I'm not entirely sure. What about a subreddit? There are already some similar things (not about solar), e.g. https://www.reddit.com/r/DIY/ and it seems to work out pretty well for them. I expect most of the HN crowd (or the relevant people, anyway, who might not be on HN) are familiar with reddit already and similar subreddits (/r/electronics, /r/hardware, /r/raspberry_pi, etc.). Simple upvote system, and comments already baked in.
