HBL2350 loose contact? correct volt -> MosFail

Hi there,

I am a student from germany trying to build a electrical powered bicycle trailer.

Parts for this project are:

• HBL2350 Motor controller
• 2x directdrive motors from MXUS with 250W/36V/400rpm each
• force sensor
• 40V 10Ah Li-BAttery

Everything is working, but sometimes there are some hiccups while testing.
I narrowed the problem down to 2 possible situations which i can force by jiggeling the USB Port.

1. No MosFail, working, sometimes undervolt, low Batt (~32V) and Controller (~10,5V) Volt, jumping voltages and MCU-Temp (~80, not real)
2. MosFail after 1 sec, but stable and high voltages and low MCU-Temp, Batt 39,2V and controller 13V , 40°C MCU

I added two screenshots of the situations. I get to situation 2 by forcing the USB-cable a little up or down. If i let loose it returns to situation 1. In situation 2 there will be MosFail afer around 1 second and the contactor will cut power.
Another group of students worked with the motorcontroller before me, so I cant say if there possibly was an accident with the parts.
Is there a way to determine if this is an hardware or a software problem?

Situation 1, normal, just started


Situation 2, usb cable forced down


Situation 2, longer period


Thanks in advance!

I did a reset to default values and entered only the simplest configuration options for the bldc. (magentcount...)

The problem is still there. Constant undervolt on controller and battery voltage. MCU-Temp ist going crazy.

When i jiggle the usb-cable around everything seems to work fine.... Voltage and temp goes stable. (real battery voltage and controller voltage between 12 and 13) But only for around a second. After that the controller goes to MosFail and cuts power with the contractor.

This also happens without a computer connected, if I only plug the cable in the controller und move it around.

Under what circumstances does the controller go to mosfail? For around a second all voltages seemm allright. Then MosFail. Another jiggle and there comes the undervolt again. (battery is ok)

Thanks in advance!

Thank you very much. I will see what is possible....

One last question, sometimes i get everything working stable. BUt then MosFail is always on? why?
Here is a screenshot. As soon as i touch the usb cable it starts going up and down.

This screenshot was taken without a motor connected.
Thanks for the help.