EV Digest 5076
Topics covered in this issue include:
1) RE: Pack voltage switches for peripheral devices?
by "Don Cameron" <[EMAIL PROTECTED]>
2) Re: Pack voltage switches for peripheral devices?
by kluge <[EMAIL PROTECTED]>
3) RE: I want to build a PWM DC motor controller
by "Roger Stockton" <[EMAIL PROTECTED]>
4) Re: Neg supply for E-meter [EMAIL PROTECTED]
by Christopher Zach <[EMAIL PROTECTED]>
5) RE: Mk3 Regs
by "Roger Stockton" <[EMAIL PROTECTED]>
6) RE: EMeter quirks
by "Roger Stockton" <[EMAIL PROTECTED]>
7) RE: Pack voltage switches for peripheral devices?
by "Don Cameron" <[EMAIL PROTECTED]>
8) RE: I want to build a PWM DC motor controller
by "Roger Stockton" <[EMAIL PROTECTED]>
9) Re: Tire Ignition Sequence Photos of White Zombie???
by Victor Tikhonov <[EMAIL PROTECTED]>
10) RE: Pack voltage switches for peripheral devices?
by "Myles Twete" <[EMAIL PROTECTED]>
11) "This New Car" Radio Show now on-line
by M Bianchi <[EMAIL PROTECTED]>
12) RE: I want to build a PWM DC motor controller
by "Roger Stockton" <[EMAIL PROTECTED]>
13) RE: Tire Ignition Sequence Photos of White Zombie???
by "Roger Stockton" <[EMAIL PROTECTED]>
14) RE: Replace 2 batteries?
by "Adams, Lynn" <[EMAIL PROTECTED]>
15) Re: I want to build a PWM DC motor controller
by Danny Miller <[EMAIL PROTECTED]>
16) Need: EV repair shop
by bruce parmenter <[EMAIL PROTECTED]>
17) Re: "This New Car" Radio Show now on-line
by [EMAIL PROTECTED]
18) RE: I want to build a PWM DC motor controller
by Lee Hart <[EMAIL PROTECTED]>
19) RE: Pack voltage switches for peripheral devices?
by Lee Hart <[EMAIL PROTECTED]>
20) RE: Pack voltage switches for peripheral devices?
by Lee Hart <[EMAIL PROTECTED]>
21) Re: I want to build a PWM DC motor controller
by "Stefan T. Peters" <[EMAIL PROTECTED]>
22) "Spa Hose" (was Re: Hybrid motor mounting, poof goes the car)
by Nick Viera <[EMAIL PROTECTED]>
23) Re: honda hub adapters - any vendor done these?
by Electro Automotive <[EMAIL PROTECTED]>
--- Begin Message ---
Kluge? (do you have a better name?)
I use the P&B 655-PRD-11DH0-12 they are rated for 250VDC at 20Amps.
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of kluge
Sent: January 9, 2006 10:52 AM
To: [email protected]
Subject: Pack voltage switches for peripheral devices?
I'm currently putting together some of the peripheral equipment which will
be working off the pack voltage of my 156 volt Courier - heater, DC- DC,
etc. The maximum draw could go as high as 15 amps. I don't seem to find a
lot of 156 VDC rated switches or relays readily available, so
I'm kicking around different ways to switch them on and off short of using a
Czonka. I've got some 3 pole relay modules which are rated for
28VDC, 30 amps which I'm thinking of using by wiring the three poles in
series, then wiring two of the modules in series, giving me a cumulative
voltage rating above the pack voltage (6 x 28 = 168 > 156.) Will this
work?
--- End Message ---
--- Begin Message ---
I'm getting the picture that the DC ratings listed on the devices are
conservative. These relays (which have the distinct advantage to me of
being stuff I already have) have a rating printed on them of 30 amps at 28 VDC,
30A/15A at 300/600 VAC, and 30FLA, 75 LRA at 277 VAC. So
I'm guessing I can probably use just one with its 3 poles in series for my
sub-15 amp switching needs at 156 VDC as a cheap (i.e. free for me)
and pretty easy method of switching my stuff.
There are basically two approaches. Get a switch or relay actually rated at the
desired voltage. Common choices are the Potter & Brumfield/Siemens/Tyco PR10 or
KUEP series relays with magnetic blowout option, or old AC/DC rated switches
(like you'd find in a house built over 50 years ago).
The other approach is to use an AC-rated switch or relay at about 1/4 of its
voltage rating. For example, I have a 3-pole relay for an air conditioner here
(Furnas 42CE35AJ106) which is labelled
120vac 1ph 2hp, 3ph 5hp
240vac 40fla, 240lra, 1ph 5hp, 3ph 10hp
480vac 40fla, 200lra, 3ph 15hp
600vac 30fla, 160lra, 3ph 15hp
These are just the particular values that the manufacturer tested. "ph" is
phase, "fla" is full load amps, and "lra" is inductive-resistive amps (i.e. the
peak current it can switch to start a motor). What all this means is that each
contact is good for up to 40 amps continuous, and that 2 contacts in series can
withstand up to 600vac (because you have two contacts in series on 3-phase
power).
That means each contact is good for about 300vac. So, if you wired all 3 in
series, they could switch 900vac or 900/4=225vdc. That's adequate for your
application.
--- End Message ---
--- Begin Message ---
Stefan Peters [mailto:[EMAIL PROTECTED] wrote:
> You did see where I said you don't have to use
> any Power Modules at all?
Sure, but not having a clear idea of what the Power Modules do vs the
Subnet Switch this didn't leave me with a good understanding of what
functionality is left without them. My feeling is that one must compare
similar functionality to accurately compare costs; if eliminating the
Power Modules leaves one with less controller functionality than a plain
PWM controller then the cost comparison is flawed.
> There is a long rambling with various explanations, diagrams, and
> testing schematics at EVForge.net:
>
> http://www.evforge.net/forum/viewthread.php?forum_id=13&thread_id=10
Thanks; I have had a peek.
A couple of comments:
- most (all?) 12VDC muffin fans are BLDC and require some minimum
voltage (like 9V or so) to start. They will not likely make good test
subjects for your prototype. You might be better off with an automotive
fan motor from a wrecker.
- looking at the BatPack/RedRock site, this fellow's logic looks a bit
messed up. The Rds(on) does not increase exponentially with voltage
(for instance, just quickly picking some devices at random from
DigiKey's catalog, we have a Toshiba 2SK2993 250V, 20A, 0.082 ohm, and a
Toshiba 2SK3117 500V, 20A, 0.210 ohm, for an Rds(on) increase of <2.56
vs the factor of 7 this fellow assumes, and with a bit more searching we
find the STY60NM50 500V, 60A, <0.05 ohm part which is actually *better*
than the 250V Toshiba part (not that the 250V Toshiba part is anything
to write home about, e.g. IRFP4232 250V, 60A is only 0.030 ohm)!). And
then, of course, there is the issue that builders of 500V controllers
would almost certainly use IGBTs instead of MOSFETs anyway. Finally, he
doesn't appear to appreciate that a fundamental benefit of a PWM
controller is its ability to provide current multiplication at part
throttle operation, something which his system fails to provide.
- your Subnet Switch only appears to handle switching 2 parallel
strings, so to build a system with anything approaching the
functionality of a PWM controller (or contactor controller) would
require multiple Subnet Switches. Typically one would want voltage
steps of no more than perhaps 24V, so a 120V pack would require 5 24V
strings in parallel and 4 Subnet Switches to allow steps of
0,24,48,72,96,120V. Since the Subnet Switches must be 'stacked', they
must be built using higher voltage parts as they must handle switching
of at least 1/2 the total pack voltage (96V in this example, actually),
and the full pack current. This means that if built with MOSFETs as the
switches, they *each* ultimately end up containing much the same
complememt of devices (voltage and current ratings) as a plain PWM
controller. Even if one uses contactors for the switching, these end up
being fairly pricey boxes. Unless one imposes the limitation that there
must always be an even number of strings in the system then each Subnet
Switch must have the ability to connect either of its two inputs to its
output, or connect its two inputs in parallel to its output, or connect
its two inputs in series to its output.
> See the diagram. It is the same HV wiring that many are
> familiar with.
No, actually it is not; most are familiar with a simple series string of
batteries, not paralleled strings. In a simple series string there is a
single connection at each battery terminal, and a single piece of wire
connecting adjacent batteries together. As soon as you start paralling
strings you must pay special attention to the way that the connections
are made or else the strings will not share current evenly, and
depending on the physical arrangement of the batteries the connections
from each string to the subnet switch may require additional (long) runs
of traction cabling that a single series string would not require.
> If you wish to use the Power Modules, just mount them to each battery
> (they are the size of a smaller hardbound book, getting ready
> to start testing various mounting options). There is a BAT- and a BAT+
> input, a OUT- and OUT+ output (treat them just like the battery
> terminals when connecting in a string)
This also changes the traction wiring: there are now 2x the number of
connections and interconnects since there are cables from each battery
terminal to the input terminals of the Power Module for that battery in
addition to the interconnects used to string the Power Module output
terminals together.
Please note that I am not necessarily suggesting that the increased
wiring and connections would outweigh the potential benefits of your
system, just that it is something that must be considered as you try to
compare the costs and performance of this system to the alrernatives.
> Using the Power Modules does present
> difficulties with string charging. But why is charging each battery
> individually so bad?
I don't think it is even just the use of the power modules; I think even
the use of the subnet switches may require charging each string
individually.
The issue is usually that it is more costly to buy a bunch of smaller
chargers than to buy a single large one. In traditional systems there
is also the issue that if one charger fails undetected then its battery
will be damaged during the next discharge, however, your system should
just leave this battery unused.
> > Finally, the use of switches at each battery implies to me
> > much higher losses than a conventional system.
> This has also been traveled over (in much detail) earlier in
> the thread.
> I won't post all the numbers again, just wasted bandwidth. One of the
> reason why RedRock EV started playing with the BatPack idea
> was to lower those darn switching losses for racing applications.
> The Rds of a 500A module that is switched on will be 1.2 milliOhms.
The Redrock EV guy's logic is questionable, however.
Consider the 120V string example: even without considering the losses of
the subnet switches (that must be included to allow the "current
multiplication" benefits that Redrock EV apparently fails to understand
as one of the fundamental benefits of a PWM controller) we have the
following:
- 7 Power Modules in series (6 @ 18V each, 1 @ 12V): 8.4 milliohms
total, which is 4.62V loss @ 550A! This is 2.8x the loss of the Curtis
PWM controller! This is the *best* case, with all modules on for
maximum pack voltage to the motor, an operating condition that does not
represent the majority of one's driving.
Let's consider the case of 50% throttle (1/2 pack voltage applied to the
motor): 4 Power modules on and 3 off: 4 x 0.0012 x 550 + 3 * 1.35 = 2.64
+ 4.05 = 6.69V, or greater than 10% of the ~60V available from the
battery is lost in the Power Modules. Before you dismiss this high
current, part throttle operation as being unusual, bear in mind that it
is at such lower voltages that high motor currents are typically
required as one accelerates or climbs a grade, etc. Of course, one may
not sustain 500A+ for longish periods, but even at 200A the fact remains
that the efficiency is poor compared to a simple PWM controller even
without considering the losses due to the additional traction
connections and wires and the Subnet Switches required to keep the per
battery current low at part throttle operation.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
MIKE & PAULA WILLMON wrote:
%%From: Mike & Paula Willmon
%% Thats a good point. Balancing those things would be a pain. I do however
have boxes of 2 Amp 15V bricks that my company cuts the connector end off to
use on wireless radios, and throws away the supplies. Will tinker with this a
bit and get back to the list.
Just a side thought: The E-meter cannot be connected to the frame, even
if you have an isolated DC-DC converter. The 12 volt ground on an
E-meter is also the negative point of the traction battery.
If you were to tie that to the car's ground you just created one leg of
a ground fault. Ditto on the RS232 shield and ground on the E-meter; if
you have a laptop to monitor it make sure you either run on batteries
(bad idea) or use an RS232 isolator with optoisolators at the E-meter.
Best bet is to use a little DC-DC converter as close to the E-meter as
possible.
Chris
--- End Message ---
--- Begin Message ---
Chris Brune [mailto:[EMAIL PROTECTED] wrote:
> I suspect that if what Bruce and Sheer have put together
> works it will make all the recent EVILbus protocol discussions mute.
I'm afraid that at $75 a pop, no matter how wonderful this product is,
it doesn't impact the validity of the EVILbus discussions in the
least...
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Neon John [mailto:[EMAIL PROTECTED] wrote:
> This is the one major gripe that I have with the E-meter.
> There should be some threshold
> below which the measured value is assumed to be 0.
Although the E-Meter will happily report currents as low as 0.1A, it
will not accumulate or dissipate Ah for currents of 0.1A or less. 0.2A
*will* accumulate or dissipate Ah.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
In reading the spec sheets, DC rated relays and switches have some different
electronics (for things like arc extinguishing) as well as their contacts
are made differently than their AC counterparts.
I am sure Lee/Victor/NJ/Roger can explain much better...
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of kluge
Sent: January 9, 2006 12:36 PM
To: [email protected]
Subject: Re: Pack voltage switches for peripheral devices?
I'm getting the picture that the DC ratings listed on the devices are
conservative. These relays (which have the distinct advantage to me of
being stuff I already have) have a rating printed on them of 30 amps at 28
VDC, 30A/15A at 300/600 VAC, and 30FLA, 75 LRA at 277 VAC. So I'm guessing
I can probably use just one with its 3 poles in series for my sub-15 amp
switching needs at 156 VDC as a cheap (i.e. free for me) and pretty easy
method of switching my stuff.
There are basically two approaches. Get a switch or relay actually rated at
the desired voltage. Common choices are the Potter & Brumfield/Siemens/Tyco
PR10 or KUEP series relays with magnetic blowout option, or old AC/DC rated
switches (like you'd find in a house built over 50 years ago).
The other approach is to use an AC-rated switch or relay at about 1/4 of its
voltage rating. For example, I have a 3-pole relay for an air conditioner
here (Furnas 42CE35AJ106) which is labelled
120vac 1ph 2hp, 3ph 5hp
240vac 40fla, 240lra, 1ph 5hp, 3ph 10hp
480vac 40fla, 200lra, 3ph 15hp
600vac 30fla, 160lra, 3ph 15hp
These are just the particular values that the manufacturer tested. "ph" is
phase, "fla" is full load amps, and "lra" is inductive-resistive amps (i.e.
the peak current it can switch to start a motor). What all this means is
that each contact is good for up to 40 amps continuous, and that 2 contacts
in series can withstand up to 600vac (because you have two contacts in
series on 3-phase power).
That means each contact is good for about 300vac. So, if you wired all 3 in
series, they could switch 900vac or 900/4=225vdc. That's adequate for your
application.
--- End Message ---
--- Begin Message ---
Danny Miller [mailto:[EMAIL PROTECTED] wrote:
> Just keep in mind that the proper interpretation is "where the skin
> depth is large in relation to conductor diameter".
And keep in mind that it is only of concern when one is concerned with
passing relatively large amounts of AC current. In our EVs the AC
component is significantly less than the DC, so it is sensible to size
the conductors based on their DC behaviour instead of worrying about
skin effect and their suitability with respect to high freqency AC.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
John, I also have few photos of Zombie from 2005 Woodvurn and PIR,
but not burning tires ones. I think to get best photos you'd need
to arrange someone, say, at PIR to take such a photos specifically for this
purpose, someone with stable tripod and good zoom lens on the camera.
BTW, it doesn't have to be digital camera and selection of such
optics for film SLR cameras is still much larger (scanning negatives
yields the same if not better resolution than most (but pro) digital
cameras. Many can shoot photos in bursts at the rate of 0.3s apart.
Thus after just one launch and whole 36 slides roll (10sec) you'd
definitely have something to pick out best few from.
Best dig cameras these days can do it too, but amount of shots in
a single burst is limited (usually <10).
My 2mm.
Victor
John Wayland wrote:
Hello to All,
Concerning the DragTimes.com web page for White Zombie, in late December
I had written:
>If any list members have a good photo of WZ they'd like to see there
instead, send it to me, and I'll pick my favorite of what I receive and
>resend it to the site.
I've just received a very nice email from Brooks again, this time about
his feelings that WZ will indeed, be the February Timeslip car of the
month. He's made a generous offer to make up a nice combination collage
type photo for the car to properly introduce the gasser crowd to fast
electrics. He's going to take a smoking tires type picture of my choice
as the main photo and will add in my photos of the motor bay, battery
pack, and perhaps a few side shots of the car as well. Which brings me
to the point of this email....
Each year I've had White Zombie at the Woodburn drags, there's been at
least 10 different folks with digital cameras snapping pictures of the
car, especially whenever I would do my signature burnouts. And yet, now
about two weeks after asking for photos from those who were there,
there's been nothing but tumble weeds blowing by.....I received exactly
one picture, but it wasn't a real action type photo.
Come on everyone, here's your chance to have your photo up for all to
see for a long, long time at the DragTime.com web page.
So.....I'll ask again. Anyone out there with a clean digital photo of WZ
baking its tires? In particular, the most recent 2005 Woodburn EVent
where Tim lit 'em pretty good on many occasions. The last run, the one
where we did the little arcy-sparky thing was quite the tire ignition
sequence! Surely, someone got that on camera from the front or a
side-view shot???? I'd really prefer photos from this race, as it has
the car be-stickered with my battery sponsor's logo 'Hawker
AeroBatteries' and it would be great for them.
Hopefully, someone who missed my last request will remember they have a
few shots of the car for me :-)
See Ya....John Wayland
--- End Message ---
--- Begin Message ---
Or there's the $10 DPST 30amp 120vAC P&B relays I've used for our spa:
-----------------------------------------------------------------
2 655-T92S7A22-120 2 9.720 19.44
P&B General Purpose
DPST-NO PNL MT 120AC
Mouser carries them.
--- End Message ---
--- Begin Message ---
The first episode, of thirteen, of "This New Car" is now on-line at
http://www.bestrateofclimb.com/TNC
I like it!
The entire schedule of 13 weeks ...
#1: Pros and Cons of Hybrid Vehicles
#2: Pros and Cons of Alternative-Energy Vehicles
#3 Hydrogen-combustion vehicles
#4 Fuel-cell vehicles
#5 Electric & plug-in vehicles
#6 New-technology vehicles
#7 What makes a hybrid a hybrid?
#8 Saving fuel with computers
#9 Detroit: Can the Motor City be hybrid-ized?
#10 "Green" vehicles: What are they and does the average consumer really care?
#11 What can we with the cars we're now driving to become cleaner?
#12 Is government doing enough to back "green" vehicles?
#13 Does everyone need to own a vehicle?
Hear "This New Car," a special 13-week edition of The Business Beat, on
WICN/90.5 FM and at WICN.org in Worcester, MA, the NPR affiliate serving
Central New England. The experts for this lively, informative discussion on
hybrid and alternative-fuel vehicles are Jim Dunn of the NASA Center for
Technology Commercialization in Westboro, MA, Gilles Labelle of the Hybrid
Center of Massachusetts at Westboro Toyota in Westboro, MA, and Craig Van
Batenburg of the Automotive Career Development Center in Worcester, MA. "This
New Car" is hosted by Steven Jones-D'Agostino of Best Rate Of Climb in
Worcester, MA, and sponsored exclusively by Westboro Toyota.
--
Mike Bianchi
--- End Message ---
--- Begin Message ---
Lee Hart [mailto:[EMAIL PROTECTED] wrote:
> Adding inductance to the motor loop may not reduce battery
> ripple current enough to matter, unless the motor ripple is
> huge. A typical forklift motor has about 300uH of inductance.
> Let's say your EV1 applies 48v at 300 Hz and 50% duty cycle
> (1.66 msec on-time). Then peak-peak motor ripple is I=VT/L =
> 48v x 0.0016ms / 0.003h = 266 amps. That's not bad.
>
> But if you used an Advanced DC motor that has more like 100uH
> of inductance, peak-peak ripple would be tripled, to 800 amps.
> That's pretty bad!
Exactly, and that is the situation in a typical on-road EV such as mine
(120V, EV1, ADC 8"). I have observed the current in my prior EV (96V,
EV1, 7.1" Prestolite) and have verified it to be discontinuous (i.e. it
drops all the way back to 0A before the SCR switches back on).
> However, the EV1 doesn't run at 300hz except when just
> getting started from a dead stop. It quickly brings the
> frequency up to 1 KHz or so, bringing the ripple back down
> under 250 amps.
I wish this were the case. My EV1 manual states that the frequency
*peaks* at 300Hz at half throttle and is actually about 50Hz at low and
full throttle. A long, long time ago I posted the following paraphrase:
"frequency varies from ~50Hz at min (~5%) and max (~95%) duty cycle
to ~300Hz at 50% duty cycle. At min. duty cycle ON time is ~0.8ms,
OFF time is ~20ms; at 50% duty cycle ON & OFF time are ~1.7ms; at
max. duty cycle ON time is ~20ms and OFF time is ~0.8ms."
> So, I think you still may be better off
> adding input capacitors instead of output inductors.
My plan is to do both, it just happens that an output inductor is *much*
cheaper than input capacitance, so if I can use it to reduce the stress
on the input cap bank I can afford it seems like a prudent approach.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Victor Tikhonov [mailto:[EMAIL PROTECTED] wrote:
> BTW, it doesn't have
> to be digital camera and selection of such optics for film
> SLR cameras is still much larger (scanning negatives yields
> the same if not better resolution than most (but pro) digital
> cameras.
This is true, even pro digital cameras don't (yet) compete with the
amount of information that analog film can capture. You just can't scan
a 35mm negative/positive with a typical home scanner and expect to get
all the information off of it; have it scanned professionally.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
The way I generally test the capacity of my batteries is by running
them to 50% or so discharge and then test with a volt meter under load (
I use my heater and headlights about 15 Amps). Testing with a voltmeter
under load provides a quick indication of the batteries that are the
weakest. I then follow up with sg measurements at both discharged and
charged levels. The voltage under load method proves to be a good
indicator of a dying battery.
Lynn Adams
See my 100% electric car at http://www.austinev.org/evalbum/379.html
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of W Bryan Andrews
Sent: Monday, January 09, 2006 12:16 PM
To: [email protected]
Subject: Replace 2 batteries?
Folks,
Unfortunately, I let a family member borrow my EV and it was run
down into the "limping mode" for about 5 miles. This isn't the first
time it's been punished like this, but it certainly was the longest.
After charging it back up, I took it out for a test spin and ran it
down so the SOC was about halfway down the 'good' range. I then popped
the battery cases and started reading voltages.
Two adjacent batteries (of the 6v , cheap, capped, lead-acid
variety) are reading 0.1 v lower than everything else in the pack. The
battery pack is about a year and a half hold.
Should I replace these two? What are some rules of thumb for when to
replace sagging batteries?
Thanks!
Bryan
--- End Message ---
--- Begin Message ---
Certainly true, but one should not assume that the current is mostly DC
without taking an actual reading. A DC induction clamp or shunt can
provide this information.
Danny
Roger Stockton wrote:
Danny Miller [mailto:[EMAIL PROTECTED] wrote:
Just keep in mind that the proper interpretation is "where the skin
depth is large in relation to conductor diameter".
And keep in mind that it is only of concern when one is concerned with
passing relatively large amounts of AC current. In our EVs the AC
component is significantly less than the DC, so it is sensible to size
the conductors based on their DC behaviour instead of worrying about
skin effect and their suitability with respect to high freqency AC.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Well the 2005 New Year storm flood damage keeps showing its ugly
head.
My motor is growling and getting louder. This means the bearings
were damaged by the flood waters, and I will need to either repair
or replace the 9" Advanced DC motor.
I don't know of any EV repair business in the SF area. If you do,
please email me directly with how to get a hold of them.
I might be able to haul my EV on a Uhaul flatbed to a EV repair
business up in Washington. I sent an email to them already.
I will need the motor taken out, either repaired or replaced, the
DC to DC replaced, transmission and differencial fluids replaced,
all four wheel bearings repacked, and basically the EV checked over
for any other damage the flood waters may have caused.
I will be bicycling into work as often as I can to minimize my use
of the EV. That will prolong the life of my EV. But at some
point the noise will be too loud, and the bearings will seize.
Please email me directly with any ideas on this.
-Bruce
Bruce {EVangel} Parmenter
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor, RE & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
__________________________________________
Yahoo! DSL Something to write home about.
Just $16.99/mo. or less.
dsl.yahoo.com
--- End Message ---
--- Begin Message ---
In a message dated 1/9/2006 1:20:26 PM Pacific Standard Time,
[EMAIL PROTECTED] writes:
> http://www.bestrateofclimb.com/TNC
I live in the sticks where i can only get dial -up. Is it possible to buy a
cd of all 13 weeks of the pros and cons of alternative vehicles?
Larry Cronk 72 Datsun
Elec tk
--- End Message ---
--- Begin Message ---
From: Roger Stockton
> My EV1 manual states that the frequency *peaks* at 300Hz at
> half throttle and is actually about 50Hz at low and full throttle...
>"frequency varies from ~50Hz at min (~5%) and max (~95%) duty
> cycle to ~300Hz at 50% duty cycle. At min. duty cycle ON time is
> ~0.8ms, OFF time is ~20ms; at 50% duty cycle ON & OFF time
> are ~1.7ms; at max. duty cycle ON time is ~20ms and OFF time
> is ~0.8ms."
Interesting! I've never seen the EV1 manual; I was just guessing at the
frequency from hearing a few EV1's in operation.
If it really is 300 Hz max, no wonder it has such an impact on range. It sounds
like GE "cheaped out" on the SCRs and used plain old 60hz parts instead of the
faster inverter-grade SCRs, and this forced them to keep the frequency so low.
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--- Begin Message ---
From: Myles Twete
>Or there's the $10 DPST 30amp 120vAC P&B relays I've used for our spa:
>-----------------------------------------------------------------
> 2 655-T92S7A22-120 2 9.720 19.44
> P&B General Purpose
> DPST-NO PNL MT 120AC
I used the T92 series in my Balancer, and one is switching the heater in my
132vdc EV. The ratings are:
30a at 277vac
25a at 380vac resistive
20a at 28vdc
1hp at 120vac
3hp at 240vac
TV10 120vac
Basically, this means the two contacts in series are good up to 380vac, or
380vac/4 = 70vdc. This isn't good enough for a 132vdc pack. Indeed, when I
tried it without an RC snubber, sure enough, the relay welded after a few dozen
cycles!
So, I used two relays (4 contacts) in series, which is theoretically good for
140vdc. I also placed a 47ohm/0.25uF RC snubber across each contact. That
hasn't failed in almost 8 years.
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--- Begin Message ---
From: Don Cameron <[EMAIL PROTECTED]>
> In reading the spec sheets, DC rated relays and switches have some different
> electronics (for things like arc extinguishing) as well as their contacts are
> made
> differently than their AC counterparts.
Right. If the manufacturer *knows* it will be used on DC, he tailors the
contacts
for DC. But it's more likely he doesn't know what the customer will use. So,
most
relays and contactors have general-purpose contacts that do reasonably well with
either AC or DC loads.
kluge wrote
> I'm getting the picture that the DC ratings listed on the devices are
> conservative.
Kind of true. Mainly, it's just that 28-30vdc is a very common DC voltage, so
lots
of manufacturers do their DC testing at this voltage. They'll only test at some
other
voltage if some customer is willing to pay for it.
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Roger Stockton wrote:
My feeling is that one must compare
similar functionality to accurately compare costs; if eliminating the
Power Modules leaves one with less controller functionality than a plain
PWM controller then the cost comparison is flawed.
Preface -> I think that I will be needing to change the names I'm using
for the various parts of the system (network). I see it from a network
engineers perspective, but most users will see it from a more
traditional EV perspective. So:
Speed Controller = System Controller (that is it's primary purpose, to
control all the parts of the system)
Power Modules = Battery Controllers (they monitor and potentially
manipulate the output of each battery)
Subnet Switch = Motor Controller (it controls the power the motor
actually sees, plus it will likely be closest)
Subnet = Battery String (common name)
The system without the Battery Controllers would be comparable to a
programmable contactor controller, as you described. The cost would be
~$60 plus whatever you use for switching (contactors, FETS) and remote
sensors. They nice thing is by adding ~$50 a battery, you would be able
to instantly upgrade to finer voltage control with battery fail-over and
basic BMS capabilities.
- most (all?) 12VDC muffin fans are BLDC and require some minimum
voltage (like 9V or so) to start. They will not likely make good test
subjects for your prototype. You might be better off with an automotive
fan motor from a wrecker.
Yeah, bad idea. I have a Prestolite MKH4002 pump motor that is being
mounted to a steel go-kart frame right now that will be used as a test bed.
- looking at the BatPack/RedRock site, this fellow's logic looks a bit
messed up. The Rds(on) does not increase exponentially with voltage
I have asked him about that. He said the site is quite dated, and he
last worked on the project about six years ago. MOSFET and IGBT
technology has probably changed enough so that some of the points he
originally made aren't valid anymore.
- your Subnet Switch only appears to handle switching 2 parallel
strings, so to build a system with anything approaching the
functionality of a PWM controller (or contactor controller) would
require multiple Subnet Switches.
I'm attempting to build the Motor Controller approximately as you
described a modern contactor controller should be. I was planning on
using a set of SPDT 1000A relays to begin with. Later I can try more
then two strings/different FET options.
This means that if built with MOSFETs as the
switches, they *each* ultimately end up containing much the same
complememt of devices (voltage and current ratings) as a plain PWM
controller.
In which case the system would effectively act as a monolithic PWM
controller. The System Controller can query the Motor Controller for the
following values:
* Capabilities
* Current Motor Amperage (absolute)
* Current Motor Voltage (absolute)
* Current Motor Temperature (absolute)
(plus any others that are needed/added)
And can send the following commands:
* Assign String Voltage - to let the switch know what the strings can
produce since with the power modules off it would be unable to sense
that, and with them on it is a variable
* Set Motor Voltage - the switch will approximate if it needs to
(contactor controller style), or it could PWM to get an exact result.
The Battery Controllers will query the bus for their addresses (to
support plug-and-play style functionality), or use user entered
addresses. If the System Controller sees any Battery Controllers, it
will know to run in that mode. You can also omit the "switch" part of
the Battery Controllers and just use the tiny micro board for remote
isolated voltage sensing ($7 each) of each battery. The System
Controller can query the Battery Controllers for the following values:
* Capabilities (can they switch/modulate? what sensors do they have
connected? what is the optimal voltage/current of the battery(s) connected?)
* Current Battery Voltage (as a scaled percentage of optimal or absolute)
* Current Battery Amperage (optional, will be quite a few more parts)
(plus any others that are needed/added)
And can send the following commands:
* Set State (On/Off)
* Set Output Voltage (as a scaled percentage of optimal or absolute)
* Set Current Limit
Now all commands will not be supported by all the various potential
flavors of modules. That is what the capability query will report.
So if you do not what the benefits of per-battery control, you can use
the "contactor style" Motor Controller or the "variable" (PWM perhaps)
one. By using part A and part B- type 2, you have a PWM controller. By
using part A and part B-type 1 you have a contactor controller. By using
part A, part B-type 1, and a bunch of part C, you have a BatPack type
setup. This is what I mean by the LEGO analogy.\
Even if one uses contactors for the switching, these end up
being fairly pricey boxes. Unless one imposes the limitation that there
must always be an even number of strings in the system then each Subnet
Switch
That is actually what I was thinking of to keep costs & program
complexity down. But since the Motor Controller is merely being told
what voltage to deliver to the motor, it will be up to it to decide how
best to do that given it's capabilities.
most are familiar with a simple series string of
batteries, not paralleled strings.
You can use the System Controller with a single string PWM capable Motor
Controller to reduce the HV wiring to it's minimum.
The issue is usually that it is more costly to buy a bunch of smaller
chargers than to buy a single large one.
Wow, after shopping around I haven't been able to find a single
"automatic" 96V charger for less then I can get 8 12V ones for (or the
cheapest: 2 on-board marine environment rated 4-way chargers). Even less
the any "non-automatic" ones I've seen so far (except the proverbial
"bad-boy" style chargers, which I won't subject $1200 of batteries to)
- 7 Power Modules in series (6 @ 18V each, 1 @ 12V): 8.4 milliohms
total, which is 4.62V loss @ 550A! This is 2.8x the loss of the Curtis
PWM controller! This is the *best* case, with all modules on for
maximum pack voltage to the motor, an operating condition that does not
represent the majority of one's driving.
Yes, with parallel-series switching you would be pulling 1100A to the
motor in this case! Now that is one lead foot.
Let's consider the case of 50% throttle (1/2 pack voltage applied to the
motor): 4 Power modules on and 3 off: 4 x 0.0012 x 550 + 3 * 1.35 = 2.64
+ 4.05 = 6.69V, or greater than 10% of the ~60V available from the
battery is lost in the Power Modules.
That is where you would have the two strings in parallel. Yes, an even
number of strings would be what would usually work best. At 100A on the
flat, you will see 50A per battery (power module) which will help keep
the losses down. My thought is to configure the strings to deliver max
efficiency at around the speeds you commonly run. If series config, full
on = 75MPH, the parallel config, full on = ~35MPH. What would be great
would be four strings of two Battery Controller each. That would cover
48V - 144V packs (depending on what voltage each Battery Controller was
setup as: 6, 8, 12, or 18). Or you could run whatever string geometry
needed, just keep them symmetrical (i.e. two 12V, two 48V). You would
have 8 Battery Controllers in the example above, but they would only
need to be 200-300A (even cheaper, about $35 each) for a 800A - 1200A
peak system. You would have the following voltage/amperage steps
available (assuming 300A/12V battery controllers):
1200A - 12V, 24V
600A - 36V, 48V
300A - 60V, 72V, 84V, 96V
Now that would be for a medium vehicle with no battery ever seeing more
then 300A and most driving around town at much less then 100A. In my
little roadster I would use 200A/12V modules:
800A - 12V, *24V
400A - 36V, *48V
200A - 60V, 72V, *84V, *96V
(*) highest efficiency
At $35 bucks a Battery Controller, I'd feel comfortable upgrading later
to one more battery on each string, so:
800A - 12V, 24V, *36V
400A - 48V, 60V, *72V
200A - 84V, 96V, *108V, *120V
(*) highest efficiency
I believe he was talking specifically about very high voltage packs
(using 24-48V per module, with 250-500V strings) that aren't drawing
alot of amps. I'm attempting to scale down from his original racing
intentions.
I see having a very reliable (can drive the car even with some batteries
and components failed) as well as flexible system the main benefits. I
may put together the tests and find the system lacking, but the data and
schematics/prototypes I produce should help someone either way ;)
Before you dismiss this high
current, part throttle operation as being unusual, bear in mind that it
is at such lower voltages that high motor currents are typically
required as one accelerates or climbs a grade, etc.
I'm counting on it being common. The "ramped" amperage limit shown above
seems suited to on-road EV use.
--
Stefan T. Peters
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--- Begin Message ---
Hi,
Mike Brown wrote:
I use spa hose for routing electrical cables... I don't know of any
adapter to run the hose through sheet metal.
Lee Hart wrote:
Now wait a minute... spa hose may be expedient; easy to get, or maybe you
already have a roll of it laying about. But it isn't the right stuff for the
job. It has no electrical insulation and no flamability ratings.
If you're running electrical wires in a pipe, please use pipe (electrical
conduit) that is *meant* to carry wiring. It is specifically designed and
tested for electrical insulation safety and fire resistance. Besides, they
have all the needed adapters, unions, elbows, tees, and bulkhead connectors.
This is getting confusing; maybe the problem is that what was meant by
"spa hose" was not clearly defined?
When I first read this post I assumed that what was being discussed was
using the gray Non-metallic PVC, flexible Liquid-Tight electrical
conduit that is commonly used for carrying wiring to spas, pools, Air
conditioners, and other outdoor equipment. This is what I used to carry
all the high-voltage wiring in my Jeep from the rear to the front (i.e.
http://driveev.com/jeepev/photos/pg6pics/ftbwiring/liquidtightstrapped1.jpg
). As I've also seen other people use this in their EVs, and as it is UL
rated for electrical wiring use, I assume it is reasonable for use in
this application. Is this not the case?
Or was this thread instead discussing the use of some sort of spa tubing
meant to carry liquid being used to carry electrical wiring instead
(which definitely sounds like an inappropriate tool for the job)???
--
-Nick
http://Go.DriveEV.com/
1988 Jeep Cherokee 4x4 EV
---------------------------
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--- Begin Message ---
At 04:09 PM 1/8/06 -0600, you wrote:
I've got a Honda B16 SC4 5-speed manual transmission. I'd like to get an
adapter made for an Advanced DC Motor, I think the 8" motor is the best fit.
Is there any vendor that has done Honda transmission adapters?
Thanks,
Monty McGraw
Spring, TX
We have this pattern.
Shari Prange
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
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