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PAS issues

bunchie3174

100 µW
Joined
Dec 30, 2023
Messages
8
Location
Worcestershire
Hi all
I'm currently fitting a Yose Power 350w hub kit to my Boardman MTB and have run into an issue with the PAS.
Firstly as it's a top end 29er it is fitted with beefy FSA cranks and chainwheel so the kit PAS isn't any use. So to offset this I bought a 12 magnet disc and sensor (the 2 half version with circlip). I fitted it to the inside of the smaller chainring (drive side) and mounted the sensor on the seatpost with the crosshairs inline with the magnets.
Test one. Everything worked, thumb throttle, display unit etc...but I had no drive when pedalling. After some closer looks and head scratching we say that the sensor light only illuminated when pedalling backwards. So I changed the display unit parameters From Run-B to Run-F. It made no difference. I then took the chainwheel off, flipped the magnet disc 180 degrees and reassembled. No difference, still ran in reverse only. Changed display settings as per instructions, compared it to a friends bike which has an identical setup/display.
Further testing in all settings confirmed that getting up to speed normal pedalling then pedalling backwards did cause the motor to kick in. Quite a weird sensation but impractical.
I've tried a third PAS disc (8 magnet and sensor on a metal disc) and installed it non drive side. Due to the chunky nature of my BB the sensor isn't able to get within range of the magnets.
I can only get a signal from sensor v2 and guess what? It runs in reverse despite flipping the mag disc 180 and changing the settings on the display.
Do any of you esteemed experts have the remotest clue what is going on? Display is the standard Yose C500.
Ian
 
mazon.co.uk/FAMEX-RIDE-Pedals-Waterproof-Magnetic/dp/B09KGSRDYY/ref=sr_1_5?crid=2CVCR9OPYF8U5&keywords=pas+sensor&qid=1703955823&sprefix=pas+sensor%2Caps%2C86&sr=8-5 This is identical to the drive side disc/sensor. This sensor is the only one I've managed to get any signal with. No directional arrows on disc.

https://www.amazon.co.uk/Hacbop-Mag...d=1703955919&sprefix=pas+sensor,aps,86&sr=8-9 This is what I've attempted to fit to non drive side. Can't get a response from the sensor due to the diameter of the bottom bracket being only about 5mm less than the diameter of the magnet disc.
This magnet disc has directional arrows.

https://www.amazon.co.uk/Abaodam-El...=1703955919&sprefix=pas+sensor,aps,86&sr=8-11 This is very similar to the PAS supplied with kit.
None of them stated a drive side preference in the descriptions, to my knowledge.

I'm wondering if there is a way of taking kit version apart and gluing on the sensor to frame and making a custom magnet disc?
 
mazon.co.uk/FAMEX-RIDE-Pedals-Waterproof-Magnetic/dp/B09KGSRDYY/ref=sr_1_5?crid=2CVCR9OPYF8U5&keywords=pas+sensor&qid=1703955823&sprefix=pas+sensor%2Caps%2C86&sr=8-5 This is identical to the drive side disc/sensor. This sensor is the only one I've managed to get any signal with. No directional arrows on disc.

https://www.amazon.co.uk/Hacbop-Magnets-Waterproof-Connector-Electric/dp/B098DZR36F/ref=sr_1_9?crid=2CVCR9OPYF8U5&keywords=pas+sensor&qid=1703955919&sprefix=pas+sensor,aps,86&sr=8-9 This is what I've attempted to fit to non drive side. Can't get a response from the sensor due to the diameter of the bottom bracket being only about 5mm less than the diameter of the magnet disc.
This magnet disc has directional arrows.

https://www.amazon.co.uk/Abaodam-Electric-Assistant-Conversion-Accessories/dp/B09SG98JZL/ref=sr_1_11?crid=2CVCR9OPYF8U5&keywords=pas+sensor&qid=1703955919&sprefix=pas+sensor,aps,86&sr=8-11 This is very similar to the PAS supplied with kit.
None of them stated a drive side preference in the descriptions, to my knowledge.

I'm wondering if there is a way of taking kit version apart and gluing on the sensor to frame and making a custom magnet disc?

I see that you've shown three sensors. One of them can detect rotation when pedaling both forward and backward; it doesn't matter, your controller will provide power to the motor in both cases. The image below shows which sensor I'm referring to. It is usually installed on the drive side due to the teeth it has on the magnetic plate.

ps.png

The other two sensors are more intelligent, and they sense rotation only in one direction. They must be installed on only one side, and if you were to place them on the other side, you would need to change this in the LCD so that the controller is aware of it.
 
Last edited:
I see that you've shown three sensors. One of them can detect rotation when pedaling both forward and backward; it doesn't matter, your controller will provide power to the motor in both cases. The image below shows which sensor I'm referring to. It is usually installed on the drive side.

View attachment 345274

The other two sensors are more intelligent, and they sense rotation only in one direction. They must be installed on only one side, and if you were to place them on the other side, you would need to change this in the LCD so that the controller is aware of it.
This is the one currently fitted to LH side
 
This one is a left side sensor (“L” suffix).
Just found the description of the version I bought and there is no mention of handedness. I could easily remove it from crankside and fit LHS.
There were no instructions provided. Description below

3 Pin PAS 12 Magnet Electric Bike Pedal Assist Speed Sensor Ebike Clip On Tool






Description:

This PAS sensor features a 12-magnet disk, giving a higher sensor resolution than other disks with fewer magnets. This higher resolution means that less pedal operation is required before pedal assist from the motor starts.

This is an easy install clip on the sensor. No need to remove the crank arm for installation. Secure down with included zip ties.



Specification:

Cable length: 93.5 CM

Disk diameter: 83mm

Number of magnets: 12

Disk to sensor distance: Less than 3mm

Connector type: 3 pins Male waterproof (see photos)

Please ensure your controller can fit this type of plug, if not the sensor can be rewired according to your controller. (We are not liable for damage caused to your controller, proceed at your own risk!)



Package Included:

1x Electric Bike 3 Pin PAS 12 Magnet Pedal Assist Cadence Speed Sensor (3 pin waterproof)

2x black zip ties
 
This is the one currently fitted to LH side

If you have an electric screwdriver, you can attach the magnetic plate to it and rotate it near the sensor in both directions.

If it works with a screwdriver, then you have installed the sensor and magnetic plate incorrectly ,such as the distance between the magnetic plate and the sensor or whether it rotates at all.
 
If you have an electric screwdriver, you can attach the magnetic plate to it and rotate it near the sensor in both directions.

If it works with a screwdriver, then you have installed the sensor and magnetic plate incorrectly ,such as the distance between the magnetic plate and the sensor or whether it rotates at all.
The current setup, chainwheel side, works as of now. It's just that it only operates in reverse, regardless of orientation or display setting.
The magdisc only fits two possible ways. tried both, with both display settings, F & R. I cannot fathom how fitting it to the other side of the bike will make a difference. It would be the same disc in the same orientation and the same sensor. Or is there some polarity pattern with the magnets?
 
The current setup, chainwheel side, works as of now. It's just that it only operates in reverse, regardless of orientation or display setting.
The magdisc only fits two possible ways. tried both, with both display settings, F & R. I cannot fathom how fitting it to the other side of the bike will make a difference. It would be the same disc in the same orientation and the same sensor. Or is there some polarity pattern with the magnets?

See if it's possible to check whether the magnetic plate also rotates when pedaling forward.

Perhaps it somehow gets stuck when pedaling forward.
 
No rotation. It's glued to the inside of the inner chainring. It's further shaped to fit between the chainring bolts and was very secure even before I glued it

I can't think of anything else except that your sensor is one that senses both forward and backward directions, and then it could be changed in the LCD as you tried.

I hope someone with a similar controller and PAS sensor can help you.

I have similar sensors like the ones in the picture I sent earlier, and they sense both directions.
 
I found this online.

Additional Troubleshooting Tips

If pedalling backwards causes the motor to engage, simply flip the magnet disc over to reverse the required direction of movement.

Cadence sensors sometimes feature an LED that flashes each time a magnet passes the sensor head. This is handy for verifying that the PAS sensor is functioning correctly “in the field”. Illumination however, does not necessarily mean that the sensor is wired correctly. If the 5V power feed is incorrectly backfed through the signal wire, the LED will illuminate, but nothing will happen. If this is the case with a newly installed sensor, it might be worth checking if the 5V and signal wires haven't been accidentally swapped.


I reckon I may have fitted it in 3 of the possible 4 options. I'll close out the year trying to sort it once and for all. Was hoping to spend my xmas break zooming about the forest. Spent most of it in the shed
 
Hi all
I'm currently fitting a Yose Power 350w hub kit to my Boardman MTB and have run into an issue with the PAS.
Firstly as it's a top end 29er it is fitted with beefy FSA cranks and chainwheel so the kit PAS isn't any use. So to offset this I bought a 12 magnet disc and sensor (the 2 half version with circlip). I fitted it to the inside of the smaller chainring (drive side) and mounted the sensor on the seatpost with the crosshairs inline with the magnets.
Test one. Everything worked, thumb throttle, display unit etc...but I had no drive when pedalling. After some closer looks and head scratching we say that the sensor light only illuminated when pedalling backwards. So I changed the display unit parameters From Run-B to Run-F. It made no difference. I then took the chainwheel off, flipped the magnet disc 180 degrees and reassembled. No difference, still ran in reverse only. Changed display settings as per instructions, compared it to a friends bike which has an identical setup/display.
Further testing in all settings confirmed that getting up to speed normal pedalling then pedalling backwards did cause the motor to kick in. Quite a weird sensation but impractical.
I've tried a third PAS disc (8 magnet and sensor on a metal disc) and installed it non drive side. Due to the chunky nature of my BB the sensor isn't able to get within range of the magnets.
I can only get a signal from sensor v2 and guess what? It runs in reverse despite flipping the mag disc 180 and changing the settings on the display.
Do any of you esteemed experts have the remotest clue what is going on? Display is the standard Yose C500.
Ian
Hi, could you please send the photo about the installation area of the PAS sensor to our service email at service@yosepower.com? Our service team will carefully review the images and provide guidance for you. Thanks for your cooperation and support.
 
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