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  1. #1
    RC Racer
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    Motor Temps & Traxxas Link App

    Hi all

    So I'm still loving my newly built MERV, but I'm having issues with motor temps. I've tried the search function & not been able to find the answers I need.

    The only indication I have for temp is the on-board Temp Sensor that sends to the Traxxas app.
    I'm running a fairly stock truck, including the gearing, but with slightly bigger wheels. 2S batts only, with a Traxxas heat sink on the motor.
    I'm see Motor Temps of up to 140, at which point the ESC appears to be shutting things down.

    Couple of quick questions, if anyone can help please?...

    • What sort of temps should I see on the motor, is 140 too hot?
    • Does the motor temp sensor connected to the receiver somehow talk to the ESC and shut it down, or is it also an overheating ESC that I'm unaware off?
    • If I can run hotter that 140, will raising the warning on the app solve my problems with shutdown?
    • If this is a gearing issue & I need to gear down a little, can anyone suggest a good start point for my set up? I don't really want to order up a load of gears I don't need.


    Thanks for all the help guys, sorry to bring up motor temps yet again in another thread.

  2. #2
    RC Racer
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    So 140 degrees isn't too hot for the motor as it can run up to around 160 at the max, although you want to keep it much lower if possible. Most likely its not the 140 degree motor shutting you done, but instead an overly hot ESC - which is harder to judge the temperature of than the motor.

    The stock body on a merv doesn't have much space in it and also doesn't have good airflow into it. Because of these, the heatsink built into the esc doesn't become too effective. You can open up airflow in the body and/or use fans on the esc/motor.

    You can also mitigate other factors that can make the engine get hot fast, such as gearing or tire size. You said you use 2s, but in case you care, 3s does get things even hotter.

  3. #3
    RC Champion grizzly03's Avatar
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    The 1/16 erevo's don't have an onboard motor temp sensor stock that I know of. It needs to be added on. Did you install one?

  4. #4
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    Yeah, added all the telemetry.
    Forgot that wasn't stock.

  5. #5
    RC Champion grizzly03's Avatar
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    I copied this awhile ago and it has worked great for me.

    Hot motor + cool esc = under geared.
    Cool motor + hot esc = over geared
    Everything warm just right..

    Motor temps shouldn't affect the ESC into shutting down. I don't believe it has that feature, only if the ESC is getting hot itself. I could be wrong as it's been awhile since I have messed with the Traxxas app. I think you can have an adjustable alarm set on the app though.

    Do you know what the ESC temps are?
    What's your gearing? And the tires you settled in on using?

  6. #6
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    Gearing is stock, I can't remember what it is now other than I had to buy a 50t spur when converting from a Ken Block into the MERV.
    The wheels are FastTrax somethings.... a bit bigger than stock, but not too much.
    There's no binding at all on the drive train, so I suspect the ESC is just overheating. Its a shame because I like the way the truck drives.
    I might just try a fan on the ESC, see if that's an easy fix.

  7. #7
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    Quote Originally Posted by grizzly03 View Post
    I copied this awhile ago and it has worked great for me.

    Hot motor + cool esc = under geared.
    Cool motor + hot esc = over geared
    Everything warm just right..

    Motor temps shouldn't affect the ESC into shutting down. I don't believe it has that feature, only if the ESC is getting hot itself. I could be wrong as it's been awhile since I have messed with the Traxxas app. I think you can have an adjustable alarm set on the app though.

    Do you know what the ESC temps are?
    What's your gearing? And the tires you settled in on using?
    Undergearing would make both the motor and ESC run cool. Overgearing would cause the motor to pull more current which results in overheating problems.

    I believe that is a more appropriate way to think about it. Or am I wrong?
    The present is theirs; the future, is mine.

  8. #8
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by ElectricPropils View Post
    Undergearing would make both the motor and ESC run cool. Overgearing would cause the motor to pull more current which results in overheating problems.

    I believe that is a more appropriate way to think about it. Or am I wrong?
    With a brushed motor you are right. With a brushless motor it is different. An undergeared brushless motor would run hot because of always running at higher RPM's. A brushless motor likes to be loaded up.
    I'm not exactly sure why? But it does work that way. I took my Erevo 2.0 and tried gearing lower to try and get my motor temps lower, but it only went higher. Then out of curiosity I overgeared my motor by a couple of teeth from stock and my motor ran much cooler. I don't know the science why but those 3 simple rules work.

    Quote Originally Posted by Chewbacca 3 View Post
    Gearing is stock, I can't remember what it is now other than I had to buy a 50t spur when converting from a Ken Block into the MERV.
    The wheels are FastTrax somethings.... a bit bigger than stock, but not too much.
    There's no binding at all on the drive train, so I suspect the ESC is just overheating. Its a shame because I like the way the truck drives.
    I might just try a fan on the ESC, see if that's an easy fix.
    Running 2s it should be a reliable runner. Check temps of both and let us know.
    Last edited by cooleocool; 10-27-2020 at 01:15 AM. Reason: merge

  9. #9
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    I've no method of checking the ESC. I'm just guessing its shutting down because of heat.

    Although, what's the low voltage set to on these for lipo? I wonder if my battery is collapsing as it gets low?

  10. #10
    RC Champion grizzly03's Avatar
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    I found mine to hit the first stage at 3.5volts. Next time remember to check the ESC for the LED flash code.

  11. #11
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    Will do. I remember it was flashing red, but that's all.

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