Help! Motor gone wrong?

[Ravenclaw]

Hi, everyone...

This is my first post in the forum, and I hope I am in the correct thread...

Recently I have an ebike which I suspect the motor gone wrong, but I'm not 100% sure. I am planning to bring it to a ebike shop to repair it, but just in case they trick me, I will have a little bit of knowledge to judge. Hence, I wish to know if my the diagnosis is correct, and that's the reason of posting this thread...

My ebike has the following components:

Rear geared hub drive motor rated 250w, controller rated 48v 18A, YL80C display, cadence sensor, disabled half-twisted throttle, 16AH 48V new battery

During my riding, the motor occasionally stop working, usually at the same time, the speed ometer shows an abnormally high speed for a while. Afterward, when the speed dropped back to normal, and the motor will come back on again, may be for a while, and then, here we go again...

I thought it was the cadence sensor problem, so I enable the throttle for testing, but the same happened.

My guess is the component which detects the speed in the motor gone wrong, since the motor will cut off at 15.5mph, if the speed sparked to over 15.5mph, the computer will think that I was going too fast. As a result, the motor cut off.

The above symptoms only happen when I actually ride the ebike, when I put my kickstand on, rise the rear wheel, and try to activate the motor with whatever throttle or pedal, the speed on the display doesn't seems spark like when I was riding...

Also, it only happen when the air temperature is at around 10c, when the air temperature is around 17c or above, the motor seems fine...

So my question is, is this very likeily that I have to replace the motor of the ebike, or it may be something else?

Thank You!

 

[saneagle]

The motor is working fine. The problem is clearly with the speed sensor. A very easy and cheap fix would be to wire in an external wheel magnet sensor if you can't fix the one in the motor. Cost of the sensor is about £5. The work to wire in would be about 30 minutes for a competent e-bike mechanic, but I bet they wouldn't have the brain to figure out that as a solution and probably wouldn't know how to solder the two wires to the controller.

Before anything, make sure that the motor connector is pressed in all the way to the line. If it's 1mm short of the line, you can get problems like you describe. Also, have a look all the way along the motor cable to check that it's not been squished by anything, e.g. zip tie.

 

[AndyBike]

disabled half-twisted throttle,

activate the motor with whatever throttle or pedal,

Have you fitted this throttle yourself ? maybe a problem there.

 

[Ravenclaw]

The motor is working fine. The problem is clearly with the speed sensor. A very easy and cheap fix would be to wire in an external wheel magnet sensor if you can't fix the one in the motor. Cost of the sensor is about £5. The work to wire in would be about 30 minutes for a competent e-bike mechanic, but I bet they wouldn't have the brain to figure out that as a solution and probably wouldn't know how to solder the two wires to the controller.

Before anything, make sure that the motor connector is pressed in all the way to the line. If it's 1mm short of the line, you can get problems like you describe. Also, have a look all the way along the motor cable to check that it's not been squished by anything, e.g. zip tie.

Hi, thx for the solution.

 

[Ravenclaw]

Have you fitted this throttle yourself ? maybe a problem there.

The ebike came with a throttle but disabled by default. Unfortunately, the bootup sequence has a mandatory checking on the existance of the throttle. Therefore, the throttle cannot be removed otherwise the motor will not kick-in...

 

[saneagle]

The ebike came with a throttle but disabled by default. Unfortunately, the bootup sequence has a mandatory checking on the existance of the throttle. Therefore, the throttle cannot be removed otherwise the motor will not kick-in...

Did you check the motor connector like I explained above?