What is this separate component inside the controller?

[gonsp]

Hi!

I got this cheap motor controller with no specs nor diagram. I haven't been able to turn my motor... This is what I did so far:

Besides motor and battery cables, the controller has 3 other cables:

• 9 pins, called 1T5
• 3 pins. I believe this is the PAS
• 2 pins. I don't know what this is

I have traced the pins of the 1T5 cable:



Things that I have done:

• I don't have a display, so I have bypassed the ignition so the motor controller is ON
• I have identified the 3 throttle pins and connected them to a 10k ohm potentiometer
• There's a sticker saying: Brakes low level. I have found what I believe is the brake line and it's at 4.5V. So I left it untouched
• I have identified the RX and TX pins for the display communication. I left them untouched
• The ninth wire is brown, and I'm not sure what it is for. More on this later

Since the motor doesn't seem to do anything when I move the throttle, I'm trying to understand what the brown wire is for.

There's a small electronic component separate from the motherboard which basically has a large MOSFET (WSF15P10), which has 6 wires:

• Red: High gauge, connected to the battery
• Black: High gauge, connected to ground
• White: High gauge, connected to a pin called DD in the motherboard
• Brown: Low gauge, connected to one of the 9 pins of the 15T cable
• Red low gauge: Goes to the 2 pin cable that I don't know what it is for. It's directly connected to the brown wire too.
• Black low gauge: Goes to the pin cable that I don't know what is is for. It's grounded.

I'm trying to understand:

• What this separate component does
• What the brown ninth wire does
• What the 2 pin cable is for
• How can I test my motor

I'm new in the ebike world so maybe I'm doing a noob mistake...
I appreciate any kind of suggestions or guesses!
Thanks a lot!

 

[Sturmey]

With KT brand controllers, I think that center pin and the small pcb is optional and is used to powers a front light and also a rear light with latest controllers. I guess yours may be similar but not necessarily compatible.

 

[gonsp]

Okay thanks! And what about the other separate component, what is it and might it be preventing the motor to work? What is the white high gauge wire connected to the DD pin?

Also, should the throttle be at 0 when powering on in order to work? (I already tried it, but I want to l know of I have to do it om evey test)

 

[stancecoke]

This is the typical 1to4 cable pinout (cable side)
So the additional line will be the light output.
Maybe the throttle signal is checked at startup, so set the throttle output voltage to about 0.7V before switching on the controller. That's the normal idle voltage of a throttle on an E-Bike.

 

[gonsp]

Thanks! This diagram is useful! I confirm I had my connections right.

No idea what the problem is then... I guess I have to buy other controller

I would still like to understand what this separate MOSFET is. Maybe it needs to be "enabled" before current flows to the motors?

 

[stancecoke]

I would still like to understand what this separate MOSFET is.

?! We have told you already, that this is the light module, that switches the light output!

No idea what the problem is then...

Have you tried the 0.7V on the throttle input?

What the 2 pin cable is for

If it's connected to the little extra PCB, it's for the rear light. If not, it could be the "self learning" connector. Shorten both pins, then switch on the controller. The controller will check the hall and phase wire combination and will start turning slowly.

 

[gonsp]

?! We have told you already, that this is the light module, that switches the light output!

Well, I understand now that the ninth pin (brown wire) can be used to control the light, and although it's connected to the separate PCB, I'm still not very sure how it works. This wire is soldered directly to the red wire of the 2 pin cable. So I agree that you can control a light connected to the 2 pin cable, but I don't see what role the PCB plays on this. The current would flow directly from the ninth pin to the light. What is the MOSFET doing in this case?

I would understand if this PCB is used as a "switch" for a high current circuit to control the light, but I don't think it works this way, given this connection from the brown wire to the red wire

Have you tried the 0.7V on the throttle input?

Yes, but no luck...

If it's connected to the little extra PCB, it's for the rear light

Yes, it's connected to the brown wire (ninth pin) on the PCB, but still not sure what this PCB is for

 

[stancecoke]

but still not sure what this PCB is for

Why don't you believe that it's for the light? The brown wire on the ninth pin is for the headlight, the additional 2 pin connector is for the rear light, there is no doubt about it.
As the processor pin for the light can't switch high loads, an extra MOSFET is used on the extra PCB to work as a "Relais"

 

[gonsp]

Why don't you believe that it's for the light?

It's not that I don't believe it, it's just that I didn't understand how it worked.

But now I think I get it.
I thought that you had to put battery voltage (or 5V) to the brown wire, which indeed would turn on the light connected to the 2 pin cable. In this case the PCB would be doing nothing.
Now I understand that you have two lights, one for the front (connected to this ninth pin) and another to the 2 pin cable, and they are controlled by the PCB (not sure how you turn them off/on though).

So thanks, mystery solved. Unfortunately I still have the main problem where the motor doesn't turn, but now that I'm confident that all the necessary connections are fine, I will look more closely to the motor.

(I assume that I can leave the 3 pin cable, which I assume is the PAS disconnected)

 

[stancecoke]

not sure how you turn them off/on though

It's switched by the display, often with a long press on the + button.
Do you have a display? Maybe the throttle is disabled in the display setting. So try to start the motor by shorting the PAS signal line to GND in a steady rhythm. Try long shortend and short open and vice versa, as the controller expects a duty cycle different from 0.5 normally.

 

[gonsp]

I believe I have found the issue! I traced the pins on the 9 pin motor cable from the controller, and it looks as follows:


This would match with the following motor cable (random diagram found on the internet):

However, it's completely different to this other diagram:



In particular, note how the red 5V pin is next to the arrow in my controller, but on the last diagram it's at the opposite side.
So now I believe that the motor cable is not compatible with my controller. I thought that this would be standardized (Note that both cables are "Juliet")... This is so chaotic hahaha

My motor is the M131 from Ananda

Do you think I'm on the right track? I'm about to re-solder the wires on my controller to match the last diagram, assuming this is what my motor uses

 

[stancecoke]

However, it's completely different to this other diagram:

It's the same, just mirrored, as one is for the male connector, the other for the female....

But you can check the hall sensor signals easily, as you have opened the controller already anyway. Check the voltage on the Hall lines while turning the motor backwards slowly by hand. On all three lines the voltage has to jump between 4.xxV and 0 V....

Of course you can try to swap the signals, as only the right phase and hall combination works. But normally with this 9pin Higos (or Julets ) it is standardized.

you can find this flow chart in many places:

 

[gonsp]

I ended up buying a new controller that came with a kit and that one worked without problems. I learned that having a display is pretty important to see the errors and adjust settings, otherwise you are blind to those problems

Thanks!