# PakTrakr goes nuts from motor EMF



## dimitri (May 16, 2008)

Hey guys,

I got a weird problem with my PakTrakr, it goes bananas when the motor is running, but works perfectly when motor is off. Strangest thing is that it only started happening since I installed my upgraded Soliton1 yesterday. I don't suppose its controller's fault, since its made from solid aluminum and well grounded to the chassis. I checked all wires, made sure there is no high voltage on the chassis ground, I don't know what else to check.

For past 2 months I was running beta controller I had no issues with PakTrakr, but now its useless while the motor is running, it shows garbled data, random digits, pixels, etc. As soon as I shut off the motor, it settles down and shows correct data.

Any ideas?


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## TheSGC (Nov 15, 2007)

It's not the controller entirely, but the noise in the battery cables resulting from the PWM the controller makes to controller the motor. Mine does it too, depending on what controller settings I have running. I also find it goes nuts when I am pulling over 200 battery AMPs, or if I let off the throttle really fast. This is with the Kelly set to SPEED, but if I set it to BALANCED it will not go crazy.

I have been adding EMI chokes to the serial cables on the PakTrakr, and I am hoping it will go away when I get my Synkomotive controller. I am also going to rearrange the Remotes further away from the battery cables, and if I can't, put the Remote wires perpendicular to the battery 2/0 cables.


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## dimitri (May 16, 2008)

TheSGC said:


> I have been adding EMI chokes to the serial cables on the PakTrakr, and I am hoping it will go away.


So, did EMI chokes helped at all or is it still pretty bad? Can you provide a link to where I can get those chokes? I don't have experience with this type of thing...


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## racunniff (Jan 14, 2009)

dimitri said:


> So, did EMI chokes helped at all or is it still pretty bad? Can you provide a link to where I can get those chokes? I don't have experience with this type of thing...


I also have had this problem. I have an AC system (Azure Dynamics) which might be contributing. Working with Ken Hall, I tried:


Adding ferrite beads
Relocating cables to avoid parallel power / data cable runs
Rewiring the order of sensor modules

The only thing that "works" is to avoid the use of the ammeter option. Without that, it runs pretty reliably. But adding the ammeter into my system causes it to go insane.

At some point, I need to hook up a data logger to send the results to Ken, but I have other priorities keeping me busy.


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## BWH (Sep 26, 2008)

There are always snap on Ferrite cores. http://www.bestofferbuy.com/emi-noi...ead-core-ring-for-data-usb-cable-p-14754.html <-- Random Google link, not a company endorsement.

Looping your data cables through one of these a few times should clean things up a quite a bit. I think they sell them at Radio Shack as well.


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## TheSGC (Nov 15, 2007)

dimitri said:


> So, did EMI chokes helped at all or is it still pretty bad? Can you provide a link to where I can get those chokes? I don't have experience with this type of thing...


They helped A LOT! My Paktrakr went from complete garbage (showing weird voltages from 10 volts to 300 volts, fake errors and resetting the gauge) to pretty much usable, except when exceeding 200 AMPs, which I try not to do as much as possible as its pure murder to my floodies.

I am using those Snap on EMI Chokes that BWH made a link to an example of, but I got mine from the Rat Shack. I have one on each of the Remote's serial cable, right up to the Remote and that seems to work well. If one slips down, but PakTrakr goes wacko again, so I ended up taping them down. 

This is what I have: http://www.radioshack.com/product/index.jsp?productId=2996360

I'll try and get some pictures this weekend of how I set mine up.


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## HDS (Aug 11, 2008)

Hi all:
I am a novice here with no EV experience, but are you using shielded cable for your data? If it is shielded and you are still getting the interference, try grounding the shield on one end only. 

In traffic signal controls, it is not uncommon to get interference on the interconnecting data lines that link multiple controllers for the coordination of sequencial intersections. The above technique can often solve the problem.

Good luck, 
HDS


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## dimitri (May 16, 2008)

Unfortunately PakTrakr remotes do not come with shielded cables, although for what they cost they should be better built to resist interference.

I will be implementing your ideas over the weekend, and will post results here. Thanks all for your feedback.


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## BWH (Sep 26, 2008)

TheSGC said:


> I have one on each of the Remote's serial cable, right up to the Remote and that seems to work well. If one slips down, but PakTrakr goes wacko again, so I ended up taping them down.




You should loop the wire through the core as many times as will fit and still reach the plug. This will both further reduce the interference (to a point) and keep the cores from moving around.


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## tj4fa (May 25, 2008)

I don't know if this is related, but someone recently told me that a rememdy for some jerkiness in a Curtis Controller was to take the short 2/0 cable from S1 to S2 of the motor and replace it with a 10' coil.

He said something about wrapping it around a peice of PVC pipe and reconnecting the ends to S1-S2.

I guess if the controller is too close to this cable on the motor it may pick up some eddy currents/line hysterisis from the wire and interfere with something inside the controller.

I have a little jerkiness about 35 mph that may possibly be from this condition and maybe instead of replacing the short S1-S2 cable and installing this large coil, installing a couple of those chokes you guys linked on the existing S1-S2 motor cable might help or be an easier remedy to try.

A fun thing to hear how much frequency noise your electronics (controller) is generating is to turn on your AM radio and tune in until you find the station where you can hear your frequency changing based on your throttle inputs while driving.


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## dimitri (May 16, 2008)

I bought all 8 chokes that were in my local Rat Shack, put them on PakTrakr wires as suggested, also looped all the slacks and moved them away from battery cables where possible. Nothing helped, absolutely no results 

I'm starting to think that controller PWM frequency creates some resonance in PakTrakr wires, which may be communicating its serial data on similar frequency. I don't know, its just a guess. EVNetics team is going to offer PWM frequency selection in future software releases, maybe that will help.


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## AmpEater (Mar 10, 2008)

Doesnt the solitron1 have an adjustable switching frequency? You could try adjusting that to see if there is any difference.


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## dimitri (May 16, 2008)

This feature is not available yet, it will be in future software updates. I can't wait to test it and see how it affects PakTrakr.


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## BWH (Sep 26, 2008)

That's not good. Sorry that didn't work out for you.

Do you have them right up against the remote like SGC does?


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## tj4fa (May 25, 2008)

dimitri said:


> I bought all 8 chokes that were in my local Rat Shack, put them on PakTrakr wires as suggested, also looped all the slacks and moved them away from battery cables where possible. Nothing helped, absolutely no results
> 
> I'm starting to think that controller PWM frequency creates some resonance in PakTrakr wires, which may be communicating its serial data on similar frequency. I don't know, its just a guess. EVNetics team is going to offer PWM frequency selection in future software releases, maybe that will help.


Since it's the motor that is causing the EMF, can you try putting the noise suppression on the motor wires (particularly the S1-S2)?.

The closer the motor (wires) are to the Pak-Trakr/controller, it would seem that the EMF the motor produces would be stronger and induce the noise on those devices/wires. Just a thought...try to work your issue at the source of the problem...the motor.


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## HDS (Aug 11, 2008)

Dimitri:
I forgot to mention, if it is at all possible, in addition to shielded cable get twisted pair cable.

HDS


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## dimitri (May 16, 2008)

For past few days I have been scrambling to reduce EMI noise in my EV which has dramatic impact on PakTrakr. I determined that noise comes mostly from battery cables which act as antennas, since they pass pulses of high current based on PWM nature of the system, they emit EMI on the same frequency as the controller PWM. 

Best way to reduce this noise is to twist the cables, but its easier said than done since 2 cables run in separate plastic conduits under the car from the trunk to the engine compartment. 

However, I had some slack of cable where it connects to the controller, so I twisted those 2 as much as I could, see the picture.

This little trick had unexpectedly positive effect on PakTrakr  , its now working almost 100% solid while motor is running. It still glitches occasionally when current rises rapidly ( flooring the pedal ) , but its significantly better than before, very dramatic difference.

Needless to say I am pretty happy 

Since I installed ferrite beads on PakTrakr cables, I'm also thinking of putting large ones on battery cables. I found some ferrite rings on Ebay with 1.5 inch ID, which should slip over the 2/0 terminal onto the battery cable. Do you guys think its worth trying? Its about $20 for 4 rings shipped.


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## tj4fa (May 25, 2008)

dimitri said:


> Since I installed ferrite beads on PakTrakr cables, I'm also thinking of putting large ones on battery cables. I found some ferrite rings on Ebay with 1.5 inch ID, which should slip over the 2/0 terminal onto the battery cable. Do you guys think its worth trying? Its about $20 for 4 rings shipped.


Yes.

The first few sentences from this study:

http://www.x2y.com/publications/dcmotors/aug8-04tp.pdf

*"Abstract​​​—Traditionally, DC motors have only been filtered for
narrow frequency bands of interest, such as the AM and FM
bands. However, as more electronic devices are implemented in
consumer applications such as automobiles, requirements now
demand filtering from kilohertz to several gigahertz. Capacitors,
inductors, and ferrites characteristically are used to filter narrow​
frequency bands."
*


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## jaspersk (Jun 26, 2008)

HDS said:


> Dimitri:
> I forgot to mention, if it is at all possible, in addition to shielded cable get twisted pair cable.
> 
> HDS


Theoretically, that is right on. Unfortunately, I had the exact same problem and thought the same thing. I worked extensively to solve the exact same noise problems. What I learned is that the source of the noise, at least for me, was the fact that the communication to the meter is powered directly from the batteries via the remote. The noise is induced in the communication line but it gets there because the meter is powered by the batteries. The noise is in the batteries and goes into the communication directly through the remote so shielding had absolutely no positive impact for me.

Unfortunately, powering the meter from a separate source doesn't work either. I actually cut the meters wires so I could power them from a 9V. This did not help the problem.

Further investigation revealed that the remotes talked to each other OK so why can a remote read a remote but the meter cannot read the remote without seeing these problems during motoring? After taking the remote and the meter apart, I realized that there were opto-couplers between the remotes, however there is no opto-coupler in the meter itself so it has difficulty reading the signal. Theoretically, that should be OK since both the meter and the last remote are fed from the same power source (a noisy battery) but in practice the noise shows up differently in both places, I assume due to inductances and capacitance between the two.

I did all this troubleshooting while in close communication with Ken Hall. My next step was to install an opto-coupler in the communication between the last remote and the meter. That was a little beyond what I could do with my very limited knowledge of electronics. Coincidentally, at that point Ken felt that I had done enough work to warrant a return and refund. I took him up on the offer and used the money to buy a PLC so I could build my own BMS system. 

If any of this is helpful, I know I posted my saga and learnings somewhere while I was going through it. I don't remember if it was this board or evdl but if you search here for paktrakr jaspersk or evdl for steveskarda, you can read more details.

Overall, I still highly recommend the Paktrakr to folks. I don't know what puts some of us over the edge where we see these noise problems but others don't. I have some of my power cabling in metal conduit so I have wondered if that created some capacitance in the power system that others don't have. Ken's support was outstanding. He even gave me money for a remote I destroyed during troubleshooting. After trying to design my own system to get instantaneous voltage readings to a central controller, I realized it is pretty impressive that he has a product that can do that at the cost he charges. To date, my bms can only read one battery at a time. More than that would cost me +$500.

Hopefully, the optocoupler really is the answer and we'll see that show up in the meter in the future.


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## tj4fa (May 25, 2008)

dimitri said:


> For past few days I have been scrambling to reduce EMI noise in my EV which has dramatic impact on PakTrakr. I determined that noise comes mostly from battery cables which act as antennas, since they pass pulses of high current based on PWM nature of the system, they emit EMI on the same frequency as the controller PWM.
> 
> Best way to reduce this noise is to twist the cables, but its easier said than done since 2 cables run in separate plastic conduits under the car from the trunk to the engine compartment.
> 
> ...


Hmmm...gets better when twisting cables, glitches occasionally when currents rise rapidly...

Maybe your battery cables should be in the same conduit, and your controller looks to be right next to your batteries. Check out this article concerning inductance in the batteries and battery cables and the capacitor in the controller. Also notice the mention about placing an ammeter in the battery wiring:

http://www.4qdtec.com/pwm-01.html#cap

Just a thought...since the batteries and the battery cables have a lot of inductance from the controller/motor, maybe you should try to move the red 2/0 cable off the top of your battery pack and the PakTraker wires? Maybe slide it into the channel where your vacuum pump hoses are?


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## Tesseract (Sep 27, 2008)

dimitri said:


> ...
> Best way to reduce this noise is to twist the cables
> ...
> Needless to say I am pretty happy


Your welcome... now, how about a report on the relative effectiveness of the tech support you received from each party... 




dimitri said:


> Since I installed ferrite beads on PakTrakr cables, I'm also thinking of putting large ones on battery cables. I found some ferrite rings on Ebay with 1.5 inch ID, which should slip over the 2/0 terminal onto the battery cable.


Oops... you need to run BOTH battery cables through the core so that it only sees the common mode currents, not the normal mode. All transformers are rated to support a certain number of AT (amp-turns), also referred to as LI^2 (same thing, different units). When you pass a single battery cable, rather than both, through the core it is subjected to the full current and one that is 1.5" ID will assuredly saturate. When the core saturates the inductance collapses, creating a spike (good thing there is plenty of voltage margin in the Soliton1...  ) and then the core rapidly overheats. Like to its Curie temperature, which is usually well above 100C (~170-250C is common).

If you're lucky, the core material you picked is so inappropriate for the expected frequency range of the noise that it won't add any inductance to the battery loop nor overheat from the high field strength.

Twisting the battery cables is really the best way to reduce EMI in an EV (i.e. - electromagnetic shielding through field cancellation). Next best is to electrostatically shield the motor cables because the nature of the noise radiated from the motor is completely different from that of the battery cables (and usually much better tolerated by other electronic devices, oddly enough). Oh, all of this assumes that the controller is totally enclosed by metal, and therefore shielded, too... (sadly, that is not often the case (with one notable exception... ahem)).


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## dimitri (May 16, 2008)

tj4fa said:


> Just a thought...since the batteries and the battery cables have a lot of inductance from the controller/motor, maybe you should try to move the red 2/0 cable off the top of your battery pack and the PakTraker wires? Maybe slide it into the channel where your vacuum pump hoses are?


Thanks for your links and suggestions, very good info. My next step after playing with ferrite rings will be to replace short red cable that goes over the battery with a longer cable which will be twisted around the other cable coming from the rear, this way entire battery cable path in engine compartment will be twisted. If twisting just one foot run had such profound effect, then twisting 3 more feet should make things even better.

Jaspersk, thanks for such detailed write up, this was very interesting. I'm glad I didn't start replacing data cables with shielded ones, that would have been so much work for nothing. Did you ever look at PakTrakr serial comm signal with a scope? What frequency does it run at? I could theoretically insert an optocouple between display unit and first remote, but I seem to be very close to perfect PakTrakr by simply twisting and rearranging battery cables.


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## tj4fa (May 25, 2008)

You're welcome Dimiti. I learn a lot from going out on the web and researching people's problems and from really knowledgeable people's comments like Tesseract and others here. Hopefully, I didn't steer you wrong about the eBay ferrite cores on the 2/0 motor wiring. It sounds like it might be a bad thing to do on a single conductor.

I know from running regular AC electrical wiring, by code the hot and the neutrals have to be run in the same conduit to avoid overheating the wires. Running these together appears to be the "cancellation" effect Tesseract was referring to.

Also by code, higher and lower voltage (ex 120VAC vs 12VAC) needs to be seperated or partitioned so that the 12V doesn't pick up a more voltage by induction from the higher voltage line.

It seemed like at the time I was running my 2/0 cables from my rear battery pack to the front, someone said to run them in the same conduit probably to accomodate this cancellation effect.


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## Tesseract (Sep 27, 2008)

tj4fa said:


> I know from running regular AC electrical wiring, by code the hot and the neutrals have to be run in the same conduit to avoid overheating the wires. Running these together appears to be the "cancellation" effect Tesseract was referring to.


Exactly right!




tj4fa said:


> Also by code, higher and lower voltage (ex 120VAC vs 12VAC) needs to be seperated or partitioned so that the 12V doesn't pick up a more voltage by induction from the higher voltage line.


I'm not sure about that one... Differences in voltage will result in capacitive coupling between the two wires, which over long distances can result in substantial "hum" or noise pickup, but the NEC doesn't care whether your circuit is noisy or not... 

I think the real reason you have to keep low voltage and high voltage wiring separate has more to do with NFPA/Life Safety requirements... Class 2 wiring is, by definition, "low" power, and if it were run close to mains wiring, and there was a fault in the mains wiring that caused the insulation to melt, it would then subject the equipment connected to the Class 2 wiring to hazardous voltages/power levels.




tj4fa said:


> It seemed like at the time I was running my 2/0 cables from my rear battery pack to the front, someone said to run them in the same conduit probably to accomodate this cancellation effect.



Also correct and excellent advice, if I do say so myself 

I know Dimitri BELIEVES it now


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## tj4fa (May 25, 2008)

Tesseract said:


> ...
> I'm not sure about that one... Differences in voltage will result in capacitive coupling between the two wires, which over long distances can result in substantial "hum" or noise pickup, but the NEC doesn't care whether your circuit is noisy or not...
> 
> I think the real reason you have to keep low voltage and high voltage wiring separate has more to do with NFPA/Life Safety requirements... Class 2 wiring is, by definition, "low" power, and if it were run close to mains wiring, and there was a fault in the mains wiring that caused the insulation to melt, it would then subject the equipment connected to the Class 2 wiring to hazardous voltages/power levels...


Oh yeah...that's what I meant to say.  

Below is another thread I found about the Paktrakr problem. A lot of "I tried this and that" (and they didn't work) in the posts.

http://www.evdl.org/archive/index.html#nabble-td23225577

Interesting point made by someone that by disconnecting his current loop and the problem went away.

Is there an ammeter shunt and gauge somewhere in this system that could be radiating a lot of EMF?

In one of the links I posted earlier, there was mentioneded an ammeter gauge could be a potential source.


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## HDS (Aug 11, 2008)

"I think the real reason you have to keep low voltage and high voltage wiring separate has more to do with NFPA/Life Safety requirements... Class 2 wiring is, by definition, "low" power, and if it were run close to mains wiring, and there was a fault in the mains wiring that caused the insulation to melt, it would then subject the equipment connected to the Class 2 wiring to hazardous voltages/power levels." (I haven't figured out how to do quotes correctly )

Hi Tesseract:
You are correct in the above statement. I haven't yet started an EV project but I am the local wiring inspector. Article 725.54 requires the separation of Class 2 & 3 wiring with line voltage wiring. If this separation is not maintained, you can get some of the same types of interference with electronic thermostats, as dimitri and others are gettting with the PakTrakR.
Good stuff to know ahead of time, like bundling or twisting the battery leads, so that when I finally start a project, I can plan for this.

I have said it before, I learn something every time I read these posts.

Best of luck to all,
HDS


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## dimitri (May 16, 2008)

Well folks, after reading the EVDL thread linked above ( thanks tj4fa for finding it and jaspersk for writing it ) I decided to scope the PakTrakr wires and see for myself. Indeed the power bus entering the display unit ( red and black wires ) had 9.5V power and was riddled with 2V spikes at the controller's PWM frequency of 8kHz. Data line ( green wire ) carries serial data with clock frequency 10kHz and amplitude of 4V and also had some spikes, but less than 1V amplitude. The scope reading was taken with motor idling at 500 RPM and battery current about 20amp.

To filter out the noise and smooth out the signal I put 4700 µF capacitor across red and black wires and 0.1 µF capacitor across green and black wires. This was done at the display unit's end of the data cable.

Results are incredible, PakTrakr is absolutely 100% rock solid now, woohoo! I drove around few miles going from zero to full throttle, making battery current jump from 0 to 450 amps back and forth, not a single glitch on the PakTrakr 

So, bottom line, twisting battery cables and generally locating them close to each other, putting few ferrite chokes in strategic places and adding capacitors at the display unit makes a huge difference. I hope this helps others as well.

Thanks everyone for the info and suggestions, this has been a great learning experience for me!!!


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## Dave Koller (Nov 15, 2008)

Thanks to all for this thread - as I am going to add a lot of "extra" electronics the advice has been right down home!

I always bypass way too much on my circuit boards - and I can see it will pay off in this RF environment... One question from me Dimitri - have you noticed any loss of noise on the radio (AM)... or were you too into just getting the PakTrakr going?

Dave


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## tj4fa (May 25, 2008)

Cool - Way to Go!! 

Now if only someone knew this Ken Hall guy who I assume builds these things (ahem...Jaspersk?) and point him to this thread to let him know what was done to fix the problem, then maybe this is something he can incorporate into future Paktrakr's design and construction.

He might also want to consider mentioning in the installation instructions some of the other wiring techniques to minimize EMF (twisting cables, installing EMI filters; ect.).

Note: While searching to see who the Paktrakr inventor is, I ran into this Paktrakr noise thread and found someone else found a fix to the problem for the current sensor thing. I wish I had found this one sooner but still might help someone who stumbles into this thread.

http://visforvoltage.org/forum/2987-paktrakr-data-noise


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## dimitri (May 16, 2008)

tj4fa said:


> Now if only someone knew this Ken Hall guy who I assume builds these things (ahem...Jaspersk?) and point him to this thread to let him know what was done to fix the problem, then maybe this is something he can incorporate into future Paktrakr's design and construction.


Actually I am communicating with Ken Hall via Emails and I sent him the link to this thread. I will report my results to him as well.

Dave, I never actually listen to AM radio. For past couple years I don't even listen to FM radio, only XM satellite and my MP3s. My car tuner doesn't even have antenna connected, I only use it as a reciever for XM and MP3s.

I don't think you can do much for AM in close proximity with large DC motor. Can you imagine the noise produced by constant sparking of the commutator? Maybe AC drive would be better, but I am no expert in this kind of thing.


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## Dave Koller (Nov 15, 2008)

dimitri said:


> Dave, I never actually listen to AM radio. For past couple years I don't even listen to FM radio, only XM satellite and my MP3s. My car tuner doesn't even have antenna connected, I only use it as a reciever for XM and MP3s.
> 
> I don't think you can do much for AM in close proximity with large DC motor. Can you imagine the noise produced by constant sparking of the commutator? Maybe AC drive would be better, but I am no expert in this kind of thing.


LOL you are right ! But I use a small AM radio to "sniff out" noise in other situations - assumed AM will be a good test of any noise suppression.. relative to just the "Before and after" - instead of using the scope. Got ta love those spark transmitters! ( I do remember tubes as an old "Ham" person here and made some "spark" transmitters as a kid!) 

Dave


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## jaspersk (Jun 26, 2008)

dimitri said:


> To filter out the noise and smooth out the signal I put 4700 µF capacitor across red and black wires and 0.1 µF capacitor across green and black wires. This was done at the display unit's end of the data cable.
> 
> Results are incredible, PakTrakr is absolutely 100% rock solid now, woohoo! I drove around few miles going from zero to full throttle, making battery current jump from 0 to 450 amps back and forth, not a single glitch on the PakTrakr
> 
> ...


Very cool! I am impressed and a bit jealous. I tried messing around with capacitors on the line between the remote and the meter but I must not have had the right combination or maybe I put them on the wrong line. Great work!! I tried the ferrite cores as well but they never seemed to help me. It sounds like you really have to attack the problem from all angles to nail it.

Someone asked if I ever scoped mine. Wish I had a scope!!! The answer is no. I am really happy to see Dimitri get some great data and solid results.

Ken is obviously a smart guy to build the product he has. It seems like a couple of small adjustments might provide some real gain. I wonder if he just built so many of them that his inventory is too large to make improvements?


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## tj4fa (May 25, 2008)

jaspersk said:


> I wonder if he just built so many of them that his inventory is too large to make improvements?





dimitri said:


> ...To filter out the noise and smooth out the signal I put 4700 µF capacitor across red and black wires and 0.1 µF capacitor across green and black wires. This was done at the display unit's end of the data cable...


Maybe Ken could make an inline plug-in modular box?


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## Nsharit (Mar 17, 2009)

tj4fa said:


> Maybe Ken could make an inline plug-in modular box?
> 
> Wouldn't the entire system be safe from EMF if shielded wires were used? I kinda figured that would be standard for any discrete indication wiring.


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## tj4fa (May 25, 2008)

Nsharit said:


> tj4fa said:
> 
> 
> > Maybe Ken could make an inline plug-in modular box?
> ...


Possibly, but all EV builds components, wiring, ect are not the same and the "dirty" environments have different frequencies and different types of EMI (magnetic/electric). Apparently, some EV builds have no problems at all, while a few others have. 

That's why I think a plug-in module that can be easily connected between the existing wiring may be the easier way to go if there has been a lot of the units already fabricated. 

It seems like the best cure right now is something filtering the EMI in the final wiring close to the indicator itself whether it be the method Dimitri found earlier in this thread or someone else found in this thread:

http://visforvoltage.org/forum/2987-paktrakr-data-noise

Perhaps shielded twisted pairs installed in the final wire segment inside the passenger compartment from the Paktrakr display unit to the next Paktrakr junction box being may do the trick. 

[PJ-box] = Plug-in Passenger compartment J-box

Meter------[ PJ-box ]------shielded pr------[ PJ-box ]--------[ Last battery J-box ]

Unfortunately, I don't have the system to give this a try.

Here is a good article about EMI and filtering that might be of value.

http://www.woodward.com/PDF/IC/50532.PDF


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## jaspersk (Jun 26, 2008)

Nsharit said:


> tj4fa said:
> 
> 
> > Maybe Ken could make an inline plug-in modular box?
> ...


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## jaspersk (Jun 26, 2008)

tj4fa said:


> Maybe Ken could make an inline plug-in modular box?


I agree. It is probably would hurt is marketing to have that option listed.

I think the capacitors are a reasonable fix. Personally, if Ken is reading I'd be much more in favor of an optocoupler and power to the final meter coming from the 12V SLI power. And some filtering on top of that.


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## ElectriCar (Jun 15, 2008)

I'm going to try the capacitors trick. Makes sense the noise could be inductively picked up AND directly from the battery source as well.


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## ElectriCar (Jun 15, 2008)

Well I installed the 4700 cap months ago between the red and black leads and after a week or so the display went out. Found the fuse blown on the 1st remote from the battery. I replaced the fuse but still no blinking light, no display. Now I've ordered another remote module after talking to Ken @ PakTrakr, $90 delivered.

I was thinking about it and maybe I should have installed a resistor in line with the cap to limit inrush current and allow the resistor to burn off the spike. I don't know the frequency of the noise but I've listened to it on my AM radio. It varies with the load and throttle so it may be difficult to design a filter to cover it, especially without interfering with the data coming through. 

Meantime I put a clip on ferrite core around the sensor cable and looped it through twice but won't know until the new remote is installed. Hoping it arrives today. Fingers crossed...


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## dimitri (May 16, 2008)

ElectriCar said:


> Well I installed the 4700 cap months ago between the red and black leads and after a week or so the display went out. Found the fuse blown on the 1st remote from the battery. I replaced the fuse but still no blinking light, no display. Now I've ordered another remote module after talking to Ken @ PakTrakr, $90 delivered.
> 
> I was thinking about it and maybe I should have installed a resistor in line with the cap to limit inrush current and allow the resistor to burn off the spike. I don't know the frequency of the noise but I've listened to it on my AM radio. It varies with the load and throttle so it may be difficult to design a filter to cover it, especially without interfering with the data coming through.
> 
> Meantime I put a clip on ferrite core around the sensor cable and looped it through twice but won't know until the new remote is installed. Hoping it arrives today. Fingers crossed...


Yes, the fuse is blown because of inrush, happened to me too.
After months of painful attempts to make it work, I gave up and threw Paktrakr in a trash bin. Since then I designed and made my own EV Display and forgot what a PITA Paktrakr was.


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## ElectriCar (Jun 15, 2008)

Well I think there is now a fix but it's one you do, not the OEM. I installed the two ferrite snap on cores to the current sensor cable and looped it through once. Also installed one on the line from the remote and looped it about three times. 

So far I've driven it about 40 miles with no issues. Hope I've not spoken too soon.


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## Dave Koller (Nov 15, 2008)

ElectriCar said:


> Well I think there is now a fix but it's one you do, not the OEM. I installed the two ferrite snap on cores to the current sensor cable and looped it through once. Also installed one on the line from the remote and looped it about three times.
> 
> So far I've driven it about 40 miles with no issues. Hope I've not spoken too soon.


The snap on cores from Radio Shack? Good luck sounds like you might have solved your noise ...


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## dimitri (May 16, 2008)

I put a dozen or so ferrite cores in many places too, at first it seemed to have helped, but it would still glitch randomly, although not as frequently.

I scoped the signals between remotes and at the display, so I know exactly what the noise looks like and where it comes from. Once I learned that, I decided it was not worth the trouble and dumped the whole thing.

Sorry for sounding negative, but this whole Paktrakr saga was a huge waste of time and money for me, your mileage may vary


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## ElectriCar (Jun 15, 2008)

Yes Dimitri it is much less than desirable but it serves its purpose and replacing it would be a whole 'nuther issue. It's working well now so I'm going to keep it for now. Had I known all the issues before hand I would likely have another system installed instead.


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