Is this a noise or just a sound? (Solved)

MattZ

100 W
Joined
Jul 14, 2021
Messages
101
My first build, it's made this sound from the start but I'm not sure it's something to be concerned about or not. I've never ridden or even seen another ebike so I don't have anything to go on. There's about 50 miles on it now, everything seems to work fine. Motor, controller, connections, battery do not get hot while riding. It only makes the sound under acceleration or heavier load uphill. No load top speed is 45mph. I have it limited to 25 to ride, which it does no problem.
Bike has a 1200w QS DD hub motor, KT 36/48v 15A square wave controller, 48v 20Ah battery.
There were issues in assembly. Motor phase wires had 2 colors changed: blue wire had green heat shrink and the green wire had blue tape wrapped around it. I connected it assuming the changes were there for a reason (green heat shrink to green wire from controller, etc). The motor would lock up, no rotation. I checked for cogging by touching phase wires together, it seemed fine. I then checked voltage of hall sensors which also seemed fine.
I found the really helpful BLDC wiring flowchart located here https://endless-sphere.com/forums/download/file.php?id=197293&mode=view and went through that and got it working. I did not change phase wires, only hall sensor connections.
It sounds like a spray paint rattle can but describing a sound is tough so I uploaded a short video
https://youtu.be/kjylK7Fo_JU

So is that sound normal or should I keep going through the flowchart?
 
MattZ said:
There were issues in assembly. Motor phase wires had 2 colors changed: blue wire had green heat shrink and the green wire had blue tape wrapped around it. I connected it assuming the changes were there for a reason (green heat shrink to green wire from controller, etc). The motor would lock up, no rotation. I checked for cogging by touching phase wires together, it seemed fine. I then checked voltage of hall sensors which also seemed fine.

Was your kit purchased used? The noise doesn't seem normal.
 
MattZ said:
E-HP said:
Was your kit purchased used? The noise doesn't seem normal.

It was new, nothing about it gave the impression anything was used. The motor / controller kit and the battery kit came from two different suppliers.
Here's the motor - https://www.ebay.com/itm/114321127205?epid=13037986380&hash=item1a9e11f725:g:2WcAAOSw6EtfG2vl

The thing about the heat shrinked phase wires with the color's swapped seems odd for a new motor. I wonder if it's a loose magnet rattling around inside.
 
E-HP said:
MattZ said:
E-HP said:
Was your kit purchased used? The noise doesn't seem normal.

It was new, nothing about it gave the impression anything was used. The motor / controller kit and the battery kit came from two different suppliers.
Here's the motor - https://www.ebay.com/itm/114321127205?epid=13037986380&hash=item1a9e11f725:g:2WcAAOSw6EtfG2vl

The thing about the heat shrinked phase wires with the color's swapped seems odd for a new motor. I wonder if it's a loose magnet rattling around inside.

I thought it might be something loose but it only makes that sound when accelerating. When it's just putting along it doesn't make that sound. I figure if something's loose it's going to make the sound all the time, or the loose part will break or jam something up.
The heat shrink and tape seemed odd until I read that's it's not unusual for motors to not work correctly out of the box when colors are connected to corresponding colors and assumed whoever put the kit together was trying to avoid that situation. Then I stumbled on that flow chart and started following the steps in that. In going through it I discovered the hall connectors when plugged together weren't connected to their corresponding colors before I changed anything.
What I have now is the connections made as shown in the top left box of the flowchart. I'm trying to figure out if I should follow the 'noisy rotation' decision. It sounds like I should based on you saying it doesn't sound normal, but I'm not sure if what I have is 'noisy rotation'.
 
E-HP said:
It sounds like this one:
https://youtu.be/xBrJ_aXWRCk?t=110

Is the person that assembled the kit familiar with ebikes?
Does the controller get hot after riding?
Thanks for taking the time to help with this E-HP, I really appreciate it.
It does sound exactly like that one. Unfortunately he cooked his controller before figuring it out.
I assume whoever put the kit together was familiar with ebikes. The box looked like it was sealed in China, one layer of tape holding it closed, mostly useless instruction pamphlet, and it looked like the pics I've seen of kits with round styrofoam on axle, nothing unusual about it. Although I should have been suspicious when I saw the last page of the instructions were titled "Finishing the Fight".
After riding the controller is slightly warm, it doesn't feel warm enough to be a concern.
Maybe I need to open up the box in front of the battery that all the wire connections are crammed into and see if wires are getting hot. The box itself wasn't warm after a 10 mile ride but maybe a problem with a single wire wouldn't be enough to heat the whole box. I did extend the phase wires from the controller with butt connections and replaced the screw-down terminal block with XT60 connectors but I was real careful making those changes.
 
Does your KT controller come with a display? If so, what is the no load power/watts that the controller draws when the wheel is off the ground and throttle wide open? It should be very small if it's configured correctly.
 
E-HP said:
Does your KT controller come with a display? If so, what is the no load power/watts that the controller draws when the wheel is off the ground and throttle wide open? It should be very small if it's configured correctly.

Yes, it has an LCD-3.
Wheel off the ground, assist level 5 (not sure if that affects throttle), speed limited to 25mph, when I hit the throttle it goes up to 145w, 190w for a flash, then settles down to varying between 25 and 35w while maintaining 25mph.
 
MattZ said:
E-HP said:
Does your KT controller come with a display? If so, what is the no load power/watts that the controller draws when the wheel is off the ground and throttle wide open? It should be very small if it's configured correctly.

Yes, it has an LCD-3.
Wheel off the ground, assist level 5 (not sure if that affects throttle), speed limited to 25mph, when I hit the throttle it goes up to 145w, 190w for a flash, then settles down to varying between 25 and 35w while maintaining 25mph.

That's pretty normal. Usually a false positive (wheel turning in the correct direction, but not smoothly) will consume more watts. Not sure what else could be causing the noise, but perhaps some of the forum experts can chime in.
 
Still fighting with the seller over this. He saying it's the disc brake, freewheel, moon phase, covid, you name it. So I made a better video showing the problem.
https://youtu.be/hREUzF86sQw
Maybe someone's heard this before. It sounds to me like something hitting the motor casing from the inside. Stator hitting magnets maybe. I feel no play in the bearings, pretty much at a loss to resolve it myself without opening the motor but I'm not at that point yet.
 
AHicks said:
Maybe right in there with moon phase or Covid, but have you checked your spokes?
I have, and found one loose one. Tightened it and the wheel's a bit truer but no change in the sound.
 
nicobie said:
If it's not your spokes and still in warranty, I'd run the piss out of it up a really big hill a few times. If it doesn't fail, your golden. If it does, your problem is solved. Send it back for another. These kind of problems are hard to solve.

Good luck. :)
Thanks! That's been my plan up until nothing broke and I got sick of the noise. I made this for my wife and found the sound annoying. I just finished mine yesterday and took it for a spin and it's practically silent which refreshed my aggravation with the noise. Hers has 80 miles on it so far but nothing's fallen off or started on fire yet.
 
Noise, on your bike or hers, would make me crazy. Sounds like it's time to pull it down. Screw the warranty worry. It needs to be fixed! If you can find the reason inside, take a pic and send it off to be reimbursed.
 
AHicks said:
Noise, on your bike or hers, would make me crazy. Sounds like it's time to pull it down. Screw the warranty worry. It needs to be fixed! If you can find the reason inside, take a pic and send it off to be reimbursed.

Yeah it's making me crazy. She was loving that bike, riding it after work almost every day. Now that mine's done and she heard what one is supposed to sound like (or not sound like in this case) she's really pissed and says she's embarrassed to ride it.
I'm reluctant to open the motor, only because I have so much time invested already. Ideally the seller will just send a new one and I'll send the old one back after swapping it out.
 
Difference in philosophies. For me, I would rather pull it down and get it over with vs. screw with a reluctant seller. Often I'll have an issue fixed and back on the road by time they get around to replying to my email. Bottom line, I hate down time.....
 
This continues to be a very frustrating problem. Went for a ride last weekend and the noise is intolerable and seems to be getting louder. No need for a bell to let walkers know we're coming up behind them. https://youtu.be/SC9NRm8RpfY
I got an 8" gear puller, took the wheel off and took the motor apart. I can't see anything that looks like it's rubbing, don't feel any loose magnets, and can't feel any play in the bearings. Had a hard time putting the motor back together. I assume the rotor was up against the side cover and wouldn't spin. Took it apart again, pushed the axle through a side cover a bit more, reassembled and it turned freely.

I put the motor back on the bike to test it, and it's making the same goddamn noise. https://youtu.be/mJkfYNtbTPs
So then I'm thinking maybe it's something fishy with the controller. Made an adapter to connect the motor to the controller of my bike (52v sine wave controller vs. 48v square wave controller on her bike) and it still makes the noise but not as loud or as long. https://youtu.be/Bx7DdDviglM Maybe the difference in the noise between the 2 controllers is a clue, but a clue to what, I don't know.

It sounds so much like something hitting the motor case, but only under acceleration or under load going uphill.
Now I'm thinking 1) Change bearings anyway, even though I can't feel any play. Just need to find a place to press them out and new ones in.
2) Try to make sure rotor is centered between side covers. I'm thinking disassemble the motor again and put some type of putty between layers of saran wrap on top and bottom of rotor at the outer edge. Then reassemble the motor, squishing the putty. Then disassemble the motor yet again and examine thickness of putty on either side of the rotor. Take measurements of the putty thickness and figure out if it's centered. If not, scribe a line on the axle at outer edge of a bearing where that line would indicate rotor is centered.
After the first reassembly of the motor when the rotor wouldn't turn I tried pushing the axle in and out using the gear puller. This did get it to turn but only when under pressure from the puller. Apparently the side case just flexed without the bearing moving in or out on the axle since once the puller was removed the rotor wouldn't spin.

Anyone have any thoughts on that plan, or other suggestions to try?
 
Thought-
I've experienced a square wave controller making noise coming from the motor before. I ended up tossing it and installing a sine wave controller as it made me just as crazy as this one seems to be making you.

Noise while accelerating from a stop and accelerating/climbing a hill when underway describes the times ours made the noise perfectly. I described it as a ringing noise.

You are familiar with the fact KT makes both square and sine wave controllers, right? From a note taken when posted by somebody not long ago-
KT36/48SVxx = sine wave controller
KT36/48ZWxx = square wave controller

Confirm P3=1

Maybe post a pic of all your parameter settings.
 
MattZ said:
There were issues in assembly. Motor phase wires had 2 colors changed: blue wire had green heat shrink and the green wire had blue tape wrapped around it. I connected it assuming the changes were there for a reason (green heat shrink to green wire from controller, etc). The motor would lock up, no rotation. I checked for cogging by touching phase wires together, it seemed fine. I then checked voltage of hall sensors which also seemed fine.
I found the really helpful BLDC wiring flowchart located here https://endless-sphere.com/forums/download/file.php?id=197293&mode=view and went through that and got it working. I did not change phase wires, only hall sensor connections.
It sounds like a spray paint rattle can but describing a sound is tough so I uploaded a short video
https://youtu.be/kjylK7Fo_JU

OK, so I re-read your first post, and something doesn't make sense. If you used the chart that you referenced, and your starting point was the "stuck" motor condition, then per the chart, you would swap two phase wires, not hall sensor wires. Per that chart, the only wires ever swapped are phase wires, and the only scenario on the chart where the hall sensor wires are swapped is in the lower right, if the wheel is rotating in the wrong direction.

The whole thing about the hokey heat shrink/color swap on the phase wires seems to indicate that the kit provider had to do something to get the controller and motor to work together, but maybe only went as far (like in the chart) to get it spinning, and not worrying about the noise. Did you try connecting the phases based on the actual wire colors?

I would try putting the hall sensor wires back to where they were, then use the chart to get the motor spinning, and then eliminating the "noisy rotation" condition.
 
AHicks said:
Thought-
I've experienced a square wave controller making noise coming from the motor before. I ended up tossing it and installing a sine wave controller as it made me just as crazy as this one seems to be making you.

Noise while accelerating from a stop and accelerating/climbing a hill when underway describes the times ours made the noise perfectly. I described it as a ringing noise.

You are familiar with the fact KT makes both square and sine wave controllers, right? From a note taken when posted by somebody not long ago-
KT36/48SVxx = sine wave controller
KT36/48ZWxx = square wave controller

Confirm P3=1

Maybe post a pic of all your parameter settings.

Thanks again for your time and advice, I do appreciate it. Yes it's definitely a ringing sound, like an aluminum bell which has been leading me to think something's hitting the motor casing.
Yes I'm familiar with KT square vs. sine and ZW vs. SV. I have been looking for the SV version of the ZW controller on her bike but sellers seem to purposely post out of focus pics of that sticker. Out of focus and upside down in fact, doesn't seem like an accident. They say it's a sine wave controller but I'm getting skeptical of these sellers.
Even with that change, it still makes the noise when connected to the SV controller on my bike, although not as bad.
Here are the settings -
26 settings.jpg
Settings on the SV controller are the same except for P5 due to the 52v battery. That controller also has the L settings. L3 has to do with ignoring hall sensors if one fails. 'Ignore' is turned off now but I'll try switching it to see if it makes a difference although the sensors tested out OK.
I'm now thinking this motor is just an electric bell. Something is weird electrically, maybe one magnet is upside down, who knows. I don't know that I'll ever figure it out. I'm hounding the seller over this but he's not losing any sleep.
 
E-HP said:
MattZ said:
There were issues in assembly. Motor phase wires had 2 colors changed: blue wire had green heat shrink and the green wire had blue tape wrapped around it. I connected it assuming the changes were there for a reason (green heat shrink to green wire from controller, etc). The motor would lock up, no rotation. I checked for cogging by touching phase wires together, it seemed fine. I then checked voltage of hall sensors which also seemed fine.
I found the really helpful BLDC wiring flowchart located here https://endless-sphere.com/forums/download/file.php?id=197293&mode=view and went through that and got it working. I did not change phase wires, only hall sensor connections.
It sounds like a spray paint rattle can but describing a sound is tough so I uploaded a short video
https://youtu.be/kjylK7Fo_JU

OK, so I re-read your first post, and something doesn't make sense. If you used the chart that you referenced, and your starting point was the "stuck" motor condition, then per the chart, you would swap two phase wires, not hall sensor wires. Per that chart, the only wires ever swapped are phase wires, and the only scenario on the chart where the hall sensor wires are swapped is in the lower right, if the wheel is rotating in the wrong direction.

The whole thing about the hokey heat shrink/color swap on the phase wires seems to indicate that the kit provider had to do something to get the controller and motor to work together, but maybe only went as far (like in the chart) to get it spinning, and not worrying about the noise. Did you try connecting the phases based on the actual wire colors?

I would try putting the hall sensor wires back to where they were, then use the chart to get the motor spinning, and then eliminating the "noisy rotation" condition.

Thanks for taking the time to re-read, noodle on it and reply E-HP.
I've tried a lot of things since my original post. I've tried the phase wires both ways - Actual color and 'modified' color. I went as far as making a chart of every possible hall sensor color combination and tried them all with both phase combinations. Noisy rotation is really noisy, different than the ringing sound the motor makes under acceleration or load, and probably uses a lot of power although I didn't check since it was obvious that combination didn't work. When it's making the ringing sound the motor uses 25 - 35 watts at full speed with no load. We rode 35 miles on Saturday, trying to break whatever's making the noise. I'm no expert but I don't think the battery would last that long if the wires were wrong, and nothing got hotter than slightly warm. But I could be wrong, this adventure is definitely causing me to question my diagnostic skills.

Do you know if I'm correct in my assumption that for every color combination of phase wires there will be one correct combination of hall wires? I kind of recall reading that somewhere but I'm not certain.
 
Maybe read though this post and see if the symptoms sound similar. The answer in this case was wheel bearings.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=112890

You're correct on the combos.
 
I can tell you that in my experience the phase wire color combination, motor side vs. controller side, will MATCH when it comes to the hall wires. It's about the firing order. The phase color firing order must match the hall sensor firing order.

"Do you know if I'm correct in my assumption that for every color combination of phase wires there will be one correct combination of hall wires? I kind of recall reading that somewhere but I'm not certain."

I say you need a controller.
 
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