PAS stopped working - any advice on what to check?

jake369

Finding my (electric) wheels
Jan 6, 2017
22
4
Sussex
Hi all - conversion been going well for 12 months and 4000+ miles using the kit from here http://www.oxydrive.co.uk/electric-bike-kit/oxydrive-cst-ht-13ah.html

With all the wet weather, the pedal assist has stopped working. I had some moments where it stopped and restarted after some minutes when it has been really wet - this recent lot of wet weather when it stopped and hasn't come back for a couple of days I thought it wise to look a bit closer.

I've unplugged the sensor and the connections were all dry inside, I've re-positioned it closer/further from the plastic wheel on the bottom bracket. I notice the red LED that is on it is very dim.

Any advice on what I should check next?

(everything else working, am using the throttle at the moment instead).



2018-01-27 11.37.jpg



Thanks
 

Woosh

Trade Member
May 19, 2012
19,473
16,419
Southend on Sea
wooshbikes.co.uk
the LED is supposed to flash when the magnets pass in front.
 
D

Deleted member 4366

Guest
There are additional connectors inside the controller box. They're glued in IIRC, so don't pull them out of the PCB. Instead, check to see if a pin or wire has been pulled. You need to follow the PAS wire to see which three come out of it and where they join to the PCB connectors.

If you pull any of the wires that come out of the controller box too hard, it can compromise the PCB connection because there's nothing to hold the wire. I'd put cable-ties around the cable on the inside of the box to work as stops to prevent the connectors being pulled.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,785
The European Union
Is the disk slipping?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,110
8,219
60
West Sx RH
My Oxydrive pas developed the same fault in wet drizzly conditions, I could only assume it was water ingress via the cable entry conflicting the 5v line, it cured it self in a dry garage after a day or two. I then sealed around the cable entry and it never occurred again. In my case the sensor was a BB type fitting with the sensor in the horizontal plain.

I would also suspect water getting into the sensor from your description, noticed your sensor could be prone to possible water damage due to the cable entry orientation. Water can easily track down via cable entry and cause a short issue, sensor ideally needs to be fitted like a hub motor wire to prevent water ingress.
If their is enough wire length try and refit the sensor ( remove and dry thoroughly first, airing cupboard or warm radiator for a day or two) with cable entry at the bottom and a bit of sealant around the cable entry super glue may work or a non setting mouldable butyl mastic ( Everflex 145) that is very sticky and elastic but once open to the air cures somewhat but remains pliable and looses its stickiness and is water proofing

Other wise the most obvious cause of malfunction is the disc or sensor gets knocked and one will be out of alignment maybe because the chain coming off or accidentally by foot or debris damage.
Also the gap between the sensor and disc magnet should be very close 1 or 2 mm for a good signal and as Woosh stated as the magnets pass the sensor the red led should blink.
 
Last edited:

minexplorer

Esteemed Pedelecer
Aug 22, 2017
532
93
55
Four Lanes,Cornwall
Hi all - conversion been going well for 12 months and 4000+ miles using the kit from here http://www.oxydrive.co.uk/electric-bike-kit/oxydrive-cst-ht-13ah.html

With all the wet weather, the pedal assist has stopped working. I had some moments where it stopped and restarted after some minutes when it has been really wet - this recent lot of wet weather when it stopped and hasn't come back for a couple of days I thought it wise to look a bit closer.

I've unplugged the sensor and the connections were all dry inside, I've re-positioned it closer/further from the plastic wheel on the bottom bracket. I notice the red LED that is on it is very dim.

Any advice on what I should check next?

(everything else working, am using the throttle at the moment instead).



View attachment 23176



Thanks
Not much help but rain was the cause of my PAS dying completely.Prob different reason but....After a few days it came randomly back to life.After 2 weeks it was back to normal.
 

jake369

Finding my (electric) wheels
Jan 6, 2017
22
4
Sussex
Now it is mentioned, I do remember it stopping working before after a week of rain but by the afternoon it must have had dried out and suddenly started again.

I'll look at the possibility of re positioning the sensor and the cable, maybe horizontal - although I'm pretty sure I found the only possible position in such a tight space when I first fitted it.

The disk is turning and I've tried different positions just in case the sensor has got knocked. I've never noticed the LED flashing before, but then I don't think I've ever looked. With a continuity meter I am thinking I should see a reading off the 3 pins from the sensor (I haven't tried, but I might have a go).

I can see how water could also get into the controller too as the wires go in right at the bottom - it's all pretty grubby down there.

Thanks for replies - water and the recent constant rain sounds to be the likely cause. It really has not stopped and while I don't cycle through large floods, I do have to go through puddles which seem to be little lakes at times, much to the delight of having wet feet/legs for the rest of the day.