E-bike with lost connection between motor and battery

E-driver_

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May 22, 2022
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Hi

So I have an ebike that has a functioning battery. The 36-volt battery gives current to the display of the ebike. But the connection between the motor and the battery seems to be lost. Why this is happening is a mystery :)

As you can see from the pictures, I have opened up the box below close to the pedals, where the controller sits, and I have measured current there going from the connection, from the inside of the bike's screwed up box. And it seems on the multimeter that the battery is giving current into the controller, since the multimeter is measuring 41-42 volts there, right below where the battery is connected to the bike.

And from here on I would like to get some help. Because looking at the other cables I don't quite know what and how to measure if there is current going into the motor.

The Julet connector from the motor I am not sure about how to measure. Is it possible to measure plus and minus inside of that with the multimeter somehow? And if so how? There are several little holes in that Julet connector and I don't know what is plus and minus or if that is a possible alternative ?

Also, from the controller to the motor there are several cables, with many different colors. And I am not sure how to find the issue going forward. Any suggestions? How do I measure the current(or non existent current) going from the controller to the motor with the multimeter? (If you think that is the problem). And if it could be something else, please let me know.

Seems to be around five cables going from the controller to the motor. But only the black and red going into the controller, to give it current. So I am not sure about how to measure current going out of the controller. Or to see if the controller might have some issue inside of it.

Here is a video:

https://www.veed.io/view/03e9d4f0-1b59-4fcf-a52c-fc3df06687b8
 

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I would proceed a little differently. This will be easier then what you are trying to do.

Q: does your motor do anything when you have all the connections in place, your battery fully charged and you press your throttle?

First: since it looks like that bike has had a lot of moisture exposure I would make sure all the connections seemed good. No corrosion about them. Also, make sure your brakes handles are in proper adjustment and not cutting off current to the motor. Sometimes a loose brake handle can cause the controller to think you have pulled the brake levers.

Then I would go here https://ebikes.ca/learn/troubleshooting.html and proceed with these two tests.

Testing for Blown Mosfets
https://ebikes.ca/documents/BlownMosfets.pdf

Testing a Throttle
https://ebikes.ca/documents/ThrottleTesting.pdf

Once you have done these tests report back.

:D :bolt:
 
e-beach said:
Q: does your motor do anything when you have all the connections in place, your battery fully charged and you press your throttle?
:D :bolt:

No it does not. It does sometimes though. Perhaps every 60th try or so. So nothing happens for 59 tries and then all of a sudden it might give a little wheel power for two-three seconds. What might this be an indication of?

I will try to do this other stuff that you speak of :)
 
e-beach said:
First: since it looks like that bike has had a lot of moisture exposure I would make sure all the connections seemed good. No corrosion about them.

:D :bolt:

How do you see that is has had a lot of moisture exposure? Because of the mud or something? 🤔

I sprayed CRC electrofix-cleaner on the connections between battery and bike. Those four golden things sticking up there to connect the battery. Also, I sprayed this into the battery holes to hopefully clean out corrosion and other shit in there.

I will try to spray a bit onto the actual controller connections now if you think it has been exposed to a lot of corrosion and wetness. Then I will proceed with your other advice.

By the way. How do I know which cable is the throttle cable down at the controller? Thing is the cable of that one is going in through the frame of the bike, at the top, and coming out down where the controllers sits. So I am not sure how to know which color it has. I guess I could very carefully cut open the black cable around the gas throttle at the top. To see what the colors there are ?
 
e-beach said:
Also, make sure your brakes handles are in proper adjustment and not cutting off current to the motor.

:D :bolt:

Hmm they look like this. But I think the handles are in place(?).

Below they look like in the pictures from underneath. On top they look like the whole pictures of the brakes here.
 

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E-driver_ said:
e-beach said:
Q: does your motor do anything when you have all the connections in place, your battery fully charged and you press your throttle?
:D :bolt:

No it does not. It does sometimes though. Perhaps every 60th try or so. So nothing happens for 59 tries and then all of a sudden it might give a little wheel power for two-three seconds. What might this be an indication of?

I will try to do this other stuff that you speak of :)

So it does do something.
And it's a positive sign. Try applying throttle with the wheel off the ground and hand spinning the wheel to give it a push start to see if you can replicate the movement.
 
E-HP said:
E-driver_ said:
e-beach said:
Q: does your motor do anything when you have all the connections in place, your battery fully charged and you press your throttle?
:D :bolt:

No it does not. It does sometimes though. Perhaps every 60th try or so. So nothing happens for 59 tries and then all of a sudden it might give a little wheel power for two-three seconds. What might this be an indication of?

I will try to do this other stuff that you speak of :)

So it does do something.
And it's a positive sign. Try applying throttle with the wheel off the ground and hand spinning the wheel to give it a push start to see if you can replicate the movement.

OK. I've tried this now. Nothing happened
 
I have now went through the first step of checking the throttle with the multimeter.

The multimeter did do everything as was described in the manual. So I guess the problem is somewhere else then probably.

I am going to try the mosfet-thing later today after work.
 
E-HP said:
E-driver_ said:
OK. I've tried this now. Nothing happened

Did the bike ever run correctly, and if so, what happened the last time you rode it before it stopped?

Yup, worked and then it stopped working. The display is showing power. Battery is showing power. And now throttle is showing power. It is a bit of a mystery. It just aiiint wannnna go forward :)
 
I am doing the mosfets-test now. But I am most certainly doing it wrong.

The multimeter shows OL from the start and never changes from this mode, even after I have measured(?) the contacts.

I am not quite certain if I should measure like this or if I am doing it wrong ? Are the multimeter-pins in the right place in these pictures? And does it tell you anything? the setting shows OL all the time in the diode mode. So both when not using the multimeter pins for anything and having them in the free air. And also when measuring these connections as in the instruction it is showing OL.

In the top picture I am trying to measure the yellow. In the one below I am trying to measure the blue. While at the same time having the black negative pin on the black negative connector, quite close to the battery connection.

The battery is screwed off since I read ohms does not need voltage(?) in the instruction.
 

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At this point your are testing the mosfets of your controller.

2 things..

1: when you touch the two probe leads together do they show continuity?

2: disconnect the phase wires from the motor and disconnect the battery from the controller. Put your positive probe to one of the phase wire connectors on your controller, and then touch the negative probe to the negative battery connector of the controller. (both probes need to be metering the controller ,not the motor or battery.

let us know how it goes.
 
e-beach said:
At this point your are testing the mosfets of your controller.

2 things..

1: when you touch the two probe leads together do they show continuity?

2: disconnect the phase wires from the motor and disconnect the battery from the controller. Put your positive probe to one of the phase wire connectors on your controller, and then touch the negative probe to the negative battery connector of the controller. (both probes need to be metering the controller ,not the motor or battery.

let us know how it goes.

Okay

When I put the probes together they made a beeping sound and showed zero/null like the picture below at the bottom.

When I then measured the poles again it looks like the picture on top, and it showed OL again. Let me know if I am measuring correctly. So the controller is cut off from the motor and battery in both ends that I am measuring now. Still that OL mode is showing.
 

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The beeping sound is a good thing. You have continuity.

OL means you have an opening in the circuit. Otherwise known in this case as a blown mosfet. Make sure you are getting good contact with your probes.

Leave the negative probe connected to the controller battery ground and put the positive probe to the other phase wire connectors on the controller and see if you also get a open reading.
 
Sorry I forget to ask. Does your controller have an on/off switch?.
 
e-beach said:
The beeping sound is a good thing. You have continuity.

OL means you have an opening in the circuit. Otherwise known in this case as a blown mosfet. Make sure you are getting good contact with your probes.

Leave the negative probe connected to the controller battery ground and put the positive probe to the other phase wire connectors on the controller and see if you also get a open reading.

The controller has no on and off.

I have measured again. I believe I am doing it correctly. Trying to do what you wrote. I have the red probe in one of the three mosfet colored cables coming out of the controllers. I have the black one in the ground/negative coming out of the controller.

The battery is off and not connected to the controller doing this measuring.

I am not sure if my connection with the probes are good enough but I can feel I have material connection between the probe and the brass/copper-thing there in the cables. Still showing OL when measuring.
 

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Sounds like you are doing it properly. Have you measured the other two phase wires in the same manor?

It is beginning to sound like a blown controller.

Please post the results after testing all three phase wire leads coming out of the controller.

Once you post those results we will walk you through testing your motor hall sensors.
 
Watch this video as a primer.

[youtube]efYFOHnXh0E[/youtube]
 
e-beach said:
Sounds like you are doing it properly. Have you measured the other two phase wires in the same manor?

It is beginning to sound like a blown controller.

Please post the results after testing all three phase wire leads coming out of the controller.

Once you post those results we will walk you through testing your motor hall sensors.

Ok I have now tried them all in the same manner. Dead chart :thumb:

Now just to be sure I tested the exact same measurement on two other controllers I have lying around. And I am starting to believe I am doing something wrong in the measurement ? because they also show OL when I do the same thing to them with the probes.

Are you sure I don't have to connect a battery or switch the setting on the multimeter or something? Because these controllers also show OL when I do this. And those two are working controllers. See pictures below.
 

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No voltage required. You are checking for continuity, not voltage.

However lets shift gears a little.

Set your DMM to 20kΩ. Put the red prob into the black battery connector of your controller, and put the black probe to one of your controller phase wires.

look for a reading. (a number)

Then move the black probe to the other phase wires and see if you get a reading

If you get a 0, then you have a short in a mosfet.
 
E-driver_ said:
No it does not. It does sometimes though. Perhaps every 60th try or so. So nothing happens for 59 tries and then all of a sudden it might give a little wheel power for two-three seconds. What might this be an indication of?

I wouldn't limit your testing to the controller, but test the phase wire and halls of the motor. The behavior above indicates that no one component has completely failed, but partial failure of one or more components, that somehow the working parts magically align to allow the bike to runs for a few seconds every 60th try. Perhaps a bad phase winding and a couple of fried halls, that took out some Mosfets when they failed. Who knows. Something doesn't add up, especially that the bike just stopped running out of nowhere and not under high loads, etc.
 
E-HP said:
I wouldn't limit your testing to the controller, .....

I agree 100%. I was trying to walk him through the controller before the motor. But I am fully with you on testing the phase wire and motor halls.

Although, he says his wheel spins freely so I think the phase wires are probably OK, unless he has a full open short not shorting any wiring in the motor.
 
e-beach said:
E-HP said:
I wouldn't limit your testing to the controller, .....

I agree 100%. I was trying to walk him through the controller before the motor. But I am fully with you on testing the phase wire and motor halls.

Although, he says his wheel spins freely so I think the phase wires are probably OK, unless he has a full open short not shorting any wiring in the motor.

It's a real puzzle, but possibly some motor testing results will shed some light. :thumb:
I've been mainly following to see what the resolution is. You methodical approach makes sense.
 
To OP:

First post to the board, so please excuse any mistake.

I'm having a similar problem to OP, and have just registered to this board looking for help. I've ran the same "blown mosfet" test as mentioned in the PDF, and got the same error (discontinuity) as OP. I finally figured out, because reistance will be in the 10K range, that I needed to use the 20K ohm setting as vs the diode or 20-ohm setting as mentioned in the PDF (which obviously will result in OP's OL readout). Suggest retry at the higher resistance setting.

I still haven't solved my issue yet, and will post in a separate thread for that. But just adding my observation. HTH.
 
I figured out that I get a reading on my multimeter when I press the yellow button called HOLD/SEL first.

So after I did that I got a reading of approximately 1,7 on the other controllers. But on the one that the thread is about I still got OL. So I guess then perhaps the mosfets are blown in it then? or I am doing it wrong.

In the picture below I have pressed the yellow button and it is showing me a sign on the other controller(not the bike controller).
 

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