diy solar

diy solar

The Solar Pergola Project - Repurposing a pergola I once built to power our home

Really respect the structural joinery of the frame; nice to see design driven by ideas instead of rules. There's a lot to be said for overbuilt when it can be done as a do it yourself.

The moment you finish install of any kind of rain drippage mitigation it will start degrading. The cost/benefit ratio is seriously questionable.

Given that there is no insulation, high dew point events will result in drips from condensate underneath the panels anyways.

Filling the gaps between panels will possibly interfere with expansion/contraction of panels as well as be unsightly, possibly corroding areas that collect dust and debris.

The height of your structure makes it all but impossible to shield against some blowing rain anyways, so you will be planning for things to get wet under it.

You live in a dry environment; things will dry out sooner than what a lot of readers here experience at their location.

Right now you have a clean, attractive install. Gilding the lily by feeding an obsessive/compulsive bent does not serve anyone.

Maybe you can ride with what you've got for a year and assess then?
 
KITROBASKIN said:
Really respect the structural joinery of the frame; nice to see design driven by ideas instead of rules. There's a lot to be said for overbuilt when it can be done as a do it yourself.

The moment you finish install of any kind of rain drippage mitigation it will start degrading. The cost/benefit ratio is seriously questionable.

Given that there is no insulation, high dew point events will result in drips from condensate underneath the panels anyways.

Filling the gaps between panels will possibly interfere with expansion/contraction of panels as well as be unsightly, possibly corroding areas that collect dust and debris.

The height of your structure makes it all but impossible to shield against some blowing rain anyways, so you will be planning for things to get wet under it.

You live in a dry environment; things will dry out sooner than what a lot of readers here experience at their location.

Right now you have a clean, attractive install. Gilding the lily by feeding an obsessive/compulsive bent does not serve anyone.

Maybe you can ride with what you've got for a year and assess then?
Click to expand...
Much appreciated!

I agree completely. The pergola is located in such a way that rain almost never blows in the main opening, we just don’t get much wind from that direction, but that said, we just don’t get much rain to begin with. When we do, it’s not like we can’t make a conscious decision to simply stay inside.

We’re at 4,500’ of elevation, and per a quick google we have an average of 300 days of sunshine, and 7.48” of rainfall. We’re in what’s called the shadow effect of the Sierra Nevada mountains, we can watch the storms up there, they just don’t come down here much which is great, Lake Tahoe fills with water and we don’t have to worry about drought as often. Specifically where we are, it’s even less often that it rains, we’re just on the side of the city with the most temperate weather if you could put it that way. I would also assume that 7.48” number is highly comprised of snow, we really don’t get much rain, but certainly get snow in the winter.

Initially I thought it would be awesome to sit out there in snow storms, but we don’t actually do it that often and it would accumulate and fill the voids anyways.

I think for now I’m just going to go with it and let it be a shade structure. On the handful of rainy days we can find somewhere else to stand, or just pick a nice place under the many large panels that isn’t dripping, they are all quite big, I think we can make due :)
 
So, how are you liking how your plan is working out? The rafters are 2' O.C.? Any thoughts on how you might do it differently if you built the pergola again with solar on the roof?
 
superchachi said:
So, how are you liking how your plan is working out? The rafters are 2' O.C.? Any thoughts on how you might do it differently if you built the pergola again with solar on the roof?
Click to expand...
So far it’s great, correct, rafters at 2’. Not sure what I’d do different honestly, maybe just a slight dimension change to fit panels perfectly but you’d have to know what panels you were using before starting. Otherwise, it’s going great!
 
Foam Backer Rod from your local big box store. Flow a layer of Dicor self-leveling lap sealant over the top.
Water proof, UV resistant, flexible.
 
Watts Happening said:
I assume you’re talking about whether or not the panels are bonded to the structure? Your most basic test is a continuity test and I’d be shocked if it didn’t check out perfectly. But maybe over time it fades, mayyyybe.
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You should totally do a continuity test. The solar panel frame is not conductive because is anodized aluminum. It has a surface layer of aluminum oxide so resting on the guide rail is very probably not enough.
 
Years ago I was part of a team that did a natural gas pipe corrosion survey in a remote area (we did find a small leak; kind of scary). I was checking soil conductivity over and over again. Took us something like 3 weeks. I just wonder if there is a way to check ground from some random spot on a panel frame all the way into the ground (we used about 8 electrically connected huge nail spikes spread in a line attached to a box with circuitry and a meter)
 
KITROBASKIN said:
Years ago I was part of a team that did a natural gas pipe corrosion survey in a remote area (we did find a small leak; kind of scary). I was checking soil conductivity over and over again. Took us something like 3 weeks. I just wonder if there is a way to check ground from some random spot on a panel frame all the way into the ground (we used about 8 electrically connected huge nail spikes spread in a line attached to a box with circuitry and a meter)
Click to expand...
I’ve installed the grounding plates, I think it’ll be solid across the board. Regardless the structure is bonded to ground so as a whole it should be fine.

Main post updated, got another row of five panels installed and online today.

IMG_6204.jpeg
 
Hey, thanks for sharing.

My solar panels have an indented area on the side profile of the aluminum. It feels like a perfect place/size for a rubber garden hose to go. Then you just push the panels and the hose acts a bit like a gasket. It wouldn't be perfect for drips I'd argue it doesn't have to be. But you'd also have a free system to cool a part of your panels and heat some water, which humans always find a use for. I think it could be done in a very stealthy way.

Your bifacials look flat on the sides, which I guess could still work in a similar way. If the flexible garden hose has a cross section of 20mm, you essentially mount the panels at like 18mm apart. Maybe super leaky over time and seasons changes, not sure. It still seems 99% better than a 1" gap (which I still think would be fine actually).

It just seems more useful than paying as much for some foam tape.. I assume there are garden hoses or tubing designed to last a while in the sun, but maybe that is a stupid assumption.

Can I also ask, subjectively, how much different does it feel to have partial sun coming through the glass vs when it was all wood? Those bifacials seem so cool and infinitely better to look at than just white plastic.
 
orangezero said:
Hey, thanks for sharing.

My solar panels have an indented area on the side profile of the aluminum. It feels like a perfect place/size for a rubber garden hose to go. Then you just push the panels and the hose acts a bit like a gasket. It wouldn't be perfect for drips I'd argue it doesn't have to be. But you'd also have a free system to cool a part of your panels and heat some water, which humans always find a use for. I think it could be done in a very stealthy way.

Your bifacials look flat on the sides, which I guess could still work in a similar way. If the flexible garden hose has a cross section of 20mm, you essentially mount the panels at like 18mm apart. Maybe super leaky over time and seasons changes, not sure. It still seems 99% better than a 1" gap (which I still think would be fine actually).

It just seems more useful than paying as much for some foam tape.. I assume there are garden hoses or tubing designed to last a while in the sun, but maybe that is a stupid assumption.

Can I also ask, subjectively, how much different does it feel to have partial sun coming through the glass vs when it was all wood? Those bifacials seem so cool and infinitely better to look at than just white plastic.
Click to expand...
Good idea with the hose, but I'm not even going to try to fight it. We live in the high desert and have minimal rain, we can just hang out inside during the few rain showers we get :)

As for the sun, we're just now transitioning from "summer" to "fall", there has certainly been a noticeable difference in how harsh the sun is over the last couple of weeks. That said, the panels provide plenty of shade, it may not be perfect shade like the old roof was (wood with corrugated roofing above it) but it's plenty good for shade! Looks neat, is functional and has powered our home 100% for the last 3 days.
 
Update 9/12/23:
Finished the install of the remaining (5) panels, we now have (15) 445w bifacial panels running for a total of 6.675kw. Also added a secondary 50a plug in the garage today. The one on the right has grid power 24/7 so I can always charge my car, the one on the left was added today and is connected to the Sol-Ark inverter utilizing something called “smart loads”. It only provides power if certain conditions are met, in this case I have it set to switch the plug on when the batteries are above 95% state of charge and solar is providing at least 1,500 watts of power. It will automatically shut off when batteries get down to 90%. This is just for testing but what it effectively does is lets the solar system power the house first, charge the batteries second and when there is excess power it automatically dumps it into the Tesla so it’s not wasted, but also won’t let the car discharge the batteries overnight.

IMG_6237.jpeg

IMG_6243.jpeg

IMG_6244.jpeg
 
An example of condensation forming underneath a covered area. Water from the part of the roofing in contact with the purlin builds up enough to drip down. IMG_2623.jpegIMG_2638.png
 
This is a great idea. Really like how it looks. Curious what kind of real numbers you are getting from the nominal 6.675kw. Are you seeing a lift from the bifacial nature? How many hours a day is it producing reasonable wattage?
 
joshn said:
This is a great idea. Really like how it looks. Curious what kind of real numbers you are getting from the nominal 6.675kw. Are you seeing a lift from the bifacial nature? How many hours a day is it producing reasonable wattage?
Click to expand...
Simply put, it’s been doing ~30kWh per day for the last week. Peaking around 5kw
 
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