EV Digest 4318
Topics covered in this issue include:
1) Re: probably need new shocks/springs (struts) on the VoltsRabbit,
also drilling polypro
by Rush <[EMAIL PROTECTED]>
2) Re: probably need new shocks/springs (struts) on the VoltsRabbit,
also drilling polypro
by Seth Allen <[EMAIL PROTECTED]>
3) Re:Pukka e-minibike gets a CVT transmission
by "Tim" <[EMAIL PROTECTED]>
4) Re: Contactor controller, Was:RE: Mechanical PWM Controllers
by Lightning Ryan <[EMAIL PROTECTED]>
5) Re: probably need new shocks/springs (struts) on the
VoltsRabbit, also drilling polypro
by Electro Automotive <[EMAIL PROTECTED]>
6) Re: Very small electric vehicle batteries
by Matt Holthausen <[EMAIL PROTECTED]>
7) An AC style "bypass"?
by Ryan Stotts <[EMAIL PROTECTED]>
8) Ballsy hybrid
by Dave Cover <[EMAIL PROTECTED]>
9) Re: Ballsy hybrid
by Ryan Stotts <[EMAIL PROTECTED]>
10) Re: An AC style "bypass"?
by Rod Hower <[EMAIL PROTECTED]>
11) Re: Ballsy hybrid
by Ryan Stotts <[EMAIL PROTECTED]>
12) Re: An AC style "bypass"?
by Quin Pendragon <[EMAIL PROTECTED]>
13) Re: An AC style "bypass"?
by Rod Hower <[EMAIL PROTECTED]>
14) Re: An AC style "bypass"?
by Ryan Stotts <[EMAIL PROTECTED]>
15) Re: An AC style "bypass"?
by Quin Pendragon <[EMAIL PROTECTED]>
16) Re: More Plasma Boy Racing News
by "STEVE CLUNN" <[EMAIL PROTECTED]>
17) Re: An AC style "bypass"?
by Nick Austin <[EMAIL PROTECTED]>
18) Is this possible?
by Ryan Stotts <[EMAIL PROTECTED]>
19) Re: An AC style "bypass"?
by Nick Viera <[EMAIL PROTECTED]>
20) Re: An AC style "bypass"?
by [EMAIL PROTECTED]
21) Re: An AC style "bypass"?
by Rod Hower <[EMAIL PROTECTED]>
22) Re: An AC style "bypass"?
by [EMAIL PROTECTED]
23) IRS Replacement
by "Bill Dennis" <[EMAIL PROTECTED]>
24) Re: Is this possible?
by Quin Pendragon <[EMAIL PROTECTED]>
25) Fluke 77 Heaven
by "Bill Dennis" <[EMAIL PROTECTED]>
26) Re: An AC style "bypass"?
by Ryan Stotts <[EMAIL PROTECTED]>
27) Re: An AC style 'bypass'?
by "Christopher Robison" <[EMAIL PROTECTED]>
28) Re: Pukka e-minibike gets a CVT transmission
by Larry Skidmore <[EMAIL PROTECTED]>
29) Re: Transfer case as transmission
by Ryan Stotts <[EMAIL PROTECTED]>
30) Re: IRS Replacement
by "Christopher Robison" <[EMAIL PROTECTED]>
31) Re: Fluke 77 Heaven
by "Mark Ward" <[EMAIL PROTECTED]>
32) Re: Is this possible?
by Edward Ang <[EMAIL PROTECTED]>
33) Re: Transfer case as transmission
by "Christopher Robison" <[EMAIL PROTECTED]>
34) Re: Contactor controller, Was:RE: Mechanical PWM Controllers
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Rush Dougherty
Tucson AZ
www.ironandwood.org
----- Original Message -----
From: "Chuck Hursch"
Sent: Wednesday, April 27, 2005 3:19 PM
Subject: probably need new shocks/springs (struts) on the VoltsRabbit, also
drilling polypro
> Also, I'd like to drill some small holes in my rear battery box
> to pass wires through. It's a white semi-rigid material, and I
> believe it is polypropolene, about 1/4" thick. The largest hole
> to go through would be to accept a 6-ga cable. Will an ordinary
> drill bit work on this stuff w/o cracking it (my feeling is yes,
> but I'd like a second opinion)? Mike Brown had drilled two nice
> holes to accept 2/0 cables, so I know it can be done.
Sure, no problem. Polypropylene is very easy stuff to drill, it is also
relatively soft so don't exert much pressure, let the weight of the drill do
the drilling.
Rush
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--- Begin Message ---
For the springs: shine racing services (www.srsvw.com) offers all kinds
of spring rates for stock ride heights for rabbits and golfs. You can
mix and match, I think they were $60 a corner a few years ago. A set of
Bilstein shocks and struts (the HD are nice) are good too. But the best
price for those used to be at RD Enterprises, now www.shox.com
The HD Bilsteins will be a better match for you heavy car with high
spring rates.
HTH
Seth
On Apr 27, 2005, at 6:19 PM, Chuck Hursch wrote:
I will have driveway/helper time reserved in late May for
installing a new battery pack and attending to other projects on
my VoltsRabbit.
The conversion is ten years old now, and I believe I need new
rear springs and shocks (struts). For the last couple of years,
I frequently have heard a thunking sound coming from the area of
the passenger-side rear shock going over bumpy roads. The
suspension also seems to have settled a bit more in that corner.
Several days ago I emailed Mike Brown for info on obtaining
replacements, but have not heard back from him. I'm definitely
going to need part #s if I'm going to do a stock VoltsRabbit
spring/shock replacement. It has also been suggested by others
to try air shocks to help me dial in a flat ride stance, but I'm
starting to gain the impression that air shocks are not going to
be available for this vehicle, since the rears are struts. Any
thoughts out there in EVDL Land?
Also, I'd like to drill some small holes in my rear battery box
to pass wires through. It's a white semi-rigid material, and I
believe it is polypropolene, about 1/4" thick. The largest hole
to go through would be to accept a 6-ga cable. Will an ordinary
drill bit work on this stuff w/o cracking it (my feeling is yes,
but I'd like a second opinion)? Mike Brown had drilled two nice
holes to accept 2/0 cables, so I know it can be done.
Thanks,
Chuck
Chuck Hursch
Larkspur, CA
NBEAA treasurer and webmaster
http://nbeaa.org
http://www.austinev.org/evalbum/339.html
http://www.geocities.com/chursch/bizcard.bmp
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--- Begin Message ---
If this new CVT can handle the electric motor's repeated high startup
torques, as well as the physical torque shocks that will get routed back
when the driven wheel/tire stops abruptly, then we have a serious winner.
I'm keeping my eye on this one.
It looks like this technology is fitting for many different modes of
transportation and beyond.
Tim
----- Original Message -----
From: "John Schuyler" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, April 26, 2005 11:17 AM
Subject: [zappy] Pukka e-minibike gets a CVT transmission
Here's a link relating that the Pukka electric mini-bike will be
getting a breakthrough state of the art Contuously Variable Transmision
(CVT) in the 2005 model:
http://www.fallbrooktech.com/Partners.asp
Other areas of the Fallbrook tech site describe in detail the cool
operation of the new CVT hub. The video shows a close up of the
internal processes. Oh boy, 'heavy weights' can now climb hills
and 'fly weights' can go fast WITH THE SAME SCOOTER!
John Schuyler
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--- Begin Message ---
I would also like to put together a "Low Tech" controller, as the
saying goes "Low Tech Rulz", but alas I've decided to first use
some modern controllers to make sure that my vehicle/motor/battery
choices will work to begin with. Once it's working with some modern
PWM's perhaps I'll go back and work on the contactor controller 4 fun.
Anyway, as far as how they work: ( I don't know, but I have some ideas )
Basically you'll always end up with a finite number of cruse speeds.
For example: Step1-5mph, 2-10mph, 3-20mph, 4-40mph, 5-60mph, 6-80mph.
So, you may not be able to cruse at some arbitrary speed, say 53 mph.
Since there's no Step that delivers this speed, anyway...
- The accellerator might determine the contactor setting directly.
--- So you would have to be light on the throttle as to not skip steps.
--- This would seem to deliver only preset cruse speeds.
--- For 50mph you would Step5 from 40->(50)->55, Step4 55->50->45, etc
--- So, you probably only cruse at whatever Step speeds you've got.
- There could be a "Go Button" aswell as contactor settings.
--- So you choose Step1 and hit the go button, zoom up to 5mph.
--- Then choose Step2, hit go button, zoom up to 10mph, etc till Step5.
--- Now to cruse at 50mph, you just duty cycle Step5 with the go button.
So, it might be really fun to build a "Smart" Contactor controller which
would do all the things you mentioned. Not skip steps, or only skip a
limited number of steps for soft/hard accell/regen. Automatically duty
cycle so the accellerator is a "Target Speed" not a "Raw Step Setting".
Make sure not to exceed some preset current for both Accel and Regen.
Then again, it would probably turn into a total pain in the neck.?!?.
Anyway, good luck, and I'de also like to hear about how these old school
contactor controller vehicles worked, in practical driving situations.
L8r
Ryan
Justin Southam wrote:
Hi All, several weeks ago i asked about methods of reducing contator
arcing. Guess why :-).
I planning a contactor controller with
current limiting,
rev limiting,
and maybe cruise control :-),
and other yet to be discovered features.
2 resistors with temp monitoring and possibly force cooling (cabin heat :-))
and a PIC for housekeeping
Below are some random thoughts i've been contemplating
PIC controls throttle, this and current limit should stop full voltage at
motor while stopped. RPM feedback could stop voltage increase while rpm is
too low.
Current limit and rev limiting have direct control of the main contactor.
Both resistors will be in circuit each time the voltage increases and
bypassed sequentially and automatically after a few seconds. During this
time it should be possible to predict the current after the resistors are
bypassed and manage it. Actually current should be continuously monitored.
resistors will soften the inrush current seen by the diodes. They may need
to be water cooled. (more cabin heating)
I'm planning a 96v system. 24/48/96V.
4 24-12v dc-dc converters
Oil filled main contactor will be only contactor switching under load.
I have drawn a circuit which has 4 batteries, 8 diodes and 3 contactors for
1/4, 1/2 and full voltage. I suspect it is a recollection of Lees rectactor
circuit. The largest diodes i have so far located here are 400A rms @120C.
At full voltage the 2 diodes still in circuit could be bypassed to increase
efficiency and stop current being limited to diode limits.
While you don't get current multiplication like PWM at low motor voltage at
1/4 battery voltage you do have 4 batteries in parallel so 4 times the
current available so the effect is similar.
I'd love to hear how a contactor car is driven. I.E. When travelling at
speed would battery voltage vary between full and off or full and half to
maintain speed. Accelerating through voltage steps and gears. Bob Rice???
Justin
--- End Message ---
--- Begin Message ---
Sorry, Chuck, been buried in email here lately. Maybe something to do with
gas prices, hmm?
As for drilling your battery box, yes, regular drill bits are fine. What
was said earlier about letting the drill weight do the job is good advice.
For the springs: shine racing services (www.srsvw.com) offers all kinds of
spring rates for stock ride heights for rabbits and golfs. You can mix and
match, I think they were $60 a corner a few years ago. A set of Bilstein
shocks and struts (the HD are nice) are good too. But the best price for
those used to be at RD Enterprises, now www.shox.com
These are unlikely to be appropriate. They are probably designed for
lowering or stiffening, not for added load carrying ability. Yes, Chuck,
we can get you more of the rear springs. We have them custom wound. $150
each. These ARE specced out for the extra weight.
The HD Bilsteins will be a better match for you heavy car with high spring
rates.
These are good shocks, may cost more than the KYB gas shocks in the kit,
though.
Mike Brown
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
--- End Message ---
--- Begin Message ---
Message-ID: <[EMAIL PROTECTED]>
Date: Wed, 27 Apr 2005 21:55:08 -0700
From: Lee Hart <[EMAIL PROTECTED]>
MIME-Version: 1.0
To: [email protected]
Subject: Re: Contactor controller, Was:RE: Mechanical PWM Controllers
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Justin Southam wrote:
> I'm planning a contactor controller with current limiting, rev
> limiting, and maybe cruise control :-), and other yet to be
> discovered features. 2 resistors with temp monitoring and possibly
> force cooling (cabin heat :-) and a PIC for housekeeping...
> PIC controls throttle, this and current limit should stop full
> voltage at motor while stopped. RPM feedback could stop voltage
> increase while rpm is too low. Current limit and rev limiting
> have direct control of the main contactor.
For a given motor, the PIC can predict what current it will draw by
knowing its present rpm and the voltage you plan to apply. So
technically, you don't need a current sensor; just an RPM sensor. I'd
include one anyway, just as a backup system in case something goes
wrong. If you're a clever programmer, the PIC can then figure out the
motor's rpm-vs-current relationship for itself.
> Both resistors will be in circuit each time the voltage increases and
> bypassed sequentially and automatically after a few seconds.
The life of a contact is on the order of 100,000 cycles at rated load.
So, you don't want to operate them needlessly or you'll wear them out
sooner. There's no need to use the resistors except for starting, unless
you have a very high-powered vehicle and/or large voltage steps.
> resistors will soften the inrush current seen by the diodes. They
> may need to be water cooled. (more cabin heating)
You shouldn't need the resistors except for a few seconds when starting
from a dead stop. This won't produce enough heat to be worth trying to
put in your cabin.
I suppose you could deliberately run the resistors to produce cabin
heat; however, that would wear out your contactors pretty quickly as
they would have to cycle on/off pretty often.
> I'm planning a 96v system. 24/48/96V.
With 2 resistor steps, this should be fine. Especially if you also have
a transmission.
> Oil filled main contactor will be only contactor switching under
> load.
Why oil-filled?
> I have drawn a circuit which has 4 batteries, 8 diodes and 3
> contactors for 1/4, 1/2 and full voltage. I suspect it is a
> recollection of Lee's rectactor circuit.
...which is in turn a recollection of many others. The rectactor has
been around at least a few decades now.
> The largest diodes I have so far located here are 400A rms @120C.
You can get diodes a lot bigger than this if needed! Look at
International Rectifer's website.
> At full voltage the 2 diodes still in circuit could be bypassed
There shouldn't be any diodes in the circuit at full voltage -- just
contacts and batteries.
> While you don't get current multiplication like PWM at low motor
> voltage at 1/4 battery voltage you do have 4 batteries in parallel
> so 4 times the current available so the effect is similar.
Right. It multiplies current; just not the same way as a PWM controller.
But the consequences are the same (1/4th voltage means 4 times the
current).
> I'd love to hear how a contactor car is driven. I.E. When travelling
> at speed would battery voltage vary between full and off or full
> and half to maintain speed. Accelerating through voltage steps and
> gears.
You've pretty much got it. To drive at a given speed, you need a
particular value of torque. This requires a particular motor current,
which in turn requires a particular motor voltage.
With a contactor controller, you can only set the motor voltage in
discrete steps. If you want something in between, then you have to cycle
back and forth between steps. For instance, if 55 mph requires 55v, and
your contactor controller only provides 24v, 48v, or 96v, then you cycle
back and forth between 48v and 96v steps.
With a PM motor (Lynch, Lemco, Etek, etc.), you'd get rather abrupt
lurches in speed as you switched voltages. This is because a PM motor
fights to run at exactly the speed commanded by the voltage. A 2:1
voltage change can cause a 100:1 current change, and this causes drastic
changes in torque. It would be like driving a normal ICE car where you
could only operate the gas pedal as an on/off switch -- drastic
accelleration followed by drastic engine braking.
But with a series motor, the steps are quite gradual. A 2:1 voltage
change only produces about a 2:1 torque change. This is only enough to
cause mild accelleration and mild decelleration. Thus with a series
motor, you only need to switch the voltage up/down a few times a minute.
--
"The two most common elements in the universe
are hydrogen and stupidity." -- Harlan Ellison
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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