Solved! How should a cadence PAS work

[jai134]

I have two questions about PAS.
I have Golden Motor Magic Pie 5 with pedelec sensor. It is a cadence sensor.
My first question is why PAS level 1 (there are 5 levels) doesn't work? I've tried changing PAS Ratio from 30 to 100 in steps of 10 and level 1 does not work at all. From 70 and up it works from 2. At 30 from level 4.
Second question is if the bike, when the motor kicks in should accelerate up to the speed I've set as top speed without me putting any effort in pedalling. I just continue in the same pace. If I want it to slow down I have to pedal very, very slow for some seconds. That is level 2.
PAS is unusable like this because it is not possible to control the speed.

 

[yooper2001]

With a cadence sensor, each level 1 to 5 has a set voltage percentage of full throttle. So for each level it tops out at a certain speed. When a cadence sensor shows you are pedaling, it will excelerate with its full throttle till that speed is reached. There are 3 controller settings that some controllers may have that effect cadence sensors.
1. Sensor magnet number (12 is most common)
2. Pedal delay(SENSITIVITY). Sets how far you need to pedal till PAS activates.
3. PAS ramp up strength. Sets how fast initial activation ramps up so it doesn't jerk you into the street.

The menu names may be different...but those are the common cadence settings.

My crappy cheap URlife E20 ebike was unusable due to the cheap controller software not being able to adjust the 2nd and 3rd setting. Making riders jerked into the street when bumping the pedal...or even gravity making the crank barely turn. So I upgraded the controller! .

I don't know which setting 'PAS' ratio is referring to.

 

[jai134]

Thanks! I have to check how the levels are set in my controller software.

 

[E-HP]

I have two questions about PAS.
I have Golden Motor Magic Pie 5 with pedelec sensor. It is a cadence sensor.
My first question is why PAS level 1 (there are 5 levels) doesn't work? I've tried changing PAS Ratio from 30 to 100 in steps of 10 and level 1 does not work at all. From 70 and up it works from 2. At 30 from level 4.
Second question is if the bike, when the motor kicks in should accelerate up to the speed I've set as top speed without me putting any effort in pedalling. I just continue in the same pace. If I want it to slow down I have to pedal very, very slow for some seconds. That is level 2.
PAS is unusable like this because it is not possible to control the speed.

Did you buy the system new, or used with the PAS sensor already installed?

 

[yooper2001]

Golden motor is a conversion kit company. I don't think they sell complete ebikes.

I do see that it uses Grins controllers and display.
.....The cycle analyst guys can help you more than I can with that.

 

[E-HP]

Golden motor is a conversion kit company. I don't think they sell complete ebikes.

I do see that it uses Grins controllers and display.
.....The cycle analyst guys can help you more than I can with that.

The PAS is not standard and the option requires soldering the sensor to the conductor pigtails from the controller.
I didn’t say anything about a complete bike.

 

[jai134]

The PAS is not standard and the option requires soldering the sensor to the conductor pigtails from the controller.
I didn’t say anything about a complete bike.

PAS is not standard, that is correct, but the controller harness is prepared for it. Cycle analyst would be a dream but this system comes with golden motor BAC-601 LCD display which is a quite non-smart unit. I do the setting from my Android phone connected with Bluetooth.

 

[stancecoke]

BAC-601 LCD display

Quelle: Golden Motor https://share.google/hdp2J6rpgfuFTchvF

This seems to be a really antique system. Golden Motor has motor integrated "Magic Pie" controllers or external BACxxx controllers.

Bike Conversion Kits, Hub Motor, Magic Pie Edge, LiFePO4 Battery Pack, brushless dc motor, MagicPie-Edge,MagicPie 5,bike conversion kit

I'm not sure, if this are ASI BAC controllers. That's the original manufacturer of grins Base/Phaserunners. ASI BAC controllers are known to be very flexible to setup, but need expert level knowledge to configure them properly.
There are different principles for PAS operation
- speed levels: the PAS level sets the duty cycle of the PWM directly, this leads to a almost constant speed, if you pedal harder, the battery current decreases, but you don't get faster, until you are doing all the job with your legs
- power levels: the PAS level defines the battery current. With this, the motor provides a constant input power if the pedals are turning. So you can get faster with more personal effort. But you can't get slower, without stopping to pedal or choosing a lower level.
From my opinion, both modes are crap. You will get a natural bicycle feeling with a torquesensor based system only.

 

[jai134]

When I start pedal the motor kicks in an accelerates to approx. 25km/h and I don't have to put any effort in keeping that speed. If I pedal really slowly, about 1 turn in 3 seconds the speed decreases to around 15km/h still just pedalling "in the air", completely no resistance. The motor does all the job.
I would like to be able to set level 2 to a lower speed, or get level 1 to work, but you mean that I can not because I need someone with "epert level knowledge" to do it?
It seems like my system is a combination of both mentioned above?

 

[stancecoke]

I would like to be able to set level 2 to a lower speed, or get level 1 to work, but you mean that I can not because I need someone with "epert level knowledge" to do it?

At the bottom ot the linked page, Golden Motor offers programming cables and software tools to tune the controllers. Without them, you will get no access, I guess.

 

[jai134]

I'm using Golden Motor Android app. These are my settings

 

[jai134]

I'd like to say that I really appreciate your help. I don't see any real difference between the options given. Can you?

 

[E-HP]

The PAS options, based on reading their material, the GM forums, and here, only changes how quickly assist kicks in when you start pedaling. The cadence sensor functions as a switch with no scaling relative to pedaling speed or effort.
The behavior you and others describe is that of a speed based controller rather than power/current based. The motor will run full power until reaching the speed for the selected assist level, rather than adding a certain level of assist/power, that will reach that speed more gradually (or faster with some pedaling effort) which would feel more natural.
The CA option would allow for tuning the assist or using a torque sensing pas instead of cadence. It can also use a cadence pas that can adjust assist up or down based on pedaling rpm.

 

[jai134]

CA is a future option. I don't have the money for that now.
It would be nice if I could get level 1 going. If I set 380 rpm as top speed I have different speed at different levels except for level 1. Level 1 and 0 are the same. The problem is that it is way to fast at level 2 with 380. It is ok of I set speed to 170 but then I only have one level that works or three steps are so small so I cant fel the difference.

 

[stancecoke]

CA is a future option

The CA is outdated and bulky. Just buy a controller that is configurable properly. There are tons of offers meanwhile.

 

[jai134]

The nice thing about the Magic Pie is that the controller is inside the hub. I guess I'll have an external controller if I buy a new one?

 

[E-HP]

The CA is outdated and bulky. Just buy a controller that is configurable properly. There are tons of offers meanwhile.

I wasn’t sure that he was willing to perform surgery on the motor, but it’s a decent motor, so might be worth it.
A pro is that the opening for the conductors looks large enough, and if a 9 pin HiGo motor cable is used, fishing the cable through shouldn’t be too hard. There are a few conversion threads on ES, but not very well documented.

 

[fill]

Fwiw I really struggled for my first few rides on a pedal assist bike, it didnt work as i anticipated at all. Now however i have acclimatised to the basic speed capped pas control, and have adapted successfully.

Having a slight amount of play in the rear brake cable/pressure allowing a crack of the brake to activate the cut off without engaging brakes provides the ability to select a high pas level and apply a virtual throttle by feathering the rear brake lever between closed and cracked. the cadence sensor will register 'on' with a ridiculously slow cadence maintained so relaxed zero effort 'ghost' pedalling is available in all cases other than steep climbs.. Although i do try to maintain a level of input myself on most rides.

but the fine control it provides does come in handy when negotiating slow speed obstacles such as offset gates, dogs pedestrians etc..

 

[jai134]

I wasn’t sure that he was willing to perform surgery on the motor, but it’s a decent motor, so might be worth it.

Surgery is not a problem but I want a clean look of the bike. Perfect solution would be just a torque sensor and pas. No display, throttle or cruise control.
I don't want ghost pedalling, I want to feel a good resistance from the pedals. That is one reson for me to try to get more civilized settings in pas levels.

 

[E-HP]

Surgery is not a problem but I want a clean look of the bike. Perfect solution would be just a torque sensor and pas. No display, throttle or cruise control.
I don't want ghost pedalling, I want to feel a good resistance from the pedals. That is one reson for me to try to get more civilized settings in pas levels.

Yup, with no throttle, then the torque sensor is the best solution, since it will provide assistance from a standstill, while the cadence sensor will require at least a half a turn of the crank or more to start providing assistance. So, with the latter, you'd need to make sure you downshift before stopping so you can start off on pedal power alone before assist kicks in.

If the latter is acceptable, then a power/current based controller will provide a better experience, since you can set the assist power slightly lower, and then just add leg power beyond that to maintain your desired speed. Not as nice as a torque sensor, but still a decent experience when pedaling. This option would benefit from having a throttle or button that provides a throttle input, in case you forget to downshift before stopping, so you can give a little assistance for the start, but it's not necessary.

If you go the torque sensor route, research the different sensors available. Some only detect pressure from one pedal input (e.g. only the left pedal, or right), while others detect pressure from left or right. I had almost bought one of the popular sensors, then noticed the issue, and in my case, since I start from a stop with my right leg, I did more research before getting one that would work for me.

 

[stancecoke]

No display, throttle or cruise control.
I don't want ghost pedalling, I want to feel a good resistance from the pedals.

Then the A3 set from Yose Power would be a good choice. I've written a review on it a while ago. I've tested the A3 Pro, that comes with a display, but the normal A3 has no display.

First DIY conversion kit with cassette integrated torquesensor

Yose Power has a new offer for a complete conversion kit. I was looking forward to find something like that, since I've startet experimenting with this sensor in 2022. I had to write my own firmware to make my Lishui controller communicate with the sensor :). There is just one cable from the...

endless-sphere.com

 

[jai134]

Thank you both for great input.