Golden motor SP4 vibration problem

I was riding to work one morning last week and stopped for a red light. I didn't stop hard or anything, it was actually at the top of a hill. When I went to go again I got response from the throttle initially until I started moving then when it did cut in it was with noise and vibration as well as reduced power.

Opened it up checked the hall sensors. One of the three seemed to be not working. Looking back now I wonder if I just didn't press the probe in correctly and that's why I got no signal but it doesn't seem likely, I tested multiple times with the wheel in multiple positions.

So I ordered some Honeywell SS41 hall sensors. While I was waiting I got some OH137s from a friend, from the data sheets they seemed to have suitable characteristics so I put one in. Tested it before assembling the wheel, just like the other 2 turned on and off with the same poles of a magnet as they did.

Tried it out, same problem..I chalked it up to some property of the OH137 not being suitable. Last night the SS41s arrived so today I put one of those in there. Same problem.

This is where I am now. Golden Motor Smart Pie 4 Vector rear wheel, 36v thumb throttle, 4X12v10Ah SLAs running at 48v. When I test on the connector for the hall sensors I get 4.2v on the red wire and either 0.01v or between 3.2 and 3.24v on the yellow, blue and green wires as I rotate the wheel. Each phase wire for the motor shows 0.06v at rest. When I apply throttle I hear a faint click, either in the controller or the motor itself, hard to say which but no other response besides a green flashing led on the controller board. Checking the phase wires in this state shows the same 0.06v on all three. I release the throttle, spin the wheel up by hand and apply throttle and cruise control so my hands are free and check again. Same 4.5v on the red wire for the hall sensors power and 1.6v on each signal wire. I assume that's because they are on half the time. Checking the phase wires for the motors is the same, 26v on each half the supply voltage.

So from this I'm thinking the 3 sensors are working and the 3 phases of the motor are all working g. What could be the cause of the vibration, noise and reduced power? It's not mechanical, it coasts and pedals under human power smoothly. The amount of noise and vibration gets stronger with speed. Could my controller be sending g pulses out of phase for some reason? Any ideas what to test to narrow down my problem?

That should have read no response from the throttle in the first paragraph.

Tried some more testing on the phase wires and posts. I posted this on another forum:


Wish I had an oscilloscope. :-\ I disconnected each wire one at a time. At a stop each wire reads 0.06v. With the yellow disconnected the post reads the same when off. Hand spin the motor, apply throttle and cruise control, the blue and green read 26v, the yellow wire 26v, the yellow post 6v, varying by approx 0.5v once or twice a second.

With the blue and green wires off (one at a time) I was unable to get the throttle to engage at all. While the wheel was spinning with the throttle held down (but as I said no power being applied from the motor) all wires and the disconnected post were showing 26v for both blue and green being disconnected.

If I had someone here to help I'd test what happens with the braking (it vibrates when I brake too) but I just don't have enough arms.

So what does that mean engaging with the yellow off but not the other two? And the mismatch in voltages on the posts?

I've been reading all afternoon about controllers and one site said something about controllers blowing when a hall sensor fails and you give throttle from a dead stop. Exactly the conditions I experienced. I had just gone up a fairly long but not steep hill. I can't imagine the motor was hot, I had just left the house and it was about 6 degrees out. I stopped just fine and went to go and nothing. Kicked with my feet and it came on.

If it was just a sensor why does it have to be faster than 7km/hr to engage? Wouldn't the problem be limited to trying to move when the magnets were not in the right position? How would the speed be a factor? Any motion should line the other 2 phases up for the motor to engage. Or has the sensor driven mode failed completely and the motor only runs in sensorless mode which only cuts in about 7km/hr assuming this controller has sensorless mode? And the vibration is due to something being wrong on the yellow phase, initially caused by whatever blew the hall sensor? Or maybe the controller went first and took the sensor with it?

My head hurts lol. Im leaning towards buying another controller (my third) and trying that. I've only got a bit over 400kms on it, disappointed in the failure rate. Did I get a lemon or do these things break a lot?

Is this the model with the internal sine wave controller?

It sounds like the halls are working.
You might try disconnecting all the phase wires, turn off the power, and measure resistance from each phase wire to the battery negative wire on the controller. Repeat measuring against the positive battery wire on the controller. Each combination should measure like a diode. If one is shorted, it would point to a blown FET in the controller.

If this tests out OK, you might trace the hall signals up to the controller and make sure there isn't a broken wire somewhere.

Yes it is. In discussions with someone on another forum I'm leaning towards a faulty hall sensor initially that ruined my first controller somehow and now this one too. The hall sensors seem to be doing what they should now, it's the phase wires that are wrong now, specifically that yellow one only showing 6v. The yellow hall sensor was the one I replaced. I'm waiting to hear back from the vendor regarding warranty now.

On a side note, the OH137 hall sensor I put in was probably working fine, it did everything the Honeywell SS41 is now doing. So if you are replacing hall sensors and can't find the SS41s they might be an option.