Intermittent pedelec sensor - Wisper 905 SE - faulty?

[z0mb13e]

Hi All,

The last few weeks I have been getting intermittent power in pedelec mode. That is to say when I first start pedalling I get power for a few seconds or between 2 and 5 reveolutions of the crank.

I've been relying on throttle until now and I've just opened up the controller housing to check all the connections and everything looks clean and dry. I've unplugged and replugged all the connections just to be sure and it still works on throttle, but the pedelec sensor works even less now though that could be because it has been powered up while testing.

I've also checked the sensor disc and all the magnets are in place (and its the right way round).

Is the hall effect sensor likely to be faulty? Or could it be the controller?

 

[Mussels]

I had similar problems with the detector on my 905 but then I had moved it around a fair bit, I just relied on the throttle. The pedal sensor on my 906 is much better but I don't know why, it could be a new part or I think more likely it's just better protected from the elements.

 

[z0mb13e]

I had similar problems with the detector on my 905 but then I had moved it around a fair bit, I just relied on the throttle. The pedal sensor on my 906 is much better but I don't know why, it could be a new part or I think more likely it's just better protected from the elements.

Did you ever get the sensor on the 905 working again?

 

[Deleted member 4366]

If the wire gets stretched, it can break inside the insulation. I had that on one bike and it gave a similar intermittent function. One other possibility is the brake switch. Unlikely in you case, but in case anybody else has a problem: Either the brake switch isn't adjusted properly so it comes on by itself, or, if you ride with a finger on the brake, it can be enough to operate the switch. Normally the switches are on a screw thread, which can be wound in and out to adjust the sensitivity.

 

[Mussels]

Did you ever get the sensor on the 905 working again?

I never solved it as I had a full width throttle that was easy to use, if I had a half width one I would have put a lot more effort into it.

 

[z0mb13e]

If the wire gets stretched, it can break inside the insulation. I had that on one bike and it gave a similar intermittent function. One other possibility is the brake switch. Unlikely in you case, but in case anybody else has a problem: Either the brake switch isn't adjusted properly so it comes on by itself, or, if you ride with a finger on the brake, it can be enough to operate the switch. Normally the switches are on a screw thread, which can be wound in and out to adjust the sensitivity.

I did try wiggling the sensor cable at along its length (to see if it was a broken wire) while turning the crank but it didn't seem to make any difference so I figured it wasn't that.

I also checked the brake cut out switch (the front brake isn't fitted with a cut out switch as it is a standard hydraulic disc brake) and as it worked on throttle anyway I didn't think it could be that (throttle cuts out when the brake switches are active).

So unless I'm missing something else I guess the sensor or controller must be faulty. I think I will order a replacement sensor and see if that makes any difference.

 

[z0mb13e]

I never solved it as I had a full width throttle that was easy to use, if I had a half width one I would have put a lot more effort into it.

I have the half width throttle and it is a pain to use all the time. Quite literally painful to hold all the time!

 

[Mussels]

I have the half width throttle and it is a pain to use all the time. Quite literally painful to hold all the time!

I second that, thankfully the sensor on my 906 works very well.

 

[bazwaldo]

My Bearprint recently had a problem with the pedal sensor becoming intermittent and then stopping all together.
It turned out to be physically broken, the part with the screw holding it in place had actually broken off some how.
The suppliers popped one in the post for me as it is still within warranty and this fixed the issue.
Phil and Steve at Bearprint have done me proud really having also sent out 2 replacement controllers and just this week a replacement front light bracket which had snapped off from a stress fracture caused by the constant bumping on the uneven roads. Touch wood my bike is working well with no problems at the moment.
I hope the new sensor resolves your problem.
Best wishes,
Barry.

 

[z0mb13e]

My Bearprint recently had a problem with the pedal sensor becoming intermittent and then stopping all together.
It turned out to be physically broken, the part with the screw holding it in place had actually broken off some how.
The suppliers popped one in the post for me as it is still within warranty and this fixed the issue.
Phil and Steve at Bearprint have done me proud really having also sent out 2 replacement controllers and just this week a replacement front light bracket which had snapped off from a stress fracture caused by the constant bumping on the uneven roads. Touch wood my bike is working well with no problems at the moment.
I hope the new sensor resolves your problem.
Best wishes,
Barry.

I had a simmilar problem on the Cyclamatic on Friday, the chain jumped off the chain ring and smashed the plastic sensor off of the metal mount. I was able to glue it back on and thankfully it still works. For some reason the throttle on the Cyclamatic doesn't seem to kick out as much power as the pedelec mode so I don't fancy riding that on throttle only!

As for the sensor on the Whisper, it is physicaly intact so fingers crossed the replacement fixes it.