Ray,
Thanks for the clarification on the photo. Years ago Solar World stopped
making modules with the metal strip on the frame for back mounting;
folks complained and they brought back the provision for back mounting.
But as you say the frames are very thin these days and the module area
is huge - especially compared to the 75 watt modules I started with.
Kent Osterberg
Blue Mountain Solar
On 3/10/2024 1:14 AM, Ray Walters via RE-wrenches wrote:
That's just distortion in the image, from when I zoomed and cropped
it. Its module frame direct to the 2" angle aluminum support rail.
Nothing in between. High winds ripped two other modules completely
off the rack leaving all the hardware still attached with a bit of
module frame still under the washers .
This is on a mountain top in Wyoming. Believe me, when I tell you
that bottom mounting is no longer a safe method with today's big
modules, at least not in high wind situations (> 90 mph). I measured
the thickness of the module frame, and its about 1/2 the thickness of
an old Siemens SP75 that I compared it to. These were Solar World
modules, but I've noticed most modules today have significantly less
robust frames than the old days.
More surface area to catch the wind + thinner metal = failure at high
enough wind speed.
BTW, the rack is a DPW high wind model, both the rack and the 4" pole
didn't budge at all, just the modules themselves. I've had a second
system, same configuration have similar damage in a wind storm just
last year. Its just on the top modules, not all of them. I have
quite a few MT Solar racks with the top down mounting, and no
losses. I've been suspicious of top down module racking; and I was
quite satisfied with actual bolts and hardware to hold modules in
place. But its just not true anymore. I added 3/4" angle stainless
steel to reinforce the attachments on the top modules.
Ray Walters
On 3/9/2024 12:44 PM, Kent via RE-wrenches wrote:
Ray,
It appears that there is something between the module frame and rail
that may have introduced the frame crack. Perhaps as it was
tightened, and not due to the wind. What is the light material that
looks like it is sandwiched between the module and rail?
Kent Osterberg
On 3/8/2024 4:23 PM, Ray Walters via RE-wrenches wrote:
Here's another mount at the edge of failure, from the same system.
Hardware is tight. Like many, I had lots of love for good ol'
fashion bottom mounting vs top mount, until this happened about 5
years ago.
This is how we learn.
On 3/8/2024 5:15 PM, Ray Walters via RE-wrenches wrote:
I've had several modules pull off of bottom mount racking in high
winds, but never top mount racking. Newer modules have much
thinner frames, but are much more surface area than the old days.
Ray Walters
Remote Solar
On 3/8/2024 3:50 PM, Kent via RE-wrenches wrote:
and for the life of me I don't understand the logic of of a top
mount clamp on a TPM.
Kent Osterberg
Blue Mountain Solar
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