Motor revs to max speed during pedal assist

[blaster]

When I pedal the bike, the hub motor spins at the max rpm.    In other words the bike travels at the max speed the rear hub motor will take it.   If I want to go slower,  I have to turn the battery power off.

All or nothing... Any ideas? 

I changed out the controller as I thought that was the problem.  And I replaced the sensor at the crank.  The bike has a hand throttle and I do get varable speed.  If I rode it like a scooter I'd be fine but I prefer the pedal assist.

I was thinking that it could be something in the hall sensor but the fact the I get a full speed range using the hand throttle makes me think maybe not.

Help!!!

[Helgeo]

I'm afraid this is just the way it was designed. It works the same way for me.

Actually I cannot think of a way this could be made to work with just the magnetic pedelec sensor. If the motor was to run faster when pedalling faster, what would then happen when you change to a lower gear? You would go faster and load the motor even more.

A torque sensor would be needed to apply throttle proportonally to the pedalling force.

Another solution would be to use the pedelec and the throttle together so that the throttle works just like now, but only when pedalling.

And yet another solution would be to have a current regulator in the controller, that would reduce the power when the current  gets too high. Like when going up-hill or when not pedalling enough.

Hope to see a new advanced controller with some or all of the above 
An option for updating firmware via USB  would also be nice.

Helge

[blaster]

It did run at a lower speed during pedal assist and then something happened.  I thought it was the controller that would limit the hub speed but I installed a new controller and that did not fix the problem. 

So I disagree with you and still feel that something else is the blame.

Thanks for the reply and I hope that your wrong on this one.

[GoldenMotor]

Dear sir/s,

We are sorry to inform you that the only way to go slower is to stop pedaling. This is one of the limitations of the manually-installed Pedelec System. It is not a true torque sensor. The true torque sensor is only available on the entire e-bike we manufacture. However be afraid ... not. Our new Magic Pie hub motor will have a true torque sensor built into the motor. You have two options:
1)Order whole bike with true torque sensor
2)Wait for the Magic Pie
3)Continue with your existing controller.

Yours,
Yao Yuan

[liared]

Yao Yuan wrote:
"Wait for the Magic Pie" as alternative 2.
I am interested to get a Golden Motor kit with Pedelec function which is reqired where I live (Sweden/EU).
I think of a 36 V mini motor system with the 16AH long range Lifepo4 battery.
Some E bike systemes here on the market have true torque sensor systems. These systems sometimes also have different motor assist levels that can be chosen (for instance Strong motor assist (Sport), Neutral assist and Economy assist for longest range).
Does the new magic Pie system offer a pedelc system that has a true torque sensor combined with choosable levels of assist as described abobe?
Will the true torque sensor be more complicated to mount on a DIY bike than the present magnetic sensor?
I imagine that a true torque sensor must somehow "feel" how hard the pedals are pressed on!?
When will the Magic Pie motor be available to buy?
Regards
Bengt

[e-lmer]

The torque sensor must measure the force on the crank arm, and so must
be integrated into the cranks.

For this reason it is unlikely that you will be able to purchase a true
torque sensor.

(I suppose a chain deflection guage would work on a bike with no
deurailer, but who wants a cruiser e-bike.)

[Helgeo]

Sounds like GM is installing the torque sensor inside the new motor/wheel. This could work well in a rear wheel if it actually senses the torque that is applied on the gear casette.

Helge

[Perbear]

Beside "Magic Pie" there are plenty other options, here are some that come to my mind:

1. The pedelec sensor could be used to turn on/off power to the throttle. This way the throttle would only work when pedals are used. Voilá - EU legal ebike. This can be made with a very simple circuit using a 555 timer or similar.  But: EN 15194 require that motor must stop before cycle has moved more than 5 m after pedaling ceased when brake switches are installed, and within 2 m if cycle lack brake switches. Unfortunately the GM PAS has only five pulses per pedal revolution making it difficult to follow the standard. A better version would be to use two inductive sensors (with quadrature timing required to sense rotational direction, the PAS shall only react when pedaling forward). By locating the sensors close to the krank sprocket teeth you would get 40-50 pulses per revolution.  This way no brake switches would be required, and the PAS would turn on power to the throttle immediately.

2. Torque sensor integrated into the krank axle could me made to control the throttle input on the GM controller. I would suggest using sensor supplied by this company, but they seem to only sell to distributors: http://www.jc-ebike.com/ywlj/indexp.html

3. A spring loaded chain (or belt) tensioner with a switch that is triggered when tension is applied. The switch turn on/off power to the throttle. This is probably the simplest and best solution to make the existing GM controller legal here in Europe. Then you would not need the PAS, only a simple microswitch activated by a tensioner arm with a wheel on the chain (or belt).