Speed reading incorrect on KT lcd5 on Carrera Subway e bike upgrade

[ArtNuevo]

Hi,
I have recently replaced the controller, screen and PAS on 2 Carrera ebikes. One earlier model and one later model. All works perfectly on the early model and have been able to use existing battery. All works fine on the later model but needed to replace the battery as it would not work with existing battery due to BMS i believe. However on the later model the speed is incorrect. All the settings match the settings on the early model on which the speed shows correctly. On the later model the speed goes almost instantly upto 49 mph. It does it gradually so if slowing down the speed slows down or speeds up etc, but obviously a lot faster than actully travelling. This also means walk assist is not working correctly as it cuts out above 6kmh which is hit almost instantly at walking pace. I have adjusted the P1 setting from 01 right upto 225 and lots in between but speed readout stays the same. Any ideas anyone. Thanks for reading
Jerry

 

[Saracen]

From another frum.

Depending on the type of speed sensor, it is usually a combination of the Wheel size and the number of poles in the motor or number of magnets in the speed sensor. If your speed is reading as 2-3 times faster than it should be and your wheel size is correct, check if your controller has an option for number of poles in your motor or PAS sensor. it is probably set to be 2-3 times different than it should be and is counting one full rotation as 2-3 rotations.

 

[Woosh]

I have adjusted the P1 setting from 01 right upto 225 and lots in between but speed readout stays the same. Any ideas anyone.

it seems that your LCD5 does not communicate with the new controller. Can you swap LCD between your two bikes?

 

[ArtNuevo]

it seems that your LCD5 does not communicate with the new controller. Can you swap LCD between your two bikes?

All the kit is identical and I upgraded both bikes with exactly the same kit. I can only assume the speed sensor on the later model is different. However I will swap the screens and see if that works.
Thanks for your replies.

 

[saneagle]

If the kit is identical, the motors are different. Bafang hub-motors of the same type can have one or six magnets for the speed sensor. It looks like Suntour ones are the same. Your later motor has six and the earlier one has one magnet. It's therefore P2=6. P1 is for the hall sensor signal, and it affects the interpretation of the motor RPM for the speed limit. The speed display is calculated directly from P2 unless you set P2=0 for a direct drive motor or a installation without a speed sensor.

 

[ArtNuevo]

If the kit is identical, the motors are different. Bafang hub-motors of the same type can have one or six magnets for the speed sensor. It looks like Suntour ones are the same. Your later motor has six and the earlier one has one magnet. It's therefore P2=6. P1 is for the hall sensor signal, and it affects the interpretation of the motor RPM for the speed limit. The speed display is calculated directly from P2 unless you set P2=0 for a direct drive motor or a installation without a speed sensor.

Hi,
Changed the P2 setting to P2 = 6 and that has worked. Thank you for the advice. Pleased that I now have 2 Carreras that we can be confident of not breaking down. I was also able to conceal the controllers in the space where the existing controller were, by the bottom bracket, with a bit of fettling. So they look like 2 standard Carreras.
Thanks again

 

[saneagle]

Hi,
Changed the P2 setting to P2 = 6 and that has worked. Thank you for the advice. Pleased that I now have 2 Carreras that we can be confident of not breaking down. I was also able to conceal the controllers in the space where the existing controller were, by the bottom bracket, with a bit of fettling. So they look like 2 standard Carreras.
Thanks again

Thanks for the update. this all helps the many other Carrera bike owners, who are going to want to go through this.