Bafang Hub Motor Noise

[Salty Souls]

Hi,

Ive recently completed the build of my new ebike and am now encountering a couple of issues:
- Hub motor noise
- Hub motor drawing high watts under no load
- Hub motor cutting out at certain point (speed)

Background
- Battery is 52v 20ah, 50A BMS (new)
- Controller KT sinewave DC 40v - 75v, 45A (new)
- Motor bafang RM - G0F4 1000w (believe this is the same as a GF062 1000w) (second hand)

Situation
- All the componenents are new to me so I dont have a baseline of noise or performance.
- The hub motor was puchased second hand and it had a hall sensor issue which I fixed (i believe). I've tested all the hall sensors with a multi meter and an ebike tester, all appears to be ok. I also tested the phase wires, etc of the hub motor, once again all appears to be ok.

Issues
Video- Noise - when accelerating with the throttle the motor is making a loud noise. The noise is louder than my other ebike and so Im just not sure if this is normal. A loud whirring noise
Video- Watts - the motor appears to be drawing in excess of 100W under no load when accelerating. I didnt think it should draw this many watts under no load. Also I wondered how accurate the KT display is with regards to Watts?
- Motor cut out - the motor cuts out at what appears to be between 20kmh to 30kmh

Ive tried the 36 different combinations of phase and hall wires configurations and this appears to be the best.

Ive also posted a picture of my current settings.

Any help / guidance would be great.

Thanks

 

[amberwolf]

Ive recently completed the build of my new ebike and am now encountering a couple of issues:
- Hub motor noise
- Hub motor drawing high watts under no load
- Hub motor cutting out at certain point (speed)

Those symptoms generally indicate an incorrect phase/hall wiring combination. The KT's I know of don't have an autolearn function, so you have to swap hall signals around until it runs correctly at lowest curretn in the correct direction and speed. you may also have to swap phases, but start with the halls if it's already running in the right directoin.

 

[Salty Souls]

Thanks for the response amberwolf.

I orginally tried all 36 different phase and hall wire combinations. After your response I went back and double checked phase wire combinations and there was still no improvement.

I then took the motor out of the hub and mounted back into the bike - this provided some insights. It appears once the motor speed goes above 8km h that the whirring noise kicks in. It actually appears to be some sort of vibration and I was wondering could the rotor and stator be out of alignment, even just minor? It did appear that the rotor was not rotating in a straight alingment - a slight wobble, if that all makes sense?

Thanks

 

[amberwolf]

If the cover was removed by anyone in it's chain of owners, and put back on differently than it was built (rotated by one or more screw holes, etc), and it was originally machined out-of-round/offset, you could get a wobble. reinstalling in the original positions would fix or minimize it.

If the cover or housing bearings are worn out, the axle could wiggle around.

Rereading the original post I discovered the word "video" is actually a link (isn't clear from the text, only if I hover over it to get a tooltip), but the URLs point to facebook. Can't access FB without a login to see the videos, but if you post them on youtube you can put them directly into your post for readers to view them.

 

[Salty Souls]

Thanks amderwolf. Let me see if i can work out how to load videos onto youtube.

cheers