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    1500w Hub Motor Noise

    Hey everyone! New here but so glad to find this forum. So many rad builds and smart people here!

    I just started building e-bikes a few months ago, with decent electrical knowledge, but not much about hub motors. I have built 2 hub motor bikes before my new 48v 1500w fat-bike build, and the new fatbike motor makes a really odd growling sound, which gets worse under load. Of course I ordered the motor from China through eBay, so they've been not very helpful in troubleshooting/diagnosing. They say that it's normal but it doesn't sound good to me.

    Edit: I should add that it also has a bit of a skip at low speeds sometimes. Like if Im rolling and then open the throttle, it will start to accelerate, then the motor will sort of "turn off" for a second, come back on and then accelerate through the rest of the range.

    Here's the kit I'm using: https://www.ebay.com/itm/26-Fat-E-bi...72.m2749.l2648

    Here's a video of the noise: https://drive.google.com/file/d/1bBN...ew?usp=sharing


    Thoughts? What could be causing that sound, and any ideas on a fix?
    Last edited by BenPryce; 10-02-2020, 12:42 PM.

    #2
    I suspect there is a problem with the wheel bearings. There are not that many moving parts in a hub motor.
    "I need another SimuLatte"

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      #3
      To be honest--I don't hear anything at all which sounds abnormal.

      The dominant sound in your video--the hum when you're starting to roll--if that's the "growl" you meant--that's a normal sound (and it's not that loud, all things considered). That growling-sound results from the electrical pulses trying to turn your motor.

      That's pretty much exactly how my Suring brand (Aliexpress vendor) 1500W DD motors sound (I've got two 1500W DD front-wheel hub-motors under the front of my bakfiets), and mine are working perfectly.

      If you read up here: https://electricbike.com/forum/forum...ect-drive-hubs in the Direct Drive forums, you'll find many folks using optional aftermarket controllers (there's a number of different ones out there) and one of the frequent advantages they've named, with a higher-quality sine-wave controller, is quieter operation.

      So, if you want to reduce that already pretty quiet noise, you may find solutions over there.

      Now--as far as your acceleration-curve, and that pause--no, that's not normal. But since your motor seems to behave otherwise normally, I suspect that acceleration-pause has likely got something to do with your controller. Perhaps there's an advanced-setting which can help correct that issue.

      Or maybe it's your throttle...

      But again, I'd suggest you dig around that Direct Drive forum. I bet there's other users who've had similar problems.

      Best of luck with your project, it looks like fun!

      tklop
      Last edited by tklop; 10-03-2020, 09:56 AM.

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      • BenPryce
        BenPryce commented
        Editing a comment
        Thanks tklop! That's super helpful. I assumed that the noise was the electrical pulses, but on my other 48v 1500w hub motor (Voilamart Amazon brand) is actually silent so I thought there was something wrong. Great to hear that its a normal noise. I'll definitely try a controller swap and see what happens.

        As for the acceleration skip, I have the KT-LCD8 display which looks like its highly programmable, so I'll look into it. If you have any suggestions on threads for that display/controller settings I'd gladly check it.

        Thanks again.

      #4
      Ben, are you running the same 1500w type motor on 2 different 48v bikes? If so, can you try the controller from the quiet bike on the growler? That will at least let you know if it is the controller causing the noise (if the sound goes away) ... or if it is the motor (if the sound remains)

      I am by no means an ebike guru... I don't pretend to be, as I am a noob myself (although an auto electrician in a past life)... but I would make sure your motor connections are clean and pushed home (with a bit of dialectric grease) ... as if one of the motor connections is not 'complete'... it could explain a noise and the slight pause on take off.

      I would also open up the controller and look/smell for any 'burnt bits' on the motherboard.... and lastly, for good measure, try moving the 3 motor wires around where they plug into the controller... you may just have the wires in a phase that the controller/motor aren't happy with... you may find if you mark how you have the 3 wires now, then plug them back in in a different order, it may make the motor happier. Just be careful when testing, the wheel may want to go backward (change again 2 of the wires)


      BTW, can you please measure the length of your rear wheel spokes for me? I am wanting to put a fatbike 26" rim on my 1500w Voilamart motor... wondering what the spoke lengths are (I have a spoke threading machine coming... but you may be able to let me know the correct length)

      Here is my thread on the subject https://electricbike.com/forum/forum...a-26-fat-wheel

      Comment


        #5
        Originally posted by Calcifer View Post
        Ben, are you running the same 1500w type motor on 2 different 48v bikes? If so, can you try the controller from the quiet bike on the growler? That will at least let you know if it is the controller causing the noise (if the sound goes away) ... or if it is the motor (if the sound remains)

        I am by no means an ebike guru... I don't pretend to be, as I am a noob myself (although an auto electrician in a past life)... but I would make sure your motor connections are clean and pushed home (with a bit of dialectric grease) ... as if one of the motor connections is not 'complete'... it could explain a noise and the slight pause on take off.
        Good advice, thank you! I’ll give that a shot eventually but the controller on my other bike is pretty deep right now and i don’t feel like digging it out. Sounds like the noise is ok to run for now.

        that being said, I did try to mess with the motor phase on my KT LCD8 controller and now the bike will sometimes move a cm or so in reverse before starting to roll forward. Any ideas? https://drive.google.com/file/d/1iPr...w?usp=drivesdk

        for the skip in acceleration, i was messing with the max power/soft start and low voltage cutoffs thinking that those may be the culprit, but haven’t pinpointed it yet.

        as for spoke lengths, it looks like it’s about 160-165mm. Hope that helps!
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