not I.
>
> John
>
> On Friday, September 29, 2006, at 10:09 AM, Steve
> Kobb wrote:
>
> > I had AN idea... but I'm a newbie, so I don't know
> if it's a GOOD
> > idea. Perhaps the EVDL can give me some insight.
> >
> > Here's the concept:
> >
> > What if go to a neighborhood mechanic or engine
> re-builder and make
> > him this offer: I will go out and buy a running,
> decent, not-too-old
> > Ford Ranger...
> >
> > ...and then GIVE him for FREE the entire engine
> and all associated ICE
> > hardware, IF...
> >
> > ...he does the labor to remove all that stuff from
> the vehicle. In
> > other words, he gets an engine; I get his time.
> >
> > The attraction to me, of course, is that it would
> get me to a
> > completed conversion much faster than if I removed
> the equipment
> > myself.
> >
> > Now here's my question to you: If this IS a good
> idea, who is it good
> > FOR? Both me and the mechanic? Or just him? Or
> just me?
> >
> > Let's say that it's just good for him. That would
> mean that I'm giving
> > away something MUCH more valuable than what he's
> giving me.
> >
> > Or maybe it's the reverse. I just don't know.
> >
> > Your comments are welcome.
> >
> > Steve Kobb
> >
>
>
--- End Message ---
--- Begin Message ---
This afternoon I checked the torque of all of the 10-32 redtop BB600's.
They were all fine. Spot checked a bunch of the 10mm green tops and
they were fine too.
So the new pack has 473 miles on it as of this message. The Rally in
Palo Alto and the weekend in general should add another 100 miles. I'm
driving this thing like an ice.
So far the untreated/unplated copper bars are clean except for some
tiny specks. So this weekend they get coated with the "A Special WW"
compound like the redtop busbars were.
The thermal probe, a cheap lcd unit, is reading in the mid 30C range.
Once it read 42.7C which is 107F. That's still under the 120F in the
manual. The box has no ventilation. So it seems that other than hot
summer days the pack will run in a decent temperature range.
The LED monitoring system is being worked on as we speak. It looks like
there will be 28 leds, each representing 9 cells. That's 252 cells
total. Maybe the LCD setup would be better. We'll see.
Mike
--- End Message ---
