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imlost
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Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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Superstrut and Uni-strut are not proprietary hold-down systems for solar equipment. It's primarily used in commercial construction for hanging
equipment from, such as electrical, HVAC, etc. My very first post in this thread identified this as my preferred mounting system. It's inexpensive and
widely available in the US - I'm just not sure I can get it in BCS. Quote: Originally posted by mtgoat666  | You said you did not want a commercial system, then you said you are looking at uni strut's designed systems. You are making little sense. Isn't uni
strut a commercial system?
There are several mfgs of solar rack systems. Just go buy the one recommended for your roof type. Call or email the mfg or distributor to ask which
type is best for your particular roof.
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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| Quote: Originally posted by Fernweh | I built my own solar panel rack system, mounted to a flat roof with approx. 22" high parapet walls.
The roof structure, 12" metal joist, 3/4" plywood, torched on hd roofing.
I had bolted two rows of Uni-struts, for each solar array, through the roof structure, sealed the penetrations with a good polyurethane sealer.
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Thanks for the pictures. That's a tight, professional looking install! It's giving me great ideas for how to assemble my framework.
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imlost
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Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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We're off-grid. Not sure if my generator will handle a wire feed welder, so I may not have a choice other than bolts.
I think it's rated at 7500w.
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Fernweh
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Posts: 444
Registered: 2-24-2011
Location: Centenario, BCS
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| Quote: Originally posted by imlost | We're off-grid. Not sure if my generator will handle a wire feed welder, so I may not have a choice other than bolts.
I think it's rated at 7500w. |
Good tools make happy workers.....
Nice Miller Multimatic 200 (wire, stick and tic welder), 120 & 240V, works well with 3500W generator.
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larryC
Super Nomad
Posts: 1496
Registered: 8-11-2008
Location: BoLA
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7500 watt generator will handle a pretty big wire welder. I use a 175 amp mig welder and a 200 amp tig welder (one at a time) on my 6500 watt Kubota
generator with no problems.
Off grid, 12-190 watt evergreen solar panels on solar trackers, 2-3648 stacked Outback inverters, 610ah LiFePo4 48v battery bank, FM 60 and MX60
Outback charge controllers, X-240 Outback transformer for 240v from inverters, 6500 watt Kubota diesel generator.
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Fernweh
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Posts: 444
Registered: 2-24-2011
Location: Centenario, BCS
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| Quote: Originally posted by soulpatch | 67 from perpendicular sounds about right.
For year round production on a fixed array we use latitude (from flat so that would be 23 degrees)... the closer to the equator the less latitude (for
lack of a better term) needs to be accurate.
Anything less than about 12 you don't get the benefit of rain cleaning them or just using a hose.
Soiling and heat kills production.
If you expect more demand during winter add 15 degrees to latitude and if summer time is your peak demand go down to about 12 degrees.
All about keeping that sun perpendicular to the array for as long as possible.
I love these discussions.
Probably not all that much weight, either... area of the modules divided by the weight of everything.... I am certain it is fine.
[Edited on 5-22-2016 by soulpatch] |
Good points!
Another thoughts for grid-tied systems like mine:
When producing more power than you are using, you will feed into the CFE grid, and create KWh credits.
The different level CFE charging tiers, are have lower limits in the winter time, and it will cost more money to have a higher usage - so you want to
produce the most solar energy during this period:
1.) to keep the CFE bill low
2.) to create more KWh credits, to use up in the summer time, when the AC's are running.
In the summer, the sun is almost directly overhead (La Paz), the day has more productive solar hrs, and this will compensate for any "summer
misalignment", of your solar array.
Since the new digital meter has been installed, my CFE power usage is 2,300KWh, and I have send 4,500KWh back into the grid......
My solar array produced 17.52KWh on 5-21-2016. My bi-monthly CFE bill amounts to 46 Pesos.
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durrelllrobert
Elite Nomad
Posts: 7393
Registered: 11-22-2007
Location: Punta Banda BC
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Mood: thriving in Baja
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| Quote: Originally posted by Fernweh | I built my own solar panel rack system, mounted to a flat roof with approx. 22" high parapet walls.
The roof structure, 12" metal joist, 3/4" plywood, torched on hd roofing.
I had bolted two rows of Uni-struts, for each solar array, through the roof structure, sealed the penetrations with a good polyurethane sealer.
Built the welded support structures from 1-1/2" x 1-1/2" x 1/8" angle, not higher than the parapet walls (almost perfect solar angle for La Paz), and
bolted them to the Uni-struts with 3/8" spring nut system.
Using Uni-struts again, but this time welded to the support structure, layout to match the mounting holes in the solar panels. The Enphase inverter
and cables are also mounted to these Uni-struts as well.
I then bolted the separate solar panels to the Uni-strut line, from underneath for theft protection (not that easy to do).
To increase the theft protection, I did install a steel 1" x 1" 1/8" angle over the edges of the solar panels, welded to the sub-structure.
Apparently that angle installation was to tight on one of the panels, it cracked the glass of it.......not so good, but is still working with 70%
output.
Oh, by the way, Odile went over my place in 2014 - no damage to my homemade lousy structure 
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Very impresive and profesional. Since you hve plenty of kWh why not add a PVC pipe recirculating solar hot
water heating system too?
Bob Durrell
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Fernweh
Nomad
Posts: 444
Registered: 2-24-2011
Location: Centenario, BCS
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Thanks Bob,
for your kind words.
How about a solar only hot water heater? No LP gas connection, no electrical connection, but 50 Gal of hot water?
Two 96" x 48" hot water solar panels, copper interior with aluminum heat sinks, under tempered glass. 10W 12V solar panel for the tiny 12V re-circling
pump at the water (heater) storage tank. Special bottom inlet/outlet fitting, with PEX pipe to and from the solar panel on the flat roof, next to the
electrical solar array.
Water Works in my Bodega (no solar connection yet)
50 Gal LP Water heater, with solar panels connected - no Gas or Electrical
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durrelllrobert
Elite Nomad
Posts: 7393
Registered: 11-22-2007
Location: Punta Banda BC
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Mood: thriving in Baja
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| Quote: Originally posted by Fernweh | Thanks Bob,
for your kind words.
How about a solar only hot water heater? No LP gas connection, no electrical connection, but 50 Gal of hot water?
Two 96" x 48" hot water solar panels, copper interior with aluminum heat sinks, under tempered glass. 10W 12V solar panel for the tiny 12V re-circling
pump at the water (heater) storage tank. Special bottom inlet/outlet fitting, with PEX pipe to and from the solar panel on the flat roof, next to the
electrical solar array.
Where do buy the PEX tubing and fittings?
Water Works in my Bodega (no solar connection yet)
50 Gal LP Water heater, with solar panels connected - no Gas or Electrical
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Bob Durrell
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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Fernweh,
That's very cool. Are the panels commercially made? Are they for heating pools? Did you import them, or are they available in Baja? Is this a gravity
feed system to your casa? - I noticed your water heater is mounted up high on the wall. | Quote: Originally posted by Fernweh | Thanks Bob,
for your kind words.
How about a solar only hot water heater? No LP gas connection, no electrical connection, but 50 Gal of hot water?
Two 96" x 48" hot water solar panels, copper interior with aluminum heat sinks, under tempered glass. 10W 12V solar panel for the tiny 12V re-circling
pump at the water (heater) storage tank. Special bottom inlet/outlet fitting, with PEX pipe to and from the solar panel on the flat roof, next to the
electrical solar array.
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monoloco
Elite Nomad
Posts: 6667
Registered: 7-13-2009
Location: Pescadero BCS
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| Quote: Originally posted by imlost | Great question. My roof is Tri-D construction, so I'm
thinking it would be best to not make penetrations. If I did connect it directly, I'd question the ability of the Tri-D construction to hold down the
panels in strong winds. For this reason, I'm leaning toward a ballast type mount - Either pre-made solid concrete blocks or hand-poured curbs.
My roof has parapet walls that are about 2' in height. They are also constructed of Tri-D. |
I used 2"
aluminum angle to make panel mounts, and attached them to the roof using stainless lag screws into lead anchors, and bedded them in with 3M 5200, my
next door neighbor used a ballast mounting system produced specifically for solar panels. My panels made it through hurricane Odile and he lost 18 out
of 20 panels. The problem wasn't with the ballasted system, it was all intact, what failed were the provided clips that attach the panels to the
mounting system, the wind load on the panels straightened them out. If you bed the anchors for the mounts with 5200 or another type of polyurethane
marine sealant you will have no problems with leakage.
[Edited on 5-24-2016 by monoloco]
"The future ain't what it used to be"
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Fernweh
Nomad
Posts: 444
Registered: 2-24-2011
Location: Centenario, BCS
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| Quote: Originally posted by imlost | Fernweh,
That's very cool. Are the panels commercially made? Are they for heating pools? Did you import them, or are they available in Baja? Is this a gravity
feed system to your casa? - I noticed your water heater is mounted up high on the wall. |
Yes, those panel were commercial made, for hot water - not for pool use. I had them for a long time, maybe twenty years or so. They were used then
already. I brought the to La Paz, gave my friend two, and kept the other two. Had them re-worked a bit, the copper interior still perfect.
The water heater is mounted high, to utilize the space underneath, and to reduce the head height for my little 12V Chinese made solar pump.
It is not a gravity fed system, everything is under pressure from a separate pump system, but I do have a separate 1100 L tank on the roof for
emergencies......
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monoloco
Elite Nomad
Posts: 6667
Registered: 7-13-2009
Location: Pescadero BCS
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| Quote: Originally posted by soulpatch | Wow, those must have been crappy clips because, usually, you spec a ballasted mount for expected wind speeds.
I wonder if they low-balled it.
We are waiting word on a system we bid south of Sayulita that we are building for 200mph winds.
It is a ground mount but we will also build some walls around it to reduce lift.
Thank god for capable engineers! |
The funny thing is that my neighbor's an electrical contractor from
California, and the kind of guy that researches the hell out of things before hand, and he installed the mounts himself. It all looked bombproof but a
bunch of 50 cent parts were it's downfall.
"The future ain't what it used to be"
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Cancamo
Nomad
Posts: 360
Registered: 4-5-2011
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Aluminum angle available at shop up on " Calle Hancha ", (the next big street west of "Alta Tension"), in Zacatal, ((easy to find). Buy in 5 meter
pieces, cut to size, use small angle pieces for mounts. Use taquete inserts for mounts, seal accordingly. Easy to cut, drill, won't rust....bolt down
flat in hurricane season, raise to the south in winter.
About three sixteenths of an inch thick.
Has endured hurricane Juan, Odile,....and other storms, mounted on flat roof with parapet sides.
Easy, and permanent.
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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There's a construction supply place on Hwy 1 in Zacatal. I think it's called "Panel Rey". Is this the place you're talking about?
Another person who has a house in my area, sent me some pictures of the frame he built out of aluminum angle - It looks very similar to what you
described. I like the idea of being able to raise & lower the frame, especially during hurricane season. I'm leaning toward this type of
construction. It seems really simple and effective, and I like the idea that it would be aluminum (angle) against aluminum (panels). | Quote: Originally posted by Cancamo | Aluminum angle available at shop up on " Calle Hancha ", (the next big street west of "Alta Tension"), in Zacatal, ((easy to find). Buy in 5 meter
pieces, cut to size, use small angle pieces for mounts. Use taquete inserts for mounts, seal accordingly. Easy to cut, drill, won't rust....bolt down
flat in hurricane season, raise to the south in winter.
About three sixteenths of an inch thick.
Has endured hurricane Juan, Odile,....and other storms, mounted on flat roof with parapet sides.
Easy, and permanent. |
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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I like the idea of concrete anchors, but with Tri-D construction, I'm concerned that there may not be enough bite in the concrete to make it work.
maybe stainless steel Toggelers would be the better way to go. Thay way, I could penetrate through the concrete layer and have the hold-down on the
styrofoam-side of the wire mesh. Alternately, I can use concrete blocks or poured concrete curbs for ballast with typical concrete anchors.
I agree - Polyurethane sealants are pretty bomber. | Quote: Originally posted by monoloco | | Quote: Originally posted by imlost | Great question. My roof is Tri-D construction, so I'm
thinking it would be best to not make penetrations. If I did connect it directly, I'd question the ability of the Tri-D construction to hold down the
panels in strong winds. For this reason, I'm leaning toward a ballast type mount - Either pre-made solid concrete blocks or hand-poured curbs.
My roof has parapet walls that are about 2' in height. They are also constructed of Tri-D. |
I used 2"
aluminum angle to make panel mounts, and attached them to the roof using stainless lag screws into lead anchors, and bedded them in with 3M 5200, my
next door neighbor used a ballast mounting system produced specifically for solar panels. My panels made it through hurricane Odile and he lost 18 out
of 20 panels. The problem wasn't with the ballasted system, it was all intact, what failed were the provided clips that attach the panels to the
mounting system, the wind load on the panels straightened them out. If you bed the anchors for the mounts with 5200 or another type of polyurethane
marine sealant you will have no problems with leakage.
[Edited on 5-24-2016 by monoloco] |
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surfhat
Senior Nomad
Posts: 548
Registered: 6-4-2012
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I built a tri-d panel structure twenty five years ago on the east cape and had my PV panels mounted in a tracker frame that gives the most efficient
energy absorption and allows plenty of air space for the panels to work at their highest efficiency. They have survived several hurricanes and the
thought of mounting them on the roof never entered the equation. Tracking that sun throughout day is key. The hydraulic oil in the tracking frame
automatically follows the suns angle so there is no energy loss whatsoever. Penetrating a sealed roof for whatever reason should be avoided. I hauled
the tracker frame on the top of a small suv and at 5am crushed right on through. Things may have changed since then but the efficiency of the tracker
remains. Thanks to all here.
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surfhat
Senior Nomad
Posts: 548
Registered: 6-4-2012
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I meant to say that the border crossing at that early hour of 'cruising through' was a breeze back then. My vehicle was stuffed inside and up on the
roof rack with the tracker frame, gel cell batteries inside, a trace inverter, and a whole host of other items that made it down there easily through
the border crossing.
The value of an automatic tracker cannot be disputed. There is no need to put any holes in your roof when such a better option is available.
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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The tracking mount sounds interesting, but I haven't found any of this type of system that is cost effective. Yes, you can get about 25% or more
efficiency out of your panels with tracking, but panels are relatively inexpensive now, so believe the loss of efficiency is made up for by increasing
the quantity and/or output of panels - which is considerably less expensive.
Mounting the panels anywhere else but the roof is not an option for my circumstance.
Importing this system in to Mexico was fairly painful. including freight and duty it added more than a third to the original cost of of the system
(than the purchase price in the US).
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imlost
Nomad
Posts: 218
Registered: 3-31-2015
Location: PNW & East Cape
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Oh. I'm all about low complexity. I'm like a completely different person in Baja. It's more about less.
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