# [EVDL] Curtis controller issues



## EVDL List (Jul 27, 2007)

Hello all
New member here. I want to drive a converted '98 VW Golf with a
Curtis 1231 controller, but it lurches. In the past 25 miles it has
lurched (while stopped or at low speed) violently about 5 times. A
couple seemed to be big bumps in roads that looked smooth to me, but
when one happened while I was stopped at a traffic light, I thought I
had bit hit from behind. Thank goodness I haven't struck anyone in
front of me. Also, the engine has revved way up beyond 5K RPM a
couple of times while I was standing still but in neutral.

Anyone seen this kind of thing with Curtis, or other controller?
I'd love to get it fixed and get rolling, safely.

Thanks-
xformbykr

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## EVDL List (Jul 27, 2007)

> Charles Eldridge wrote:
> 
> > Hello all
> > New member here. I want to drive a converted '98 VW Golf with a
> ...


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## EVDL List (Jul 27, 2007)

Correct, this sounds like either:
- broken potbox (wiper losing contact or crack in track)
- broken cabling (ground failing, wiper goes to +5)
- shorting cabling (potbox wiper to +5)
- failing controller, possibly from moisture?
- external noise leaking in and tricking controller.

The latter can come from different sources, either in your
car (DC/DC converter, cell phone, CB or HAM transceiver, ...)
or outside (passing car with bad ignition shielding, cell or
broadcast tower, radar or other radio equipment, welding, ...)

Most potboxes have a "pedal up" microswitch, which can be used
to disable the controller (open a contactor) so that even if
there is a bad problem, all you need to do to stop is to
release the accelerator pedal.

You can easily measure the resistance of the potbox with the
car powered off. Between the end contacts you should have a
constant resistance, for example 5000 Ohm, irrespective of
pedal position (except when the wiper is wired to one of
the end contacts). The wiper will have a continuous varying
resistance to one of the end contacts, from near zero
(for example 100 Ohms) to near max (for example 4900 Ohms)
If you see jumps or can hear cracking sounds when you attach
a small speaker/headphone with a capacitor across the meter 
while doing this measurement then your potbox is dirty or broken.

"dirty" can be solved with contact cleaner and some mechanical
action (pushing the pedal several times)

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Martin WINLOW
Sent: Saturday, March 31, 2012 3:04 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Curtis controller issues




> Charles Eldridge wrote:
> 
> > Hello all
> > New member here. I want to drive a converted '98 VW Golf with a
> ...


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## EVDL List (Jul 27, 2007)

I had that same symptom after several years of driving my S-10 Blazer
which was converted back in 1992. The components used back in those 
days were what was available, and not the robust/longer lasting ones 
EVs use today.

I concur with Cor as I used a spray can of contact cleaner made for 
use on potentiometers. Today's volume controls hardly use a pot, and 
when they do they are a better design than we way back then. For 
cleaning old pots of my EV's era, today I find a pot/fader/slider 
cleaner for guitars of the same period.

I am not recommending the following link, and it is likely not the 
cleaner I used way back when. It is an example of what to look for
http://www.stewmac.com/shopby/item/5027
The key search words were electrical contact pot cleaner

Once I had a spray cleaner I could trust to use on my baby, I took 
the pot box assembly apart and then gently took the the pot apart (be 
kind, the metal tabs holding it together do not like being bent too 
often, they'll break off).

Once open, I saw the pot was the older, cheaper carbon coated paper 
type, not the longer lasting metal wire wound type. I lightly sprayed 
the surface the pot wiper was using, and the end of a cotton swap. I 
used that swab to clean off the surface. It took quite a few swabs to 
get all the loose carbon dust particles that had come off from the 
surface with use. Remember not to scrub the surface, just lightly 
wipe it down to get the particles that cause your EV to jump and buck.

After letting it dry for at least half an hour, and putting the pot
back together, it worked fine. But know that this effort is not a 
cure, only a temporary fix. You need to plan to replace that EV 
accelerator pot box with today's off the shelf EV technology.

I say that because sho'nuff, in less than a year, I had more problems 
again. Remember that the amount of use on that pot we give it with 
our foot is like turning an old volume control soft to loud and soft 
again thousands of times a year. It is going to wear out (like a 
shiny seat on an old pair of pants
http://farm6.static.flickr.com/5219/5433683279_15bb4075af.jpg
). 
...
http://www.urbandictionary.com/define.php?term=sho-nuff



{brucedp.150m.com}




-
>


> Charles Eldridge wrote:
> >
> > > Hello all
> > > New member here. I want to drive a converted '98 VW Golf with a
> ...


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## EVDL List (Jul 27, 2007)

> On 31 Mar 2012 at 12:07, Bruce EVangel Parmenter wrote:
> 
> > Once I had a spray cleaner I could trust to use on my baby ...
> 
> ...


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## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> > Correct, this sounds like either:
> > - broken potbox (wiper losing contact or crack in track)
> > - broken cabling (ground failing, wiper goes to +5)
> ...


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## EVDL List (Jul 27, 2007)

Cor van de Water wrote
> 
> Most potboxes have a "pedal up" microswitch, which can be used
> to disable the controller (open a contactor) so that even if
> there is a bad problem, all you need to do to stop is to
> release the accelerator pedal.
> 

You should definitely wire in the pedal up switch on the controller, and if
you have two contactors, have one set to pedal up as well, at least until
you get the pot/lurching issue sorted out.

--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Curtis-controller-issues-tp4520939p4523684.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
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## EVDL List (Jul 27, 2007)

Thanks for all of the comments regarding the Curtis controller issues.
They motivated me to inspect the potbox-to-controller linkages and
observe an ohmmeter deflection while I depressed and released the
accelerator pedal about 30 times. The advice to clean and protect the
potbox is noted. During one of the depress-release cycles the
resistance jumped off of its low by maybe 100 ohms, lingered for a
second and then dropped back to its low. I'll try listening to the
potbox as Cor suggested.

BTW, there is no precharge resistor across the main contactor
terminals, as is recommended by many, including the Curtis manual.
But I have not been able to locate any failure stories related to the
omission of this resistor. I understand that the lifespan of
capacitors internal to the controller would be reduced, but what would
happen when they fail? The vehicle is a converted 98 VW Golf; I've
driven it less than 50 miles. Its controller, main contactor and 16
deep discharge 6V lead-acid batteries are used.

I haven't truly eliminated the potbox as a potential problem but I
believe nonetheless that a new controller and probably a new
transducer are needed. (At least one of the comments recommended this
as well.) The compelling reason is that the force-severity of a
couple of the lurches well exceeded anything that I've done with the
accelerator pedal. I don't believe that any throttle inputs (i.e.,
changes on the 0-5k ohm resistance) could produce such severe lurches.
Plus at least one happened when my foot was off of the accelerator
pedal. Thus, I suspect a bad controller.



> Voltswagon <[email protected]> wrote:
> >
> > Cor van de Water wrote
> >>
> ...


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## EVDL List (Jul 27, 2007)

There is a chance that AllTrax in Grants Pass, OR might lend/give you/provide a price break to test their new controller. You should check into it...

Sent from my iPod



> Charles Eldridge <[email protected]> wrote:
> 
> > Thanks for all of the comments regarding the Curtis controller issues.
> > They motivated me to inspect the potbox-to-controller linkages and
> ...


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