Best sensorless controller for geared (freewheel) motor

[feyris]

Hi!
Hi have lots of issues with my current controller (don't know the brand/model/chip..)
My hub motor is a Bafang SWXH: rear wheel, sensorless.
I have lots of 'hammerring' (the controller seems to don't synchonise) in hills, in accelerations.
Sometimes it don't work at all after the controller failed to run the motor from stop.

Someone in the same configuration (sensorless+freewheel) can run without problem?

I was thinking about the E-crazyman one, it seems to work better.

Thanks!

 

[dogman dan]

Sounds a lot to me like bad connections on either hall or phase wires. I had similar sypmtoms with a wire that rubbed the tire, and connectors that pushed out of the housings.

 

[feyris]

Sounds a lot to me like bad connections on either hall or phase wires. I had similar sypmtoms with a wire that rubbed the tire, and connectors that pushed out of the housings.

I don't have hall wires (from the motor, but maybe the throttle use an hall sensor)
The motor is hard to start, but when it works, it run without problems until I stop it, so I don't think a phase wire is broken.
I'll open my controller tomorow to see wich one is it. And perhaps I'll see something wrong inside.

 

[wshi]

Sensor-less BLDC operation have a nature disadvantage which is the rotor position cannot be obtain easily and correctly, especially in the low RPM range (0~100RPM). This disadvantage usually causes knocking, over current and decreased controller life. The drawback may be minimized with fast back-EMF sampling / calculating but the controller cost will rocket high since DSP is usually involved signal processing. IMO low cost sensor-less BLDC controller should never be used to drive high power motor since a single mistaken phase could destroy the controller itself.

 

[feyris]

Maybe my controller is now a bit destoyed
It worked better before.
Should I use a better (more power, more Amps) controller?
My bafang mottor is rated for 250W, the controller for 350W but I can see 700+W peaks on my power monitor.

 

[wshi]

I think you should replace both your BLDC and controller. Use a BLDC with hall sensor and hall sensor supported controller this time instead.

PS: Being working for controller & e-bike manufacture In the past 3 years I saw a somewhat 40% fault rate with sensor-less controller where as only 5% with sensored controller. Sensored controller is the way to go.

 

[Russell]

Hi!
Hi have lots of issues with my current controller (don't know the brand/model/chip..)
My hub motor is a Bafang SWXH: rear wheel, sensorless.
I have lots of 'hammerring' (the controller seems to don't synchonise) in hills, in accelerations.
Sometimes it don't work at all after the controller failed to run the motor from stop.

Someone in the same configuration (sensorless+freewheel) can run without problem?

I was thinking about the E-crazyman one, it seems to work better.

Thanks!

Yeah the E-crazyman (Shenzen) sensorless controller is said to work better with freewheeling geared motors but I can't say first-hand whether it's true. I use a bmsbattery/ecitypower dual-mode controller with my Bafang and wasn't happy with the performance when running without halls therefore I locked up the clutch so the motor no longer freewheels and now it works great. http://endless-sphere.com/forums/viewtopic.php?f=4&t=10458&start=45#p212576

I would suggest trying the E-crazyman sensorless controller first because I'd like to hear more user reports about it :wink:

-R

 

[dogman dan]

Just wanted you to check your wires before shucking out bux. The exact same symptoms for me were caused by a damaged phase wire, that sometimes made no contact, and sometimes made contact but poorly. It was a coin flip if it would run , not run, or run poorly till I found the nick in the wires, that was easy to miss.

 

[feyris]

Just wanted you to check your wires before shucking out bux. The exact same symptoms for me were caused by a damaged phase wire, that sometimes made no contact, and sometimes made contact but poorly. It was a coin flip if it would run , not run, or run poorly till I found the nick in the wires, that was easy to miss.

You might be right.
I opened my controller to check for damage inside (don't see anything) but it works now with no load. I'll try tomorow a few km.
I saw some humidity on a plug, maybe that's the problem.

Yeah the E-crazyman (Shenzen) sensorless controller is said to work better with freewheeling geared motors but I can't say first-hand whether it's true. I use a bmsbattery/ecitypower dual-mode controller with my Bafang and wasn't happy with the performance when running without halls therefore I locked up the clutch so the motor no longer freewheels and now it works great. http://endless-sphere.com/forums/viewtopic.php?f=4&t=10458&start=45#p212576

I would suggest trying the E-crazyman sensorless controller first because I'd like to hear more user reports about it :wink:

-R

If my issue come back, I'll try this one, not very expensive.

About my controller: he has 9 FETs (p75nf75), a nec F9234 µC, looks clean, no burned things. I didn't find any controller like this here.
I think about lock the clutch like you, is it hard to pedal without battery now?

 

[Russell]

I think about lock the clutch like you, is it hard to pedal without battery now?

The resistance isn't higher than a direct drive motor but whether or not it makes a difference to you depends on how much you ride w/o the throttle. I use the throttle to some degree about 90% of the time on that bike so the loss of freewheeling ability is of little consequence and the major advantages of the motor; small size, low weight and good torque, remain.

Freewheeling motors are tricky to run sensorless since they can’t provide feedback to the controller until the throttle is applied but with the locked-up clutch it works great just like a direct drive motor would. There will always be some hammering if the throttle is yanked from an absolute standstill however all it takes is the slightest forward rotation of the wheel and my non-freewheeling Bafang starts with ease.

People have said good things about the Shenzen controller so I'll have to try it for myself on my other freewheeling geared motor some day.

-R

 

[feyris]

50km with the new controller (the one from E-crazyman ) later:
it's better! No 'hammering" during acceleration, restarts, hills like before, it's near perfect.

I just have a problem about the throttle range:
in range 0% to 20% : the motor is off
20% to 60% : speed increase (and it's not the same feeling than the older controller: now it feel like a speed increase, before it was like a power increase)
60% to 80%: max speed
80% to 100%: motor off.
I checked the throttle: mine is hall type.
I read that I can fix that with some resistor, i'll try this. Or just glue a piece of plastic to stop the throttle at 80%

 

[chvidgov.bc.ca]

This is exactly the same pattern my throttle exibits, with my FusinMotor geared brushless. I'd also like a more linear response.

 

[itselectric]

Hi!
Hi have lots of issues with my current controller (don't know the brand/model/chip..)
My hub motor is a Bafang SWXH: rear wheel, sensorless.
I have lots of 'hammerring' (the controller seems to don't synchonise) in hills, in accelerations.
Sometimes it don't work at all after the controller failed to run the motor from stop.

Someone in the same configuration (sensorless+freewheel) can run without problem?

I was thinking about the E-crazyman one, it seems to work better.

Thanks!

Feyris:

The sensorless controller that you were having problem with, was it similar to this following link:

http://www.velectris.com/catalog/48v450w-brushless-sensorless-private-road-pi-143.html

Can you possible post a closeup picture for you defected controller. I would like to avoid the same problem that you were having. thanks!

 

[feyris]

Feyris:

The sensorless controller that you were having problem with, was it similar to this following link:

http://www.velectris.com/catalog/48v450w-brushless-sensorless-private-road-pi-143.html

Can you possible post a closeup picture for you defected controller. I would like to avoid the same problem that you were having. thanks!

I'm at work so I can't take pictures but can see it on my bike photo (it's the older one).
Anyway It don't look like yours.