ToM+, das einzigartige 2 in 1 Display für den Twizy

OK finally we had some good weather AND I had some time (rare combination).

The permanent 12V was easy, I just took that off the GND / battery pins in the OBD2 plug.



I measured it, and my little setup is now connected directly to the 12V of the aux battery. Perfect.

But now I'm running into something weird. When the Twizy is off (ignition key not inserted), and the ToM plugged in as normal, I measure 5V on the red and black wires of the expansion port. This seems to be permanent? On the yellow I blue wires, I measure a little over 3V. Starting the Twizy does not change this situation; 5V on the red wire, 3+V on the expansion pins.

After this discovery, I did not connect the relay to the GND/5V lines of the expansion port, because this would keep it energised the entire time, connecting the 12V/5V converter to 12V the entire time, thus keeping the 4G modem on all the time. This would drain the 12V aux battery, which is exactly what I want to prevent.

So, do I misunderstand something? I thought the 5V on the expansion port would switch on and off with the ToM. Or have I missed a setting?

I hope this help, more than words.

This is 100% clear, thank you! Weather and time permitting, I'll build this tomorrow.