Had some time to troubleshoot my setup, and it turns out that my problem has nothing to do with mysensors.... :)
As usual it was a user error.
I have put both of the mosfets on the same cooler and the middle pins (drain) got in contact throught the screw that held the mostfet to the cooler.
Separated the coolers and voila everything works
Yeah!

@tbowmo
Ok guys, thanks for the response.
As I understand your response, then I do not need the stuff from github on my pi.
Just connect the arduino, load the sketch, and configure HA.
Everything works like magic?

tom

@mfalkvidd
Sorry didn't mean to be sarcastic!
I meant magic as that I have been spending two weeks now to try to set up my frist motion sensor, with trying different options with configure command, so for me it is magic for now.
But it seems like I have been over thinking things a little.

But now that you mention documentation....
All the docs I have found searching for "no radio", "no nrf24", has the nrf24 in the shopping list. Their sensors maybe wired, but their arduino, nodemcu, etc. communicates over the radio with the controller, and the only one I found to be almost usable is the power metering forum post (and some other post mentioning/linking the power metering post) but thats too complicated for a newbie like me.

but for me it seems that 98% of people is using radio happily with mysensors.