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Old 05-29-2012, 08:19 AM   #1
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Question Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

First electronics post. And I've found nothing on the issue. (Could be my lack of electronics vocabulary, sorry)

I've had a small problem that I havent been able to solve since I got the novak goat 2s ESC and 18.5t brushless. Occasionally when I have the throttle in neutral, and give .5% throttle the truck will jerk forward for a millisecond and then stop again. Its hooked to my Lipo battery with a traxxas to tamiya adapter. My on/off switch doesn't exist, so it is hard wired. And I have a castle creations B.E.C. from the battery to my receiver.

The jerk only seems to be present when you give minimal throttle (.5%-1%) and back to neutral repeatedly. Any ideas??? I'm no genius when it comes to electronics. I'll post a video if needed.
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Old 05-29-2012, 08:21 AM   #2
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

any knicks or breaks in the sensor wire harness?
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Old 05-29-2012, 08:29 AM   #3
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by crawler nut View Post
any knicks or breaks in the sensor wire harness?
To my knowledge, the wires look okay. I've looked each one over thoroughly. I've tried routing them different ways, keeping them away from heat and vibration. I'm really at a loss.

What kind of issues could cause this? Anything specific I can look for?
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Old 05-29-2012, 08:35 AM   #4
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

Disconnect the sensor wire and see if the drivability changes.
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Old 05-29-2012, 08:37 AM   #5
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

could just be a glitch. could be that there is a small knick in a wire somewhere that is shorting out. give the whole car a good once over looking for anything like that. also if all of the elecrtonics and wires are bunched together it can cause small glitches like that.
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Old 05-29-2012, 09:24 AM   #6
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by Duuuuuuuude View Post
Disconnect the sensor wire and see if the drivability changes.
I'll try that very shortly. I didn't know that was an option. (I know basically nothing about brushless setups)

But I'm fairly sure there are no knicks or anything. My wires are all pretty tightly packed. If that is the case, I guess I'm stuck with it. I have everything in the front half of my SCX10 and there is no where else to route everything :/
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Old 06-02-2012, 11:45 AM   #7
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

DC motors draw highest amps at start. If your power system isn't up to the task it'll cause cogging issues. I had some serious cogging going brushless on a 6-cell nimh pack. Switching to lipo solved it.

Assuming your battery can supply the juice, you might look into eliminating that Tamiya connector. They're not capable of handling the amps of a Traxxas connector. Try going straight Traxxas, and see if that helps. Is the Tamiya on the ESC side or the battery side?
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Old 06-02-2012, 12:13 PM   #8
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by Duuuuuuuude View Post
Disconnect the sensor wire and see if the drivability changes.

try this first! if the driveability changes then you have problems elsewhere, if it stays the same either the sensor cable is bad or the plugs are not seated good.
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Old 06-03-2012, 08:22 AM   #9
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by DogSpoon View Post
DC motors draw highest amps at start. If your power system isn't up to the task it'll cause cogging issues. I had some serious cogging going brushless on a 6-cell nimh pack. Switching to lipo solved it.

Assuming your battery can supply the juice, you might look into eliminating that Tamiya connector. They're not capable of handling the amps of a Traxxas connector. Try going straight Traxxas, and see if that helps. Is the Tamiya on the ESC side or the battery side?

I was thinking the same. Soo lazy though, haha. I hate soldering. The tamiya is on the ESC side. And it looks like the negative side has been arching a little (slightly blackened)
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Old 06-03-2012, 10:32 AM   #10
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by ProjectSCX10 View Post
I was thinking the same. Soo lazy though, haha. I hate soldering. The tamiya is on the ESC side. And it looks like the negative side has been arching a little (slightly blackened)
You need to ditch the Tamiya connector ASAP.
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Old 06-03-2012, 10:47 AM   #11
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by Duuuuuuuude View Post
You need to ditch the Tamiya connector ASAP.
+1,000,000.....

Also, since you have the BEC going to the RX, did you pull the red wire out of the ESC to RX connection & tape it up? If not, do it. Otherwise you are feeding 2 power inputs to the RX which can also create issues.
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Old 06-03-2012, 10:48 AM   #12
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by ProjectSCX10 View Post
I was thinking the same. Soo lazy though, haha. I hate soldering. The tamiya is on the ESC side. And it looks like the negative side has been arching a little (slightly blackened)
Nice, as long as you disconnect the battery, you won't have to worry about shorting it while you solder. Regardless of whether that's the root cause of your current problem (no pun intended) the tamiya must go. I wouldn't run tamiyas on a fisher price rc.
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Old 06-03-2012, 11:35 AM   #13
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by ProjectSCX10 View Post
I was thinking the same. Soo lazy though, haha. I hate soldering. The tamiya is on the ESC side. And it looks like the negative side has been arching a little (slightly blackened)
If you're not willing to fix it, then why come on and ask for help?

But seriously, get rid of the tamiya connector. If you're using any type of rc electronics made within the last 5-10yrs, its the weakest link.
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Old 06-03-2012, 11:49 AM   #14
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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If you're not willing to fix it, then why come on and ask for help?
Well, I guess more than one of us was thinking it
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Old 06-04-2012, 09:55 AM   #15
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by Meatwad View Post
If you're not willing to fix it, then why come on and ask for help?

But seriously, get rid of the tamiya connector. If you're using any type of rc electronics made within the last 5-10yrs, its the weakest link.
Geeze, hater. I'll get around to it, haha. I was just hoping no one said that.

But it confirms my suspicions. I'll get to it asap and let you guys know.
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Old 06-04-2012, 09:56 AM   #16
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by Charlie-III View Post
+1,000,000.....

Also, since you have the BEC going to the RX, did you pull the red wire out of the ESC to RX connection & tape it up? If not, do it. Otherwise you are feeding 2 power inputs to the RX which can also create issues.
Even though the Goat has the built in BEC? I've read doubling up can be good for higher power servos? Correct me if I'm wrong anyone.
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Old 06-04-2012, 10:33 AM   #17
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by ProjectSCX10 View Post
Even though the Goat has the built in BEC? I've read doubling up can be good for higher power servos? Correct me if I'm wrong anyone.
Doubling up is a bad idea unless you have some way to prevent backfeeding the lower voltage source. It will actually lower the amount of current you can output. Thread on it here: Does having two esc double the bec ratings

Batteries work in parallel because one will backfeed the other only until the voltages equalize, then you get the same voltage with double the amps. BECs are not batteries and don't behave that way.

If you've got both the ESC BEC and the stand-alone BEC hooked up to the receiver, disconnect the red wire on the ESC like suggested. That could be another source of trouble for you.
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Old 06-05-2012, 01:14 PM   #18
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

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Originally Posted by DogSpoon View Post
Doubling up is a bad idea unless you have some way to prevent backfeeding the lower voltage source. It will actually lower the amount of current you can output. Thread on it here: Does having two esc double the bec ratings

Batteries work in parallel because one will backfeed the other only until the voltages equalize, then you get the same voltage with double the amps. BECs are not batteries and don't behave that way.

If you've got both the ESC BEC and the stand-alone BEC hooked up to the receiver, disconnect the red wire on the ESC like suggested. That could be another source of trouble for you.
Nice! Thanks for the info! I might just do away with the stand alone. The Goat has a built in 6 volt 5 amp BEC. Should be sufficient for my 208oz servo (unless someone thinks otherwise?)

The stand alone one looks pretty rough (came on my Goat used)

THANKS FOR THE HELP GUYS!
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Old 06-05-2012, 09:18 PM   #19
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

Disconnected the Castle BEC today. No jerky glitch. But crappy servo power. There was also a little knick in one of the BEC wires going to the receiver that I couldn't see before. So I found the source! Thanks for the pointers guys! I'll get a new Castle BEC and see what happens! Stay tuned?

Here is the truck in it's current state if anyone was interested





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Old 06-05-2012, 10:12 PM   #20
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Default Re: Novak Goat 2s ESC brushless jolts/jerks under minimal throttle

Just use electrical tape to cover bare spots in the wires.....no need to replace it.
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