QS 273 Motor 8000W

[ratos]

Hello everyone,
I'm upgrading an old Bereco Amperio 8000W scooter. I've replaced the old batteries with new, higher-capacity ones and installed a new 13-inch QS 273 E-Scooter In-Wheel Hub Motor (50H) 8000W V2 Type.
The controller is a Sevcon Gen4, and I have the IXXAT connection board and a DVT software license, but I don't know the motor characterization parameters required by the controller.
I've contacted the manufacturer, but they haven't been very helpful, and I don't know where to find them.

Can anyone help me?

Thanks

 

[ratos]

I'm gradually making progress and discovering new problems.

This motor has a KTY83 type thermistor to control the internal temperature. I've connected the cable to pin 33 of the Sevcon controller and configured it as a "user-defined" thermistor since the dropdown menu doesn't offer that option for this model.

According to the Sevcon manual, pin 33 has a 2.2kΩ pull-up resistor, so the calculated voltage values for 0 and 100 degrees are:

According to the thermistor datasheet:
R(0°C) = 828 ohms
R(100°C) = 1687 ohms

VRT0 = (828 / (2200 + 828)) x 5 = 1.3672391017V

VRT100 = (1687 / (2200 + 1687)) x 5 = 2.17V

With these values entered via DVT, Sevcon displays an overheating error for the motor when in reality the temperature does not exceed 25°C.
(Photo attached)
Any suggestions?

 

[adsc]

I would actually measure the resistance of the temp probe, just to be sure. Datasheets are good, but measurements are better. I think the QS 273 comes with different temp sensors, some with KTY83-122 and some with KTY-83-110. Shouldn't really make that big of a difference, certainly not 312° C when it should show 25° C, so something is very wrong indeed.

Can you show all screens where you entered something for the configuration of the temp probe?

Also, it would be nice to update the thread with answers to your own questions, if you have managed to find them, so that others who come later can also profit.

 

[ratos]

Thanks for your reply. I also verified that the thermistor resistance matches the expected value according to the manufacturer's datasheet. This motor, according to the manufacturer, has a KTY83-122 installed, and in this case, at 25°C, the probe reading coincides with the curve for that temperature (approximately 1kΩ). Therefore, I understand that the probe is in good condition and DVT should be registering that temperature instead of 312°C. I suspect I'm doing something wrong, but I don't know what.

The calculated configuration data is entered via DVT on the attached screens.

 

[adsc]

I think your calculated voltage values are correct. Are you sure that the sensor cannot be selected directly? It is mentioned in the sevcon gen4 manual as a possible selection. Maybe you have to select something else as Thermistor Type and KTY-83 will then show up as a sub-option or something.

But the user-defined configuration you have should also work. So the problem is somewhere else. Where have you connected the other lead of the sensor? It should go to the B- terminal of the controller.

In DVT monitor, can you check Object 6C01h → Motor Thermistor Voltage?

 

[ratos]

It's true that the user manual says it's possible to directly select KTY83, but at least in my case, it's not possible, and I can only select KTY84 or "User defined," as you can see in the attached image.
Looking at Object 0x6C01, as you wisely pointed out, the voltage across the thermistor terminals is approximately 3.89V, which is very interesting because it suggests that the pull-up resistor is connected to 12V, not 5V as the manual indicates.

Assuming the voltage is 12V, the values for 0°C and 100°C are:

VR(t=0°C)=3.2V
VR(t=100°C)=5.2V
With these new values, the probe voltage at 25°C remains clearly within the calculated range.
Pending confirmation, I believe this is resolved

 

[ratos]

After loading the new configuration, I confirm that there is no engine overheating error and it also provides a reasonable measurement with a cold engine (33°C) which increases when the engine is turned for approximately one minute (43°C), which means that the probe is working correctly.