Testing BLDC motor's Phase Wiring - Hall Sensors and Wiring.

[Tommycat]

It's good to see voltage during testing for sure.

Test 1: Definitely below normal voltage, but within usable range I would think. (still no battery display)
Test 2: Relatively expected as you drop the load of the motor's hall sensors. Nothing seems to be shorted. (still no battery display)
Test 3: This is more as expected. But what has changed between this and test # 1or 2? What is and isn't connected at this time? Just battery, motor, display, and throttle? (can't see display for battery...)

A loss of 1 volt seems substantial... what's causing it?

Any error codes at any time? Any status indicators displaying?

Try checking the output of the throttle by keeping the meter's BLACK lead on the black wire. And moving the RED probe to the last remaining throttle wire. Closed to open = .8vdc to 3.6vdc. And what the input voltage was at the time.

Then you might want to try with the display bypassed... This is a KT controller's manufactures instructions for bypassing. CAREFUL, both low voltage and high voltage connections here. Make good solid secure jumps with battery disconnected, and controller's capacitors discharged.




Hey, you can't ride a toaster! :-)

[Valerio]

Test 3: This is more as expected. But what has changed between this and test # 1or 2? What is and isn't connected at this time? Just battery, motor, display, and throttle? (can't see display for battery...)

the only difference was the motor plug, which in test 2 is NOT connected. everything else is the same.

Any error codes at any time? Any status indicators displaying?

nothing unfortunately, no error codes nothing changes on the display.

Then you might want to try with the display bypassed... This is a KT controller's manufactures instructions for bypassing. CAREFUL, both low voltage and high voltage connections here. Make good solid secure jumps with battery disconnected, and controller's capacitors discharged.

• Once I combined those cables together and connect the display to the controller, should I connected the battery as last thing and turn on the display?
• or those are only the small cables INSIDE the controller? (in that case how do I turn the system on?)
• how do I discharge the capacitors?

forgive my naiveness, by now you are a saint...
V.

[Tommycat]

If you have the patience to wait for my replies, I'll do my best to help!

the only difference was the motor plug, which in test 2 is NOT connected. everything else is the same.

Usable results can be repeated under the same conditions... since the results are different between test #1 and #3 under the same conditions, which voltage reading is accurate? Did you test again after #3 by re-connecting the motor?

Once I combined those cables together and connect the display to the controller, should I connected the battery as last thing and turn on the display?
(in that case how do I turn the system on?)

The jumper wires take the place of the display. You do not re-connect the display with the jumpers in place. As per my description of the display's wiring above, you can see that the jumpers will...
1) provide full battery power to the control or ignition circuit of the controller.
2) connect the receive communication wire to ground. (I do not know why this is done... perhaps to let the controller think it is still in communication with the missing display.)

This jumper is often used to test to see if the display is defective. And by those riders that like a minimal E-bike footprint, or stealth mode. It also sticks the PAS level at the place it was before removal on some systems, or to a default level on others...
Hoping it lets the controller at least try to start the motor.

how do I discharge the capacitors?

Typically they will drain by themselves in a short amount of time. To see exactly how long. Put your voltage meter on the battery connector to the controller quickly after you remove the battery, and see how long the voltage takes to go to zero. It may be fairly quick. But something you need to be aware of. As always, disconnect battery when connecting/disconnecting any parts or pieces...display certainly!



On reading a bit thru the LCD manual, I see where it has a couple different communication protocols... have you tried both? ( C11 parameter, page 31...)
Just checking, you are using the "save" protocol when making changes? Do your selections "stick" after review later?

[Valerio]

Dear Tommycat,

having a no-display solution is no a viable solution for me, I need to set the speed and I want the ability to turn lights on etc...

all I wanted was to have a programmable display and controller so I could set the speed a lil higher than the out of factory settings for this bike...

But before giving up on this endeavour I will definitely try to play with the C11 parameter you mentioned,
I actually wondered if this all thing was solvable by playing with the parameters but they are so many and most are very difficult to understand for me.

In addition to this one thing really caught my attention looking at the page where you grabbed the screenshot about shorting the display cable...
Look below:

• I had never seen the information in the red box, I really wonder if this could make a difference,
  especially cause it mentions that the batter level only becomes accurate after pedalling for a while, so strange, could this really be the cause of all this mess?

I'll do a test soon and let you know.

[Tommycat]

having a no-display solution is no a viable solution for me, I need to set the speed and I want the ability to turn lights on etc...

For you, suggested for troubleshooting only as a possible way of eliminating the display as the problem...

I actually wondered if this all thing was solvable by playing with the parameters but they are so many and most are very difficult to understand for me.

Agreed. Can't hurt to try... but stay away from the PASSWORD options! Many a display bricked by loss of PIN. :-/

In addition to this one thing really caught my attention looking at the page where you grabbed the screenshot about shorting the display cable...
Look below:

• I had never seen the information in the red box, I really wonder if this could make a difference,
  especially cause it mentions that the batter level only becomes accurate after pedalling for a while, so strange, could this really be the cause of all this mess?

I'll do a test soon and let you know.

Wow, great catch! Hoping your battery display propagates and everything starts working!

[Valerio]

Dear Tommycat,

I have done the test using the parameters in the screenshot.

Nothing works.
I am at square one.

before I officially give up, I have 2 questions:

• if I find out that the motor starts after shorting the display, I guess that would be the proof that the controller works... what would the next step be? buying another display?
  I am starting to be suspicious of KT displays at this point...
• Now that we find out that there is current in the controller, is there any hope to make it work trying re-matching the phase cables using your initial diagram or this would a totally different problem?

Thanks.
V.

[Tommycat]

if I find out that the motor starts after shorting the display, I guess that would be the proof that the controller works... what would the next step be? buying another display?
I am starting to be suspicious of KT displays at this point...

Getting the motor to at least try to start would be a good advancement. And having it start after bypassing the display would be a good indication that the display is involved. I still would do a few more troubleshooting steps to pin it entirely on the display if you'd like to try at that time. (see recommendations below)
My first step would be to contact the seller and give the details of your problem and trouble shooting, as well as verify that the correct one was sent in the first place. Then go from there.

Now that we find out that there is current in the controller, is there any hope to make it work trying re-matching the phase cables using your initial diagram or this would a totally different problem?

It seems to me to be a totally different problem. That said, it would not hurt anything to try... As long as you don't draw to many amps when testing. AKA keep throttle inputs low and short. This is where an inline current meter would help to determine if the motor is trying to do anything at all...?



Further electrical testing recommendations...

Verify that all the connector pins are not bent and making proper contact. And that they are fully snapped together.
Check for full battery voltage between display connection RED wire and Black wires.
Check for full battery voltage between display connection BLUE and BLACK wires after display is turned on.
Verify correct throttle voltage output on signal wire as suggested above.

The controller communicates with the display between the YELLOW (receive) and GREEN (transmit) wires with short bursts of data packets. If you where to check from each of these wires to ground for voltage spikes of 3.3vdc or perhaps 5vdc to 0vdc. It may provide a clue. Open wire, dead, ETC.

[Valerio]

Hey Tommycat,

today I tested with the display shorted,

no signs of life.

should I proceed with your diagram thing? what do you suggest?
V.

[Tommycat]

Just to verify...

You only have the controller, bypassed display connection, throttle, motor and battery connected together... and nothing else?

See testing recommendations above.

You may switch motor's phase wires if you desire... see cautions.


Have you contacted your supplier yet?

[Valerio]

You only have the controller, bypassed display connection, throttle, motor and battery connected together... and nothing else?

I tried with the PAS, pedalling, no throttle, everything else connected. I think its the same no?

You may switch motor's phase wires if you desire... see cautions.

what else is left to try?
V.

[Tommycat]

Try with the PAS disconnected, and using the throttle only. Give you a good opportunity to check its signal output. DISCONNECT every thing else except what’s mentioned as absolutely needed above.

I f after completing the above voltage checks and recommendations, my next effort would be to open up the controller and check for damage and/or wiring problems…

[Valerio]

Hello Tommycat,
I finally got some time to try the hall sensor cable thing…
This is how I’m planning to do it, see the pic below



Now, would you perform the actions in the order below to prevent blowing out everything?

1-connect all the cables

2-plug in the controller to the battery

3-turn on the display

4-try to pedal and see what happens

5-turn off display

6-swap the hall cables (one at the time, following your diagram)

7 Repeat steps 3 to 6

Should I disconnect the controller from the battery before swapping any connection?

What do you suggest? Any changes?

Please let me know.
Thanks.
V.

[Tommycat]

Hello Valerio,

That looks like a very nice testing harness to use.

Should I disconnect the controller from the battery before swapping any connection?

This is what I would recommend above all else. Allowing time for the controller's capacitors to discharge after battery disconnect as mentioned previously, before making any connection changes....
Do you know if your PAS sensor is wired correctly and working properly? Try pedaling in reverse as another check.


After reviewing your controller specifications, it looks to me that it may be a dual mode type. From what I understand, this type model can run a motor that has hall sensors as well as a motor that has none. Or can switch to sensor less mode if a problem does arise with a sensored motor's hall sensors or wiring.
With this in mind you may try running it with all the motor's hall sensor wiring disconnected and see if it runs in "sensor less" mode... (isolate the controller's hall signal lines from each other and from shorting.)

You may want to consider reposting your problem in the "troubleshooting" section where I believe it may get more views than in this location... the more help, the better.

[Tash]

Tommycat

Thanks for the guide! And really nice to follow diagram for phase swapping, that really helped out a lot!
I still got some challenges that I hope you could help me with?

1. the parts - not the same brands, trying to build a "garbage e-bike" with my son:

Offbrand 250w e bike hub motor
Offbrand 250w Controller from old e-scooter, kick scooter
36v batterypack.

My problem:
After a lot of time, tweaking the programming on controller, and then finding your guide, and startet swopping phases it got it all running.

The problem is that I feel the controller getting quite hot (only testing unloaded, with minimum throttle)
Im not quite sure how to measure amp, as you suggest in the guide?

the wiring setup that works is:

Phase:

Y - Y
B - G
G - B

Hall
R - R
BL - BL

B - B
G - G
Y - Y

I have not tried to swap the hall sensor cables, and don't know If I should?

Hope you can help me out with some recommendations.