Attaching and securing a large solar array to a van roof two ways for safety
I have a 170" wheelbase Sprinter and 5 100W panels. I plan on bolting the long edges of the panels together to make one large panel, 5 panels wide. I will also bolt the short edges to two 8 foot aluminum angle brackets. Here's an illustration of what I mean. (The light gray lines between the panels indicate where bolts would be, underneath the panels, holding them together. Though, I might use aluminum or steel plates and bolt the plates to the panels using their existing holes.
Once that's all done, I'm going to be mounting it onto two Superstruts that I will bolt through my roof. The Superstruts are 10 feet long and mount with the U shape upright. They have special nuts that sit under the lip of the U opening that you can bolt down into. The nuts have little teeth on them to bite into the strut.
I'm thinking of using four of these heavy duty angle brackets to hold the panels to the Superstruts in such a way that one edge could hinge up for tilting the panels. These might look small in the image, but those holes are over 1/2" in diameter. These are seriously heavy duty brackets made for Superstruts.
Even if using Loctite thread locker and plenty of torque, there's always the chance that a bolt or two will work its way loose on the highway leading to a catastrophic failure. The panels could fly off the roof and hit another motorist. I'd only lose $550 in panels, but they could injure or kill someone. I'm thinking I need a secondary safety mechanism to prevent this, making the worst case scenario be some damage to the panels themselves or to my van.
My first thought was to drill a hole (or pair of holes) at each of the four corners of the combined panels, and thread 1/8" coated steel cable through them, then permanently or temporarily crimping the cable together. (The image shows temporary crimping hardware. I could also do permanent crimps.) The other end of the cable would go through holes I drill into the sides of the Superstruts, where I'd crimp them again. Then, if the bolts worked themselves loose, the cable would stop the panels from flying off, but they'd probably make a hell of a racket bouncing around, alerting me to the problem.
One problem with this idea is I'd like to tilt the panels. I would tilt them all at once as a unit towards the side of the van. I'd either have to only add this safety cable to the hinged side of the panels, or come up with a quick release mechanism for the cable on the tilted edge.
One idea I had was to see if I could use PC locking cables. I could thread the cable through holes in the panel, and add the lock to the end. Then I'd probably need some place to stick the lock to prevent it from rattling around. A little mounting bracket of some sort. Then, I could undo the lock, unbolt the panels, and tilt them with whatever tilting mechanism I end up with. In addition, this would add a little security, Especially if I add some kind of knobbed bolt as a quick release.
I could use the angle brackets, ratcheting knobs, and rivnuts. The ratcheting knobs can be torqued down pretty well, even with limited space to get your hand around it. The rivnuts would also be used for the vertical support that keeps the panels tilted up. I could have upright supports with several holes for various latitudes, and use some more of the same knobs. I'd need some wingnuts for the bottom, or female knobs.
Instead of cables, I could probably find a way to incorporate locking pins or something similar. They are inherently quick-release, which is nice. I'm having trouble visualizing where they would go, though, especially on the hinged side. On the side that tilts up, maybe I could use a couple of small hasps. And then why use pins when I could lock them! (Panel theft is definitely a risk.) The hasps could be screwed to the panels and Superstruts if I pre-drilled some holes.
Maybe I'm too set on trying to use the angle brackets I linked above. Maybe I should use traditional hinges all the way along one edge. With so many hinges and bolts along one edge, it seems like there'd be little to no chance of them all coming loose. I'll just have to figure out a way to attach the hinges to the Superstruts. I don't think I could use those fancy nuts. The bolts would just get in the way. Might have to drill holes on the side and bolt them on that way. Unless I could find some special hinges that had a good amount of clearance between the two plates. Or some sort of offset hinges. Googling "offset hinges" produced all sorts of interesting results.
At this point I'm just thinking out loud. Any other ideas? Has anyone else done something similar?