So, I have good news, and I have good news. Very good for a change.
First, regarding Bluetti customer service: Not only did I get a positive response from the company’s regular customer service department that was actually helpful, this morning I got an email from an actual engineer at the company to discuss specifics about the problems I encountered. As noted before the voltage fluctuation problem went away by itself but they’re concerned about that light flickering and wanted specific information about the brand, model and other details about that light so they could look into it. That’s not a big issue though because I believe the problem is related to that particular model light and that one only. All the others I tested had no problems. I suspect it is an issue with the design of that light fixture.
So that makes me feel a lot better when it comes to customer service.

My solar panels arrived! I ordered 4, 100W panels from a company called HQST mainly because they were very cheap. And it turns out that not only were they very cheap, they’re very good as well. It took me all of about 10 minutes to set them up leaning against the backside of the garage, one of them shaded by that stupid bush out there. And at the moment I’m getting almost 300 watts out of them (hooked in series) If I didn’t have that one panel being partly shaded and had them at the right angle relative to the sun I’d be getting close to the full 400 watts out of them. So I’m enormously pleased with that too.

Right now I’m getting between 250 – 300 watts out of ’em. We have some intermittent high, thin clouds that shade them out a bit which is why there is the fluctuation in output. I’m drawing 190W in the office at the moment running my laptop with 2 monitors, stereo speakers and a few other things, so the panels are making about 100W more than what I’m consuming here in the office.
I tried dual charging the AC200 as well, charging with the AC200Max’s AC charger and the solar panels and it was happily sucking down about 750 – 800 watts from both sources at the same time.
So I am enormously pleased. (Squeals like small child)