Vehicle work today was limited to continued progress on the erector-set-style build of the roof deck solar panel mount for the Suburban. I'm off to Temecula this Saturday and I'm hoping to get the frame sufficiently complete to mount it on the vehicle for a test. I may install a 'simulated' panel crafted out of a triple-layer of 1/2 polystyrene sheet insulation. That way if the mount fails at my ludicrous highway speeds I am much less likely to kill someone.
My envisioned design is still working out ok. There's some unplanned-for height / thicknesses to correct due to the materials used and the assembly method. I'm using 1-1/2" L-angle aluminum, 1/16" thick. The panel corners are a full 1-1/2" thick. Since I'm planning on some foam / rubber insulation strips within the frame - so the panel is trapped in a compression fit, the spacing between top and bottom inner faces has to be at least 1/8" larger. So I'm crafting the vaguely 'C'-channel-shaped front and trailing frames by overlapping sections of L-angle.
Too, I am overlapping the L-angle sides of the frame under the front and trailing frame elements, at their corner junctions. That induces other unanticipated height considerations and creates an unsightly gap and front and back where the top of the C is hanging ~1/4" above the sides.
I'm destroying an already damaged carbide-tooth 10" saw blade in my tablesaw, using it to trim down the aluminum. It works, but it's an ugly business. I've read tell of a method of installing the blade backwards, but it's too late to matter.
My design idea of using hot rodder flush hood locks as the method of clamping and securing the panel in the frame is working out swell. The big fender washers that come with the locks are too big for their install locations and will either have to be cut down or replaced with something else.
The panel has a narrow margin around its periphery, no more than 1/2" or so, by which to secure the panel in this mount design. Any more overlap of the panel and the solar cells get obscured and no workee. I've made the frame about 2" wider than the panel, fore and aft so I can both fit the placement of the hood locks and provide for some rubber / vinyl bumpers which will also help trap and cushion the panel. Some additional foam / rubber adhesive insulation stripping will also help trap the panel and prevent rattles and wind whistling (I hope).
I'm also going to be fashioning a 45deg slope on the front edge to help aerodynamics.
I really don't know if this thin aluminum will work well enough. I'm using pop rivets right now, but when this Mk1 design is complete Im going to drill them out and epoxy the overlapping joints and re-rivet them. And then possibly drill the rivets out again when the epoxy has cured. and I intend to also epoxy all the other angled joints in turn. And I must do something about gaps at the ends of the C channels. I'm really concerned about road-wind getting into the whole thing and tearing it apart. Mk2 will be 1/8" thick aluminum, probably. Steel would be better, but 40-lbs just for the frame is undesirable.
bunch of pics to follow.
The aforementioned gap where the C-channel shape stands proud of the L-angle sides. I might correct this in a later version by using 2" L-angle for the sides of the frame and cutting it down to fit the height I need. In the meantime I'll fill it in some other way.
Some generic bumpers pressed into service, a set riveted to the mounting frame and a set riveted to the panel frame itself, so they line up with each other.
Figuring out the placement of the widest part of the hood lock mechanisms, to find my centers for drilling. The locks are not in the center of the L-angle face, they're closer to the hinge side of things.
A couple images of the hood lock stack. The top portion twist-locks into the channel in the bottom stud. Their shortest assembled height is just under 1-1/2" tall, which just works for me. Any taller than say 1-5/8" and they wouldn't work with my desired minimum height design.
The threaded stud of the lower lock will get cut off below that lower nut. I'll use a forstner bit to drill a cup in my plywood roof deck for that lower nut to nestle in. I'll drill it bigger and do some touch-up with the 'hammered finish' paint. That 'cup' will be a water trap in a plywood sheet. Bad JuJu.
A look at how the hinged trailing frame works. Idea being you open the hinged portion, put the panel into the frame and seat the front edge into the C-channel and lower the trailing edge and then flip the hinged portion shut into a compression fit on the trailing edge of the panel and lock it into place. This is a portable hinged panel kit for ground setup that I am pressing into a flat rooftop mount for transport and charging on the move. Alternately, I can park the vehicle in the shade and dismount the panel and set it up in the sun and plug it in with a long lead. Both my rear power connection panel and the future roof connector will be wired into the charge controller in the vehicle.
The piano hinge I'm using is large and just happens to be 1-1/2" across the flanges. Too bad that's too small for me. So I had to shim the placement of it when temp-attaching it to the two halves of the trailing channel so the total interior height is more like 1-5/8"+
The pick is a mockup of how the pieces fit in relation to each other.
I used the washers of the lock kit as a template for the keyed hole that lock will be mounted thru. I'll file / grind out the red areas later and find some smaller fender washers or just cut chords off the large washers that came with the lock kit.
the hinged channel, temporarily riveted together
and farting around with alternate bumper positioning, since the rear spacing is too large to double them up like the front. And the slope of the sides of the bumpers would sort of work for a front to rear compression fit for the panel. With the hinged channel compressing top to bottom.
More on this soon.
My process is admittedly crude and iterative. I don't have the budget, time or attention or equipment to make it better and 'correct' the first time. I've already thought of two other different arrangements that would more snugly trap the panel, at much greater cost and delay in fabrication / tooling access. And one would be too wide to fit between the channels of the factory Z71 roof rack.
And another design just occurs to me, with non-locking pins, it could be a good bit more compact. And the rear could jus tbe a channel that's pinned in place to secure the panel in the frame. But I want locks. I've got a vandalism / idle hands problem around here. No small part of why I want a low profile hard to notice mounting.
