# jumpy, unenjoyable acceleration



## Tesseract (Sep 27, 2008)

socko said:


> ...
> I ... installed a Zilla 1k HV, kept the same ADC 9" motor, curtis PB-6.
> ...
> Any ideas? Is the Evnetics throttle any better? http://www.amprevolt.com/content/big-boy-pants


The Evnetics throttle is not compatible with the Zilla so whether it is better than a PB-6 or not is a moot point.


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## major (Apr 4, 2008)

socko said:


> .........the thing is still jumpy, esp starting out.
> 
> Any ideas?


Hi socko,

Nice conversion. Real neat. A couple of thoughts. Stiffer spring on the throttle? Alter the mechanical throw on the PB6 lever to be less sensitive? Start out in higher gear? Turn down the motor current limit? Use valet mode to start 

major


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## Otmar (Dec 4, 2008)

socko said:


> When first test-driving the upgraded car, acceleration was REALLY jumpy and awful, so I finally replaced the actual pot inside the PB-6 - just $25 or so. This made a huge difference. The thing was completely worn after only 11,000 miles.
> 
> Even with the throttle fix, the thing is still jumpy, esp starting out.
> 
> Any ideas?


Hi Brandon, 
I like your car, looks like fun!

I'm sorry you are not getting smooth starts. I can hear in your video that the current limit is working at the reduced settings as it should at light throttle. 

Have you read my FAQ? 
There is one here that covers rough starts and potential causes. 
http://cafeelectric.com/Sfaq.php

I hope this helps.


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## PStechPaul (May 1, 2012)

Hey, I really enjoyed your video. It was very nicely done, as was the conversion itself. You drove just a couple miles past my house in Cockeysville on your way down 83 from Lancaster to DC. If you're back in my neighborhood, feel free to give me a buzz. I've actually never driven or ridden in an electric car (or hybrid), so I probably need the experience to become a "true believer". 

I sometimes get up into the Amish country around Lancaster. A friend who is very much involved with sustainable products and methods has an Amish welding shop in Airville, and I plan to visit it some day. I will need to do some welding when I finish up my tractor projects, so I may learn to use my own little welder or have stuff fabricated up there. 

I hope you have fixed your acceleration problem. There's probably not much I can do to help, but if this is a common problem there may be some alternatives. It may be worthwhile to look into an LVDT system:
http://www.activesensors.com/motorsport-position-sensors

The principle is actually very simple. You can use a coil and a plunger, and read the inductance change as the plunger is moved within the coil. A solenoid will do the job, with linkage similar to a brake or clutch or even an ordinary ICE throttle using a cable to a carburetor or air horn.

If interested, I can dig into the particulars a bit, and I may even use it to control my tractor. The hand-held knob is hard to use while steering, especially when I'm also holding a videocam! 

Congrats on your vehicle's "graduation", and also kudos for your solar installation. Maybe you would be interested in describing your projects and displaying your 100% 100 mile EV at one of our upcoming meetings this Fall at www.baltimoregreenforum.com. I'm also involved with the Sierra Club and maybe some of our members would be interested in your projects. At least I can put a link on our website http://maryland.sierraclub.org/baltimore.


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## gdirwin (Apr 7, 2009)

The Zilla hall effect option is great - I have incredibly smooth starts with the Z1KHV using HEPA - I can crawl slower than someone walking (bad for commutating, but good control). Feels natural, no moving parts/contactors that wear out, dual wiring for reliability/safety - all good. Manzanita micro site sells them (as well as other places I am sure).

Does your hairball support the HEPA option?


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## EVfun (Mar 14, 2010)

Have you come up with the fix to your jumpy throttle? 

I'm running a Z1k-HV with a 38 cell pack in a 1200 lb. car. Even at half the weight of your car my throttle is butter smooth. I can maintain a slow walking speed (if my right foot doesn't develop an itch.)


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## dillond666 (Dec 27, 2010)

How about a mechanical solution?
On EFI cars using a single large throttle body, very often the throttle cable goes on to a cam shaped / eccentric pulley on the throttle spindle.
The effect of this is to vary the pedal ratio from "not sensitive" to "sensitive" as the pedal is pushed further. This would help to smooth your launches.


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## Ace_bridger (Nov 22, 2011)

I would avoid LVDTs like the plague, way too complex. Using an LVDT is not as simple as described here. You need an AC supply to drive the LVDT and then a demod to convert back from the AC output to DC. Then you have the game of matching the controller throttle input requirements with the LVDT output. Then to convert linear to rotary motion...no, avoid it.

There are much easier methods of getting an alternative throttle output like those mentioned in this thread already.



PStechPaul said:


> It may be worthwhile to look into an LVDT system:
> http://www.activesensors.com/motorsport-position-sensors
> 
> The principle is actually very simple. You can use a coil and a plunger, and read the inductance change as the plunger is moved within the coil. A solenoid will do the job, with linkage similar to a brake or clutch or even an ordinary ICE throttle using a cable to a carburetor or air horn.


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## notailpipe (May 25, 2010)

Hey Socko, nice build! Love your fabrication skills (and video editing). I've wanted to do something like that but haven't yet.

I also have jumpy starts with a similar system, but I know why mine is. Wondering if your reason might be the same.

Without too much backstory, I bought a crappy PB-6 ripoff from China that I just wanted temporarily to get me on the road. In my haste (was also trying to qualify for a tax credit by the end of last year), I mounted my throttle box to wherever the quickest place to hook it up was. That ended up being to a unused threaded hole on my transmission. 

The result is that when I press the pedal, the transmission torques a bit due to the motor, which alters the throttle position a little bit, essentially it's sending an oscillating signal to my controller. I was aware of this when I set it up, but didn't think I'd finish in time if I tried to find a better fix. Now that crappy potbox died on me, I'm forced to find another solution anyway. But is yours possibly mounted in a similar fashion? i.e. to something that moves in response to the throttle?


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