Can't make simple PAS work

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Firedog   10 W

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Can't make simple PAS work

Post by Firedog » Apr 19 2020 12:08pm

I've built dozens of kit ebikes. I've never been a fan of simple cadence PAS finding a throttle with cruise control and several levels of power better.

I doing a build now that requires PAS, but I can't make it work. I tried 3 controllers that have both throttle and simple crank mounted, magnet activated PAS sensor. Two of the set ups were complete Crystalyte kits (36v Journey controllers, with Hall sensor brakes, throttle, PAS hardware and a 408 front hub motor). The throttle works great. But just pedaling...nothing. The sensor show proper voltage on the 5v and ground and the signal wire changes V state with each magnet pass. It's not a brake switch set on. The Journey controllers have a on/off switch marked "Pedal assist system"; I assume to turn off PAS. Whenever the switch is changed from of to on, the motor makes brief shake which I assume is a reminder that PAS is now active. But, whatever position: no PAS.

I switched to a 36v500w controller from an Ebay kit with PAS. Same results; thottle works fine, PAS voltages and output fine; no motor assist when pedaling,

I search for a similar problem, but no one seems to have problems making PAS work. It's got to be something simple. What am I missing?

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E-HP   1 MW

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Re: Can't make simple PAS work

Post by E-HP » Apr 19 2020 12:19pm

While testing, did you turn the crank in both directions?

Firedog   10 W

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Re: Can't make simple PAS work

Post by Firedog » Apr 19 2020 2:40pm

Yes, both directions..... but not for long enough!! It starts after 2 or 3 cranks in reverse. Thank you, so much.

I'll have figure how to remount the PAS to give the controller the direction it wants. Or is there a better way?

AHicks   1 kW

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Re: Can't make simple PAS work

Post by AHicks » Apr 19 2020 2:54pm

I think you'll find it works fine when mounted on the opposite side of the crank from where it is now. Some controller displays will allow you to do this in the parameters.

Too, if you don't like to have to crank 2 revs to get power, some times there is a "number of magnets" variable that can be played with.

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E-HP   1 MW

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Re: Can't make simple PAS work

Post by E-HP » Apr 19 2020 3:14pm

Firedog wrote:
Apr 19 2020 2:40pm
Yes, both directions..... but not for long enough!! It starts after 2 or 3 cranks in reverse. Thank you, so much.

I'll have figure how to remount the PAS to give the controller the direction it wants. Or is there a better way?
They are directional, and sometimes have an "R" or "L" in the model name, but not always, with "L" being mounted on the left side of the crank for example. If you want it to activate sooner, then you want one with more magnets (some have only 5 magnets, and others have up to 12.

Nutsnbolts23   1 µW

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Re: Can't make simple PAS work

Post by Nutsnbolts23 » Oct 07 2020 12:22am

I have a basic 48v 1000w brushless gearless ebike kit /the kit came with a pass sensor though no display do I need a display for pass assist to work /the sensor is getting installed on bigger diameter crank shaft and the disc with the magnets center hole had to be made bigger to fit over the crank shaft and I don't think that would change the height of the magnets/ would you know approximately how much distance is allowed between the magnet disc and the sensor

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