mrbill
10 kW
Today I went out for a test ride on a new direct-drive hub motor (NC3006) and used the temperature sensor (10k thermistor as installed in the motor by Grin) for the first time.
As I climbed the first major hill, I watched the motor temperature rise gradually as expected. When the temperature reached about 75 C the CAV3 (Prelim8) display intermittently showed the AuxAdjust screen, even though I had not adjusted the dial. (I realize I had complained to Justin about this screen not persisting for as long as I wished, but even I don't want to see the AuxAdjust screen at random intervals.) As I continued the AuxAdjust screen persisted longer, up to 90% of the time. (Was Justin teasing me from afar?) During this time I observed that wh/mi was zero, even though watt-hours was greater than zero, as was miles. The calculation was not being made.
I stopped, went into Setup, and disabled the temperature sensor. Now wh/mi was displayed correctly, and I no longer saw the AuxAdjust screen pop up unbidden.
Not wanting to be without a temperature reading while I was climbing a long hill, I stopped again and enabled the temperature sensor. Now wh/mi showed "-3.5", and the AuxAdjust display only showed up when the dial was adjusted.
I continued my ride.
On the second long hill, I again observed the motor temperature rise gradually. When the reading reached about 90 C I noticed that it jumped erratically between 88.5 and 91.5, faster than I would have expected it to change due to heating. At about this time I noticed again unbidden flickering appearances of the AuxAdjust screen. When the AuxAdjust screen disappeared long enough for me to see the temperature of the motor, I could see that it jumped erratically between 92 and 120 C. Oddly, motor power was not throttled back, even though the temperature was in the throttle-back range (90-130C).
I stopped again and turned off the CAV3, hoping perhaps that a reboot would clear the problem. After turning on the CAV3 again, I saw the temperature now read 160 C and 0.16v. Alarmed that I had overheated the motor I felt the hub near the spoke flange. It was hot but not so hot that I couldn't firmly place my fingers on it indefinitely. My guess would have been 50-60C at most, but perhaps the temperature sensor is buried deep inside where the motor gets hottest.
Now that the temperature sensor was reading in excess of the maximum threshold temperature, the throttle-back feature appeared to function, and I could get no power from the system. I disabled the temperature sensor and resumed my climb. The system functioned properly for a while, and the motor appeared to have suffered no damage.
For the remainder of my ride I sporadically saw the AuxAdjust screen when I had not adjusted the dial. The last time I saw the screen it showed incorrectly, "0 watts". At this time I also observed current Watts at 10, even though I could feel the motor pushing into my backside and had just seen it display about 600 watts. Also, the current speed reading did not change, even though I could feel acceleration.
I stopped again and disconnected the temperature sensor cable from the motor and rebooted the CAV3. The CAV3 behaved normally for the remainder of my ride.
After I got home I reconnected the temperature sensor. The CAV3 displayed 172 C and 0.10 volts. The motor was barely warmer than ambient temperature, 25 C at most.
There appears to be some funky error in the temperature sensor code in Prelim8 that causes it to overwrite other display data and cause random appearances of the AuxAdjust screen when the temperature circuit is closed. I may also have a wonky thermistor in my NC3006.
Has anyone else noticed similar odd behavior with Prelim8 when using a thermistor?
Do I have a bad thermistor in my NC3006?
As I climbed the first major hill, I watched the motor temperature rise gradually as expected. When the temperature reached about 75 C the CAV3 (Prelim8) display intermittently showed the AuxAdjust screen, even though I had not adjusted the dial. (I realize I had complained to Justin about this screen not persisting for as long as I wished, but even I don't want to see the AuxAdjust screen at random intervals.) As I continued the AuxAdjust screen persisted longer, up to 90% of the time. (Was Justin teasing me from afar?) During this time I observed that wh/mi was zero, even though watt-hours was greater than zero, as was miles. The calculation was not being made.
I stopped, went into Setup, and disabled the temperature sensor. Now wh/mi was displayed correctly, and I no longer saw the AuxAdjust screen pop up unbidden.
Not wanting to be without a temperature reading while I was climbing a long hill, I stopped again and enabled the temperature sensor. Now wh/mi showed "-3.5", and the AuxAdjust display only showed up when the dial was adjusted.
I continued my ride.
On the second long hill, I again observed the motor temperature rise gradually. When the reading reached about 90 C I noticed that it jumped erratically between 88.5 and 91.5, faster than I would have expected it to change due to heating. At about this time I noticed again unbidden flickering appearances of the AuxAdjust screen. When the AuxAdjust screen disappeared long enough for me to see the temperature of the motor, I could see that it jumped erratically between 92 and 120 C. Oddly, motor power was not throttled back, even though the temperature was in the throttle-back range (90-130C).
I stopped again and turned off the CAV3, hoping perhaps that a reboot would clear the problem. After turning on the CAV3 again, I saw the temperature now read 160 C and 0.16v. Alarmed that I had overheated the motor I felt the hub near the spoke flange. It was hot but not so hot that I couldn't firmly place my fingers on it indefinitely. My guess would have been 50-60C at most, but perhaps the temperature sensor is buried deep inside where the motor gets hottest.
Now that the temperature sensor was reading in excess of the maximum threshold temperature, the throttle-back feature appeared to function, and I could get no power from the system. I disabled the temperature sensor and resumed my climb. The system functioned properly for a while, and the motor appeared to have suffered no damage.
For the remainder of my ride I sporadically saw the AuxAdjust screen when I had not adjusted the dial. The last time I saw the screen it showed incorrectly, "0 watts". At this time I also observed current Watts at 10, even though I could feel the motor pushing into my backside and had just seen it display about 600 watts. Also, the current speed reading did not change, even though I could feel acceleration.
I stopped again and disconnected the temperature sensor cable from the motor and rebooted the CAV3. The CAV3 behaved normally for the remainder of my ride.
After I got home I reconnected the temperature sensor. The CAV3 displayed 172 C and 0.10 volts. The motor was barely warmer than ambient temperature, 25 C at most.
There appears to be some funky error in the temperature sensor code in Prelim8 that causes it to overwrite other display data and cause random appearances of the AuxAdjust screen when the temperature circuit is closed. I may also have a wonky thermistor in my NC3006.
Has anyone else noticed similar odd behavior with Prelim8 when using a thermistor?
Do I have a bad thermistor in my NC3006?