Solar Sunroof ‘hack’.
 

Stumbled upon this YouTuber who’s redirected the feed from the solar sunroof to the car’s battery. He says it previously powered HVAC and battery. I thought it just powered HVAC TBH.

https://youtu.be/iOohKDb0m6I

The fella seems to have gone about it the right way. How effective it is I’m not sure....

That's a long video, I got a bit bored and did not watch it all. From factory solar roof only drives fan, does not charge battery.

I did try to make it charge battery as well as drive fan on my PF D2 but the solar panel is not powerful/efficient enough. Newer cars have more powerful panels and if you diverted all of the power to battery it might work better. I wanted to keep cooling fan working as well. It was slowing down discharge of battery if I left car without driving for like a month but did not keep it fully charged so I still needed to connect it to mains charger if not using car for long period of time. This also slowed down fan and reduced cooling so in the end I reverted back to fan only. I was looking at changing sunroof with a one from FL car with 4 rows of solar cells instead of 3 but decided that it will probably not be enough anyway.

As you say, a long video, but for me, it overlooked the important aspects of the project, and that was how it was all connected.

There was a 3-pin connector going to the HVAC unit, but he didn't show how he took the feed from the sunroof into the solar controller and back to the HVAC. Nor did he show where he connected the wires to the battery (although he did mention the battery management unit).

I've yet to fit my solar sunroof, but it would be a nice addition if it worked (and cost less than a tenner on eBay), and could also fit a switch to the HVAC feed so it could be turned off during the winter months (just like HPsauce has done on his S8).

A D2 is relatively simple in comparison to a D3; I expect you could do something similar there relatively easily as there's no battery management unit to contend with.
In fact I vaguely recall someone has, maybe integrated with a CTEK charger connection?