KT controller issues

[akh2992]

Hello,

Ive been lurking on here and other forums for a while trying to find answers.

I have 3 electric hub motors. 2 motors are identical 1500watt ebay motors one is QS205 V1 knockoff by CSC.

I have 4 brand new KT sinewave controllers. 2 of which are 45A max current and 2 that are 30A max current. I also have 1 generic 30A max controller which I presume is squarewave. See pics

I have tested each controller with each motor. I tested all 36 wiring combos each time. I disconnected power and made sure the caps were drianed each time I switched combos. Every combo i do the motor kicks slightly in the opposite direction on start, and then spins. When spinning i get a buzz. This happens with every motor/controller combo I went through. I also tried each controller to each motor without hooking up the halls as well since these controller can run without halls. Still same results.

But when I hook up the generic no name controller (yellow to yellow, blue to blue and green to green) to any of my 3 motors, it works perfectly, no buzzing, no kick in the opposite direction on start.

What is up with these KT controllers? I need help, this is getting pretty frustrating.

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[AHicks]

All I can add is that KT sells both sine and square wave. If yours are wired correctly and making noise, especially when starting out and under load, I think you have square wave - no matter what they told you when selling them.

 

[akh2992]

Thank you for your input.

Im not so much worried about the noise if that how it is supposed to be. But the fact that the motor starts off rotating ome direction for a split second, and then abruptly switches directions and maintains that rotation direction is what concerns me. I know for a fact that should not be happening.

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[akh2992]

I also forgot to mention that the controllers heat up pretty quickly. I said eff it and took a bike for a ride. If I give it 3 min worth of full throttle on flat ground the temperature of my controller is 160°F.

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[AHicks]

Is this heat build up happening while located in a "bag" or out where air can circulate around it (strapped to the seat post for instance)?

 

[akh2992]

Is this heat build up happening while located in a "bag" or out where air can circulate around it (strapped to the seat post for instance)?

It was sitting exactly like this with the top wide open and the controller was strapped down with velcro.

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[TommyCat]

Hard to tell but just curious if the display connector has the jumper installed to allow correct operation of a KT controller with-out the display? I see what looks to be your "key lock" jumper.
That is, if your not using a display...

Regards,
T.C.

 

[docw009]

You're talking about rolling on throttle with wheel in the air, the wheel jerks backward and than spins up in the right direction? What happens if you brake the wheel. It does the same thing again? That is quite strange. With all that heat, you must be running a false positive. Did your testing of the 36 combos give you a best result that has color mismatches on the Hall and Phases?

I didn't start doing ebikes til 2015, but I've wired about six different makes of motors, and always found that matching the phase and Hall colors worked for me. I'm mostly KT controllers, but I have about four other brands. All of the veterans here say they've seen differently. Either I'm lucky, or the major motor/controller shops are following better standards now?

I didn't know there were KT sinewave controllers that could work sensorless. I know that their higher power square wave boxes are sensorless, and have no phase wires.

 

[AHicks]

You're talking about rolling on throttle with wheel in the air, the wheel jerks backward and than spins up in the right direction? What happens if you brake the wheel. It does the same thing again? That is quite strange. With all that heat, you must be running a false positive. Did your testing of the 36 combos give you a best result that has color mismatches on the Hall and Phases?

I didn't start doing ebikes til 2015, but I've wired about six different makes of motors, and always found that matching the phase and Hall colors worked for me. I'm mostly KT controllers, but I have about four other brands. All of the veterans here say they've seen differently. Either I'm lucky, or the major motor/controller shops are following better standards now?

I didn't know there were KT sinewave controllers that could work sensorless. I know that their higher power square wave boxes are sensorless, and have no phase wires.

My experience as well....

 

[Oli.Hall]

Hi,

Looking at the model number of both of those KT controllers, both of them definitely appear to be square wave controllers which is why they are making the buzzing. Usually KT controllers with model numbers containing SV are sine wave, and ZW are square wave. i.e.:

KT36/48SVxx = sine wave controller
KT36/48ZWxx = square wave controller.

So, some amount of buzzing noise is completely normal, but an excessive buzzing noise and overheating of the controller could possibly be due to the hall sensors being connected in the wrong order. If the controller will run without the hall sensors connected then disconnect them and take the bike for a spin in sensorless mode and see if the controller still gets hot. If the controller runs much cooler (or quieter) without the sensors connected then start troubleshooting the hall sensors and their wiring for correct operation. Start by testing them with a multimeter as below. If the controller still gets hot then either this is just the temperature you should expect and you should plan for appropriate airflow over the controller, or there may be a different issue that is not related to the hall sensors.

Sensored vs. Sensorless mode
When starting from rest, the controller reads the hall sensors and uses them to determine the position of the wheel so it knows which phase to energise first to make the wheel turn forwards. If all the hall sensors are working properly then the controller should be able to start the motor in the correct direction first time, every time. If the hall signals are faulty in any way, the controller doesn't know which phase to energise to make the wheel turn forwards, so instead it energises a single phase (which may make the wheel turn backwards at first) to put the motor into a known position. After this it will start to energise the phases in the correct order to start the motor rotating forwards.

If the wheel jerks backwards before starting to rotate forwards, this could be a possible sign that the controller is starting in sensorless mode because the hall sensor signals are not being received properly which could be caused by bad or faulty wiring, or a faulty hall sensor.

Test the hall sensors
Put your multimeter on the voltage measurement setting (and the test leads in the correct sockets for measuring voltage!), and with the controller powered on, the phase wires disconnected, and the hall wires connected, test each of the hall sensors in-turn.

Hall Sensor Plug
Black = ground, connect your black multimeter probe to this wire.
Red = should be 5v all the time the controller is powered on
Yellow / Blue / Green = these should each read either near to 5V, or near to 0V and each should breifly change as the wheel is rotated.

Connect the multimeter probe to one of the Y/B/G hall sensor wires and rotate the wheel by hand very very slowly. You should be able to see the signal go from 5V, briefly to 0V, then back to 5V. Repeat this test with all three of the Y/B/G hall sensor leads. If any of the hall signals stays at or near 5V, or stays at or near 0v as you rotate the wheel then the hall sensor or the wiring to that sensor is broken.

If all the hall sensors appear to the outputting the correct signal then check all of the wiring for loose connections.

Good luck!
Oli.

 

[akh2992]

Thanks for your input. Ill find some motivation soon to start testing again

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[Oli.Hall]

You're welcome.

TommyCat has written a great guide for testing hall sensors and also determining correct phase and hall wiring combination:

https://electricbike.com/forum/foru...-motor-s-phase-wiring-hall-sensors-and-wiring

Good luck!
Oli.

 

[Norwegian54]

Thank GOD someone else seem to have the same problem as me with this stuff from CSC. The exact same controller it seems.
A couple of days this crap could easilly have killed me. Wheel lock in 40km/h.
I'll be reading this post VERY closely, and hope to god this is the answer to my prairs, lol..
I just wanted to say thanks to all of you for taking this problem up.

 

[Norwegian54]

It would seem like our problems could be somewhat related.
I don't have any buzzing sound in the controller at startup. Or any time else. Neither does it heat up much, despite the fact that I am using two 52v batteries in parallel.
Mine starts to pull as normal for a second or so, then to "skip" pulling for half a second to go on pulling as if nothing happend.
How ever, the explanation from Oli.Hall makes a lot of sense in my situation too. That could easilly be why, after a "skip" the hall sensors don't know the position of the wheel and can easilly jerk the wheel bakcwards to find a sensor point again and go on from there.
For me, this happens regardless of if I'm using the pedal assist or the throttle.
But not all the time. The intervals between this happening are totally random. I have the bike in the air now, and just using the throttle I get theese random skipps. And it only happens after I have been idling and continue to pedal or twist the throttle. Never any kind of startup problems.
I have checked the hall sensors and can't find anything wrong with them. They all go from 0 to 4.99v in intervals when turning the wheel. Also the red power wire shows 5v all the time, even when the skips happens.
I'll be diong some more testing with the multimeter connected to the hall sensors when the wheel are spinning, but I don't think I'll be able to see any voltage drops due to the frequency of the spinning magnets.
I might see a drop, thoug, in the half a second it apparently are no power to turn the wheel..

 

[akh2992]

A little update:

I have connected both 12 mofset controllers with the halls disconnected to this dual hub motor bike. Even in the bag, The controllers dont get too hot after a 10 minute harsh ride in 90°+ weather. I dont take it easy on these motors. It still bumps backwards sometimes, but seems tonwork well otherwise.

On the other setup(the CSC) hub motor, the 18 mosfet controller gets pretty hot after about 3 minutes with the controller exposed to the outside air as pictured earlier in this thread. The motor also got pretty hot. This test ride was a full throttle run and was performed on a flat road.

What could be causing the hot motor/controller?

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[Mattmatthews]

It seems to happen to me only after I use the break, and get back on the throttle then sometimes it will bump backwards at low speed but if I use the break and am still going pretty fast it will buzz and try to spin backwards hard I am running 1500w csc 18 fet 52v 20ah on a ProLight 757 or something. It seems to do it much more often when the voltage it high in the battery, I think it might have something to do with using a 52v battery on a 48v controller

 

[Mattmatthews]

Oh also my halls "work" as tested, but if you look with an oscilloscope the I see that the signal is not clean in any way, when I first got my bike going and had the bump backwards issues I took apart my hub "had to replace bearing also i put in some 10awg wires and a temp sensor and new hall wires and acrylic enameled the shit out of it. One of my halls was dipped down in the stater and the other 2 were flush with the outside of the stater so I fixed that as well.

 

[justlooking808]

just out of curiosity, what displays are you guys using with the KT controllers?

i know the default setting will work most of the time, but i have encountered some bikes that have to be fine tuned in the setting before the bike worked well.

one thing that overheated some of my controllers fast was when the pas wire was wired incorrectly. for some reason, pas would work but battery draw would be insane and that's because the pas wires were in reverse order. so that might be one thing to check if the controller gets hot fast.

on another note, all 3 of my KT controllers would overheat on the first long ride for a quick bit before working normally. ( i think i just have bad luck :lol: ) but after that, my controllers stay cool and even though i push it hard, it has never overheated and the motor doesn't come one bit hot anymore.

this is my experience and i know that everyone is more lucky than me. :thumb: