Faulty controller or motor?

Adrian_ · Apr 14, 2022

I was out riding my bike (48v 1000w) and everything was fine and then I stopped at a red light, when I tried to set off, the motor was very loud like it was running without hall sensor and it was lacking power, it felt like 300w. I stopped, checked all connections and everything seemed fine, I did notice that the controller was extremely hot, could not keep my hand on it for more than 2 seconds, not sure if controllers get hot like this, motor was warm aswell but it felt normal. I disconnected the hall sensor to see if it made any difference and the motor started turning in reverse with healthy amount of power as if nothing was wrong (I forgot to plug in the hall sensor couple of times and the motor span forward everytime, this is the first time that it span in reverse without hall sensor). I didn't want to walk home or ride the bike with what it felt like 300w so I disconnected the hall sensor and swapped blue and green phase wires, this caused the motor to turn forward and that's how I got home.

Now the question is, did the controller just get too hot and something inside melted or burned or is it the motor? Without the hall sensor and blue and green phase wires swapped, it rode home just fine except the motor being loud but that's probably due to the hall sensor being unplugged. Wanted to get some opinions just incase it's obvious.

Adrian_ · Apr 15, 2022

I did some troubleshooting today, I don't have a spare controller however, I do have a spare working motor, I plugged it into the controller and it was exhibiting exact same behaviour, it was running better without a hall sensor than it did with a hall sensor and it was spinning backwards without a hall sensor, this makes me 98% confident that it's a controller issue. I checked hall sensor voltages since the controller seems to work fine if I unplug the hall sensor and swap the green and blue phase wires, they all show 5.03v except one which is 4.78v, not sure if this is normal or withing margin or its the issue or part of the issue. I ordered another controller but for now I will just ride around without a hall sensor and phase wires swapped.

Adrian_ · Apr 25, 2022

I'm planning to open my QS 273 V3 so I can add statorade ferrofluid and to repair a phase wire that received some damage to insulation after my brake disc rotor exploded. While I'm in here, I would like to install a temp. sensor so I can monitor the temprature of it as I did get it toasty couple of times last summer during heat waves.

I'm wondering if anyone has recommendations for which temp sensor I should use or any 125C/260F will do. Thanks!

larsb · May 5, 2022

It depends on your controller and which input it requires.

amberwolf · May 5, 2022

Or whatever you are going to read the sensor with.

Each reading device will have a specific sensor requirement.

If all you need is a display readout you can see, you can take apart a BBQ thermometer and put the sensor inside the motor, and the display on your handlebars.

Adrian_ · May 6, 2022

I bought a 36v 750w ebike from a friend who was getting rid of it as he needed space, the bike sat for over 2 years with "motor problem". When I tried to test it, the motor spins for about 2 to 3 seconds very loudly and it's vibrating like hell as if it's trying to run without a hall sensor before the motor stops spinning and "(M)" shows up on the display which according to manual, it means motor problem. I tried unplugging the hall sensor but the motor doesn't spin so I guess the controller is sensored and doesn't have sensorless mode. The next thing I tried was plugging in a known working motor and it works fine, which rules out the controller. I suspected that it might be hall sensor inside the motor so I tested the voltages and all 3 report 5v, I then tested all of them again while spinning the motor and the voltages change on yellow and green hall sensor but blue stays 5v. I wanted to check if this is a bad hall sensor as this is my first time dealing with an issue like this before I decide if I want to replace the hall sensor or if I should get a sensorless controller and "fix" is that way.

TommyCat · May 6, 2022

Sounds like a bad hall sensor to me...

Check out to this thread to verify correct testing procedures of your motor's hall sensors. And how to check the phase wiring whilst you're at it.

https://electricbike.com/forum/foru...-motor-s-phase-wiring-hall-sensors-and-wiring

As far as which to replace might depend on your repair skills. I've heard that sensorless controllers may be a bit rough on start-up.
I like to solder and would have fun opening up a motor. And if it's a sine wave controller would go with the hall sensor replacement.
But that's just me... :wink:

Regards,
T.C.

Faulty controller or motor?

Adrian_

10 W

Adrian_

10 W

Adrian_

10 W

larsb

1 MW

amberwolf

Administrator

Adrian_

10 W

TommyCat

10 kW

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