EV Digest 4623
Topics covered in this issue include:
1) Re: e-meter type gadget wish list wanted.
by Neon John <[EMAIL PROTECTED]>
2) Re: Help me decide!
by "Peter VanDerWal" <[EMAIL PROTECTED]>
3) EV4Sale: Dead Ranger EV in Watkinsville, GA
by bruce parmenter <[EMAIL PROTECTED]>
4) Re: Ampabout ... Plain Vanilla
by bruce parmenter <[EMAIL PROTECTED]>
5) Re: Zilla FS (was Re: Zilla Backorders)
by Cwarman <[EMAIL PROTECTED]>
6) Re: e-meter type gadget wish list wanted.
by Gordon Niessen <[EMAIL PROTECTED]>
7) Re: Battery calculation, NiCad vs. LeadAcid
by Matthew Trevaskis <[EMAIL PROTECTED]>
8) Re: e-meter type gadget wish list wanted.
by Victor Tikhonov <[EMAIL PROTECTED]>
9) Re: e-meter type gadget wish list wanted.
by Danny Miller <[EMAIL PROTECTED]>
10) RE: EV4Sale: Dead Ranger EV in Watkinsville, GA
by "Bill Dennis" <[EMAIL PROTECTED]>
11) Re: Help me decide!
by Victor Tikhonov <[EMAIL PROTECTED]>
12) Re: e-meter type gadget wish list wanted.
by Victor Tikhonov <[EMAIL PROTECTED]>
13) Re: e-meter type gadget wish list wanted.
by Danny Miller <[EMAIL PROTECTED]>
14) Re: e-meter type gadget wish list wanted.
by Danny Miller <[EMAIL PROTECTED]>
15) RE: e-meter type gadget wish list wanted.
by "Jamie Marshall \(GAMES\)" <[EMAIL PROTECTED]>
16) RE: Help me decide!
by "Roger Stockton" <[EMAIL PROTECTED]>
17) Re: Confusing arising (Direct Drive and Transaxle)
by Lee Hart <[EMAIL PROTECTED]>
18) Re: e-meter type gadget wish list wanted.
by Lee Hart <[EMAIL PROTECTED]>
19) Re: e-meter type gadget wish list wanted.
by Lee Hart <[EMAIL PROTECTED]>
20) Re: Plus and Minus Together
by Lee Hart <[EMAIL PROTECTED]>
21) Re: Battery design
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
High temperature LCD materials are available. Expensive though, which
is probably why the auto companies have limited its use to just the
tiny odometer display. Since that display is practically static,
other parameters such as update speed can be sacrificed for
temperature range.
I have one of those displays in my motorhome (chevy chassis). I have
seen it hot enough to be practically unreadable. It didn't turn black
like cheaper displays. It just loses contrast and turns a general
gray color.
John
On Wed, 24 Aug 2005 11:30:37 -0700, "Paul G." <[EMAIL PROTECTED]>
wrote:
>
>On Aug 24, 2005, at 10:41 AM, Neon John wrote:
>
>> LCDs were and are totally unsuited for those conditions. That's why
>> the auto companies have avoided LCD technology. It just can't take
>> the cold or the heat.
>
>I'm curious. One place that a number of cars have adopted the LCD is
>the the odometer display. How are they keeping that thing readable? It
>seems like it could get WAY to hot packaged behind clear plastic in the
>generally dark color speedometer head.
>
>Paul "neon" G.
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
>>> How about a Lynch, Lemco, or Etek motor and 4QD or Sevcon controller?
>>> This should match the efficiency of the expensive AC drives and still
>>> cost less.
>
> Peter VanDerWal wrote:
>> The Etek is not even in the running, it's at least 5% lower in
>> efficiency than the Lynch/Lemco. IIRC the Lynch motor runs at less
>> than 90% efficiency when set for neutral timing. I'm not sure how
>> efficient the 4QD or Sevcon controllers are, but the motor alone
>> is already behind.
>
> These motors are all about 85-90% efficient, battery to shaft.
Only if you don't use a controller. I'll grant you that's possible with
DC motors, but not terribly efficient in a vehicle that needs to travel at
various speeds.
> essentially the same as an AC drive, battery to shaft.
If you consider +or- 5% essentially the same, then it's pointless to
continous this discussion, because I don't.
The E-cycle motor is approx the same power level as the Etek or Lynch. It
tops out at 96% efficient (not counting the controller), and over 95% for
a large portion of the torque curve. That makes it almost 10% more
efficient than the Etek and 6% better than the Lynch (when the lynch is
setup for regen).
> You have to
> remember that the AC drives generally require liquid cooling, and they
> leave out the power used for the cooling system. The DC systems are
> generally air-cooled, and cooling losses are already included in their
> stated efficiency.
Probably because power required for the pump typically negligible, far
less than 1%.
Also many AC motors do NOT require liquid cooling, the E-cycle doesn't and
I don't think the solectria does (can't remember right now).
> Also, the AC drives require an inverter. Most use IGBTs which have a 4-6
> volt drop per phase (2-3v per IGBT, 2 in series per phase). The brushed
> DC motors can be run straight to the battery with no controller at all,
> if you worship efficiency.
Only at a single speed per battery voltage.
> And, most AC drives use induction motors, which always lose several more
> percent efficiency to slip.
The E-cycle motor uses rare earth magnets.
>
> So all I'm saying is that brushed DC motors can have essentially the
> same efficiency as an AC drive, if you're willing to spend the same
> amount of money.
I don't agree. Since you haven't pointed out a hgih efficiency DC motor
that is equal to the Siemens motor, lets compare AC systems that are
similar power to the Lynch motor (the best of the above)
The E-cycle single stack motor is rated at 6kw continous, and the double
stack is 12kw.
These motors are significantly cheaper than the Lynch motor. Enough so
that I suspect that even with the extra cost of the AC inverter, the total
price might just favor the Ecycle motor.
In fact Ecycle sells a motor with electronic comutator built in (the CMG
series) and you can drive it directly from a battery, or using a standard
DC motor controller.
It's efficiency is 95% (including the comutator), AND that's setup to do
regen. That makes it approx 5% better than the Lynch motor setup for
Regen. AND it will maintain this efficiency over a wider portion of the
torque band than the Lynch, AND it will run at higher continous voltages
than the Lync.
Finally, it CHEAPER than the Lynch.
AND it doesn't have brushes to wear out.
>
>> Assuming we are doing a full size conversion, like the original
>> message, youll need at least 15-20 kw continuous output. Thats
>> at least three Sevcon controller $1800, and two Lemco motors $3700,
>
> At least two Lemcos and Sevcon controllers (Sevcon has models big enough
> to do it with two, but not one controller).
>
> A better choice would be to get a larger brushed high-efficiency motor.
> A scaled-up version of the Lynch motor would be even more efficient.
> However, I don't know of one offhand (though they clearly could be
> built).
One could also build a scalled up version of the Ecycle motor and maintain
it's lead on the Lynch type motor.
>
>> plus circuit breakers, contactors, etc. Add it all up and youre
>> right at the price for a more capable (and more efficient) Siemens
>> system.
>
> All these parts have to exist in both systems. No "wins" for AC vs. DC
> here.
Sure, but they are included in the $6K+ price for the Siemens systems.
>>> If cost matters more than efficiency, how about any of the sepex
>>> motors and controllers now used in golf cars? Or a Curtis 1221R
>>> and ADC series motor? Or Zapi H2 controller and Kostov series motor?
>
>> But they don't match the efficiency of the AC drive systems do they?
>
> Why harp on efficiency? Are you building a solar car?
Because the Arguement was about efficiency, duh!!
> I'm thinking more
> of practicality. You can build a *practical* EV with either an AC or DC
> drive system. Assuming you spend the same amount on each, their
> efficiency can be close enough to the same that you can't tell without
> careful measurements.
Probably true, 5% is only an extra 2.5 miles on a 50 mile range EV. Most
folks won't notice the difference.
If you wish to change the basic premis of the arguement, I'll concede the
point to you.
>
>>> Eteks and other PM motors don't have (or need) interpoles because
>>> they never run at weak field. The optimum brush position moves
>>> because of armature reaction, which occurs with a high armature
>>> current and low field strength.
>
>> Hold on a second...this is Lee talking right? Come on Lee, you know
>> better. The optimum brush position DOES move on PMDC motors when
>> switching from motor to regen. I know this from my own experiments and
>> LEMCO has it clearly posted on their website.
>
> {My, are you in a bad mood today :-)
>
> I didn't say armature reaction was zero in a PM motor. I just said they
> don't put interpoles on PM motors. This is because armature reaction
> isn't big enough to justify interpoles.
Unless you are running a Lynch type motor and don't want to burn out the
brushes when you use regen. This sugests to me that the armature reaction
isn't exactly trival.
>
> But, you can still run a high enough armature current to cause the
> optimum brush position to shift. For this reason, they do build PM
> motors with advanced, retarded or neutral brush positions depending on
> direction of rotation and whether it will be used as a motor and/or
> generator.
Like the Lynch/Etek that we were discussing.
>
>>> Traction motors with interpoles are fairly common.
>
>> GE doesn't make traction motors any more.
>
> That would surprise me. I'll have to check. Perhaps with all GE's
> financial troubles and merger mania they've sold that division and it's
> still operating under another name.
Sorry, GE dropped their EV division about 10 years(?) ago. I supose they
might make a locomotive traction motor small enough for a conversion.
>
>> As far as I know you can't buy an ADC motor with interpoles.
>
> True. They are a low-end supplier.
>
>> I can't find anyone who carries new Kostov motors, are they still
>> in business?
> Again, they probably do. But I don't know who imports them.
As near as I can tell, nobody.
>
>> Who sells Westinghouse motors?
>
> Westinghouse, I suppose.
>
>> Are they available/affordable for the hobbyist?
>
> I'm a hobbyist; I bought 4 of them a few years ago for $500 each.
OK, now you have my attention. You bought 4 EV size westinghouse motors
with interpoles? Details please.
>> ...or that cost more than better systems (i.e. AC)
>
> The Siemens AC system is about the only affordable AC option for
> hobbyists. I applaud Victor Tikhonov offering them for sale. But they
> are surplus, too; not current production.
>
>>> I maintain that the efficiency difference between AC and DC systems is
>>> largely artificial.
>
>> Come on Lee, can you say "Brushes"? ... as long as motors have
>> brushes, they will lag behind brushless AC motors by a couple percent.
>
> The voltage drop of a brush is 1-2 volts. The voltage drop of an IGBT is
> 2-3 volts.
IGBTs are not REQUIRED for AC drive systems. You could use FETs just like
DC motor controllers, and therefor the losses (in the controller) would be
the same.
Controllerless DC setps aren't really all that practical for conversions,
which is what we are talking about.
>>> For example, if you budget $2000 for motor and controller, you can
>>> get a plain old series motor and PWM controller. Or a plain old 60hz
>>> AC induction motor and industrial motor controller. Both will be
>>> about 80% efficient, and neither has regen.
>
>> Are you talking used or just small?
>
> Small, new. I was thinking of an ADC 6.7" motor and Curtis 1221C
> controller.
Check out www.ecycle.com, not a lot more expensive than ADCs of similar
power and lots cheaper than Lynch.
At 10-15% higher efficiency compared to a ADC 6.7, I'd think even you'd
agree that is significant.
I'll admit I haven't tried to actually buy a motor from them yet.
>> The available low voltage controllers tend to be less efficient
>> than the high voltage ones.
>
> The low-voltage controllers use MOSFETs; the high-voltage ones use IGBTs
> (both AC and DC). And both have essentially the same efficiency.
>
>> And, of course, any voltage drop across a brush is going to be
>> higher than no voltage drop with no brushes (i.e. AC motors).
>
> All motors are AC motors, and all need some kind of switch. All switches
> have a voltage drop. The brush of a DC motor is the same as the
> transistor in an AC motor. Neither has any intrinsic advantage, and both
> can be made arbitrarily small if you are so inclined.
Perhaps, but when you are talking about electric vehicles, a controller is
normally used. When you factor in the controller, which also functions as
the switch for the AC motor, TOTAL system efficiency favors the AC motor
setup.
AC systems don't HAVE to be high voltage, nor do they HAVE to use IGBTs.
--
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 ---
- [Edited]
http://www.world.org/weo/ranger
Includes DS-50 240-volt Portable Charger
This vehicle had been working perfectly, getting up to 70 miles
on a charge, until last week. It no longer will start. We have
no idea if this is a minor or major problem. Since there are no
repair facilities in our area, we have decided to sell this
vehicle AS-IS to the best offer we receive. Funds paid for this
vehicle will be used exclusively to further our efforts related
to renewable energy.
Additional features: Stereo, Power Window/Door Locks, air bags,
4-wheel ABS
Please call Jeff Gold at (706) 769-1000 or email: [EMAIL PROTECTED]
Watkinsville, GA 30677
-
Bruce {EVangel} Parmenter
' ____
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'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor, RE & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
I got my newly painted EV back from the Auto Body. My fear is that
they only did a once over and sprayed some paint, even though I
paid
for the best paint package. Only time will tell.
Next time I do this, I will have the windows taken out, and then I
will do the sanding in the nooks and crannies I am sure they only
hit with paint. Then I turn in the vehicle for painting I will be
sure to get a better job. Once the paint is dry, I could then get
the windows put back in.
So, right now with the hood changed out, I do not have solar panels
in the hood. I will need to update my Blazer EV web page. Also, the
old-n-yellowed "Electric" decal that Solar Electric put on, and the
California HOV stickers have been taken off.
My EV is plain Vanilla. No one can tell that it is Electric. Funny,
I am getting less irate drivers hugging my rear bumper anxious for
me to speed up. I guess if they do not see the "Electric" signage,
they must think I am a slow driving old coot out for a Sunday
drive.
But I am thinking of putting a couple "Electric" Emblems on my
Blazer EV. Then I won't feel like such a plain Jane.
ta
Bruce {EVangel} Parmenter
' ____
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'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor, RE & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
____________________________________________________
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
--- End Message ---
--- Begin Message ---
Please email me at [EMAIL PROTECTED] as im very interested in that
Zilla1k, im assuming it comes with the Hairball
Cwarman
Derrick J Brashear wrote:
On Wed, 24 Aug 2005, Cwarman wrote:
Derrick, how much are you asking for your Zilla ?
It's brand new and unused or installed, $1950, I'll entertain other
offers.
.
--- End Message ---
--- Begin Message ---
Medium Importance
- high visibility of user interface in most light conditions
Is your preference LEDs or LCD?
IF you want 2 (say, 7-segmet LED) displays,
do you mind to have digits smaller or you'd rather have
the face bigger?
I would say a LCD is far more flexible. It is nice to have the
display have various different display modes. Different font sizes
are helpful. It is nice to have a simple display for casual driving,
but lots of details are great when you are testing things.
Do you want to keep it round or square (BRUSA style) is OK?
Do you think most people would install it into the
instrument cluster (so remote buttons needed) or into/onto
the dash?
How about with a removable case front where the unit can be dash mounted?
Anyone else?
Have the firmware upgradable. The once you have the hardware with
the right features, you can still fix bugs later without having to
ship them in for factory service. You may find a few programming
geniuses that will add new features you never thought of (free added
value). It also lets you support EV and PV needs with one unit.
--- End Message ---
--- Begin Message ---
As a rule-of-thumb, the Saft STM5-100s give you a kW per monoblock -
observing that the Peugeot 106/Citroen Saxo have 20 batts and 20kW (peak);
the Peugeot Partner/Citroen Berlingo have 27 batts and quote 27kW peak; and
the Renault Kangoo has 22 batts and 22kW peak, though with the range
extender genset running (if fitted) this peak is raised to 29kW. They seem
to have chosen to keep the battery amps < 180A most of the time.
Philippe, the controllers wouldn't allow 200A over a long period though
surely? Or would it only cut back if the motor/batt sensors start to
indicate high temperatures?
(I don't drive with the ECO in the red very often ;-)
Matt
> From: "Philippe Borges" <[EMAIL PROTECTED]>
> Date: Wed, 24 Aug 2005 20:24:35 +0200
> To: <ev@listproc.sjsu.edu>
> Subject: Re: Battery calculation, NiCad vs. LeadAcid
>
> Saft STM5-100 are rated by Saft for 200A CONSTANT and 500A (10sec)
> in 120V French electric car, battery amp allowed is 200A max (full throttle,
> red part of "eco-meter")
> I controled max bat amp with OEM diag console while driving.
>
> cordialement,
> Philippe
>
> Et si le pot d'échappement sortait au centre du volant ?
> quel carburant choisiriez-vous ?
> http://vehiculeselectriques.free.fr
> Forum de discussion sur les véhicules électriques
> http://vehiculeselectriques.free.fr/Forum/index.php
>
>
> ----- Original Message -----
> From: "Evan Tuer" <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Sent: Wednesday, August 24, 2005 2:51 PM
> Subject: Re: Battery calculation, NiCad vs. LeadAcid
>
>
>> On 8/24/05, Michaela Merz <[EMAIL PROTECTED]> wrote:
>>>
>>> Hello Everybody:
>>>
>>> I have started to do some basic calculations on my new S-10 project.
> Based
>>> on the experiences with my current Nissan pickup, I have some figures to
>>> work with.
>>>
>>> Trojan T-125, 22 batteries, 130 Ah/C1
>>>
>>> Available energy: 17 Kw (Voltage sag not calculated)
>>> Weight: 660 Kg (1455 pounds)
>>> Range at 60 Mph: About 35 Miles
>>>
>>> Saft Nicad STM 5-100 100 AH/C3
>>> Available energy: 14.4 Kw (Voltage sag not calculated)
>>> Weight: 286 Kg (631 pounds)
>>
>> ^^^^^^ Be careful - kW is a measurement of power, not energy.
>>
>>> I don't know the C/1 value for those Safts, but I can save 800 pounds of
>>> weight by losing about 3 Kw of available energy. Question is, how can I
>>> set the weight loss in relation to the loss of Kws?
>>
>> That's about 22 x 100MREs. With a current limit of 180A, you will
>> have more like 22kW of power, and around 15kWh of stored energy.
>>
>> With only 22kW in a heavy truck, the acceleration will be pretty poor
>> and keeping up with 55mph traffic would be "flat out". Also the range
>> won't be very impressive.
>> I would recommend more batteries (meaning a higher system voltage), or
>> use the higher capacity 140 or 180AH modules.
>>
>> Of course, it depends on what your requirements and budget is... what is
> it? :)
>>
>> --
>>
>> EVan
>> http://www.tuer.co.uk/evs2
>>
>
--- End Message ---
--- Begin Message ---
Thanks Gordon for feedback
Gordon Niessen wrote:
I would say a LCD is far more flexible. It is nice to have the display
have various different display modes. Different font sizes are
helpful. It is nice to have a simple display for casual driving, but
lots of details are great when you are testing things.
LEDs will be first. The custom LCD (with units, icons,
analog bars and other things I want) will follow.
How about with a removable case front where the unit can be dash mounted?
I've settled on two separate units - only display is dash mounted.
The main controller is under dash somewhere - no need to be visible.
LED dash display unit is swappable for LCD one - so you plug in the
type you like the most. Connecting both semultaneously is technically
possible too, though don't know who'd do that :-)
The only instance I see it can be useful is if a passenger gets
a monitoring display too (other than driver).
Have the firmware upgradable.
Naturally, firmware is upgradable off flash card (SD card) or more
traditional way - via RS232 and bootloader for those who don't
want to use external memory.
Latest upgrades of course will be free downloadable off the web site-
this is the plan.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
So how are you building the shunt input stage? These are quite tricky
to do with low offset errors and good accuracy.
Danny
--- End Message ---
--- Begin Message ---
Jeff, what's the exact model number on the DS-50? For example,
DS50-20-S2-10, DS50-30-S2-10, DS50-40-S2-10.
Thanks.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of bruce parmenter
Sent: Wednesday, August 24, 2005 11:58 AM
To: evlist
Subject: EV4Sale: Dead Ranger EV in Watkinsville, GA
- [Edited]
http://www.world.org/weo/ranger
Includes DS-50 240-volt Portable Charger
This vehicle had been working perfectly, getting up to 70 miles
on a charge, until last week. It no longer will start. We have
no idea if this is a minor or major problem. Since there are no
repair facilities in our area, we have decided to sell this
vehicle AS-IS to the best offer we receive. Funds paid for this
vehicle will be used exclusively to further our efforts related
to renewable energy.
Additional features: Stereo, Power Window/Door Locks, air bags,
4-wheel ABS
Please call Jeff Gold at (706) 769-1000 or email: [EMAIL PROTECTED]
Watkinsville, GA 30677
-
Bruce {EVangel} Parmenter
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor, RE & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
You have to
remember that the AC drives generally require liquid cooling, and they
leave out the power used for the cooling system. The DC systems are
generally air-cooled, and cooling losses are already included in their
stated efficiency.
Probably because power required for the pump typically negligible, far
less than 1%.
Also many AC motors do NOT require liquid cooling, the E-cycle doesn't and
I don't think the solectria does (can't remember right now).
Any motor *must* to be cooled, and thus if you discuss efficiencies,
you must view cooling hardware as part of the motor factoring in
energy spent for the cooling. If you do this, liquid cooled motor
will be ahead of the air cooled one by quite wide margin (provided,
same size and asked for the same power). Way oversized air cooled
motor which is thus stone cold no matter what does not count).
The water pump in my ACRX which cools off 30 kW rated motor
AND inverter AND charger is a size of my fist, weigh 200g
(less than half pound), totally silent
and consumes 400mA from 12V source. This allows
the motor to run continuously putting out 30kW.
Take a look how much ACP t-zero's blower consumes, not to
mention its weight, size and noise it creates. The power for the
blower comes from your traction battery, so you can't ignore it
discussing motors efficiency - you're not talking about
efficiency demonstrated on the bench or a dyno.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
With BRUSA cooperation, initially I'm using front end they
developed for their Ah counters. The challenges you describe
have been solved long ago and the accuracy is 1% as of now.
The conversion electronics sits right on top of the shunt itself.
Additional PCB massaging incoming data (MME design) sits next to
BRUSA conversion PCB.
Later if this option will continue to cost more than I'd like
(that depends on the production volume) I will develop replacement
for their front end.
Danny Miller wrote:
So how are you building the shunt input stage? These are quite tricky
to do with low offset errors and good accuracy.
Danny
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
There's one other type of display we're overlooking, the VFD (Vacuum
Fluorescent Display). Those are bright blue on a very dark background.
They're a relatively expensive alphanumberic display.
Now keep in mind "daylight readable" is not necessarily required
depending on how it's installed. Many of the electronic displays and
indicator lights on a commercial dash would not be visible if placed
under direct sunlight as opposed to the shaded area inside the dash.
Nor would nonreflective car stereo displays.
We could modify an LED belt buckle:
http://tinyurl.com/9r6q6
Just kidding.
The graphical display I've been using in my van outside in Texas summer
is on a cord and kept in an overhead shelf above the driver's seat. I
temp-comp'ed the LCD contrast and never had a problem. That van's
insulated though and doesn't reach the temps of a sedan with much more
glass.
Danny
Gordon Niessen wrote:
Medium Importance
- high visibility of user interface in most light conditions
Is your preference LEDs or LCD?
IF you want 2 (say, 7-segmet LED) displays,
do you mind to have digits smaller or you'd rather have
the face bigger?
--- End Message ---
--- Begin Message ---
Actually, a Nixie tube WOULD be pretty cool. They're retro and if it
was going into something like a Karman Ghia conversion that would be so
awesome.
http://en.wikipedia.org/wiki/Nixie_tube
May have vibration problems, either coming out of its socket if not
damage to the electrodes. I think with proper attention to mounting
concerns this issue can be accomodated.
Danny
--- End Message ---
--- Begin Message ---
How about a VFD display? Pretty easy to read in dark and light both.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: Tuesday, August 23, 2005 6:48 PM
To: ev@listproc.sjsu.edu
Subject: Re: e-meter type gadget wish list wanted.
Thanks for the input Lee.
The consensus seem to be about everything but display unit.
LEDs are "old" technology (nothing wrong with them in itself).
Not as old as Nixie tubes, so we'll survive :-)
Hard to read at direct sun light.
LCDs are more fragile, but the brighter - the better.
Wide view angle isn't really nesessary - driver's
position is pretty much fixed and you can point the
unit torard you. But the temp affects LCD the most.
There can be 3 small analog (270 degree pointer swing)
gauges with no digital readout at all. No problem with
reading in bright conditions, but of course you loose
precison of a digital display. It is relevant
if you have 216V or 219V, and no analog pointer can
tell you.
So, super bright 7-segment LEDs, LCD, or both?
(you can get and plug either one you like including both
at the same time)?
----snip------------
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Victor Tikhonov [mailto:[EMAIL PROTECTED] wrote:
> Any motor *must* to be cooled, and thus if you discuss
> efficiencies, you must view cooling hardware as part of the
> motor factoring in energy spent for the cooling. If you do
> this, liquid cooled motor will be ahead of the air cooled one
> by quite wide margin (provided, same size and asked for the
> same power). Way oversized air cooled motor which is thus
> stone cold no matter what does not count).
>
> The water pump in my ACRX which cools off 30 kW rated motor
> AND inverter AND charger is a size of my fist, weigh 200g
> (less than half pound), totally silent
> and consumes 400mA from 12V source. This allows
> the motor to run continuously putting out 30kW.
I've no interest in actiavely participating in this debate, however, I
must point out that the water pump does *not* cool anything. It merely
circulates the coolant which transports the heat energy from the source
to the sink. So, the weight of the pump alone is meaningless. If you
want to compare your liquid cooled system to an aircooled one, you must
include the weight of the coolant, the hoses, the pump, the radiator,
coolant resevoir/expansion tank, and any additional brackets, etc. for
securing these bits to the vehicle.
In comparison, an air-cooled motor has one part, the internal fan.
Instead of additional brackets, etc. to support the bits of the cooling
system what you need are holes (which tend to be quite lightweight ;^)
in the bodywork and motor case to allow air to circulate.
Cheers,
Roger.
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--- Begin Message ---
Don Cameron wrote:
> Pascal, here are your options:
>
> 1. Motor to drive the transmission through a clutch - you can
> shift normally. This is very common.
>
> 2. Motor to drive the transmission directly to the transmission
> input shaft (i.e. no clutch) ... Some people can shift on go.
> Others have to put it into the selected gear when the car is
> at a standstill.
Agreed. These are the best choices when converting an existing vehicle,
which already has a differential and transmission.
> 3. Motor to drive to a differential (no transmission or clutch).
> This is often called "direct drive". This is technically
> possible, but there are limitations to the ratios available.
This is the most common setup for scratch-built EVs where there is no
existing transmission or differential. Direct drive requires a bigger
motor and controller to make up for the lack of a transmission. But the
cost and weight savings from eliminating the transmission usually make
it cheaper and more efficient overall.
> Variations of the direct drive (3) might be a chain drive or a
> belt drive to a rear axle. This is quite possible, but without
> some sort of differential you will get chattering and wheel hop
> when going around corners.
One straightforward way to eliminate the differential is to use two
motors and two fixed-ratio gearboxes, chains, or belts, one for each
wheel. That could work out nicely for an UrbaCar; for instance two Etek
motors driving each back wheel thru a 5:1 ratio (or thereabouts; it
depends on your tire size and top speed needed).
Finally, one scheme I like; use a single motor with a shaft on each end.
Put a variable-speed pulley on each shaft, driving each rear wheel
separately. The variable-speed pulleys provide both the reduction and
the differential action.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
[on power]
Victor Tikhonov wrote:
> As far s power for it - shunt circuit gets power from
> the pack directly. Display brains - from 12V house power.
> No issue to have DC-DC converter off the main pack for that
> too.
The E-meter takes 25-50ma at 12v even in "sleep" mode (all LEDs except
the state-of-charge bargraph off). This may not seem like much, but it
can kill a 12v accessory battery in a few weeks if the car isn't driven.
Or, if you try to keep the accessory battery charged by running the main
DC/DC, its low efficiency at such a light load causes it to kill the
main pack in not much longer.
I would hope that the standby power of your Evision meter could be at
least 10 times lower. But the tendency is to treat 12v power as
"infinite". So newer gadgets keep drawing more and more power, even
though technology could have allowed them to use less.
> And, not to worry, you'll get ASCII out Lee. I suppose
> no one cares how the modules talk to each other internally.
Probably not. But my own "vision" is that the shunt and prescaler could
speak in a standard, documented way so that multiple sensors could be
added to that bus. Perhaps you want two shunts, one for battery and one
for motor amps? Or two voltmeters, for two packs? Or add 3 temperature
sensors, one for each battery box? This is the sort of thing I had in
mind when I designed the EVILbus.
> I was assuming that these days it is not an issue to get
> some sort of memory card reader for a computer, but may
> be naively wrong. Anyway, RS232 will be there (isolated :-)
My experience is that RS-232 has been around "forever", and continues to
be supported on brand-new devices. But there have been dozens of
temporary, proprietary standards that come and go every few years. SD
cards weren't around a couple years ago; what makes you think they will
be a couple years in the future? More likely, they will have been
replaced by some hot new plug-in memory format.
Beware of designing your product around temporary parts or technologies!
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
[On displays]
Danny Miller wrote:
> Temp comp the LCD display. Works like a charm and you should never
> need to do a contrast adjustment.
Then you don't live in a place with "real" winters and haven't tried a
multiplexed LCD at sub-freezing temperatures. Even if you get the
temperature compensation perfect so the viewing angle and contrast don't
change, they get s-l-o-w. It can take many seconds for the segments to
turn on/off. This is fine for an odometer or clock displaying
hours/minutes, but useless for a rapidly-changing value like battery
current.
The other issue I have with LCDs is that they cost by the square inch;
not by number of segments. So there is a tendency to use the smallest
possible size and largest possible number of segments. But large numbers
of segments require deep multiplexing. This causes poor contrast and
narrow viewing angles. So we get lots of gadgets with wonderfully high
resolution graphic displays that have extremely narrow viewing angles
and poor contrast.
Victor Tikhonov wrote:
> LCDs are more fragile, but the brighter - the better.
> Wide view angle isn't really necessary - driver's position is
> pretty much fixed and you can point the unit toward you.
A add-on gauge mounted to a car's dashboard usually *cannot* be
positioned or angled to provide the optimal angle to the driver. You may
have to put it in the center of the dash, or well below the driver's
eyes because that is the only place where there is room. A display with
a fixed narrow viewing angle will have to be in a housing that lets you
tilt it to whatever odd angle is required.
LEDs are "old" technology (nothing wrong with them in itself).
Hard to read at direct sun light.
That's what they used in the old E-meter (designed 10 years ago). They
made it a power-hog, and not readable in direct sunlight.
Today, we have super-bright LEDs that can easily outshine the sun, and
colors and styles that didn't exist back then (white, blue, etc.). What
convinced me was seeing some of Datel's digital panel meters with blue
and white 7-segment LEDs -- they are bright, high-tech-looking, and very
low power -- lower than LCD displays when you include their backlights!
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
>>> When you lay the wires together -- and preferably have a slow
>>> twist (one rotation every 18" seems to be about right in
>>> industrial applications) the magnetic fields are of opposite
>>> polarity and cancel each other out.
>> Is this for AC or DC setups or both?
It works for both AC and DC. As long as the two wires are carrying equal
and opposite currents, their magnetic fields (mostly) cancel. The closer
they are, the better it works.
The twisting makes their average centerlines even closer together, which
helps further. More twists are better, but harder to do with heavy
wires.
For perfect cancellation, use coaxial cables; one wire in the center,
the other wire a hollow pipe or braided cable or bundle of individual
wires around it. For EV use, you'd probably make such a cable yourself;
the commercial versions are *very* expensive!
James Massey wrote:
> All of the commercial EV/AC systems that I know of use shielded
> wires for the motor. I guess that's a part of the total quality
> package you get when buying an AC system. Victor (and anyone else?)
> do any of the ones you have seen NOT come with screened motor wires?
The higher the power, the more likely they are to be shielded or coaxial
cables. That's because with the higher power come higher noise levels.
You reach a point where you *have* to do something about the noise or
nothing electronic will work anywhere near it!
>> Can I get some sort of shielding sleeve to put those cables in?
A "shield" is a grounded NON current carrying conductor around a wire.
It works in a very different manner. A shield adds considerable
capacitance to ground, which helps bypass RF frequency noise. But you
also need to design the controller to include this capacitance, or you
get worse switching spikes. The shielded wires between a motor and
controller need to provide the "right" capacitance that the controller
was designed for.
> Well, the simplest way is probably to do what communications cables
> often do - a bare stranded copper wire is laid as a 'drain' wire,
> over the inner bundle insulation and then is wrapped in foil, then
> insulated again over the outside. Ground only one end of the screen,
> probably to the motor case (since its housing is shielding most of
> the noise inside it). Lee?
This works fine for low-current cables. It would not work well for
high-current battery or motor cables unless you put BOTH
current-carrying wires (or all 3 for a 3-phase motor) inside the same
shield. The paired wires cancels most of the external magnetic field.
What little is left can be handled by the thin foil shield.
If you put a thin foil shield around a single high-current cable, it
acts as a shorted turn on a tranformer secondary, and the current
induced in the shield can be quite large. You'll notice that the foil
shields are often on plastic insulation, so their ends do not touch when
wrapped around a wire -- the foil forms a spiral around the wire, not a
closed loop.
The AC EV systems can get away with braided wire shields around the
individual motor wires because they are running relatively high voltages
and low currents.
Twisted pairs and shielding are going to get increasingly important as
people try converting more modern vehicles. "Old-timers" didn't shield
or pair anything. All that happened was that the AM radio didn't work
any more. There weren't any other electronics in the car.
Now we're using MOSFET controllers that switch extremely fast. This
generates a lot more noise than the older SCRs or bipolar transistors.
EVs are using higher power levels (more voltage and more current), which
again increases noise. And cars are loaded with dozens of computers,
which will crash or fail with even modest amounts of noise.
On my own EV, I ran the battery-to-controller wires in metal conduit,
and kept the motor-to-controller wires down to about 1 foot long, and
bundled in pairs. This was sufficient so that the AM radio still works
on stronger stations.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Michaela Merz wrote:
> After lots of thinking, googling and searching, I finally made up
> my mind. I found a nice '97 Chevy S-10... will convert it within
> the next few month.
That's a good choice. There have been lots of successful S-10 EVs.
> I will try to avoid Lead-Acid batteries because I don't like the
> weight and the disadvantages.
Ok. Just be aware that most EVs use lead-acid in spite of their
disadvantages, because the other types have *more* disadvantages (mainly
cost)!
> So - I'd like to talk about the necessary power (in terms of Ah/c3
> or Kwh) needed to get a highway speed range of about 60 Miles.
> I would think the S-10 needs about 350 Wh, 400 Wh or maybe 450 Wh
> to go 60 Mph - or about 4 KW/h to 4.5 KW/h for 10 Miles -- so,
> I am talking about 24 Kw/h to 27 Kw/h needed to get 60 Miles.
Your units are a bit mixed up. But we can fix that.
The S-10 will use about 350 watthours per mile, assuming you use
sensible low-rolling resistance tires, and are careful with the other
details like wheel alignment, brakes not dragging, and no silly wind
resistance adders.
350 watthours/mile x 60 mile range = 21,000 watthours = 21 kwh. If you
will drive that 60 miles at 60 mph, it takes 1 hour. So, you need a
battery pack that can deliver 21 kwh at the 1-hour rate. Assuming a 120v
pack, they need to be 21kwh / 120v = 175 amphours at the 1-hour rate.
Just for reference, let's see how many lead-acid batteries this would
take. A T-105 is about 130 amphours at the 1-hour rate. You'd need two
strings of 20 or 40 batteries to get 260 amphours. 175/260 = 67%; so
you'd be discharging them 67% to do that 60-mile drive. That's a little
deeper discharge than the optimum 50%, but workable. But this "reserve"
capacity would mean you could drive over 100 miles on a charge if you
drove a lot slower. This pack would cost $50 x 40 = $2000; not bad. But
it would weigh 62 x 40 = 2480 lbs!
> I guess that I would have to use some NiCads to get into that range.
> Anybody did an S-10 with Nicads before?
Paul Wallace did an S-10 with 6v nicads -- maybe he's listening and can
provide details. I think they were Saft, about the same size and weight
as a golf cart battery, and 200 amphours at the 1-hour rate. So, a
single string could do (barely) do it! You'd be deeply discharging them,
but that won't impact their life as badly as lead-acid. But they cost
around $300 x 20 = $6000 (and that was used)! Weight was 65 x 20 = 1300
lbs, which is almost a 2:1 reduction over lead-acid.
The big challenge with nicads is that you almost have to get them used.
No one wants to sell new EV-sized nicads except to big companies. And
when you buy used batteries, there is considerable risk of buying junk.
You could use the BB600 aircraft nicads that have recently been around.
But I wouldn't -- they are tiny 40ah individual cells and you'd need 500
of them to do the job. The interconnections, packaging, watering, and
related concerns would become a nightmare.
> Somebody (commercially) willing and able to provide technology,
> batteries and charger?
Sure! Saft, for one. But you will have to pretend you're a big company
or they will ignore you. Actually, you will probably have to do this for
any advanced battery technology (nicad, nimh, lithium). They are all
nearly "unobtainium" as far as the lone hobbyist is concerned. You will
have to trick them into thinking you are a big potential customer. Or,
buy used from some scrap dealer.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
