Internal speedometer hall sensor broken

[LithiumFan]

After some intensive testing I think the internal speed hall sensor on the pcb in the motor has broken. It is soldered to Q4 on the pcb on attached photo. It is about 25mm long and has number 1924228 on it. I'm happy to replace it as I really don't want to attach an external speed sensor with even more wiring. It broke off when I replaced the motor cable and after re-soldering on the pcb it wasn't working. After looking at various threads I realise that speed only shows on the display with signals from the other thre hall sensors.

Does anyone know where I could get a replacement as I have no idea what its specifications are.
Thanks

 

[saneagle]

After some intensive testing I think the internal speed hall sensor on the pcb in the motor has broken. It is soldered to Q4 on the pcb on attached photo. It is about 25mm long and has number 1924228 on it. I'm happy to replace it as I really don't want to attach an external speed sensor with even more wiring. It broke off when I replaced the motor cable and after re-soldering on the pcb it wasn't working. After looking at various threads I realise that speed only shows on the display with signals from the other thre hall sensors.

Does anyone know where I could get a replacement as I have no idea what its specifications are.
Thanks

It will be a standard SS41 5v bipolar hall sensor. You can get them anywhere for a few pence.:

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Are you sure it's not working? Often, you need a pull-up or pull-down resistor to test their function. If there's no resistor on a PCB in the motor, then it's in the controller, so if you test it not connected to and not powered by the controller, it won't work.

 

[LithiumFan]

Now I'm not sure. Bonnie gave me instructions as how the check all the hall sensors using the diode setting on my multimeter. So with the battery connected but the display turned off I tested the following and got results:

MM red probe into red 5v pin then green, blue, yellow and white (speed wire) in turn returns 1.55v each time.

MM red probe into black gnd pin and green, blue, yellow and white in turn return 0.63v

So this should indicate that it is working.

The only other thing I can think is that I have 12 magnets on the PAS but with a 10 magnet sensor. Hence with C1 setting at 03.

I have not connected the throttle and have P4=1 and C4=0.

The speedometer on the display shows speed only up to 15.5mph (my set limit) when using assist then slowly reverts to 0 if I stop pedalling. I understood from other threads that this means the speed is only being registered via the other hall sensors in the motor.

 

[saneagle]

Now I'm not sure. Bonnie gave me instructions as how the check all the hall sensors using the diode setting on my multimeter. So with the battery connected but the display turned off I tested the following and got results:

MM red probe into red 5v pin then green, blue, yellow and white (speed wire) in turn returns 1.55v each time.

MM red probe into black gnd pin and green, blue, yellow and white in turn return 0.63v

So this should indicate that it is working.

The only other thing I can think is that I have 12 magnets on the PAS but with a 10 magnet sensor. Hence with C1 setting at 03.

I have not connected the throttle and have P4=1 and C4=0.

The speedometer on the display shows speed only up to 15.5mph (my set limit) when using assist then slowly reverts to 0 if I stop pedalling. I understood from other threads that this means the speed is only being registered via the other hall sensors in the motor.

That happens when you set the number of magnets in the speed sensor to zero. You should have P2=1, assuming that there is one magnet stuck to the inside of the hub. It's nothing to do with P4 nor C4. They're for how the pedal assist a d throttle work. You should set p4=1 and C4=3 if you want a legal throttle. You can also get the speed display to behave like that if the magnet becomes unstuck from the hub.

 

[LithiumFan]

P2 is set to 1.

If the hall is working could there be problem with the magnet? I didn't see anything that looked like one. I think I'm going to have to open up the motor again and have a good look.

 

[LithiumFan]

I've finally redone the wiring and put in a new SS41 bipolar hall sensor. Now I have a different problem. The speedo works perfectly when power is set to zero but as soon as I add motor power the speedo goes haywire and fluctuates wildly and the distance travelled is greatly over measured. The legs look a little short. Could this be a problem? Are the phase wire hall sensors causing interference with the speed hall sensor?

Bonnie at Xiongda says the SS41F is what I need but I can't find any information about the difference between a SS41 and a SS41F.

It's getting quite frustrating. I could just use the gps on my phone but I use this this on several different bikes and not at all if just using the bike for daily use. So it's difficult to keep track in terms of servicing intervals. I really don't want to have to install an external sensor.

 

[saneagle]

Two possibilities I can think of: 1. It's being interfered with by the magnetic field from the coils either directly or by current induced into the white wire; 2 There's cable damage causing cross-over between the phase wires and one or more of the sensor wires. Considering that it already blew once, 2 is more likely. You need an oscilloscope to figure out what's going on. You could try testing with your meter set to AC and see what change there is on the white wire when you give power. Any interference from a phase wire should show up.

 

[LithiumFan]

Thanks. I don't think there is any cable damage as all the connections were carefully covered in heat shrink . I don't have access to an oscilloscope. The original hall sensor didn't blow , it broke off when I bent it to access the phase wires and then didn't work on re-attaching it with shorter legs. I think I'll try one more time with a sensor with longer legs as the replacement still doesn't reach the centre of the magnet.

 

[LithiumFan]

I've looked again at my photo of the original wiring and seen that the white wire is well away from the speed sensor. After the rewiring it actually went under the speed sensor. I've moved it and will re-assemble and try again before buying another sensor with longer legs.

 

[saneagle]

I've looked again at my photo of the original wiring and seen that the white wire is well away from the speed sensor. After the rewiring it actually went under the speed sensor. I've moved it and will re-assemble and try again before buying another sensor with longer legs.

i was thinking that the cable damage would be further up the cable, like where it comes out of the axle, or it got squished by a cable-tie that was too tight.

 

[LithiumFan]

I really don't think the wires are faulty. I was very careful pulling it through the axle when replacing it. I've been out for a trial ride and it's behaving as my last post. So my last attempt will be a different sensor. If that fails the I'll have to use an external one and tap into a different 5v and ground supply in the controller. I'm thinking I could use the throttle wires and change the third wire for the white one in the motor 6 block connector.

 

[Fatgadget]

I've finally redone the wiring and put in a new SS41 bipolar hall sensor. Now I have a different problem. The speedo works perfectly when power is set to zero but as soon as I add motor power the speedo goes haywire and fluctuates wildly and the distance travelled is greatly over measured. The legs look a little short. Could this be a problem? Are the phase wire hall sensors causing interference with the speed hall sensor?

Bonnie at Xiongda says the SS41F is what I need but I can't find any information about the difference between a SS41 and a SS41F.

It's getting quite frustrating. I could just use the gps on my phone but I use this this on several different bikes and not at all if just using the bike for daily use. So it's difficult to keep track in terms of servicing intervals. I really don't want to have to install an external sensor.

A 'dry' spliff..Sorry/ joint perhaps!

 

[saneagle]

I'm thinking I could use the throttle wires and change the third wire for the white one in the motor 6 block connector.

That's the way to do it. It only takes a few minutes, then you never have a problem again except for the occasional times you kick the sensor when getting off your bike, and you have to wiggle it back into position.