KT Controller numbers and compatibility

Dunlop

10 W
Joined
Dec 22, 2021
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65
Hi,
Attached is a pic of the KT controller that came on a BPM bike (T-Max model)... I need to replace the controller because the PAS has stopped working (Yes the cadence sensor has been check out fine).... So where does a person figure out what all of the numbers in the model number mean.... I have searched for some type of deciphering chart to interpret what things mean, with no luck! Does someone here have the secret decoder ring?? There are so many ads for controllers, but since none have the exact numbers I have, I don't know what to purchase... Any info would be appreciated.

While we are on the subject of many avenues to buy from.... Where would you purchase from?? Some places like Alibaba or Ali-express have great prices, but I would hate to wait a month to find out I ordered the wrong one (which is why I need to figure out what the numbers mean!!)

Thanks for looking, and your time,
Keith
 

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Dunlop said:
KT48ZWSRLD-GH04Q

KT = Kunteng (manufacturer name)
48 = system volts it was programmed for
S = sine wave
GH04Q = serial number
Z = ???
W = ???
R = ???
L = ???
D = ???

Everything else working except PAS is very strange. That's an unusual mode of failure given the layout of the circuit board. If PAS goes, most everything else should go. Can you take some pictures inside the case with the top lid open?
 
I get mine from Amazon, or at least try to. I MUCH prefer to deal with people having inventory state side. Ordering from China is a absolute last resort. It takes forever and getting warranty is very dicey. You should know as well that getting support from the seller is really dicey as well. About the only knowledge you can assume on their part is the price and availability. If you have questions that must be answered, ask BEFORE you order....

I don't reference that model/serial number much. I'm interested in the amperage, the type of connectors, the functions available from those connectors (is it set up for PAS for instance, and lighting?), and sine vs. square wave.
 
Dunlop said:
I need to replace the controller because the PAS has stopped working (Yes the cadence sensor has been check out fine)....

Most failures are caused by wiring faults, bad connections. The connector between sensor and controller could be not quite fully plugged in, or water could have intruded and caused a poor connection, or a wire may be broken inside the insulation anywhere between the sensor and the controller, including at the PCB inside the controller.

When you say the sensor checks out fine, is that while attached to the controller or using a separate tester?

You can test the controller's PAS input by first ensuring there is a good connection to the controller PCB inside on all PAS connector wires. If there is, then if it's a 3-wire PAS signal, any 0-5v on/off signal that repeats fast enough will trigger PAS. If the controller has 5v on boht the 5v line and the signal line, then it's a common grounding-type signal.

Flip the bike upside down or otherwise keep the powered wheel offground, with the PAS sensor disconnected, turn it on, set it to the mode where PAS will work (usually anything other than 0) and then short the signal wire to the ground wire and then disconnect it, repeatedly, as fast as you can. If the PAS input is working, then it should now begin spinning the wheel. If the system requires throttle plus PAS, then you'll need to do that, too.

If it works like this, then there's either something wrong with the sensor or it's connection to the controller.
 
Thanks for the responses..
At first it appeared there was a little difference of opinion whether it "sine-wave" or "square-wave"... but appears that square-wave is the more popular answer.
I have contacted BPM imports, and it appears they may have a controller for me, here is some of the wording I put in an e-mail recently about the cadence sensor:
When you crank the pedals, the "PAS" indicator lights up on the display.... So the sensor is working, the display knows the sensor is working.... something just isn't getting the message to send power to the rear wheel. One other note: the throttle works just fine, and when you pull the brakes, the throttle doesn't work, which is exactly the way it was designed. Lastly, the 6km/h walk mode also works just fine!
If the display knows the pedals are going around, the the sensor must be working..... Right?

I am going to try amberwolf's test of grounding the signal wire.... will report back with results.

Thanks,
Keith
 
PAS Test UPDATE:

Ok, as predicted I have 5v on both the positive and signal wires.... and repeated (quickly) grounding of the signal wire did NOTHING :( .
Just for the record this is a 5 month old bike (less than 10 miles), worked fine in MI and now in AZ it has no PAS. I have no corrosion type issues. and Yes, I inspected the cadence sensor connector .... All terminals are fully inserted, and straight.

Thanks,
Keith
 
Have you tried doing a "reset" (C10=y)?

If not, that might be a good idea. Just make sure you jot down all of your current settings - just in case.
 
hope this helps..... If your wanting to check that the air gap is small enough... well yess I have adjusted it from where I found it (about 3/16"), down to where it is now which is about .010".
 

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E-HP said:
Hmm, just to make sure, your PAS level isn't set to 0 right?

No, unless I don't understand your question..... I have a KT-LCD5 and last night when I did the repeated grounding of the signal wire, I had the PAS = 1, and blipped the throttle, and that worked, but nothing happened with the repeated grounding of the signal wire.

I have the manual for the LCD (https://cdn.fbsbx.com/v/t59.2708-21...R2C3FO9bFSICEYc0IeCSYKmGdcUg&oe=61C84E13&dl=1 )

I don't see anything in there that would disable the PAS...
 
Dunlop said:
E-HP said:
Hmm, just to make sure, your PAS level isn't set to 0 right?

No, unless I don't understand your question..... I have a KT-LCD5 and last night when I did the repeated grounding of the signal wire, I had the PAS = 1, and blipped the throttle, and that worked, but nothing happened with the repeated grounding of the signal wire.

I have the manual for the LCD (https://cdn.fbsbx.com/v/t59.2708-21...R2C3FO9bFSICEYc0IeCSYKmGdcUg&oe=61C84E13&dl=1 )

I don't see anything in there that would disable the PAS...

Have you tried both C1 = 2 and C1 = 6 to see if either works?
 
BTW, in your other thread

you noted "It has all of 2.8 miles on it, and now the PAS doesn't work :oops:".

Was the bike new from a manufacturer? Or used, from someone else?

What specifically happened between the time it worked, and the time it didn't? I ask because it may help us help you find the problem and fix it rather than finding an exact replacement controller. :)

If you prefer to just replace it that's ok, but if you'd rather fix it we can keep trying to help you do that.

If it was only simply ridden normally, and the PAS just suddenly failed, it is almost certainly a connection problem somewhere (though the readings you give for the controller-side connector indicate that is probably ok).

The other common possibility is that the magnet disc or PAS sensor bracket is slightly misaligned, either too close or to far from the sensor by as little as mm's. This has, for some people, caused the PAS to appear to not work.

If it fell over, or got wet, or crashed, or whatever, then there could be damage in the wiring harness between controller and sensor.

Also...does the system still show your speed correctly, when riding via throttle? If not, it may mean the motor wire cable is damaged and the speed sensor wire in it is broken. There are some systems that have stopped responding to PAS if the speed sensor doesn't work...though usually that doesn't stop totally, just that it stops working after some short time period after the controller doens't detect the speed signal (the PAS would still start the bike, just stop being able to drive it after that time period).


The controller itself could have failed, and the test of rapidly grounding the PAS signal wire at the controller side should cause it to engage, assuming it is the type of PAS sensor that just grounds the signal line every time the magnet on the ring passes it. If it's a different type of PAS signal then the rapid grounding won't make it work.
 
Hi,
I gave some of the bike background in the other thread, but it was bought back in July/Aug of this year.... I didn't ride it because I had rear suspension issues right out of the box. I finally just made a piece of aluminum to replace the rear shock, which locked that problem out completely. After that the PAS system worked just fine. The rest of the fall was just Michigan rain, and a lot of work preparing to make the move to AZ for the winter.
So I loaded it in the pickup, along with two small show motorcycles that are going to the Mecum Auction in Las Vegas in January. Both the LCD and the plastic box that houses the controller were wrapped in saran type shipping wrap, and then it never rained on the whole trip this year..... I transported the bike 2137 miles, and now that it is in AZ the PAS doesn't work! There were no bumps, bruises, scratches, or crashes.
This is just more of my typical luck with electronics... I would be better of if there were more mechanical moving parts!!

Thanks for your time! and thanks for looking,
Keith
 
that should help; i have to go out and do more yard cleanup while weather is good today and while i have help, but when i'm too wiped out to continue that i'll be back inside and will go thru your info and reply.
 
aroundqube said:
It looks to me that the manual says that if P4=0 the PAS is turned off .

I had to go back and re-read this one.... The P4 setting is for the THROTTLE START-UP only!! I did change this when I first got it, because the throttle didn't work unless you had already started pedaling... I prefer to start with the throttle, and then start pedaling.
Keith
 
Just some possibilities to eliminate:

Based on all the info provided so far, it sounds like it stopped working during the interstate transportation itself, is that correct?

Also, at some point (not sure if it was before or after the transport), the sensor was moved closer to the magnet.

Too small a gap between magnet and sensor can cause just as many problems as too large a gap. If the sensor worked with the original gap I would recommend using that as the gap. If there is an LED on the sensor then you can adust the gap to the farthest distance that still lights the LED, then move it back halfway from there to where it is now, and that should be right in the middle of the sensitivity range.


Does the PAS sensor plug directly into the controller, or is there a separate harness / extension cable that connects between the two? (like a connector to the display that then goes to the controller)
 
I thought that a PAS sensor puts out an assymetrical square wave, that flips when the pedals spin backward. The controller then knows when to respond to the input. On the LCD3 KT display and others, you can set the controller to respond to either pattern, and also for 5 to 12 magnets.

This is why I've always found it hard to test the sensor unless it was mounted on a crank. Just passing a magnet across the sensor has to be done methodically, or it rejects the signal.

diagram.jpg
 
I also recently had trouble with PAS on a KT 20A controller, but using the ultra cheap LCD display which has no settings to refine the PAS sensitivity,

The original integrated sensor started to only work on one half of the pedal rotation. I put on a second but different sensor. For some reason, it worked both forward and reverse. I thought I could live with that til I ran the bike into a wall adjusting the pedals. Put on a third sensor and that was OK,although it also initially only worked on a half crank, but then I saw that the magnet disk was cocked and too far away for a half rotation,

Now the original PAS sensor was a one piece unit with the magnets inside the housing, so unless they fell off, I can't see how it could mimic a cocked disk. When I would buy a motor from China, I would always add a PAS sensor for about two dollars, as the shipping hardly charged. That's why I had extra sensors.

I'd suggest a second sensor to the OP instead of a new controller. But if he does get a new controller, stay with sine wave. The square wave units are noisier. Consider going to 17A or 20A if the case still fits, If you have the LCD3 or LCD8, you can use C5 to turn down the current if you wish.
 
docw009 said:
I thought that a PAS sensor puts out an assymetrical square wave, that flips when the pedals spin backward.
THat seems to depend on the sensor--based on some people's posts with problems with certain cheap sensors, there are some that just output a signal (probably the same one) regardless of direction. (either way, I've done that test on a lishui controller, just shorting the controller PAS signal wire to ground repeatedly, and gotten it to respond as a test).

But I ever used an oscilloscope to test the pattern actually coming from any of the sensors I have here. :oops:
 
amberwolf said:
Just some possibilities to eliminate:

Based on all the info provided so far, it sounds like it stopped working during the interstate transportation itself, is that correct?
This correct... I'll bet that it was during my trip through Illinois..(The wind blows very strong from the left when traveling through there) LOL

Also, at some point (not sure if it was before or after the transport), the sensor was moved closer to the magnet.
The sensor was moved closer (2 or 3 times) in AZ, when I realized the PAS didn't work. When I got here it was about 3/16" gap... that is a little on the large side, (I had hopes of an easy fix) moved it down to about 1/8", and now down to .015" now.... I have covered the whole range.

Too small a gap between magnet and sensor can cause just as many problems as too large a gap. If the sensor worked with the original gap I would recommend using that as the gap. If there is an LED on the sensor then you can adust the gap to the farthest distance that still lights the LED, then move it back halfway from there to where it is now, and that should be right in the middle of the sensitivity range.


Does the PAS sensor plug directly into the controller, or is there a separate harness / extension cable that connects between the two? (like a connector to the display that then goes to the controller)

This sensor does NOT have the red light (but that does look like a cool and useful feature).
The sensor has quite a long wire of its own, and plugs straight into the controller.
 
docw009 said:
I thought that a PAS sensor puts out an assymetrical square wave, that flips when the pedals spin backward. The controller then knows when to respond to the input. On the LCD3 KT display and others, you can set the controller to respond to either pattern, and also for 5 to 12 magnets.

This is why I've always found it hard to test the sensor unless it was mounted on a crank. Just passing a magnet across the sensor has to be done methodically, or it rejects the signal.

diagram.jpg

When I first got the manual and saw that page, I thought "I will never wrap my head around that!".... BUT, last night I did!! Mine is the Forward 8 signal, (meaning 8 magnets on the wheel). So 00,01, or 02 are the only workable settings for me.
 
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