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Is this a brownout?

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Old 01-05-2019, 11:12 PM
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Default Is this a brownout?

I was running my T6.1 after replacing a receiver that just died. The truck now seems to randomly stop after a few min, like it is having a seizure No throttle and the wheels turn slowly on their own. A second later and everything is back to "normal". Sometimes the truck will take a second or 2 to get going if I have to come to a stop. I wonder if I am experiencing brown out and if that is what may have killed the previous newish receiver. This started happening after I changed motors from a Trackstar 10.5 to a Trackstar 9.5.

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Specs:

T6.1 temps < 130

Motor/Bat: Trackstar 9.5 / 5000mah 2S

Esc: Xerun V3.1 120A (should be good >5.5T)

Servo: Reedy 1206

Radio: spektrum dx5c/sr315
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Old 01-06-2019, 03:28 AM
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Swap the motors back or first try a different sensor cable, maybe a sensor problem in the motor or sensor wire....
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Old 01-06-2019, 07:00 AM
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.
could be a bad connection inside battery... poor weld. ... been there, done that.
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Old 01-06-2019, 11:57 AM
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It could be the bec dying in the esc. Pull the red wire out of the esc connector that goes to the receiver. Then power the receiver with a receiver pack. If the problem goes away with the battery, the bec is likely the issue.

I've had a receiver go bad, and it took out 3 different esc's and a motor before I realized that the receiver was the problem. I had a bunch of different cars, and would move electronics around, so it took that receiver killing 2 esc's in two weekends before I figured out the receiver was the issue.
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Old 01-06-2019, 12:02 PM
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Could be anything, I agree with chuck, swap the battery first to see if problem persists, I have had to repair shotty soldering on LiPo packs in the past as well. It could be a bad sensor wire or possibly a bad sensor board on the motor, if battery swap doesn't fix the problem, then I would pull the sensor wire and run it in sensorless mode. I have seen guys at the track damage their sensor board on the very first battery pack after taking a nasty crash. I have made it a point to always check the gap between the rotor and sensor board on every new motor I buy to help prevent damaging a sensor board that may be too close.. I have seen some rotors that were actually rubbing on the sensor board! I like to have at least 0.1mm gap to play it safe. It will be pretty obvious if the sensor board is damaged when you pull it out, but there are sensor testers available fairly cheap:

If you think you might ever get into any stock racing classes then I would invest in a motor analyzer which not only helps you test your sensor, but offers a myriad of other features which can help you tune stock motors for peak performance, I use this analyzer here:
https://www.rcjuice.com/skyrc-brushl...r-checker.html
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Old 01-06-2019, 06:24 PM
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Thanks for the ideas. I swapped motors to a Trinity 13.5 and batteries this morning, I didn't try changing the sensor cable yet. I noticed that the power loss occurs If I am heavy on the throttle.
Power always comes back after a few seconds. Makes me think the receiver is loosing power. Perhaps the servo is a hog.

The internal BEC should be strong on a brand new HW v3.1??? I would like to avoid clipping wires for now. The receiver is brand new also.
The shop owner said that Spektrums may need a glitch buster cap in the receiver.
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Old 01-06-2019, 06:48 PM
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Sit your car so the front tires are off the ground and on your transmitter turn the steering right to left over and over quickly. If the servo is being a hog and causing the brown outs you will see the servo get glitchy.
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Old 01-06-2019, 09:40 PM
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Also be sure to check you didn't lose your EPA settings, not sure how old your Spektrum radio is, but I recall a friend having an issue with his Spektrum where it would inadvertently reset his EPA back to 100% throw and he'd get brownouts because the servo was overloading when the EPA needed to be around 85% instead. Also be sure to set your end points with the front wheels on the ground.

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Old 01-09-2019, 02:39 PM
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Excellent advice. Ill have a chance to try these ideas tonight and report back.

Checked the servo at the track today. It was fine but the car was still acting up, especially after landing a jump.
I noticed the battery leads were being pulled out of the pack by the battery retainer. Re-positioning them seems to have helped.
Ill have to run a bit more to be sure. Im not a fan of the T6.1 tie down systems

Last edited by kenmtb; 01-09-2019 at 08:56 PM.
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Old 01-14-2019, 06:02 PM
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I just read that internal temps will be different then whats really happening on the outside it could be your esc temp settings. cutoff or it could be bad batteries
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