EV Digest 6516
Topics covered in this issue include:
1) Kilovac EV-200 as safety disconnect?
by Ben Apollonio <[EMAIL PROTECTED]>
2) Re: PIC help
by brian baumel <[EMAIL PROTECTED]>
3) Re: Largest Capacity NiMH Cells?
by "Bruce" <[EMAIL PROTECTED]>
4) Xantrex
by "Brian M. Sutin" <[EMAIL PROTECTED]>
5) Yamaha conversion for sale
by "David A. Hamner" <[EMAIL PROTECTED]>
6) LRR Tires
by "Brian M. Sutin" <[EMAIL PROTECTED]>
7) Re: Motor mods
by James Massey <[EMAIL PROTECTED]>
8) Fwd: [Evtech] SCR's last orders
by [EMAIL PROTECTED]
9) Four LiFePo4 cells from batteryspace can work as a lead-acid replacement
by Tony Hwang <[EMAIL PROTECTED]>
10) RE: LRR Tires
by "Phil Marino" <[EMAIL PROTECTED]>
11) Re: Compressed air as battery?
by "Phil Marino" <[EMAIL PROTECTED]>
12) Voltage Sag, Peukerts Effect
by "Scott Littledike" <[EMAIL PROTECTED]>
13) Chevy Metro Weight
by mike golub <[EMAIL PROTECTED]>
14) RE: Chevy Metro Weight
by "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
15) Re: Simple electronics component question
by [EMAIL PROTECTED]
16) Re: Voltage Sag, Peukerts Effect
by Bob Bath <[EMAIL PROTECTED]>
17) Re: Simple electronics component question
by [EMAIL PROTECTED]
18) Re: Compressed air as battery?
by "Peter VanDerWal" <[EMAIL PROTECTED]>
19) Re: Chevy Metro Weight
by "David Roden" <[EMAIL PROTECTED]>
20) Cooling PM motor on 22" mower conversion
by Mark Hastings <[EMAIL PROTECTED]>
21) Re: Voltage Sag, Peukerts Effect
by "Peter VanDerWal" <[EMAIL PROTECTED]>
22) Re: Compressed air as battery?
by "mike young" <[EMAIL PROTECTED]>
23) Re: Voltage Sag, Peukerts Effect
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
How reliable is the Kilovac EV-200 as a safety disconnect breaking a
192V pack of Optima YT's shorted across an ADC 9" (i.e. inductive
load)? I am using an older T-Rex 1000 and I'm concerned about the
consequences of my controller failing ON (as in, still powering the
motor). I will have a pair of contactors in series, and I prefer the
EV-200's for their low cost over the EV-250's and bubbas. I know
better than to reuse the contactors after I've opened them under that
kind of load, so it's not a repeated reliability thing so much as a
one-time thing. But will they even be up to carrying the continuous
current of my EV? I'd hate to deform them such that they didn't open
when I needed.
I plan on having a fuse too, but I'm really concerned about having a
disconnect I can initiate. The Heinemann breakers look good, except
they're only rated at 160VDC.
If you think that no, they won't work, what alternatives can you
suggest?
Thanks!
-Ben
--- End Message ---
--- Begin Message ---
Im using 3 1.5" Blue 7-segment displays and 20
bi-color leds. the 20 LED's are placed along one side
in a nice arc. they move up as the speed increases, 1
LED per 5mph. I was thinking of making the LED's
represent motor rpm or voltage, but I already have the
original guage for that. I'll be able to store/display
trip info; ave sp, max sp, total distance, etc....I'll
post a pic when I get it more complete. yes I could've
gone with a touch sceen LCD, but I like this style
much more. I'll probably have two bolts that come
through the face plate and act as touch switches. very
simple circuit and no expensive touch screens. plus im
trying to do it with 80's technology...all of the
electronics is TTL so far, excluding the controller
Brian
FRED JEANETTE MERTENS <[EMAIL PROTECTED]> wrote:
> brain what are you doing for a speedometer ? are
> you mounting a display of some sort ? I wanted to
> use a touch screen for my gt2 e but have not found
> anything that will work and be powered by dc voltage
> . I wanted to display speed / motor volts / motor
> amps and maybe rpm or pack voltage . are you using
> a pc ?
> ----- Original Message -----
> From: brian baumel<mailto:[EMAIL PROTECTED]>
> To:
> ev@listproc.sjsu.edu<mailto:ev@listproc.sjsu.edu>
> Sent: Monday, March 05, 2007 10:09 AM
> Subject: PIC help
>
>
> greetings everyone,
> I am almost done with building a custom
> speedometer
> for my EV. I am have a small problem with it
> thought,
> one pin to be exact. I am using a PIC16F872 portA
> is
> all inputs, port B and C are directly coupled to
> some
> 7447 display drivers(3 digits, 3 display drivers).
> my
> problem is in portB.3 this pin will just not
> toggle!!!
> I have tried 2 different PIC16F872 and a
> PIC16F876A
> none will toggle PORTB.3.
> I have programmed it so that ports B and C blink,
> but
> that one pin just will not toggle on any
> occassion. am
> I forgetting to disable/enable something, like
> what is
> done to turn off the ADC on portA (ADCON1=7)??
> the data sheet says something about PORTB.3 is a
> I/O
> or a PGM...some type of medium voltage programming
> mode.
> some one please help. right now I'm using a bike
> speedometer and it sucks.
>
> thank you,
>
> Brian B.
> 81' Bradley GTII
>
>
>
>
>
>
____________________________________________________________________________________
> Food fight? Enjoy some healthy debate
> in the Yahoo! Answers Food & Drink Q&A.
>
>
http://answers.yahoo.com/dir/?link=list&sid=396545367<http://answers.yahoo.com/dir/?link=list&sid=396545367>
>
>
____________________________________________________________________________________
8:00? 8:25? 8:40? Find a flick in no time
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--- End Message ---
--- Begin Message ---
Anyone know if these 30AH NiMH cells can be purchased by themselves?
Bruce
Charles Whalen wrote:
Yes, GoldPeak is producing their 30Ah NiMH cell under their Ovonics, now
Cobasys/Chevron license, and my understanding is that GoldPeak is the only
NiMH battery manufacturer to have such a permissive (grandfathered) license
allowing the production of large-format traction cells >10Ah for sale or use
in the North American market.
--- End Message ---
--- Begin Message ---
> Thanks for the info. I wish Xantrex had bothered to include a copy
> of the updated manual when they updated the meter. For some reason
> it is no longer available as a download on their site. I have a bad
> feeling they may be planning on dropping it from production.
Link-10 prescalers, thermal sensors, and the choice model are all now
out of production. They might come back, but don't hold your breath.
Brian
Alfa Romeo Electric Conversion
http://www.skewray.com/alfa
--
Brian M. Sutin, Ph.D. Space System Engineering and Optical Design
Skewray Research/316 W Green St/Claremont CA 91711 USA/(909) 621-3122
--- End Message ---
--- Begin Message ---
Anyone interested in a Yamaha motorcycle EV conversion near Akron (Mr
Roden)? It has a handbuilt sidecar for batteries, an Etek motor and
Curtis controller, three large PbA trolling motor batteries in an
unknown state of health and three 12v Soneil chargers. I ran out of
mechanical skills, my wife's patience, and space in the garage. It
runs. I've had it out on the roads a bit and it's truly a fun ride.
But it's ugly. The sidecar needs a body made by someone with those
skills, because I don't have them! The wiring isn't nicely tucked
away. It needs some cosmetic work, for sure. Besides I negotiated a
deal with Mrs Hamner that if we got a Prius the bike would have to go.
And we got the Prius.
The bike was cheap enough and the labor was volunteer, so the bulk of
the value is in the motor, controller, chargers. I've got about $1100
in it, but I'll sell it for whatever the market will bear. It's titled
under the original VIN, never scrapped - it was a recently working bike
when I picked it up. Insurance will run you under $150 per year.
The original bike is a 1981 Yamaha SR185 Exciter, a pretty little thing
to start with and valuable in its own right. Most of the go parts
beside the engine and exhaust pipe are included - excellent Ebay fodder
since this series is well loved by it's owners.
Interested parties email me directly, please. hamner3 (at) sbcglobal
(dot) net or call 330-741-9193. I can email photos. Buyer must arrange
your own shipping or pickup.
Dave Hamner
--- End Message ---
--- Begin Message ---
> The 2005 Prius was being driven the same route regularly and over a long
> period of time so it was possible to get a pretty steady average. The route
> was mainly 70 MPH highway and the Prius was getting 48 MPG with the tires at
> 40 PSI. Over time, same route, same driver, the mileage began to improve
> reaching 50 MPG at 50,000 miles. As this point the tires were worn to the
> point of needing replacement.
MPG at 70 MPH is so massively dominated by wind resistance over rolling
resistance that the experimental results are pretty meaningless for rolling
resistance. As you concluded, they say a lot about calibrating the tire
diameter. A better experiment would not exceed 40 MPH. Please drive more
slowly next time!
Brian
Alfa Romeo Electric Conversion
http://www.skewray.com/alfa/
--
Brian M. Sutin, Ph.D. Space System Engineering and Optical Design
Skewray Research/316 W Green St/Claremont CA 91711 USA/(909) 621-3122
--- End Message ---
--- Begin Message ---
At 07:21 PM 5/03/07 -0800, Jim wrote:
Hey Jeff, Mini, all
--- James Massey <[EMAIL PROTECTED]> wrote:
> G'day Jeff, Jim and All
>
> At 09:01 AM 5/03/07 -0800, Jeff wrote:
> >Hi Jim,
> > I had inquired of James if these were MKZ type
> > motors. Never got a reply.
>
> Sorry Jeff, missed that message. MKZ-4003S motors.
I seem to have the opposite problem, he writes me but
doesn't wait for my reply 8^o
Well, just because you want to work, sleep and stuff instead of waiting by
the computer. Your ESP isn't sensitive enough - sleeping in until 5AM, I
want to know NOW, before I go stuff it up!
<snip> Why not bring out 4 "A" terminals? Two
> A1's and two A2's.
Rod Wilde did this on his 9" for Gone Postal. He
didn't run them through the face but instead added two
more holes on the two remaining window supports.
It's a nice upgrade actually and one that a higher
percentage of people could do "in house" so to speak.
It isn't that hard, it may be something that a certain motor guy could
supply kits of bits for.
In the end James did it this way because the two
motors will be spinning different directions
requirering different advancements and he didn't want
to have to make two different lead sets. Being the
windows are formed in the housing it'd been tough to
have left the leads in the housing.
Sure was! It was a lot easier going out the sides of the prestolite that I
prepped for my trike project (if I can ever get the engineer to sit still
for me to catch up with!). That motor is a bit bigger than Dons', and left
me enough room to use flexible tails inside the housing, with the brush
ring mounted on a moveable plate adjustable from the outside.
Not only that, but Don (the owner of the motors) is going to be setting his
own timing, so the end plates and brush gear need to be free to move. The
way they'll end up being so that he will be able to take them apart to do
the bearings, do the timing holes etc without worrying about any cables not
going back where they might chafe.
The biggest downside is that there are more electrical
connections outside the motor.
There is space, due to the way these motors are made - there is a mounting
boss for a brake assembly that will be used for a mounting point, giving
about 1-3/4" space for the terminals and cables.
It seems you've done a few Prestolite motors using
that MCP-164 base plate for the holders. Might have
to throw a couple in the next box out after you get
done misering through the last of that Fusa Fab I sent
you.
But as soon as you send them I'll start into my "steel mule" Hitachi motor....!
<snip> You know that's not bad Mini-me. I was just wondering
because I know how fast my hours click past. BTW if
it's not top-hats it's something else you wish you had
that would save 3 hours!
>All in all, nothing particularly difficult or
>requiring exotic skills or materials, <snip>
Hey, hey, hey now, what you try to say here?!?
So easy a cave man could do it??? LMAO
What I did, a cave man with a DC TIG, a lathe and some Fusa-Fab. And a
mallet =:^o and a spray pack of "hide the sins" motor paint. What you do,
pressing armatures without smashing stuff, making those neat re-taping
jobs, cave man needs educating and a few years experience with a few 10s of
thousands of motors.
> but experience would save a lot of trial fitting
>and would make the job look much better.
Alright that's better 8^P
>With Jims' advice and Fusa-Fab supply it has been
>quite achievable - but I'm not sure I would have
>tackled it otherwise!
Regards
Mini Me (..[Technik] James)
Hey James I hope I help as much as heckle! Sorry but
last night I couldn't help but keep picturing you
running over to check that plate after reading my
email.
No, it was next morning! I'd put the motor bits in the oven for 3/4 hour
while I tidied up, pulled them out and left them on the bench to cool down
(10.30pm). Yup, ran over to the workshop early, pushed it all together and
aaaAAAARRRGHHHH!!!!!! took it apart again.
You may have found it before I wrote but it's
funnier the way I saw it! I still can't help
chuckling when thinking about it but! That's because
I've been there, done that, (redone that), LMAO!
It's fun laughing at people that make the same mistake we learned from,
isn't it? (as long as no-one gets hurt)
All kidding aside I see you putting a lot of your time
in helping others on the list and then repeating it as
needed when new people join and re-ask.
I try to. The older I get the more I get the urge to teach what I've learned.
Projects like
this allow me to offer that same help in the area I
know. Sometimes a little moral support and a little
insight is all it takes to get someone started. Kinda
what the EVDL is all about isn't it?
Sure is!
Had fun
Sure am - just that I'm pushed for time some so that makes it less so.
Jim Husted
Hi-Torque Electric
Thanks again, Jim. And glad you enjoy my learning curve.
Regards
[Technik] James
--- End Message ---
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--- Begin Message ---
Did some testing with a potential replacement for lead-acid 12V starter
batteries, using lithium iron phosphate (Li-Fe-Po4) cells from
batteryspace. Charged and discharged a string of 4 18650 LiFe cells as
a lead-acid cell.
It seems like the lithium phosphates can be used as lead-acid cells!
The LiFePo4 cells don't fully charge, and don't fully discharge when
treated as a lead-acid, but at a loss of under 150mAh (on a 1300mAh
cell). It leaves about 90mAh capacity left, and less than 50mAh or so
undercharged. I think the amount of undercharge will vary by which
lead-acid charger you are using. (I'm using a Schulze isl 6-330D
charger, which charges LiFe cells BTW) This will actually increase cell
life by undercharging them, so I think it's ok. To maximize life of a
lead-acid cell, you're only supposed to use 50% of it's capacity
anyways. The PC680 is rated for 17Ah at the 20 hour rate, and I was
able to only get slightly more than 9Ah at a 6.8A discharge rate.
So I'm still probably going to add a shunt type regulator to prevent
overcharging, though. Anyways, these can potentially be used for a motive pack,
wired up in series, since these cells are rated for 10C discharge. I put the
CBA charts up on my blog http://evconvert.blogspot.com/.
- Tony
--- End Message ---
--- Begin Message ---
From: "Brian M. Sutin" <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: EV List <ev@listproc.sjsu.edu>
Subject: LRR Tires
Date: Mon, 5 Mar 2007 22:44:19 -0800
> The 2005 Prius was being driven the same route regularly and over a long
> period of time so it was possible to get a pretty steady average. The
route
> was mainly 70 MPH highway and the Prius was getting 48 MPG with the
tires at
> 40 PSI. Over time, same route, same driver, the mileage began to improve
> reaching 50 MPG at 50,000 miles. As this point the tires were worn to
the
> point of needing replacement.
MPG at 70 MPH is so massively dominated by wind resistance over rolling
resistance that the experimental results are pretty meaningless for rolling
resistance. As you concluded, they say a lot about calibrating the tire
diameter. A better experiment would not exceed 40 MPH. Please drive more
slowly next time!
The air drag is dominant at 70 MPH for the Prius, but I wouldn't call it
massively dominant.
My calculations ( based on frontal area of 2.16 Meters squared, CD = 0.26,
road weight = 3065 #, and tire RR = 0.01) result in the following drags at
70 MPH:
Air drag = 77 #
Tire RR drag = 31 #
So, a change in tire RR could very well show up in his measured MPG.
For instance a change from 0.010 RR to 0.007 RR tires ( a moderate change)
would drop the total drag by 8.5 % . If MPG and drag were proportionally
related, that would result in a change from 48 MPG to 44 MPG. In reality,
the change in MPG would probably be less than that, since some engine
losses are independent of drag.
I agree with you, though, that driving at slower speeds would make tire drag
comparisons more meaningful.
Phil
Brian
Alfa Romeo Electric Conversion
http://www.skewray.com/alfa/
--
Brian M. Sutin, Ph.D. Space System Engineering and Optical Design
Skewray Research/316 W Green St/Claremont CA 91711 USA/(909) 621-3122
_________________________________________________________________
Dont miss your chance to WIN 10 hours of private jet travel from Microsoft®
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--- Begin Message ---
From: GWMobile <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
CC: [EMAIL PROTECTED]
Subject: Re: Compressed air as battery?
Date: Mon, 5 Mar 2007 15:17:52 -0800
Of course gas wouldn't be cheap either if gotten from scuba shops. :-)
Remember air is as cheap or cheaper than gas because it can be 100%
efficiently compressed IF the waste heat arises from compressing it is
recovered and offsets some other heat used such as building heat or water
heating. It is only inefficiently compressed if the waste heat is dumped.
The exact same argument could be made for 100% efficient ICE engines - or
anything else for that matter. If you use all the waste heat, there is no
waste, and the efficiency is 100%!!.
And, the inefficiencies during compression are only half of the story . You
also have to consider the inefficiency during the expansion ( use) of the
compressed air.
PLUS since the air is deleivered via the atmosphere for free to all the
surface of the earth there is no distribution cost to the plant unlike
natural gas or gasoline or even electricity.
This argument sounds suspiciously like the argument for the use of
hydrogen/fuel cell vehicles. ("Hydrogen!! The most abundant element in the
universe!!" )
You could also argue that electric power is free, since the are LOTS of
electrons all over the place - you don't have to import them from an
electron mine in the Mideast.
In all of these cases, having the raw material available is not particulary
relevant.
Phil
If your house had its own air compressor and you recovered all the waste
heat and offset your other electric heating needs like house heat and water
heat with it then your cost of compressed air would be minimal.
One other nice thing about compressed air is its power expansion phase
creates a cooling effect so it can be used an an alternative to otherwise
power hungry air conditioning in a car.
So that raises its over all efficiency as part of a total car system of air
and electric mix..
On Mon, 5 Mar 2007 3:08 pm, Peter VanDerWal wrote:
I have have done the math and I know the air car idea is not very
efficient but what if the compressed air half was cheap
But it's NOT cheap.
-snip-
So we buy essitially rent/exchange buy a scuba tank of air when we
need
range extension. (Last I heard it was $35-$50) to refill at the local
dive shop, we used it to refill our 3000psi paintball tanks.
Let's see. IIRC someone said that a SCUBA tank stores about 350 wh of
power. So, $100 to $150 dollars for 1 kwh. It only costs $0.10 at the
wall outlet.
Yup, DEFINITELY not cheap.
--
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The average US Credit Score is 675. The cost to see yours: $0 by Experian.
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--- Begin Message ---
Hi there,
I am looking at battery options and was wondering if anyone could help. I am
designing a high speed EV and need to pull 600 - 800 amps(800 ideally) for
around 40 seconds. I will be building the EV on a tight student budget.. so
cant afford really expensive batteries - I have been looking at the SVR 14Ah
sealed AGM lead acids.
Firstly, I am not sure what coefficient(k) to use in Peukerts eqn Cp = I^k *
t .If i use 1.1, i can theroetically pull 658 amps for 40 seconds.. but if i
use k = 1.2, i can only pull 383 amps for 40 seconds! Can anyone recommend
what value of k i should be using and what is a realistic figure for the
current i can pull?
Secondly, i was wondering if anyone could advise me on voltage sag. When
pulling these sorts of high currents, what can i expect the peak voltage to
be on a 120V system? half or more? Do you get voltage sag with other types
of batteries i.e. Lithiums and Nimh's? some comparisons would be great!
Kind Regards
Scott Littledike
_________________________________________________________________
MSN Hotmail is evolving check out the new Windows Live Mail
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--- Begin Message ---
Hello
I recently purchased a 1998 Chevy Metro.
GM dropped the "Geo" name in that year.
It seems to be a little heavier. I haven't found the
weight on the car, but some books say 1895 pounds, not
exactly the 1600 pounds, I was hoping for.
I can't get the car to scale, because it doesn't run.
Does anyone know what years of the Geo Metro were the
lightest?
And are there any improvements that are worth the
weight?
Maybe better crash protection?
Thanks a lot!
Michael Golub
Fairbanks, AK
http://community.uaf.edu/~ffmig/home.htm
____________________________________________________________________________________
Have a burning question?
Go to www.Answers.yahoo.com and get answers from real people who know.
--- End Message ---
--- Begin Message ---
My bet the extra weight was the 4 cylinder engine, air conditioning, and
the added components needed for that.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of mike golub
Sent: Tuesday, March 06, 2007 8:41
To: ev@listproc.sjsu.edu
Subject: Chevy Metro Weight
Hello
I recently purchased a 1998 Chevy Metro.
GM dropped the "Geo" name in that year.
It seems to be a little heavier. I haven't found the weight on the car,
but some books say 1895 pounds, not exactly the 1600 pounds, I was
hoping for.
I can't get the car to scale, because it doesn't run.
Does anyone know what years of the Geo Metro were the lightest?
And are there any improvements that are worth the weight?
Maybe better crash protection?
Thanks a lot!
Michael Golub
Fairbanks, AK
http://community.uaf.edu/~ffmig/home.htm
________________________________________________________________________
____________
Have a burning question?
Go to www.Answers.yahoo.com and get answers from real people who know.
--- End Message ---
--- Begin Message ---
Here is the data sheet...
http://www.st.com/stonline/books/pdf/docs/2154.pdf
Ken
-----Original Message-----
From: [EMAIL PROTECTED]
To: ev@listproc.sjsu.edu
Sent: Mon, 5 Mar 2007 9:14 PM
Subject: RE: Simple electronics component question
The -T has a TO-220 package and delivers max 1.5A
the -L has a TO-92 or SO-8 package and delivers max 0.1A
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] On
Behalf Of Dave Cover
Sent: Monday, March 05, 2007 5:42 PM
To: ev@listproc.sjsu.edu
Subject: Simple electronics component question
I read an article about a simple circuit to drive LEDs and am thinking of
using it for some running lights in my car. The circuit specifies LM317L as
a constant current source. Perfect project for my skill level. But I kept
running into LM317T modules. Is there a difference between an LM317L and an
LM317T?
Thanks
Dave Cover
________________________________________________________________________
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--- End Message ---
--- Begin Message ---
For lead acid chemistry, you take each cell down to
1.75 VPC. So on a 144V pack, you can assume that on
average, 126V is fairly safe.
Regarding Peukert's, most batteries' numbers are
listed on the web; my floodies at 1.22 or so.
-Just noting that you are on a "student budget", yet
have chosen AGM batteries, which are 2-3x the cost of
floodies, especially once you lay regulators on to
maximize their life. IMHO, that's a contradiction.
- RE: Nickel and Lithium, I don't think you'll find
many on the list using them yet, as they are usually
run in series @ higher voltages, so lower currents.
Higher currents are destructive to many models of this
chemistry. Many of us are sitting on the sidelines,
waiting until someone else tries it so we can learn
from their experiences.
Best to you,
--- Scott Littledike <[EMAIL PROTECTED]>
wrote:
> Hi there,
>
> I am looking at battery options and was wondering if
> anyone could help. I am
> designing a high speed EV and need to pull 600 - 800
> amps(800 ideally) for
> around 40 seconds. I will be building the EV on a
> tight student budget.. so
> cant afford really expensive batteries - I have been
> looking at the SVR 14Ah
> sealed AGM lead acids.
>
> Firstly, I am not sure what coefficient(k) to use in
> Peukerts eqn Cp = I^k *
> t .If i use 1.1, i can theroetically pull 658 amps
> for 40 seconds.. but if i
> use k = 1.2, i can only pull 383 amps for 40
> seconds! Can anyone recommend
> what value of k i should be using and what is a
> realistic figure for the
> current i can pull?
>
> Secondly, i was wondering if anyone could advise me
> on voltage sag. When
> pulling these sorts of high currents, what can i
> expect the peak voltage to
> be on a 120V system? half or more? Do you get
> voltage sag with other types
> of batteries i.e. Lithiums and Nimh's? some
> comparisons would be great!
>
> Kind Regards
>
> Scott Littledike
>
>
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--- Begin Message ---
Oops! Forgot the LM317-L. Here is the data sheet for the -L...
http://www.st.com/stonline/products/literature/ds/2168/lm317l.pdf
Ken
-----Original Message-----
From: [EMAIL PROTECTED]
To: ev@listproc.sjsu.edu
Sent: Tue, 6 Mar 2007 7:57 AM
Subject: Re: Simple electronics component question
Here is the data sheet...
http://www.st.com/stonline/books/pdf/docs/2154.pdf
Ken
-----Original Message-----
From: [EMAIL PROTECTED]
To: ev@listproc.sjsu.edu
Sent: Mon, 5 Mar 2007 9:14 PM
Subject: RE: Simple electronics component question
The -T has a TO-220 package and delivers max 1.5A
the -L has a TO-92 or SO-8 package and delivers max 0.1A
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Dave Cover
Sent: Monday, March 05, 2007 5:42 PM
To: ev@listproc.sjsu.edu
Subject: Simple electronics component question
I read an article about a simple circuit to drive LEDs and am thinking of
using it for some running lights in my car. The circuit specifies LM317L as
a constant current source. Perfect project for my skill level. But I kept
running into LM317T modules. Is there a difference between an LM317L and an
LM317T?
Thanks
Dave Cover
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--- Begin Message ---
>Of course gas wouldn't be cheap either if gotten from scuba shops. :-)
>
>Remember air is as cheap or cheaper than gas because it can be 100%
-snip-
>PLUS since the air is deleivered via the atmosphere for free to all the
>surface of the earth there is no distribution cost to the plant unlike
>natural gas or gasoline or even electricity.
What a silly arguement. Electrons are just as free as Air. We don't make
electrons, we don't even store them. We store potential ENERGY in
batteries, just like you store potential ENERGY in compressed air.
The AIR isn't the ENERGY any more than the individual electrons are the
energy. The AIR is NOT the fuel, it's mearly a media for storing ENERGY.
It's the ENERGY that you are storing and compressed air is a lousy way to
store ENERGY. Sice it's ENERGY that you are storing you have to look at
how efficiently the system stores and uses ENERGY.
When it comes to ENERGY efficiency, even the worst batteries being used in
EVs are better than the BEST compressed air system being used.
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
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legalistic signature is void.
--- End Message ---
--- Begin Message ---
On 6 Mar 2007 at 5:41, mike golub wrote:
> Does anyone know what years of the Geo Metro were the
> lightest?
The car was apparently lightest when it was known as the Sprint (pre-1989).
I've read somewhere that some models were in the sub-1500lb range (!), but
I've never been able to corroborate that. The early 3-cylinder engine
weighed only 150lb, IIRC, so stripping these for conversion doesn't remove
as much weight as would be the case on other cars.
The early Geo Metros ('90 through '94) were 1600-1700lb. The '95 and later
models were in the 1900lb+ range. The car definitely porked out over the
years.
>
> And are there any improvements that are worth the
> weight?
> Maybe better crash protection?
I'd almost be willing to bet on this. Also, there are probably very few of
the pre-1990 models still on the road.
David Roden - Akron, Ohio, USA
EV List Administrator
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--- Begin Message ---
As at least a short term solution to my 1 acre problem
I found a 22" self propolled mower buried in a pile of
junk.
I cleaned it up and got a new blade.
Put this motor on it (which I got somewhere else)
http://tinyurl.com/gyt5s
HP 1.54 Voltage 24 DC Amps 4.5 no load
RPM 3,200 Duty intermittent
Built as motor for cordless electric lawnmowers
I have two 33 amphour AGMs on it. 48lbs of lead.
I didn't hook up the self propelled and at first
didn't disconnect the gears in the wheels either. I
was much relieved when I realized that and with all 4
wheels actually turning it wasn't that hard to push.
The motor gets really warm though. There are no slots
for cooling nor do I think I'd want any since after
just a fwe minutes the deck was covered with grass. I
have a metal deck but it doesn't seem to be
transferring any of the heat down.
I'm wondering if there is any way to effectively cool
it down?
33amp hours is almost twice the juice the black and
decker cordless have. And I'm thinking of getting two
more batteries to make a quick change pack. I do have
a Etek which I could stick on it. That woudl be
entirely overkill though and I'm trying to find a nice
30"+ walk behind mower for that.
--- End Message ---
--- Begin Message ---
Well, you don't /pick/ the exponent. You determine it empirically by
comparing different discharge rates for the battery and then finding an
exponent that matchs.
For example if you can find the rated capacity (usually at the 20 hr rate,
but AGMs often use 10 hr) and the reserve capacity (how long the battery
will last with either a 25 amp draw or a 75 amp draw), then you can figure
out the peukerts exponent that fits both rates.
Note: Peukert is just an approximation, a rough fit. It does NOT fit all
points on the curve. It gives best estimates for discharge rates near the
measurements originally used in calculating it. I.e if you use low
discharge rates to determine Peukert, then it won't give a very accurate
estimate of the battery's performance at a high discharge rate.
Quite frankly, Peukert is pretty much useless for determining the 40
second discharge capacity. To calculate it with reasonable accurately at
that rate, you'd need measurements at something like 30 second and 1
minute discharge rates. Since you'd have to measure those rates (most
manufacturers don't have posted rates at those levels), you might as well
just measure the 40 second rate.
FWIW you are NEVER going to get 800 amps for 40 seconds out of a 14ah
lead-acid battery.
I'm not even sure you can get that out of an Optima YT and it's a 52AH
battery.
Voltage sag depends on the battery. To get maximum power from a lead-acid
battery it will sag to 1/2 norminal voltage, i.e. 1 VPC. Basically you
get maximum power when the effective external resistance is equal to the
batteries internal resistance.
If you know the batteries internal resistance (manufactures often post
this) then you can estimate the current for maximum power.
For example a Hawker Genisis G16EP (a 16Ah battery) is supposed to have
7.5 milli ohms of resistance when fully charged (it goes up as the battery
discharges).
This is a 12V battery so the max power current will be:
12V / (0.0075 battery + 0.0075 load) = 800 amps
However this is only true when the battery is FULLY charged. As it
discharges the max power level will drop. This battery wouldn't be able
to supply 800 amps for more than 1 second without droping below 1vpc (6V
total)
Some of the drag racers have used the Hawker 16EP battery, though they
typically drain the battery in less than 15 seconds. I don't think you'll
be able to find a much better battery.
Perhaps one of them can tell you how much you can get out of this battery
for 15 seconds. My guess would be somewhere around 300-350 amps.
For 40 seconds maybe 200-250 amps.
You are going to either have to use much bigger batteries, reduce your
expectations, or spend BIG bucks on high power LiIon batteries.
> Hi there,
>
> I am looking at battery options and was wondering if anyone could help. I
> am
> designing a high speed EV and need to pull 600 - 800 amps(800 ideally) for
> around 40 seconds. I will be building the EV on a tight student budget..
> so
> cant afford really expensive batteries - I have been looking at the SVR
> 14Ah
> sealed AGM lead acids.
>
> Firstly, I am not sure what coefficient(k) to use in Peukerts eqn Cp = I^k
> *
> t .If i use 1.1, i can theroetically pull 658 amps for 40 seconds.. but if
> i
> use k = 1.2, i can only pull 383 amps for 40 seconds! Can anyone recommend
> what value of k i should be using and what is a realistic figure for the
> current i can pull?
>
> Secondly, i was wondering if anyone could advise me on voltage sag. When
> pulling these sorts of high currents, what can i expect the peak voltage
> to
> be on a 120V system? half or more? Do you get voltage sag with other types
> of batteries i.e. Lithiums and Nimh's? some comparisons would be great!
>
> Kind Regards
>
> Scott Littledike
>
> _________________________________________________________________
> MSN Hotmail is evolving check out the new Windows Live Mail
> http://ideas.live.com
>
>
--
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 ---
I dont care i just wanna have an air car and an EV in my driveway-maybe i
can get to town and back with it just on a 120 psi charge from my craftsman
compressor and blow my air horn on the way past the gas stations
mike young --solectria cars
----- Original Message -----
From: "Phil Marino" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, March 06, 2007 8:38 AM
Subject: Re: Compressed air as battery?
From: GWMobile <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
CC: [EMAIL PROTECTED]
Subject: Re: Compressed air as battery?
Date: Mon, 5 Mar 2007 15:17:52 -0800
Of course gas wouldn't be cheap either if gotten from scuba shops. :-)
Remember air is as cheap or cheaper than gas because it can be 100%
efficiently compressed IF the waste heat arises from compressing it is
recovered and offsets some other heat used such as building heat or water
heating. It is only inefficiently compressed if the waste heat is dumped.
The exact same argument could be made for 100% efficient ICE engines - or
anything else for that matter. If you use all the waste heat, there is no
waste, and the efficiency is 100%!!.
And, the inefficiencies during compression are only half of the story .
You also have to consider the inefficiency during the expansion ( use) of
the compressed air.
PLUS since the air is deleivered via the atmosphere for free to all the
surface of the earth there is no distribution cost to the plant unlike
natural gas or gasoline or even electricity.
This argument sounds suspiciously like the argument for the use of
hydrogen/fuel cell vehicles. ("Hydrogen!! The most abundant element in
the universe!!" )
You could also argue that electric power is free, since the are LOTS of
electrons all over the place - you don't have to import them from an
electron mine in the Mideast.
In all of these cases, having the raw material available is not
particulary relevant.
Phil
If your house had its own air compressor and you recovered all the waste
heat and offset your other electric heating needs like house heat and
water heat with it then your cost of compressed air would be minimal.
One other nice thing about compressed air is its power expansion phase
creates a cooling effect so it can be used an an alternative to otherwise
power hungry air conditioning in a car.
So that raises its over all efficiency as part of a total car system of
air and electric mix..
On Mon, 5 Mar 2007 3:08 pm, Peter VanDerWal wrote:
I have have done the math and I know the air car idea is not very
efficient but what if the compressed air half was cheap
But it's NOT cheap.
-snip-
So we buy essitially rent/exchange buy a scuba tank of air when we
need
range extension. (Last I heard it was $35-$50) to refill at the local
dive shop, we used it to refill our 3000psi paintball tanks.
Let's see. IIRC someone said that a SCUBA tank stores about 350 wh of
power. So, $100 to $150 dollars for 1 kwh. It only costs $0.10 at the
wall outlet.
Yup, DEFINITELY not cheap.
--
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--- End Message ---
--- Begin Message ---
From: Scott Littledike
> I am designing a high speed EV and need to pull 600-800 amps
> for around 40 seconds. I will be building the EV on a tight
> student budget... SVR 14Ah sealed AGM lead acids.
We need to know more about your mission to make intelligent tradeoffs and
choices.
If the *only* thing you have to do is 800 amps for 40 seconds (for instance, a
drag racer or hybrid vehicle), then plain old automotive starting batteries
will be the cheapest option. But their cycle life is terrible if you don't
immediately recharge after each such use.
If this is for an electric vehicle where you also need to deeply discharge them
to get good range, then some type of lead-acid AGM battery is a better choice.
They are expensive new, but can be found used or surplus as they are widely
used in uninterruptible power supplies.
You could also look for used nicads (they are too expensive new). Some, like
the aircraft nicads, are excellent for delivering very high currents for a
short time. But they may be difficult to find in europe due to the tighter
environmental laws.
> I am not sure what coefficient(k) to use in Peukerts equation...
Peukert's equation just curve-fits a particular battery's capacity versus
discharge rate curve. It works best for discharge rates from C/100 to C/1, and
isn't very accurate or useful outside this range. At lower currents,
self-discharge begins to interfere, and at higher current, internal resistance
interferes.
Since you said you want a "high speed EV", I'm assuming you don't want to use
batteries big enough so that an 800-amp discharge is the 1-hour rate (i.e. 800
amphour batteries)! You'll be using 10-100 amphour batteries, so 800 amps is
far outside the range where Peukert's equation works.
> I was wondering if anyone could advise me on voltage sag. When
> pulling these sorts of high currents, what can I expect the
> peak voltage to be on a 120V system? Half or more?
Voltage sag comes from the battery's internal resistance. You have to look up
the numbers for the ones you're interested in. Or, measure it yourself; data
sheets are notoriously inaccurate and only give "best case" numbers.
As an example, an Optima 12v 55ah AGM has a best-case internal resistance of
about 3 milliohms. Suppose its no-load voltage is 12.5v (about 50% state of
charge). Then at 800 amps, the voltage sags E = IR = 800a x 0.003ohms = 2.4
volts, i.e. to 12.5v - 2.4v = 10.1 volts.
The peak power point occurs when you pull the battery down to half its no-load
voltage; 6v for a 12v battery, which would be around 2000 amps for this Optima.
However, you won't get this for 40 seconds, because the internal connections
are likely to melt first!
Your external wiring will cause more voltage drop. It is often more than the
battery's own internal resistance!
> Do you get voltage sag with other types of batteries i.e. Lithiums
> and Nimh's? some comparisons would be great!
Yes, all batteries have internal resistance, so they all sag. There are no
generalizations you can make between types, because everything depends on their
internal construction. You can build high- or low-resistance batteries with any
technology.
About all you can say in general about internal resistance is that it varies
more in lead-acids; it's affected more by temperature, age, and state of charge.
--
Lee Hart
--- End Message ---
