New (first) build with PAS issues

bah

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Jan 25, 2023
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Hi all,

Wanted to check if there is anything else I can do to resolve my non-functioning PAS situation. I'm building my first conversion with the following:

Q100H
S12S
S-LCD1
KT-V12 PAS but I have mainly been experimenting with a split disc style 12 magnet PAS (neither works, but I've been using the split style PAS to root out the problem)

I don't intend to run a throttle in my build, but I have one and the wheel runs fine with it. I don't have brake sensors or speed sensors attached.

I think my issue is either (or a combination of) the choice of the S-LCD1 or the 12 magnet PAS'.

Trouble shooting so far:
So far I have checked the controller's PAS connection seems to be working with roughly 5v going to both signal and ground. I have checked the PAS' wiring by depinning the connector and switching power/signal around. No change when I do that.

I do not think the PAS is malfunctioning because the lights on the split 12 magnet PAS do light up when run the sensor over the magnets by hand. I have also plugged the PAS into the throttle pins (respective signal to signal etc). I can get the motor to actuate when I run the sensors over the magnets when connected to the throttle line. A signal is definitely coming through, just not getting interpreted correctly (I think) at the controller end.

Going back to my identified problems, I've read in various posts that some of the PAS' with more magnets (12) send slightly different signals and they won't always work without spending time changing settings via the display. My downfall here is I chose an S-LCD1 with no ability to get to the C settings, only P (because I was planning to use a display but have it discreetly tucked away so I didn't want the extra remote attached to an S-LCD3 or S-LCD8).

Possible solutions:
Outside of ordering a new LCD with advanced C programming ability (I presume KT-LCD and S-LCD from BMS battery are the same?) or a new PAS, there's not much else to try while my bike waits on the stand? I do have a KT-V6 PAS on the way to try because for $10AUD - why not. I'll update again when I receive/test that. I would like to avoid getting a new LCD if possible, but it seems like I'm missing out on a lot of potential personalisation without the C settings.
 
Have you tried:
Testing while spinning the cranks backwards
Flipping the disc over

Assuming that your PAS level isn't set to 0.

A couple of pics of the sensor installed, one from the front, and another from the side or top, would be helpful.
 
bah said:
I do not think the PAS is malfunctioning because the lights on the split 12 magnet PAS do light up when run the sensor over the magnets by hand.
Does it light when the magnets on the 12-magnet ring pass it, when it is installed on the cranks?

If not, the spacing may be too close (or too far).

If the ring is mounted backwards, it may also trigger the sensor incorrectly (or not at all).

There have been some people that have had to install a PAS sensor backwards, on the opposite side it was intended for, so that it can read a ring running backwards on the other crank; I don't recall the specific controllers or sensors in these instances, though.

Regarding compatibility, there are a few different kinds of PAS cadence signals. I don't know which one is output by the sensor you have vs the one the controller needs, but there is probably info about that here on ES someplace (I didn't see it in a quick search, but only spent a couple minutes at it).

These may be helpful if you don't already know these things, but I don't think they'll fix your problem:
https://ebikes.ca/learn/pedal-assist.html
https://ebikes.ca/getting-started/pas-options.html
 
Thank you both for some suggestions and info.

I've tried reverse peddling the crank, and using both sides of the PAS magnet plate to no success. Though as before, the LED lit up as it passed each magnet. Just no response from the controller/hub motor.

After reading the ebikes ca site that touches on the waveform signals sent by various PAS, I looked into the S-LCD8/KT-LCD8 manual which confirms I probably need a display with access to the C settings to change C1 to accept a reverse signal since I've got the V12 (or some equivalent of) PAS. Even the KT-V6 I have on the way may not end up working if it has a reverse 6 signal output.

m6UboIJ.png


I ended up just putting in an order for an S-LCD8 amongst other things.. this will probably result in an excuse to build another conversion after this is done :D
 
I was going to suggest something better than the LCD1, which I have on one bike, As you found out, it has no provision to adjust for the KT-V12 pas sensor.

I believe these controllers really only look for a pulse train that fits within min/max timing, so lots of magnets makes for a fast pulse that doesn't fit in their window. I used to try bench testing with the disk on a drill and saw it quit working if spun too fast. Ditto if too slow.
.
 
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