EV Digest 6337
Topics covered in this issue include:
1) Re: Battery Monitor Design
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
2) RE: Battery Monitor Design
by "Dale Ulan" <[EMAIL PROTECTED]>
3) Re: Battery Monitor Design
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
4) RE: Lower price (and available) configurations
by "Roger Stockton" <[EMAIL PROTECTED]>
5) RE: Testing the pack
by "Roger Stockton" <[EMAIL PROTECTED]>
6) Re: Call for Help
by "Arthur W. Matteson" <[EMAIL PROTECTED]>
7) RE: Lower price (and available) configurations
by "Roger Stockton" <[EMAIL PROTECTED]>
8) Re: Battery Monitor Design
by Danny Miller <[EMAIL PROTECTED]>
9) Re: DC-DC for Link-10
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Goodyear Eagle GA P205/65R15 tires
by "Ted C." <[EMAIL PROTECTED]>
11) Re: Lower price (and available) configurations
by Lee Hart <[EMAIL PROTECTED]>
12) RE: Call for Help
by Mike Willmon <[EMAIL PROTECTED]>
13) different approaches .. ICE/Electric combinations ..
by "peekay" <[EMAIL PROTECTED]>
14) Volt as a biodiesel/vegetable car
by "peekay" <[EMAIL PROTECTED]>
15) Re: EV Drag racing this year
by nikki <[EMAIL PROTECTED]>
16) Re: Using Vortex Tubes for air conditioning/heating
by "Rush" <[EMAIL PROTECTED]>
17) RE: Battery Monitor Design
by "Dale Ulan" <[EMAIL PROTECTED]>
18) RE: Testing the pack
by Cor van de Water <[EMAIL PROTECTED]>
19) RE: OT Copper, was: EEstor
by Cor van de Water <[EMAIL PROTECTED]>
20) RE: Call for Help
by Cor van de Water <[EMAIL PROTECTED]>
21) Re: OT Copper, was: EEstor
by "Evan Tuer" <[EMAIL PROTECTED]>
22) Curtis 1221R regen controller wiring diagram
by "Ev Performance (Robert Chew)" <[EMAIL PROTECTED]>
23) RE: Battery Monitor Design
by Cor van de Water <[EMAIL PROTECTED]>
--- Begin Message ---
You're welcome.
Regarding the filter something in the range of .1uF to 10uF prallell
to the 6.04k ressitor will be fine. We're not interested in anything
high frequency here.
Since you used 0.01% resistors you'll probably save money by using a 10V ADC.
And you definitly need isolation, 1 Meg impedance is not enough and
you actually have less than that since there are several lt1990 in
parallel but that's not the point. From a safety standpoint the built
in resistors in the lt1990 can burn out and short much too easily and
then you have pack voltage on the dash. The easiest way to implement
isolation in your circuit is to put some optos on the 3 wire bus and
feed the sense units with their own dedicated powersupply.
On 1/23/07, Tim Wong <[EMAIL PROTECTED]> wrote:
Peter -
Thanks for the input! This is exactly the kind of stuff I wanted to hear.
Nice catch on the RC filter - I had to put one on after the system was
completed to reduce the noise while charging, and i guess I didn't add it to
the schematic... What values would you recommend? I think I added a .1uF cap
between the resistors and the ADC, but can't find what I did!! As i don't have
a lot of experience in analog design, do you have a recommendation sense of
what to add and where? It may be better than what I did...
You are right about the voltage divider - I thought I should getting an ADC
with a 10V input range after building it, which would be much cleaner,
accurate, and not much more expensive, as I used .01% high precision resistors.
The INA148 looks great - a bit more expensive, but looks nice...
Thanks for the input,
Tim
-----Original Message-----
>From: Peter Gabrielsson <[EMAIL PROTECTED]>
>Sent: Jan 23, 2007 9:17 AM
>To: [email protected]
>Subject: Re: Battery Monitor Design
>
>Just nitpicking here, you have a good design but you can significantly
>improve accuracy by getting rid of the 10k/6.04k divider just after
>the lt1990 in the sense box. You'll need to replace the AD converter
>with a higher input voltage converter if you do this.
>
>You also don't have any filtering on the inputs so I'd put an RC
>filter where the divider currently resides. A small improvement in
>linearity can also be achieved by replacing the LT1990 with an INA148,
>though for a lead acid system the LT1990 is probably good enough.
>
>That said, very nice design and thank you for sharing it.
>-Peter
>
>
>--
>www.electric-lemon.com
>
--
www.electric-lemon.com
--- End Message ---
--- Begin Message ---
It has been working well for some time now... I think it is supposed to have a
small leakage current, that is how it measures. How would you change the
system? Are you saying differential amps can't work in this application, or
that it should have been implemented differently?
>From what it looks like, if the battery pack is less than around 200 volts,
>the instrumentation amps will tend to make it work because the chassis is
>likely somewhere between the voltages of the battery. Leakage currents will
>actually make that work, as you mentioned. If you are charging with a
>non-isolated charger, this will not be the case - the chassis will be at some
>AC potential relative to the batteries (the chassis, of course, being earthed
>to electrical ground, and the batteries to one or the other side of the AC
>line, depending on where in the 50/60 Hz cycle you're at. You did ground the
>chassis for charging, right? The leakage will be relatively small, and should
>make the chassis float at the half-way point of the battery pack.
I normally would put an isolator between an A-D converter/mux arrangement and
the processor. Alternatively, I would power the instrumentation off an isolated
supply, and use something like a CAN bus with isolators between the CAN
transceiver and the processor. If you were always going to use an isolated
battery charger, and the battery voltage was always below 200V, it'll work
fine. The only danger that I can think of is a failed IC may connect some
battery to the vehicle chassis. This would show as a dead channel on the
display - until you accidentally worked on the high voltage system and
accidentally didn't remove the battery monitor's connector, and accidentally
forgot to check for a ground fault, and accidentally touched the chassis and
the battery at the same time. I would be more comfortable if there were
resistors installed at each battery rather than (or in addition to) a fuse -
ie. make them 100K matched to within .1% or so, and compensate in software for
the gains!
being something like 0.9 instead of 1.0. Something to think about.
-Dale
--- End Message ---
--- Begin Message ---
>I would be more comfortable if there were resistors installed at
each battery rather than (or in >addition to) a fuse - ie. make them
100K matched to within .1% or so, and compensate in >software for the
gains!
being something like 0.9 instead of 1.0. Something to think about.
This will kill your accuracy. The on chip resistors in the lt1990 are
not matched to absolute values, they're just matched to each other.
It's common for on chip resistors to be off by 20% so when you add
external resistors to the input you will get a large error channel to
channel.
Better to put real isolation in after the AD converter.
--
www.electric-lemon.com
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
> It's certainly possible, with a well-cooled controller and a
> poorly cooled motor. However, the current ratings of the
> motor depend strongly on RPM because of its internal cooling
> fan. You could easily fry even a 9" motor with a 1221C if you
> forced it to run at such a low RPM that the fan wasn't doing any good.
>
> With respect to John's situation, I think the L91 would be OK
> even with the 1231C as long as he kept the motor over 2000
> RPM or so. That's the setup I have in my EV.
I could be mistaken, but don't I recall seeing mention of you running
with your Curtis cranked down to 300-odd amps peak? And, there is the
small issue of the difference in power required by a 7000lb-ish truck
climbing any sort of grade vs your LeCar at under 1/2 this weight... ;^>
My concern is that the amount of power that the truck requires to move a
given speed and/or up a given grade will require sustaining motor
currents higher than the little motor can tolerate for very long at all.
You could very well be right, but I'm thinking it may be too close to
call.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
FRED JEANETTE MERTENS wrote:
> there is a standard test set for checking batteries after
> full charge cycle . another method is to charge a full cycle
> then check specfic gravity keep a record and you will be
> able to chart the life of your batteries
Something that Don didn't state and you might not be aware of if you
haven't been following the list for a while is that he is running a
string of DEKA gel batteries. That is, they are sealed and so checking
the s.g., while a very good approach for floodeds, is not an option
here.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
I spent about half an hour writing a reply, and I can't get it to show
up.
- Arthur
On Tue, 2007-01-23 at 12:03 -0500, Mike wrote:
> I hang out in the forums at CNCZone.com, a community for folks who
> are into building CNC machines. They recently started a new forum
> about global warming and it turns out some people still believe it's
> all fake. Some sort of plot by the lefties or some such BS. Of
> course the topic has turned to EVs and some people are making the
> typical quips about running the heater and destroying range and
> everyone's favorite, that EVs are slow.
>
> I've done the basic thing like post links to FAQs and stuff but if
> someone smarter than me would like to help educate I'd be much
> appreciated.
>
> http://www.cnczone.com/forums/forumdisplay.php?f=343
> http://www.cnczone.com/forums/showthread.php?t=30772
>
> Mike
--- End Message ---
--- Begin Message ---
John G. Lussmyer wrote:
> And the original statement was:I've been thinking about doing a
> full-size pickup conversion. (something like a Ford F-250).
> Starting out with a Z2K and Dual 11" motors would be nice, but is
> awfully expensive, and there is a hefty lead time. ($4500 + 2
> * $2950).
> I was thinking of a 240V pack using 6V golf cart batteries.
Thanks; not too far off what I recalled.
> As Lee said, if you keep the revs up, an L91 with a 1221C
> should be ok.
And as I said, I'm not at all so sure. Two reasons: first, the ADC
rating that states the max current vs time does not state anything about
how fast you spin the motor causing these ratings to improve or worsen;
second, anecdotal reports from people who have run ADC 8" or 9" motors
in Ranger/S10 type vehicles *with the tranny* have reported that these
motors are marginally able to avoid overheating and provide marginally
acceptable performance. I'm not at all convinced that Lee runs (or has
ever run?) his L91 at the 400A level, and suspect that in his light
vehicle it wouldn't run at this level for very long at all, which is in
stark contrast to moving a 7000lb full-size pickup, even with a pair of
them pulling.
I'm certainly not saying it *won't* work, just that there seems to be a
very good chance that a pair of 6.7's won't perform significantly
differently from a single 9", and may not be up to the task of
propelling a 7000lb truck. Even Lee only says he "thinks" it should
work, not that it "will" work.
> The prices I had found were:
> Curtis 1221C + ADC L91-4003, $975 + $840.
A bit better than the EV Parts website prices I used, but you still end
up with 4 L91's costing more than a pair of 8's (more even than a pair
of 9's?), and the L91's have only a single shaft while either the 8's or
9's are available with tailshafts. Cheaper, easier, and more efficient
to couple a pair of motors end-to-end than to devise a mounting scheme
and belt/chain/gear system to couple multiple single-shaft motors to the
tranny input.
> But the Z1K is essentially Not Available for now, at least
> the last I heard.
I don't know if Otmar is accepting more orders at present or not; I am
assuming that it would be a couple of months before you are ready for
the controller(s) anyway, and so if you got an order in the queue now
you'd probably have a controller clsoe to when you could use it.
> Which is why I was suggesting the Contactor mode Boost for 2
> more small motors.
I understand, but just wonder if it doesn't make more sense to go for
the cheaper option of a pair of larger motors (e.g. 9's) instead at this
point. Contactors cost, and one mistake with a dual 1221C system with
contactor hack and you've just doubled your controller cost.
> Also why I was keeping the transmission so I could keep the motor
> revs up. (Adding a blower for forced air cooling wouldn't be
> too bad either.)
As far as I know, the reports of the ADC 8 or 9 being marginal in a
typical Ranger/S10 were based on vehicles retaining the tranny also. A
blower for additional cooling at low speeds would probably be a wise
investment no matter what the motor choice.
> >I would also suggest that the Z1K HV (72-300V) at $2600 might be the
> >wisest controller choice.
> Yup, but you did just add another $650 to the price. (Also would need
> to add a Series/Parallel contactor, but one less On/Off contactor)
And I acknowledged the extra controller cost. Note that even with your
slightly better motor prices my suggestion of running a pair of X91's
and a Z1K HV still shaves about $1000 off your 4-motor/contactor
over-ride proposal. You could very likely run a pair of 9's and the Z1K
HV and still come out less than $500 over your approach.
> And the truck would still likely need more power for acceleration.
I'm quite skeptical you will get as much power from 4 6.7's with the
Curtii/contactor approach as you will from a pair of 6.7's and the Z1K
HV. I'm fairly certain that a pair of 8's or 9's and the Z1K will
definitely provide more power, and any of these with the Z1K fed from a
240V pack is going to give you a broader powerband than a 120V
Curtii/contactor approach.
> More Batteries == More Range. Want Range.
More batteries == more weight == more power req'd == hotter motors.
Range gets quite poor when the smoke comes out of the motors. All I'm
saying is that if you skimp on the motors to save money, you may have to
scale down the pack to provide just the range you want in order to make
the vehicle reliable.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
The amp should definitely not be used this way, it's a real problem. A
differential amp (or an instrumentation amp, which the LTC1990 is) will
not work without the supply and input having the same ground.
The amps, the +/- 15V supplies and ADC need to have their own ground.
That ground should be referenced to the battery and completely separate
and isolated from the ground at the head unit (display). That head unit
should be frame-grounded. Additionally the wires leaving the sensor
unit should all be referenced to frame ground. The common way to
achieve logical isolation is through an optoisolator, there are some
other exotic methods but the opto's what you need.
The isolated +/- 15V supply can come from a DC/DC converter off a
frame-referenced supply but Lee has expressed concerns about the degree
of voltage isolation available in common DC/DCs (1500V or so) being
inadequate for an EV. I am not completely sure this is really a problem
but am concerned nonetheless. The supplies could be also derived from
the main pack, either a multiple tap (downside is a slight tendency to
unbalance the batteries) or a DC/DC or simple reg off the full pack
voltage, which would not have isolation problems but would need to be a
custom solution. Or failing that a dedicated battery could do it.
Like I say, I'd put an analog mux after the LTC1990's and run them
through a single divider. I would make one of the analog channels a
known reference voltage so the divider ratio can be automatically
calibrated. There are issues putting a cap to make a noise filter here
on the divider, it would need some time to charge up to the new voltage
after changing channels, but it is possible.
I'd just use a PIC for the ADC. That would allow you to control the
analog mux too. There's a lot of reasons for a PIC. Versatility is a
big one, such as being able to control the mux. Highly unlikely any
unexpected problems could not be fixed by small changes in the code.
You could set it up to do oversampling for increased accuracy and noise
rejection. It's also just a part you can easily order 50 of and if you
end up with extra then just use them on the next project. Also it's
always possible the ADC you're looking at might become difficult to
obtain later (been there) but PICs basically never have this problem.
Only a few PICs have ever been made obsolete without a pin-equivalent,
improved replacement becoming available, I think they were oddball parts
anyways. Actually the MCP3008 is also a Microchip product so it should
stay available, but still. A PIC could easily be made to use a protocol
like the EVilBus or use CAN.
There are a few PICs which have CAN onboard, but it won't be isolated
and it's frankly a bad idea to try to optoisolate the CANBus itself due
to speed issues. Instead, use an external CAN node controller with a
SPI interface and optically isolate the SPI bus between the CAN
controller and the PIC. The CAN controller is actually fairly cheap.
Danny
Tim Wong wrote:
It has been working well for some time now... I think it is supposed to have a
small leakage current, that is how it measures. How would you change the
system? Are you saying differential amps can't work in this application, or
that it should have been implemented differently?
Thanks,
Tim
--- End Message ---
--- Begin Message ---
What happens if the pack sags below 85V?
Nick Austin wrote:
Typical result: http://www.smartaustin.com/~nick/flames01.JPG
You forgot the smiley. :-) Actually, this is a great picture of what
can't happen with an E (without choosing the wrong lithium batteries).
--
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 have these as the tire on the back of my EV. I keep them at 40psi. They
seem to be good tires and handle the weight of the car well. I couldn't tell
you anything about the roll resistance of the tires. But I have no problem
pushing the car by hand. I'm sure you could do better for roll resistance if
you did get a tire rated LLR.
http://www.austinev.org/evalbum/915
Ted
Olympia, WA
N47 02.743 W122 53.772
"THE Stone Age did not end for lack of stone, and the Oil Age will end long
before the world runs out of oil."
Quotation is from Sheikh Zaki Yamani, a Saudi Arabian who served as his
country's oil minister three decades ago.
----- Original Message -----
From: "bruce parmenter" <[EMAIL PROTECTED]>
To: "evlist" <[email protected]>
Sent: Tuesday, January 23, 2007 7:30 PM
Subject: Goodyear Eagle GA P205/65R15 tires
I have an opportunity to get four nearly new Goodyear Eagle GA
P205/65R15 tires.
Anyone have any experience with these tires?
A web search states these Goodyear Eagle GA P205/65R15 tires are
performance / sport use. I wonder if these are OK for EV use or
would they have too high a rolling resisatnce for EVs.
Thanks a head of time for your help.
Bruce {EVangel} Parmenter
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor, RE & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
____________________________________________________________________________________
Finding fabulous fares is fun.
Let Yahoo! FareChase search your favorite travel sites to find flight and
hotel bargains.
http://farechase.yahoo.com/promo-generic-14795097
--- End Message ---
--- Begin Message ---
Roger Stockton wrote:
Lee,
I could be mistaken, but don't I recall seeing mention of you running
with your Curtis cranked down to 300-odd amps peak?
Guilty as charged! :-) I have the current limit in my Curtis 1231C
turned down all the way. I did this because I'm running Concorde 12v
AGMs, which don't do well with high currents.
And, there is the small issue of the difference in power required
by a 7000lb-ish truck climbing any sort of grade vs your LeCar at
under 1/2 this weight... ;^>
Also correct. But John is talking about using 2 to 4 of these motors vs.
the one L91 I'm using.
My concern is that the amount of power that the truck requires to move
a given speed and/or up a given grade will require sustaining motor
currents higher than the little motor can tolerate for very long at all.
You could very well be right, but I'm thinking it may be too close to
call.
I agree. But look at it this way; the thermal rating of a motor (how
long it can withstand a given amount of heat dissipation) is roughly
proportional to its weight. A single ADC 9" motor weighs 148 lbs. Two
L91's weight 2 x 85 = 170 lbs. So if anything, the two 6.7" L91's should
be able to dissipate *more* heat, and deliver a given amount of power
*longer* than the 9".
--
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 ---
Ask them what kind of propulsion their CNC machines have...
...and why they don't consider using ICE to power them, he he.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Mike
> Sent: Tuesday, January 23, 2007 8:03 AM
> To: [email protected]
> Subject: Call for Help
>
>
> I hang out in the forums at CNCZone.com, a community for folks who
> are into building CNC machines. They recently started a new forum
> about global warming and it turns out some people still believe it's
> all fake. Some sort of plot by the lefties or some such BS. Of
> course the topic has turned to EVs and some people are making the
> typical quips about running the heater and destroying range and
> everyone's favorite, that EVs are slow.
>
> I've done the basic thing like post links to FAQs and stuff but if
> someone smarter than me would like to help educate I'd be much
> appreciated.
>
> http://www.cnczone.com/forums/forumdisplay.php?f=343
> http://www.cnczone.com/forums/showthread.php?t=30772
>
> Mike
>
>
> --
>
> The Electric Motorcycle Portal
> http://www.electricmotorcycles.net/
>
> Electric Motorcycle Listserv
> http://www.electricmotorcycles.net/listserv
>
>
--- End Message ---
--- Begin Message ---
> Posted by: "Mike Mercado" [EMAIL PROTECTED]
> Date: Mon Jan 22, 2007 9:07 am ((PST))
> On the Honda hybrids the ICE is a very fuel efficient low
> torque output unit, which requires electric assist to accelerate at a
decent
> speed, hence better fuel economy on the freeway.
> The Toyota system uses the electric drive at low speeds, low acceleration
> & adds the ICE under high loads & cruising, hence better fuel economy in
city driving.
it sounds clear .. but on re-reading, it is not very clear
which is the better of the two ?
honda runs on low torque ICE (very fuel efficient) and
requires electric assist to accelerate ..
toyota add ICE under high loads and cruising ..
since avoiding fuel is the purpose of going EV, one would want
electricity to drive .. with ICE coming in ONLY when depeleted
___________________________________________________________
The all-new Yahoo! Mail goes wherever you go - free your email address from
your Internet provider. http://uk.docs.yahoo.com/nowyoucan.html
--- End Message ---
--- Begin Message ---
> Posted by: "Mike Mercado" [EMAIL PROTECTED]
> Date: Mon Jan 22, 2007 9:07 am ((PST))
>
> Being an autorepair shop owner by trade, I have read alot about the
> Volt's E-Flex drivetrain. What sets it apart from other Hybrids is it's
> basic design.
<snipped>
> The Chevy Volt is basically a short range, Lithium Ion batteried EV, with
a
> very efficient 1.0 ltr ICE spinning a 53-kW generator onboard to power the
> EV drive when the LI batteries are spent. The best part about this design
is
> that an ICE of any design, that fits the space, can be used without any
> drivetrain changes. Wouldn't a Bio-deisel ICE be nice!
charging off the grid at low power timings could avoid using the 1.0 litre
ICE
thereby reducing pollution too !
would that translate into much cheaper running costs per mile ?
then the bio-diesel or any other fuel burning engine would be good for those
areas where there IS NO electricity at all
___________________________________________________________
The all-new Yahoo! Mail goes wherever you go - free your email address from
your Internet provider. http://uk.docs.yahoo.com/nowyoucan.html
--- End Message ---
--- Begin Message ---
Hi Chip,
Discovery Channel eh? Let me know how that goes. I'm wanting an EV
stand at the Bristol 2007 International Balloon Fiesta - which is a
big Discovery Channel Uk thing :)
Nikki.
_______________________________
Old car? New tricks?
Visit aminorjourney.com to see the transformation from Hebe to EV.
E-minor isn't just a key any more...
_______________________________
On Jan 24, 2007, at 1:16 AM, Chip Gribben wrote:
Yep, we will definitely have some racing going on out West. But as
Rich said its kind of far out right now.
This is NEDRA's 10th Anniversary so expect a big NEDRA Nationals
this year.
We may be planning something for Las Vegas too.
But right now we just have the 2 East Coast events planned.
I just had lunch with the Discovery Channel New Media folks
yesterday so we hope to be doing something with them this year.
More on that as the plans develop.
Chip Gribben
NEDRA Webmaster
http://www.nedra.com
On Jan 23, 2007, at 6:17 PM, Electric Vehicle Discussion List wrote:
From: "Rich Rudman" <[EMAIL PROTECTED]>
Date: January 23, 2007 1:53:55 PM EST
To: <[email protected]>
Subject: Re: EV Drag racing this year
keep in mind that Portland was snowed in last week. And is about
55 Deg
today, We don't do much EV racing when the weather can be this
extreme.
I am sure we will have more than a few Wayland nights at Portland.
Heck I am cahrging Goldie right now for the frist time in about 3
months..
so We will be doing some racing, it's just too far off to have any
dates in
stone yet.
Rich Rudman
Manzanita Micro
----- Original Message -----
From: "Mark Fowler" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, January 23, 2007 5:24 AM
Subject: EV Drag racing this year
(resend - original hasn't appeared after a day)
G'day all,
As I mentioned earlier, I've relocated to Edmonton, Canada for this
year.
One of the things I want to do while on this side of the planet
is to
see some electric drag racing.
So, what are the plans for EV events at Portland this summer?
Nothing on the Nedra site yet. Any Wayland stuff going on?
Mark
--- End Message ---
--- Begin Message ---
> Hmm, an interesting though. Given that they aren't efficient, can they at
> least be light weight?
> For example, if we had an onboard tank of compressed air (refilled while
> charging) and a vortex tube, how large would the tank need to be to store
> enough air for cooling the vehicle for say 20 minutes?
I had to register with Exair to get the specs on their tubes -
A large Vortex tube, model 3250, uses between 50 and 150 SCFM at 80 to 100 PSI.
A normal alum scuba tank contains 80 cu ft (at 3000 PSI), so the air in the
tank would be consumed by the 3250 Vortex (using an average of 100 SCFM) in 30
min.
No real idea about how much it would actually cool, but the pictures on the
website show the tube cooling a part on a mill. So it seems that a 3250 cools a
small area, about 3"x3".
The 3250 Vortex is about 16-20 in long and uses a 1/2" air inlet. It needs a
regulator with a gauge, a filter and oil removal filter and a noise muffler. I
guess if it just uses the air from a scuba tank, IE demoisturized and filtered
air, then the filters are not needed. But then you have to get the tank filled
at a licensed station after each use, or buy and maintain your own 3000 psi
compressor.
I guess you could use an onboard compressor, but a compressor that will put out
100 SCFM at 100 PSI is pretty big (I think it would need about 10 HP motor), it
would probably need its own trailer to contain the compressor and power source
(another battery pack to charge and balance, or just a fuel powered generator).
Sounds pretty complicated....
Rush
Tucson AZ
www.ironandwood.org
www.Airphibian.com
--- End Message ---
--- Begin Message ---
Yea, I forgot about how they are matched. You'd need to re-trim
to get the CMRR back.
>There are a few PICs which have CAN onboard, but it won't be isolated
>and it's frankly a bad idea to try to optoisolate the CANBus itself due
>to speed issues. Instead, use an external CAN node controller with a
>SPI interface and optically isolate the SPI bus between the CAN
>controller and the PIC. The CAN controller is actually fairly cheap.
I've used the really fast (10 Mbps) optos for CAN up to 500 kbps and
the phase shifts are ok. But you need to use optos that are really
fast compared to the bit rate - I use a factor of 20 so the time
delay is less than one CAN bit clock. Another option os the ADUM140x
family of isolators, if the differential voltage is going to be under
500V (which it should be). I just did a design using this part on a CAN
bus, again, the 10 Mbps isolator. It seems to work very well. My
first attempt was with a lower speed opto (rated for 1 Mbps) - it
didn't work.
-Dale
--- End Message ---
--- Begin Message ---
Don,
Testing the batteries _before_ charging brings the bad ones out
more easily.
I have had batteries that looked OK and took a charge, but after
some discharging suddenly plummeted to low voltage (cell reversal).
Testing them with a known load ( does not need to be huge - just
50 to 100A per battery will tell you within seconds if a battery
is healthy and has a decent charge still left.
Noting down the voltage after a (fixed) amount of seconds will
give you a clear idea about their SOC and if you need to supplement
their charge.
I just finished this procedure last weekend, as I have not finished
my balancer and last Friday I noticed my pack dropping more than
I expected. Well, what do you know - one battery was completely dead
and eagerly took an overnight individual charge, after which I slowly
charged the entire pack at only 2.5A, so that any battery which was
out of balance (like the one I just charged) would not vent but just
get a constant charge through it - any cell imbalance would also be
reduced this way.
By the end of the slow charge, this one battery was going up in
its voltage to about 16.2V but still did not vent due to low current.
Once other batteries were also getting full and rose to the average
14.8V I was charging to, all but two started coming to the same end
voltage. Two stayed around 13V still, so they were also low.
while I kept the pack charger slowly going at 1A and slowly tapering,
I charged these two individually with a 14.8V supply until the
current dropped to below 0.5A.
So, yes - you can charge and measure (for example near the end
of the charge procedure) if there are low batteries and charge
these by hand.
If that gets too tedious, I recommend a balancer, the easiest one
is Lee's zener regs.
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Tuesday, January 23, 2007 1:16 PM
To: [email protected]
Subject: Re: Testing the pack
Don Cameron wrote:
> Every couple of months I check my pack to see if any batteries are low.
> Here is what I do:
>
> I charge my pack
> Wait 24 hours
> Measure each battery voltage
> Supplemental charge the low ones.
>
> I get the feeling, after readying a few posts about dead packs, that this
> procedure is wrong. Can anyone please correct me?
Sounds reasonable to me. Why do you think there is something wrong with it?
--
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 ---
400A to run airco's?
Are they running a substation?
Or a serverfarm?
Possibly it would help to put insulation in the walls
and limit the amount of sun-facing windows, create
overhangs to shield sun when it is already warm - all
the things you want to learn from passive solar use
(and avoidance).
Anyway, midday summer electric rates are already in the
$0.30 to $0.50 range, I wonder what a home owner pays
for his 100 kW service when the rates go up with fuel cost.
In a previous home I used 2100 kWh _per year_ while I
encounter Americans (possibly the owner of the 100 kW house)
who say they consume 5000 kWh per month.
This means his utility bill could easily be around $2000/mo
So the time is not far off that the pain is felt in the same
way as a big SUV owner who insists that he needs the SUV to
commute to work, 100 miles each way, suddenly realizes that
of every work day the better part of the morning is spent to
earn the money to pour into the tank on the way back.
(And the night to drive home)
If gas goes to $5 (which will happen within 3 years) then
the entire morning is no longer enough to earn his commute.
Now with a car that gets approx 100 miles to the gallon, the
picture becomes quite different.
I think you can explain that to consumers, certainly after
they find themselves in dire straits - it often takes a
crisis to make people move and reconsider, otherwise it is
too easy to be a frog in a slowly heating bath.....
And when fuel cost rises causes electricity rates to double
as well?
So - you won't be able to recharge for $0.02 per mile any
longer, it will cost $0.04.
But the average 20 mpg car has gone from $0.12 to $0.24
per mile (gas price $2.40 => 4.80) while a big SUV with
10 mpg goes from $0.24 to $0.48 per mile.
If you make a 100 mile trip, 200 round-trip, then the
fuel cost alone for the SUV is $100. Use the SUV for your
commute and you can buy a new car every year for the cost
of gas that the SUV gobbles up.
If GM decides NOT to make an electric car that gets more
than 50 mpg, then they will soon find themselves at the
shrinking side of the market.
No matter the ads still crying out that you can only be
happy if you buy the all-new, bigger than ever behemoth,
simple economy will kill the dinosaur and consumers will
decide that instead of pouring half their income into
the gas tank, a more conserving car allows them more
financial freedom.
Just like in the 70's when big cars were no longer wanted
and even second hand prices of large town cars and the like
suddenly collapsed, the investment in a large SUV or truck
is a very bad investment today, in multiple aspects, the
fuel efficiency being one that can kill you slowly.
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Peter VanDerWal
Sent: Tuesday, January 23, 2007 10:32 AM
To: [email protected]
Subject: Re: OT Copper, was: EEstor
>
>> still many homes have only 4 breakers, though
>> newer homes are often built with 6 or 7.
>
> Many newer US homes have 40 or more (using subpanels). Twenty, 24, or 30
> was typical several years ago. Four and six fuses with 60 amp services
> were last fitted probably 50-75 years ago in US homes.
Hmm, I own four houses. The oldest is about 40 years old and the newest
is 12. (Bear with me for a moment and I'll bring this back to EVs.)
The main breaker panel in the old house has 4 110V circuit breakers, zero
220V. One 15 amp breaker handles the outlets and lights in the original
bedrooms, bathroom, hallway, 1/2 the living room and 1/2 the kitchen
!!??!!
I guess, back in the '60s, they just didn't have much stuff to plug in.
As I recall, only rich people had more than one TV back then and many
people didn't have any.
I'm pretty sure that originally the house only had 3 breakers (or fuses?)
since one of them is only used by the washing machine and the house was
remodeled to handle a washing machine.
The new house has a large panel that is full...16 breakers. Ok 4 of those
are 220V breakers and take up two slots. But, the panel could only hold a
max of 20 breakers.
I was going to say that with 40 breakers the hous emust be huge, but I
just checked google. Turns out my new house, which I thought was quite
large at 1400 sqf, is actually quite small.
The average American home is 2,349 sqf, the average American family has
slightly over 3 people (those 0.14 kids are hard to keep track of).
Actually the average household size is only 2.59.
That means over 900 sqf per person. I guess those commercials of the
parrents text messaging their kids while both are at home isn't so much of
a joke.
Americans are nuts.
Anyway two points about EVs:
Newer houses obviously have no problem with charging EVs. Even a high
power charger doesn't take much more juice than a sauna or dryer. But
older houses will probably need to be upgraded. Contrary to what some
folks think, there are STILL a lot of US houses out there with very
small service panels.
Second point, Americans are gready (relatively speaking) and not very
conservative (as a whole). I don't believe that we can appeal to the
majority of Americans by building small EVs, or by convincing them that
EVs will save money or the enviroment.
Obviously there will be niche markets for these types of vehicles, but
I don't think the market will support very many of them. To appeal to
large numbers, EVs need to be "New and Improved!" They'll need to be
sexy, they'll need to be fast, to have some zing. Something to appeal
to our rampant consumerism, our bigger and better lifestyle.
--
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 ---
Mike,
1. don't feed the trolls
2. reply to reasonable posts
3. ask them if they have seen an electric dragrace
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Mike
Sent: Tuesday, January 23, 2007 9:03 AM
To: [email protected]
Subject: Call for Help
I hang out in the forums at CNCZone.com, a community for folks who
are into building CNC machines. They recently started a new forum
about global warming and it turns out some people still believe it's
all fake. Some sort of plot by the lefties or some such BS. Of
course the topic has turned to EVs and some people are making the
typical quips about running the heater and destroying range and
everyone's favorite, that EVs are slow.
I've done the basic thing like post links to FAQs and stuff but if
someone smarter than me would like to help educate I'd be much
appreciated.
http://www.cnczone.com/forums/forumdisplay.php?f=343
http://www.cnczone.com/forums/showthread.php?t=30772
Mike
--
The Electric Motorcycle Portal
http://www.electricmotorcycles.net/
Electric Motorcycle Listserv
http://www.electricmotorcycles.net/listserv
--- End Message ---
--- Begin Message ---
On 1/24/07, FRED JEANETTE MERTENS <[EMAIL PROTECTED]> wrote:
you cannot compare the electric dist systems in europe and here they devoloped
entirely different and there are 23 different voltge / device systems there !!
What? Europe has had harmonised electricity for a long while now.
It's all 230VAC, 50Hz. Most areas have between 60 and 120A per
property. If you need more than that, you get 3-phase. The UK is
slightly unique in retaining our superior 13A fused plugs, with 30A
ring circuits. I have a 63A socket in my garage for my fast charger!
It seems a lot simpler than the various US standards: centre tapped
240V here, 208V there, 120 only in some places, a wide variety of
earthing and protection arrangements and no end of scary-looking
connectors..
--- End Message ---
--- Begin Message ---
Hi All,
I just acquired a curtis 1221R regen controller (120 volt 400amps)
I do not know how to wire it up. I believe i need a reversing contactor in
there some where. THere is a multi connector type socket. I am not sure how
this is wired up also.
Any help would be greatly appreciated.
Cheers
--- End Message ---
--- Begin Message ---
As Lee has pointed out numerous times: if you have a non-isolated
charger, then your car's frame is grounded though the ground prong
while the battery pack can see surges of several kV, 3000 or 5000,
I forget how high.
If you don't mind your battery monitor zapping out of existence
every time there is a nearby power surge or lightning hit, then
you can use 500V devices.
If you care about longevity, you should look for hi-pot tested
devices as used in every switching power supply.
Regards,
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Dale Ulan
Sent: Tuesday, January 23, 2007 10:04 PM
To: [email protected]
Subject: RE: Battery Monitor Design
Yea, I forgot about how they are matched. You'd need to re-trim
to get the CMRR back.
>There are a few PICs which have CAN onboard, but it won't be isolated
>and it's frankly a bad idea to try to optoisolate the CANBus itself due
>to speed issues. Instead, use an external CAN node controller with a
>SPI interface and optically isolate the SPI bus between the CAN
>controller and the PIC. The CAN controller is actually fairly cheap.
I've used the really fast (10 Mbps) optos for CAN up to 500 kbps and
the phase shifts are ok. But you need to use optos that are really
fast compared to the bit rate - I use a factor of 20 so the time
delay is less than one CAN bit clock. Another option os the ADUM140x
family of isolators, if the differential voltage is going to be under
500V (which it should be). I just did a design using this part on a CAN
bus, again, the 10 Mbps isolator. It seems to work very well. My
first attempt was with a lower speed opto (rated for 1 Mbps) - it
didn't work.
-Dale
--- End Message ---
