9C motor stuttered on last 1/3 mile

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yoyoman

1 kW
Joined
Jun 9, 2008
Messages
477
Location
San Diego, CA
I ride 5 miles to work, and on the last 1/3 mile when I left the stop light, my 9C motor started stuttering. I let off the throttle and rode for a bit, and then when I tried it again, it seemed fine.

This morning, when I went to ride to work, it stuttered or even didn't want to move. A few times, when I spun the wheel by hand and gave it throttle, it'd move. I charged the battery overnight, and I checked it today just to make sure, and it's at 50V.

Does anyone have suggestions for troubleshooting?
 
What's your voltage under max amps?

Also have you checked to make sure the hall wires are contacting.. phase wires are secure, etc?

One good test to rule that out would be to have the bike tire in the air, and jiggle the motor wires while hitting the throttle..
 
where would I measure voltage under max amps? Can I just read off my CellLog8? I don't have anything else connected that shows V during my ride.

From the prior owner, the motor phase wires are connected to bullet connectors which connect to the Andersons. That section has always looked a little melty. I guess I should jiggle and also check for continuity.
 
Well, you should get a screen that shows you how many amps you are pulling.. what your voltage is at.. so that you cannot only judge your state of charge, but your battery performance, motor performance etc..

Kinda like having a tachometer and gas gauge on a car.. i wouldn't ride without one.. and it will help you diagnose a lot of issues.

dodgy wiring could be it too, from the sounds of what you're talking about.
 
I put the bike on my stand just now, and I tested some things. One thing I noticed is that when I applied full throttle the rear wheel wouldn't move. But, while applying the throttle and slightly spinning the wheel would magically make the wheel turn at full speed. I don't know if it's different than before, but the wheel doesn't spin for a long time after throttle is released.
 
Sounds like a bad hall sensor signal. Double check all the connectors between the motor and the controller.
 
Unless you actually blew a hall sensor, your problem is a bad connection to the motor . It could be one of the blue green or yellow halls wires, or something could be wrong with a phase wire.

90% of the time, a problem like this is in the wiring or plugs to the motor. Its not the controller, or throttle, because its running on two phases.
 
Not sure how/when my bullet connectors got melty, but I have gotten rid of them. Now it's motor - Anderson/Anderson - controller. I reused the Anderson housing but replaced the contacts. It starts up without needing a push, but while on the stand I noticed that the top speed was way lower than it was before replacing the connectors. While on a test ride, I felt that stutter again, and the motor is weak enough for me to be able to put my feet down and stop.

Thoughts?
 
Possibly wrong phase hall combo. Are you certain you have the same combination of wires you had before replacing the connectors?
 
amberwolf said:
Possibly wrong phase hall combo. Are you certain you have the same combination of wires you had before replacing the connectors?
Click to expand...

Just to make sure, I checked a photo I took before I cut off the old connectors, and I looked at a photo I took after the change. The colors all match up. I also put probes on both sides of all the Andersons, and there's continuity.

An observation from another test ... the motor will turn for a period of time and then stop. No matter how much I give the throttle, it always seems to stop at the point in time.

I have some other controllers on other bikes. Am I at the point where I should try another controller?
 
OK, I checked all the connections and such to the best of my ability, and now the motor does reach full speed. However, as I said in the previous post, no matter how fast it spins, it will cut out at the exact same point a second or two after running.

What's next to check?
 
Sure seems like a controller problem then. Most have locked rotor protection that will kill the power in that time frame if it doesn't sense a hall signal. I suppose it's possible the motor has one bad hall sensor and it happens to be the one used for locked rotor detection.

You can test the hall sensors with a voltmeter. This would tell you whether it was the motor or the controller.
 
You can test the hall sensors with a voltmeter. This would tell you whether it was the motor or the controller.
Click to expand...

Thanks for the continued help! So for this, would I connect my battery, disconnect the 3 phase wires, take out the 3 hall pins from my 5 pin (blue, green, yellow, black, red) connector and test for voltage across pairs of hall pins while turning the wheel?
 
Some 9c and muxus d.d. have pcb board that the hall sensors Mount through the hall wires. In the past I have removed the board and connected direct from wire to hall making a three legged spider one black one , one red to complete the circuit. The board was for three negative connections and three positive connections to easier connect the hall sensors. With a couple baby resistors for reasons I would never know.
 
fechter said:
You can test the hall sensors with a voltmeter. This would tell you whether it was the motor or the controller.
Click to expand...

Progress isn't always good news. Yellow to ground stays at 4.6V . So, does that indicate a motor issue?
 
It means the yellow hall is not pulling hte signal to ground at all.

That could be a broken wire or bad connection anywhere between the point tested and the hall inside the motor, or it could be the sensor itself.
 
amberwolf said:
That could be a broken wire or bad connection anywhere between the point tested and the hall inside the motor, or it could be the sensor itself.
Click to expand...

So, I can rule out the controller then. I guess my next step is to nick the yellow wire as it leaves the motor and see if there's continuity to yellow at the controller plug.
 
If you're measuring right where it comes out of the motor, it would indicate a bad hall sensor.
 
ah, I guess if I'm going to cut into the wire, I might as well just the hall from there instead of just checking for continuity in the wire.

hmm, maybe time to invest in a gear puller.
 
i poked a hole in the installation right off the axle, and I tested for continuity at the controller plug. Good connection, so that means bad hall sensor =(

I'm in San Diego pretty close to UCSD off the 52 freeway.
 
It could still be a connection between the measured point and the hall sensor inside the motor (solder joint, broken wire, etc).

If you get the motor open you can check at the sensor lead itself (just waving a magnet past it will generate a signal like the motor spinning).
 
amberwolf said:
It could still be a connection between the measured point and the hall sensor inside the motor (solder joint, broken wire, etc).

If you get the motor open you can check at the sensor lead itself (just waving a magnet past it will generate a signal like the motor spinning).
Click to expand...

regardless, I still have to open the motor.
 
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