MPH not showing up on KT LCD4

[kmxtornado]

How does the bike sense speed? On my old setup, I had a magnet and sensor on the wheel that sensed the MPH on a separate cycling computer (has nothing to do with the e-bike kit). However, on my new setup with new controller (KT's 500w 25a), there's no such sensor nor connector.

I assume I just need to get a replacement sensor with cable to physically connect to the controller? I may be answering my own question but just need you guys to help verify. I do have a PAS sensor on the way. Would that replace the speed sensor? In other words, if I have the sensor plugged into the PAS connector on the controller, would I still need a separate speed sensor to plug into that corresponding wire on the controller? I'm guessing no and I can just leave that alone. My understanding of the PAS sensor is that the cadence sensor itself is a form of speed sensor and having a separate "speed sensor only" would be redundant.

My KT LCD4 display currently just reads 0 MPH. Hoping to get some suggestions or help on this. TIA.

 

[amberwolf]

How does the bike sense speed? On my old setup, I had a magnet and sensor on the wheel that sensed the MPH on a separate cycling computer (has nothing to do with the e-bike kit). However, on my new setup with new controller (KT's 500w 25a), there's no such sensor nor connector.

I assume I just need to get a replacement sensor with cable to physically connect to the controller? I may be answering my own question but just need you guys to help verify. I do have a PAS sensor on the way. Would that replace the speed sensor? In other words, if I have the sensor plugged into the PAS connector on the controller, would I still need a separate speed sensor to plug into that corresponding wire on the controller? I'm guessing no and I can just leave that alone. My understanding of the PAS sensor is that the cadence sensor itself is a form of speed sensor and having a separate "speed sensor only" would be redundant.

My KT LCD4 display currently just reads 0 MPH. Hoping to get some suggestions or help on this. TIA.

In a previous thread, you noted your controller has a wire for an additional sensor in the hall bundle, but your motor doesn't have a sensor to connect it to.
https://endless-sphere.com/forums/viewtopic.php?f=49&t=118564

Since this is almost certainly a speed sensor wire, then to have the system sense speed, you would need to connect a speed sensor to it (powered presumably from the same 5v/ground as the halls) and then setup the controller to accept the number of poles (magnets) used on that sensor.

The simplest is a frame-mounted sensor that reads magnets on a wheel (either on the spokes or glued to the rim or hub).

If you still have the one from your cycling computer, it is probably compatible with the controller. If it is only two wire, then most likely you can simply connect them to the unused sensor wire on the controller hall bundle, and the ground wire. (this will replicate the action of a hall sensor type, which just grounds the output whenever the magnet passes). No 5v would be used.

 

[kmxtornado]

In a previous thread, you noted your controller has a wire for an additional sensor in the hall bundle, but your motor doesn't have a sensor to connect it to.
https://endless-sphere.com/forums/viewtopic.php?f=49&t=118564

Since this is almost certainly a speed sensor wire, then to have the system sense speed, you would need to connect a speed sensor to it (powered presumably from the same 5v/ground as the halls) and then setup the controller to accept the number of poles (magnets) used on that sensor.

The simplest is a frame-mounted sensor that reads magnets on a wheel (either on the spokes or glued to the rim or hub).

If you still have the one from your cycling computer, it is probably compatible with the controller. If it is only two wire, then most likely you can simply connect them to the unused sensor wire on the controller hall bundle, and the ground wire. (this will replicate the action of a hall sensor type, which just grounds the output whenever the magnet passes). No 5v would be used.

Thanks for your reply. Yes, my Hall connector does have that extra sensor wire that isn't used. That also could've been a temperature sensor from what I understand. Since it's an old system, I really don't know. No diagram. However, there's also an additional separate wire coming out of my NEW controller that is labeled speed sensor. I suppose that's the one i should try first. I'll give that a shot and report back and see what happens.

Unfortunately, I cannot use the sensor from the old system b/c it was wireless to the computer. There's no wire to connect to a controller.

 

[kmxtornado]

For whatever reason, the MPH started working when I took the bike out today. No clue why or how. The numbers just started moving from 0 where it was previously. Very intermittent. I did install the PAS a few hours ago and no effect. The MPH sometimes works and sometimes doesn't. PAS is steady though, so I don't think it's a connection issue. I thought it was a display thing so I toggled through but even when not messing with the screen, the MPH will sometimes work and sometimes just stays at zero. I'm thinking it's just a faulty controller.

No biggy. Just odd that it behaves this way. Would be curious if any of you have had experiences with MPG gauges that sporadically work and not work.

 

[docw009]

Unless you set P2 to a nonzero number, a KT controller won't use the speed sensor input. That number P2 is the number of pulses per revolution from the sensor, which is 1 for a wheel mounted sensor. Usually 1 for an internal speed sensor too, but some Bafangs use 6.

If you have a direct drive motor, the KT controller will also see a Hall sensor firing whether the motor is running or coasting and it can use that for speed. If you have a geared motor, when you coast, the motor won't spin, so there is no speed signal unless a speed senor is attached..

So just buy a speed sensor, about 10 bucks at most, and wire it to the connector marked speed sensor. I think it's red, black, and white wires.

 

[slaphappygamer]

Wow. I had the same issue on my bike. The speed would intermittently drop to zero. I had a dirty open at the 6 pin connector of my (white) speed wire. You’ll know by gently tugging the wire from the connector. It may break. I placed a new connection and all is good. In the JST connector, you can remove the pins.

https://m.youtube.com/watch?v=o1ULgfSOlLk

I bought a pack from Amazon and made new ends.

https://a.co/d/1aEiJ6U

Now my speed is consistent.

 

[docw009]

One problem I've had with external speed sensors on KT controllers is jitter. It's a digital readout, but I can see the numbers flashing erratically when the speedometer switches over to coasting mode, as it goes from the motor readout to the sensor. Sometimes it settles down.

A clue to this has appeared with the mid drive TSDZ2 wheel sensor. RTFM, and it tells you to set a 1 cm spacing between sensor/magnet. I didn't read the manual, but set the spacing at 2 mm like I always do, same as a PAS sensor. It worked fine until I switched from a wheel with steel spokes to one with stainless (non magnetic) spokes. Then the TSDZ2 speedometer "jittered" and read 2x-3X the speed. Turning the magnet around to get a 1 cm spacing was my field fix. Later RTFM confirmed that, The steel spokes must have constrained the magnetic field. By the way, the OSF firmware for the TSDZ2 motor actually aets a higher threshold on the PAS sensor to remove noise. When I installed the new firmware, I got no speed input. I had to reset the magnet spacing back to 2 mm to get any speed reading. Funny stuff.

Come Spring, I'll reset the magnet spacing higher on my bikes that use wheel speed sensors and see if that eliminates the jitter I see on those KT speedometers.