PAS (Pedal Assist) is slow to disengage the Motor

bobsyleck · Mar 27, 2016

I have the PAS option on my e-bike (cadence type) and have found that it is a little slow on the uptake, i.e. it takes a few pedal revolutions before the Motor begins to contribute, but that I believe is quite normal esp. for the Cadence (Magnets on a plastic wheel) type, what is actually concerning me is that the Motor is quite slow at cutting out AFTER I've stopped pedalling!?
There is a noticeably prolonged effort to propel me forward via Motor Assist for some 4/5 seconds after I've ceased pedalling, which can be somewhat worrying at a blind junction; The only saving grace I have is that my Kit came with 'Motor Cut-Off' capability on using the brake levers - (without that function and with just the normal/original brake levers attached the situation might well have caused me some really troubling times!).

So My Question is, is this just an inherent feature of my Controller and something I'll have to learn to live with? or is there a modification/tweak I can do to improve the Motor Cut-Off/Response Time?
** I have some amateur soldering skills if needs must.

motomech · Mar 27, 2016

4 to 5 seconds seems a little excessive. My PAS "over-runs" a couple of seconds, about the same amount of time it takes to engage. Maybe one of the experts here could help re-engineer your controller, but it doesn't seem worth the effort, even if it is possible.
The controllers I use are budget units, about $40 US shipped. If your is not overly expensive or intergral to your system, you might try another varity.

bobsyleck · Mar 27, 2016

thanx ' motomech', I am indeed edging toward getting a new Controller anyway due to other issues, so spending a few Dollars/Pounds more could well be the way to go.

TheBeastie · Mar 27, 2016

I would say that my PAS engage/dis-engage is dead accurate.. no ghosting of either way.. I am using the S12S controller with an KT-LCD3 type display..

I have noticed but yet to try the various C1 PAS sensor settings as this LCD/Controller setup can adapt to different types of PAS sensors..
check out the manual and put ctrl+f "C1 parameter setting interface" or just go to page 23..
https://drive.google.com/file/d/0BzOr1Lix29NwOWhRZGdCV0o3amM/edit
I attached it as a pic for extra convenience.

bobsyleck · Mar 28, 2016

ty TheBeastie. That S12S controller looks the real business too - I've just been checking out some reviews/opinions on that 'Torque Simulation Sine Wave Controller' and all seem very impressed.

Avitt · Mar 28, 2016

bobsyleck said:
ty TheBeastie. That S12S controller looks the real business too - I've just been checking out some reviews/opinions on that 'Torque Simulation Sine Wave Controller' and all seem very impressed.

Here's another endorsement for the PAS functionality on the S12S. Mine cuts in after about 1/3-1/2 pedal rotation (with a 12 magnet sensor) and cuts out nearly instantaneously when pedaling stops.

bobsyleck · Apr 18, 2016

***In the end I've simply done away with the PAS system on my Bike as I think that with the Motor having such power/torque (1000W) it's gonna be difficult to engage it without the inevitable surge as it kicks-in. Safer to do without - there's much more control with throttle usage alone.

bobc · Apr 20, 2016

I don't know but guess it might be a general feature. The PAS sensor is looking for "edges" on a signal from the sensor. It will switch off when the edges stop. How long should the software wait before deciding that the edges have actually stopped and you're not just pedalling slowly? Maybe it's waiting 3 or 4 seconds......??

dogman dan · Apr 20, 2016

My opinion too. I just prefer a throttle big time.

But I have ridden good smooth PAS, and like it fine when it works well. Just hate jerky PAS.

Esting · Apr 20, 2016

bobsyleck said:
I have the PAS option on my e-bike (cadence type) and have found that it is a little slow on the uptake, i.e. it takes a few pedal revolutions before the Motor begins to contribute, but that I believe is quite normal esp. for the Cadence (Magnets on a plastic wheel) type, what is actually concerning me is that the Motor is quite slow at cutting out AFTER I've stopped pedalling!?
There is a noticeably prolonged effort to propel me forward via Motor Assist for some 4/5 seconds after I've ceased pedalling, which can be somewhat worrying at a blind junction; The only saving grace I have is that my Kit came with 'Motor Cut-Off' capability on using the brake levers - (without that function and with just the normal/original brake levers attached the situation might well have caused me some really troubling times!).

So My Question is, is this just an inherent feature of my Controller and something I'll have to learn to live with? or is there a modification/tweak I can do to improve the Motor Cut-Off/Response Time?
** I have some amateur soldering skills if needs must.

You don't say which make and model controller you have or system you get better help if we new that.

bobsyleck · Apr 20, 2016

esting, its a chinese eBay kit - 1000w 48V with a 15 FET unBranded/unMarked generic Controller, and Its a crank situated 5 Magnet Cadence type PAS; Which is probably the most basic type you can get and in my opinion not responsive enough for the output torque of such a Motor - thats why I have decided to disengage it. I tend to agree with dogman dan, best to rely on throttle input alone with this Motor or upgrade to a superior PAS System i.e. one with a Torque Sensor

Esting · Apr 20, 2016

bobsyleck said:
esting, its a chinese eBay kit - 1000w 48V with a 15 FET unBranded/unMarked generic Controller, and Its a crank situated 5 Magnet Cadence type PAS; Which is probably the most basic type you can get and in my opinion not responsive enough for the output torque of such a Motor - thats why I have decided to disengage it. I tend to agree with dogman dan, best to rely on throttle input alone with this Motor or upgrade to a superior PAS System i.e. one with a Torque Sensor

Well that does make it a lot more difficult when unbranded to diagnose help, 1000w and up not a good with PAS.

Avitt · Apr 20, 2016

Again, if you're looking for an excellent PAS experience, get an S12S controller, and use it in torque simulation mode. This lets you control the maximum power by adjusting the PAS assist level.

I use one with a MAC 10T on the front wheel, and a 50V battery. Because it's on the front, the traction is not ideal, and I will get a bit of wheel spin if I take off from a stop with the assist level set to 5. But if I reduce the assist level to 4, the take-off is quick and smooth. (I don't think wheel spin would be an issue with a rear drive.). And once the bike is moving, the PAS assist comes on and off in smooth, fluid and intuitive fashion.

I did end up adding a supplemental torque sensor, but even with the PAS alone, I never missed having a throttle.

PAS (Pedal Assist) is slow to disengage the Motor

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