Anyone ever tempted to run a node off a solar panel? I assume a single board computer would likely be the most realistic way of going about it.
Not..... yet! I plan to get something relatively large but still single panel that would easily power a node even on cloudy days.
The more ambitious part would be also developing a hashboard that is then dynamically powered on / off depending on sun availability. Mainly to show the counterintuitive concept of harvesting otherwise 'lost' energy (since the solar panel will produce much more than what a little pi needs on sunny days) and therefore run not only carbon-neutral, but you could argue carbon-
negative mining.

I would disagree it's carbon-negative. You need to consider carbon footprint during production[1] and whether it's recyclable after the panel reached end of life/broken[2].
1) It's not a 100% standard card and Dell has something custom either in the hardware or firmware that causes it to get funky under linux.
It's known problem that some WiFi and mobile broadband card doesn't work on linux. But what linux distro did you use? Have you tried install optional/closed-source driver (few distro require user to do it manually)?
[1]
https://www.1energysystems.com/carbon-footprint-of-solar-panel-manufacturing/[2]
https://www.nature.com/articles/s41560-020-0645-2.epdfI tried Debian and Ubuntu 1st figuring that when Debian did not work Ubuntu, although close to it may do something a bit differently. Then I switched to CentOS and still no go. Tried every driver I could find related to the card both open and closed. It's not even that smooth under Windows, after install you have to *power down* not just reboot.
As for the solar panel side, since the nodes in a box use so litter power you can probably get an older / damaged solar panel for free that will put out enough power to run the node and charge a few batts to keep it going when it's dark out. Depending on where you live. Here in the US it's going to be easier to do in say Las Vegas where you have a lot more sun then New York.
https://bitcointalk.org/index.php?topic=5158920.msg58008085#msg58008085
-Dave