The Victron buck boost DC DC converter is programmable so you get to decide what inputs turns it on and how long it runs for.  The purple and green wire are two connections that you can use, it also has a vibration sensor.  You can run the program in demo mode.  Here is a screen shot of the configuration page in demo mode.  When you have entered your settings you have to hit the "Send all settings to converter" button in the bottom right.  It is greyed out here because it is demo mode.

For any option that you choose on the screen above the contextual help box in the lower left gives you appropriate guidance.

So for example if you select that you want the purple wire to turn on and off the device:

With this option selected the contextual help screen shows you what the Powerdown option means:

If you choose the vibration sensor as your option for turning on:

The contextual help explains the other options available to go with this:

Here is the contextual help that goes with the green wire