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  1. #1
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    Motor's Extremely Hot and Pulsing With New Battery

    I've had my Slash for several years and have ran 3S in the past. My 3S puffed a while ago, so I stopped using it.

    Today after receiving my new SMC 3S,11.1V, 75C, True Spec battery with a Traxxas style first generation connector in the mail, I charged it up and tried it out. My Slash was running strange - the motor would pulse up and down, and the motor and three wires became extremely hot very quickly after barely driving it less than one minute.

    It's the Velineon motor and ran 3S fine for years. The ESC light is green and I'm pretty sure it's in the correct mode. I tried it with a 2S battery and it ran fine.

    What could the problem be? Is it the new battery?

    Thank you.
    Last edited by Jay_Dee63; 09-18-2020 at 04:10 PM.

  2. #2
    RC Qualifier GotNoRice's Avatar
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    What gearing are you using?

  3. #3
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    It has an 18 tooth pinion and the stock spur gear on it.

  4. #4
    RC Qualifier GotNoRice's Avatar
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    18/54 is pretty high gearing for the 3500kv velineon system, particularly on 3s. You could drop down to the stock 13/54 gearing, and it should still be faster on 3s than 18/54 is on 2s.


  5. #5
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    Thanks, but it ran fine for years on that gearing with my old 3 cell, and i just noticed it got extremely hot from just giving it throttle sitting on top of a bucket and not driving it.

    My old 3 cell was 50c. The new one is 75c. Is 75c too much output?

  6. #6
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    It should be fine is you lower the gearing. I would also recommend the esc fan and motor heat sink for running 3s.

  7. #7
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    You could also get a larger motor, like the Castle 1415 2400kv, but you will need some upgrades, that you might allready have

  8. #8
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    Does the 1415 do well on both 2s and 3s?

  9. #9
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    I’ve heared it’s slow on 2s, but that can be a plus, if you want inexperienced people driving your rc. I’ve also heared that its great on 4s. I have no experience, but thisis what i’ve heared

  10. #10
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    Maybe your old motor is getting tired. Has it been overheated ever? As for motors, something like a 3670 around 3200kv would work good on 2s and 3s.

    Sent from my SM-G970U using Tapatalk

  11. #11
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    CC 2400kv rules on 3S. Never tried on 2S
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    Slash 4x4 Ultimate 2400kv

  12. #12
    RC Turnbuckle Jr. El Sob's Avatar
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    Quote Originally Posted by The Bean View Post
    I’ve heared it’s slow on 2s, but that can be a plus, if you want inexperienced people driving your rc. I’ve also heared that its great on 4s. I have no experience, but thisis what i’ve heared
    My little girl's truck is ran almost entirely on 2s. Her's is slightly slower in 2s than my stock truck on 3s. It's how you gear it.
    Member of the 10,000 + posts club! Here to help!

  13. #13
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    What’s her gearing? If that’s possible, wow, the 1415 is powerful!

  14. #14
    RC Turnbuckle Jr. Greatscott's Avatar
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    Quote Originally Posted by Jay_Dee63 View Post
    I've had my Slash for several years and have ran 3S in the past. My 3S puffed a while ago, so I stopped using it.

    Today after receiving my new SMC 3S,11.1V, 75C, True Spec battery with a Traxxas style first generation connector in the mail, I charged it up and tried it out. My Slash was running strange - the motor would pulse up and down, and the motor and three wires became extremely hot very quickly after barely driving it less than one minute.

    It's the Velineon motor and ran 3S fine for years. The ESC light is green and I'm pretty sure it's in the correct mode. I tried it with a 2S battery and it ran fine.

    What could the problem be? Is it the new battery?

    Thank you.
    What was the C-rating of your old pack?
    Submarine Qualified, Chief Inducted, Navy Retired

  15. #15
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    Quote Originally Posted by Greatscott View Post
    What was the C-rating of your old pack?
    The C-rating on my old 3 cell is 50c. The new pack is 75c. Is that difference enough to be too much for the motor to handle?

    It looks like I need a new motor/esc now. It's even getting hot on 2 cell batteries after it happening on the new 3 cell.

  16. #16
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    100c works fine for me

  17. #17
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    Quote Originally Posted by El Sob View Post
    My little girl's truck is ran almost entirely on 2s. Her's is slightly slower in 2s than my stock truck on 3s. It's how you gear it.
    Do you think the 2400kv Castle is a better choice for running 2s mostly and occasionally 3s on the street in front of my house than the Hobbywing Max10 SCT ESC combo with a 3200 kv sensorless motor? I think I've narrowed it down to those two. I know you've been recommending the 2400kv for years. Thanks!

    Quote Originally Posted by The Bean View Post
    100c works fine for me
    Yeah, I didn't think that difference could be too much. Maybe my motor or esc became weak from being old (if that's even possible?)?
    Last edited by cooleocool; 09-25-2020 at 01:47 AM. Reason: merge

  18. #18
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    My ESC died a very strange death. Anything can happen with those things.

    I ran my car on the beach, it didn’t ovrheat. Got home, it still worked fine. Next day: poof! A burning smel was smelled and I quickly pulled out my battery

  19. #19
    RC Turnbuckle Jr. Greatscott's Avatar
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    Quote Originally Posted by Jay_Dee63 View Post
    The C-rating on my old 3 cell is 50c. The new pack is 75c. Is that difference enough to be too much for the motor to handle?

    It looks like I need a new motor/esc now. It's even getting hot on 2 cell batteries after it happening on the new 3 cell.
    If your old pack was 20 or 30C, then I would say yes, but 50C gives a lot of throughput, so likely not the cause.

    It might just be that your old pack was tired, and just was not delivering the amperage of the new one.
    Submarine Qualified, Chief Inducted, Navy Retired

  20. #20
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    I thought you couldn't have a to high C-rating, only a to low one. I thought getting (way) more 'C' than you need is mostly a waste of money

  21. #21
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    Quote Originally Posted by The Bean View Post
    I thought you couldn't have a to high C-rating, only a to low one. I thought getting (way) more 'C' than you need is mostly a waste of money
    That’s what I thought, too. I thought a higher c rating would just be able to handle higher needed output, not force unneeded output.

  22. #22
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    Quote Originally Posted by The Bean View Post
    I thought you couldn't have a to high C-rating, only a to low one. I thought getting (way) more 'C' than you need is mostly a waste of money
    Quote Originally Posted by Jay_Dee63 View Post
    Thatís what I thought, too. I thought a higher c rating would just be able to handle higher needed output, not force unneeded output.
    Not exactly, having a high C rating only tells you what the maximum safe discharge rate is. It's not the same as voltage where if it is too high, then it can fry circuits. Think of it like a large straw, its a bigger around and therefore lets you drink your soda faster, but you don't have to drink the soda fast with it... it just allows you to.

    Here is a better explanation of it all: https://rogershobbycenter.com/lipoguide

  23. #23
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    C rating isn't the only factor in Amp load either.

    Another good read: https://fpvfrenzy.com/lipo-c-rating/

  24. #24
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    Ah x C = AMP. 8.5Ah x 100C = 850A?

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