KTLCD5 problem throttle

[MaximilianMM]

I have been running a KT LCD5 controller on my 48v rear hub motor without problem.

I replaced the KT LCD as the previous one's display was partially broken, although still working fine.

However, although it's exactly the same controller, the throttle seems to have broken in the process of swapping it around, it just randomly stopped working, including with the original controller.

The pas also doesn't work on the new controller, although it still works on the old one. As far as I can see you don't have to turn the PAS mode on, it should just be on automatically. So I'm really stumped.

Is my throttle just broken? And why the f isn't the PAS working? Any help appreciated.

 

[E-HP]

Just for clarification, the LCD5 is a display, and it connects to the controller (for KT, the silver box). Did you replace the display, the controller, or both? If you only replaced the display, then you wouldn't need to touch the PAS or throttle connectors, so it would be good to know exactly what you changed in order to troubleshoot.

 

[docw009]

There are LCD5 P and C settings that could inhibit throttle and PAS. If you can still read the P and C parameters on the old LCD5, copy them to the new one. If not then you have to read the LCD5 manual, but P4=0 , C1 = 1, and C4=0 are what I use on my bikes to have throttle only active if PAS 1-5 are selected.

 

[MaximilianMM]

Thank you all. I shouldn't have used the word controller. I didn't touch the controller, I just swapped the display.

I'll try those settings to make sure they're not inhibiting the PAS. Although I can only see that they would inhibit the throttle, not the PAS from what you said, and what I read in the manual and other places.

Any tips on how to establish whether I need to buy a new throttle would be appreciated.

 

[MaximilianMM]

Update: I have identified the issue stopping the PAS working, it was a faulty brake sensor.

So I just need to work out my the throttle isn't working.

Also, I can't access full speed on the new LCD even though it is a KTLCD5 like the previous unit.

I have changed the top speed in settings.

The connections seem fine to the eye. See attached.

Settings are:

P1 200
P2 1
P3 1
P4 0
P5 01

C1 01
C2 0
C3 8
C4 2
C5 10
C6 3
C7 0
C8 0
C9 0
C10 N
C11 0
C12 4
C13 0
C14 2
C15 6

Top speed set to 72.

The old display is broken so I can't see what was working there unfortunately, even though it still works and full speed is still accessible, even though the throttle doesn't work on that either.

Thank you.

Any ideas on either of these greatly appreciated!

 

[MaximilianMM]

Anyone? A bit stuck here

 

[docw009]

That's the cable from the throttlle if it is a KT controller. According to my notes, the corroded pin is the signal pin. The top one opposite the notch is ground. It suggests that the pin isn't making contact.

If you know your way around resistors and diodes, make a resistor bridge that will give you about 4 volts and poke them into the female end of the connector. Or stick a diode between signal and power, positive end on the signal. Both should simulate full throttle.

 

[Chalo]

The corroded plug looks like it could cause a continuity issue. I'd apply Deoxit or the like, and very slightly bend the pins to increase contact pressure. If that didn't fix it, I'd chop off the Higo plugs and replace with JST-SM 3 pin connectors.

 

[MaximilianMM]

Thanks all. Will try those things.

Would getting a new throttle also work?!

 

[Chalo]

Would getting a new throttle also work?!

Likely. But if it has bad continuity to the controller, it will present the same problem.

 

[E-HP]

Thanks all. Will try those things.

Would getting a new throttle also work?!

If the throttle worked already, I'd spray both connectors with WD40, plug and unplug them several times, and spray them again and wipe them down, and see if that does it.

 

[MaximilianMM]

Thanks all.

I've tried cleaning the connections with a bit of vinegar and with wd40. It's still not working. I've also bought a new throttle and that doesn't work either.

Totally stumped at this point.

It was fully working, then completely stopped. I would think a connection issue would be more likely to cause intermittent function?

Any ideas? Maybe it has done something in the controller?

 

[docw009]

The question is did the corrosion seen on the throttle connector pin also propagate unseen to the controller side of the connector?

Put some pins into your connector from the controller, power it up and check for voltage on the power and signal pins. Power to ground is 4.5V, and signal to ground will be 0 volts.


The above tells you if the power is active. If you switch the probes, and measure power to signal, that will be 4 volts and tells you that the signal pin is connected.

The yellow pins are sewing kit pins. I insulate them with scraps of wire insulation so they don't short circuit.

 

[MaximilianMM]

Thank you very much. I'll do that.

Does anyone have any idea why I can't derestrict the full speed on my KTLCD5? I heard sometimes they're locked somehow.

 

[Chalo]

Thank you very much. I'll do that.

Does anyone have any idea why I can't derestrict the full speed on my KTLCD5? I heard sometimes they're locked somehow.

Did it come with an OEM e-bike, or did you buy it separately? If it was original equipment on a legally compliant e-bike, it might have a firmware restriction that limits it to a regulatory maximum speed.

 

[docw009]

KT displays have a speed limit in the menu settings. I think it generally works if you're allowed to get to these settings, All of my displays are bought, so there are not restrictions,

 

[MaximilianMM]

Did it come with an OEM e-bike, or did you buy it separately? If it was original equipment on a legally compliant e-bike, it might have a firmware restriction that limits it to a regulatory maximum speed.

No, I bought it separately. Which is why I can't figure why it seems to be slower despite increasing the speed limit to the maximum.

 

[Chalo]

No, I bought it separately. Which is why I can't figure why it seems to be slower despite increasing the speed limit to the maximum.

You need to try a simple test to figure out what is limiting your speed. Compare the top speed on level 5 when the motor wheel is up in the air, versus the top speed when you're riding it. If they're different, then it's limited gross power or limited battery voltage that is capping your speed. If they're exactly the same, then it's a controller restriction.

If you're not using the level 5 setting when you check, then the controller is probably set to speed mode and is restricting the speed to a lower level than maximum.

 

[MaximilianMM]

You need to try a simple test to figure out what is limiting your speed. Compare the top speed on level 5 when the motor wheel is up in the air, versus the top speed when you're riding it. If they're different, then it's limited gross power or limited battery voltage that is capping your speed. If they're exactly the same, then it's a controller restriction.

If you're not using the level 5 setting when you check, then the controller is probably set to speed mode and is restricting the speed to a lower level than maximum.

Thanks very much.

Any suggestion of how to address a controller restriction of the kind you describe?

 

[Chalo]

Thanks very much.

Any suggestion of how to address a controller restriction of the kind you describe?

So it's the same top speed on the road as in the work stand?

If it's electronically restricted and doesn't respond to settings, then the speed limit is in the firmware. I have no idea how to circumvent that other than using a different controller.

If you set a larger wheel size than you have, or a higher number of "magnet pieces" (or whatever they call it), then you can spoof a restricted controller into going faster, but the speed and distance data will be incorrect.

 

[E-HP]

Thanks very much.

Any suggestion of how to address a controller restriction of the kind you describe?

You may be able to perform some measurements to determine if it's worth the trouble. I believe you can measure line to line voltage to the motor with the voltmeter set to AC, and convert to phase voltage. If the phase voltage at full throttle isn't too far below the battery voltage, then there won't be much speed to be gained.