Kunteng : Does speed restriction require the speed sensor?

[djbarnat]

Hi

First of all apologies if this is duplication I have searched the forum and tried to google the answer but I am falling short of gaining clarity. I have the same kunteng controller and LCD as the one in this similar thread http://www.pedelecs.co.uk/forum/index.php?threads/18542/. This thread answers my question to some degree but I am still confused.

Is the magnetic (reed switch) speed sensor their just to give me speedometer capability or does it need to be fitted in order for the motor to stop assisting at 25km/h? Or is the speed restriction handled solely between the motor and the controller?

 

[Swytch Bike]

Hi

No the speed restriction doesn't require a speed sensor - it will be done based on the motor RPM via the controller. This may not be true in some cases, but as far as we're aware, all Kunteng controllers we've seen are speed limited without speed sensing

 

[djbarnat]

Thanks for the helpful reply. That confirms what I've observed since posting. If I set the speed restriction lower on the LCD the motor just runs at a reduced rate. I was expecting it to literally cut out completely past 25km/h and the kick back in once below it but as you say that is not the case. The motor keeps running but only up to a set RPM. Nice to get a confirmation of this, it puts my mind at ease about the regulations.

 

[djbarnat]

This brings a further question to mind. As I understand it the regs state compliant ebikes = "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h (15.5 mph) or if the cyclist stops pedaling". If this is the case how can rpm limiting be compliant. My motor is not cutting out at this 15.5mph I can hear it still running. It is continuing to run but just not contributing any more power. Am I taking this too literally? Does the motor have to actually stop completely at 15.5 to be compliant or is the behaviour I am seeing with my bike legal?

 

[flecc]

This brings a further question to mind. As I understand it the regs state compliant ebikes = "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h (15.5 mph) or if the cyclist stops pedaling". If this is the case how can rpm limiting be compliant. My motor is not cutting out at this 15.5mph I can hear it still running. It is continuing to run but just not contributing any more power. Am I taking this too literally? Does the motor have to actually stop completely at 15.5 to be compliant or is the behaviour I am seeing with my bike legal?

The important word here is "output", rather than the law referring to the motor running. It's clear that output means driving power, and your motor is no longer providing that on your system once the limiter kicks in. Therefore it is compliant with the law.
.

 

[djbarnat]

Flecc. Now you have pointed that out and I have read the sentence a second time I am not sure why I didn't come to the same conclusion myself. Thanks for the clarification