MPIII pedal assist function

[vpersiani]

Hello,

I just installed a MP3 on my VTT.
First I am really impressed by the performance / power of the beast  .

BUT, I can not make the pedal assist work as I expect:
-for me, when I set it to low, I expect to be actually pushing on the pedal meaning making a small effort to keep moving.
-what I experience: on a hill, I do have to push on the pedals and the system is helping me to move. Basically I would say the effort is quite similar to a non electric bike on a level surface: fine On a level surface however, as soon as the PAS starts, bike accelerates strongly and basically I am just rotating the pedals but not making any effort to move the bike and even like this bike ends up running very fast. On a level surface, the only way I could find to run at a medium speed is to use the cruise control I did try to change gear ratio but this did not make the trick for me.

Did anyone have similar experience?
Any idea to change that?

BTW I found out about the parameter setting software called PD_282_speed or Uint1.1 which I believe to be the latest one. I tried changing "Acceleration" in the PAS section but did not really feel any impact (between 2% and 88%). What is this expected to do?

Thanks in advance for your help
(I did a search in the forum but could not identify any relevant post)

Vincent

[Bikemad]

Hi Vincent andto the forum.

Unfortunately, the pedelec sensor unit on the Magic Pies is pretty basic and has no way of measuring the pressure being exerted on the pedals.
It simply adjusts the power relative to the rotational speed of the crank sensor magnet ring.

If the motor assistance is still too much (even in your highest gear) it might be possible to effectively reduce the power by simply reducing the number of magnets on the magnet ring, but I think you will need to make sure that the remaining magnets are evenly spaced around the plastic ring.

I suggest you mark one side of the magnets with a permanent marker before removing them, to ensure they are refitted the correct way around, as the correct polarity of the magnets is very important.

The "Acceleration" setting in the PAS section presumably adjusts how quickly the power is applied, but I have not tried the pedelec function on either of my later Magic Pies to see what effect the setting has.

I removed the pedelec sensor from my original Magic Pie because the early controllers were not programmable and the motor's assistance was far stronger than needed most of the time.
I had originally considered installing a switch so I could easily turn the assistance on or off as required, but I decided it was much quicker and easier to simply remove the sensor completely and just use the standard twist throttle control instead.

Alan
 

[vpersiani]

Thanks a lot for this prompt answer!

I did consider removing some magnets as I guess the ratio between pedals and wheel is rather low on a VTT compared to more road oriented bikes and this might well be part of my problem. In fact I tried to put some metallic tape on 2 magnets to simulate that without damaging anything but this did not have any impact. Not sure that the tape has any real shielding effect on the magnetic field.

Do you know if the magnets are just pressed into the plastic disc and therefore can be removed without damaging anything and therefore in a reversible way?

It's a pity having to do that mechanically since adjusting such gear ratio would be a very easy parameter to implement in the software. Is there any place to list request for new features in this forum or on the GM site?

Vincent

[e-lmer]

My understanding is that the intent of the pedalec is to me some eu safety requirements.  The motor is not supposed to run if you are not pedaling.
 
Torque sensitive pedalecs are built into the crank and more expensive.
 
RPM to power is not a very good way to control power IMHO.

I do pretty good with thumb control instead.

[vpersiani]

I agree with you: pedalec is mainly to be compliant with EU regulation.
However what I would like to do is to be able to use my bike on a daily basis to commute while doing some exercise but not arriving completely wet of sweat at the office. This means getting only limited motor support on level roads but more significant support when going uphill. At the moment I am not pedaling at all on level road... Well at least I was not until yesterday when I reduced nominal current to 10A in the parameters setting.
Can you control smoothly throttle / torque by thumb while pedaling or are you using your bike as a motorbike?

Vincent

[vpersiani]

I have been playing on max current to reduce power of pedal assist (well power in any case in fact). Now down to 7A and still going much much to fast when riding with the family.
Back to my previous questions:
-does anybody know if the magnets are just pressed in and therefore can be removed in a non destructive way?
-is there a place where we can express our wishes for new features? In my case I would love parameter to really adjust pedal assist in the software (maybe gear ratio and rim size could help electronics understand reality of pedal speed vs bike speed) but also a set of parameters for nominal current for instance where you could define 3 values (5 / 10 / 25A for instance) and be able to switch from one value to the other while riding through a switch.

Vincent

[e-lmer]

Vincent;

What you are asking for is a torque sensitive pedalec.

To do that, you need a new crank bearing, rpm won't do. 
RPM is dependent on the gearing, you can't just sat 30 rpm is 10 Amps.

No company can do torque sensitive power unless they make the whole bike.

Those bikes are available, but not as a kit.

I have ridden one of them at a bike shop, was not impressed.

 I control the throttle, when I ride, if the motor can't push the bike, I pedal harder.

[Bikemad]

-does anybody know if the magnets are just pressed in and therefore can be removed in a non destructive way?
-is there a place where we can express our wishes for new features? In my case I would love parameter to really adjust pedal assist in the software (maybe gear ratio and rim size could help electronics understand reality of pedal speed vs bike speed) but also a set of parameters for nominal current for instance where you could define 3 values (5 / 10 / 25A for instance) and be able to switch from one value to the other while riding through a switch.

I seem to recall that the magnets are just a press fit into the plastic ring and should be removable with a little bit of gentle force.

You are welcome to post your suggestions in the GoldenMotor Staff section, but it has been a while since I have noticed any of the GM Staff on the forum.
Alternatively, you could always try sending your suggestions direct to Philip Yao (sales@goldenmotor.com).

Alan