I didn’t design or build the ground mount system at my home on the North Shore of Maui. It was done by a professional installer who left the solar business years ago. It looks improbably flimsy, but it’s held a double row of 32 Sanyo 250 watt panels for the last 13 years through several near miss hurricanes, with the panels angled against the wind coming off the ocean in the worst possible direction at the worst possible angle–like a catchers mitt for wind. And Maui is famous for wind, from the nearly constant trades to three hurricanes that passed about 50 miles offshore.
The main supports are standard galvanized steel t-posts, the kind you see holding up barbed wire fences everywhere, pounded into the ground with no additional concrete or even gravel, bolted to 1″ square anodized aluminum tubing to make up the framework, with standard unistrut channels, T-nuts and panel brackets, all bolted together with stainless bolts. My amateur mechanical engineer persona looks at the aluminum and stainless combination on a structure basted with salt mist from monster waves (we’re the next bay over from the infamous “Jaws”) crashing on a beach less than half a mile and 440 feet below and thinks “This thing is going to electro-chemically melt itself in no time”. But it hasn’t. In fact it’s unchanged in appearance from the day it was built. It reminds me of one of those matchstick bridge projects that hold some improbably weight. It seems worthwhile to take a look at this construction.
Obviously I’m not recommending a similar design. Companies that are designing DIY solar racks are building solid, safe equipment that can be assembled by anyone that knows which end of a screwdriver to hold. I’ll be testing some of them for my container project next spring. I overbuilt the racks mounted on my container project to a ridiculous degree, because I don’t want problems with them. The racks are FAR heavier than the panels they support. But it seems worthwhile to know what is feasible. After looking at my racks here more closely, I suspect anything I build in the future will be much lighter, but better engineered, meaning more intelligently braced. Because the bracing, plus the deep placement of the T-posts is what keeps this structure standing when a structure that depended only on the strength of the posts would probably fail. I suspect anyone with an understanding of mechanical engineering will comment something like “well OF COURSE that works, and here’s why”. I look forward to the comments.