My solar Pergola build

[GXMnow]

This is the "Show and Tell" area, so I am starting a new thread about my next project. The plan here is to add nearly 4,000 watts of panels to my system to get close to 10 KW of total PV panels online. I have a HUGE thread here already from when I added a Schneider XW-Pro to add self consumption time shifting and backup power to my Enphase grid tied system. That thread is out to over 1,900 posts. Here is the link if you want to skim through that.

Thread 'Adding storage to my Enphase system'

Aug 12, 2020

I am still fairly new on the forum, tried to answer a few questions as I asked some, and have been talking about my plans and purchases. I figure this is the right place to talk about what I am doing and where it is going.

My existing system is a very typical Enphase setup. I have 2 arrays of 8 panels each. The panels are Sil Fab 300M 60 cell units with an iQ7 inverter on each one. All 16 inverters are combined in the attic and go to an Envoy iQ3 on the wall of my garage near the power meter. I am at the limit of a single run with the 16 inverters. I have space to add more, but my...

• GXMnow
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• Forum: Show and Tell

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After adding the XW-Pro and 18 KWHs of Chevy Bolt batteries, I added another 18 KWHs of battery to push it to 36 KWHs of storage and then added 2,000 watts of DC coupled solar panels to try and keep them charged. But with poor weather and more loads, it is just not keeping up anymore. I designed a very streamlined structure to support a 3x3 array of panels. I am still adjusting the exact size of the roof as I have not purchased the panels yet. I am looking in the 300-400 wat range per panel. I am waiting for a reply from Greentech Renewables, but if i don't hear back soon, I may order from San Tan Solar. The y have a few panels in the under 40 cent per watt range. For size and weight distribution with my design, I am looking at the "60 cell" form factor like my original Sil Fab 300 watt panels. The new versions about that size ae now over 350 watts at 1 meter wide and 1.7 meters long. Going 3 x 3 with that size panel, it ends up about 12 feet x 17 feet of panel. At 50 pounds per panel, it is 450 pounds of PV panels alone. Add in the racking and the wood "rafters" and it will be nearly 600 pounds. I don't have to even think about snow load here, so that is a good thing. In deck design, a single 4x4 post can support up to 600 pounds. So 4 posts has a reasonable safety factor. The 4 posts are at the corners of a rectangle just 8 foot x 10 foot. So the solar roof will overhang the 8 foot depth by a bit under 2 feet out the front and back. But in the long direction, it will be just over 3 feet out each end past the posts. Since this is in my back yard, it is north of my house. I am placing it as far west in my yard as I can, leaving room to be able to get the lawnmower behind it. That is the end of my house that is only single story. In the morning, it will get some shade from the second floor on the east end of the house. In spring to fall, there won't really be any shadow issues with this placement. But to get it up out of the shade in winter, the low end posts are 8 feet high, plus 6 inches on the concrete piers. The taller north end posts are 11 feet high on top of the piers. I drew it up at 1/2 inch - 1 foot and it looked like no big deal. But I stood up one of the 11 foot posts today. OUCH. That is higher than I pictured in my head, but it is correct. check out where the sun is hitting it in the pictures.

Here are the pre-cast concrete piers from Lowes.

That is over a cubic foot of concrete, and they are HEAVY. They are meant for a deck, but I asked and they are also acceptable for "shade structures". I measured out the area, and of course, my yard is not square, and my house is not perfectly straight in the lot. Hmmm. I did my best, and I got it within 1/4 inch of square to the back wall of the house. so it should look fine. I dug the holes. I wanted to go down a full foot, but now I know why I can't grow decent grass. The "dirt" is mostly hard clay with sand in it, and not even 8 inches down, I was hitting hard rock. I managed to get all 4 of them in place and sunk 6 to 8 inches to get them all at the same height.

If this was in an open field, I would want them deeper to deal with wind, but the structure is all going to be shaded from wind, and with my rock hard ground packed in around the pyramid shape, these are not going to move. A day after I packed the dirt in around one, I tried to pull up on it with a lever. It felt like I was just pulling against a concrete slab, and my lever was over 8:1 and I still could not make it move at all. So I am not going to try and dig them any deeper. I would need a jackhammer to go lower into the rock.

Here are the two west end posts up in position. They are being held vertical by temporary braces and stakes for now.

At 7 feet off the ground, I will have level 2x6s connecting the 4 posts. Those will have 45 degree braces to the posts as well as between each horizontal bean inside the corners. That will keep everything square and I can then remove the temp braces holding the posts straight.

I took these pics at 4 pm, my rooftop Enphase system was down to just 200 watts from 4,800 watts of panels. In the middle of those 3 pics, you can see where the sunlight is hitting the top 4 feet of the taller north post. The south end post had just gone into shade. Due to how the shade moves in, I plan to split this array. The bottom south most panels are probably going on microinverters as they will have shade issues from time to time. The next row of 3 panels will be in series, and run in parallel with the top 3 panels that are also in series. Depending on the panel voltage I get, I hope to be able to use a 150 volt Victron and not have to get a 250 volt as the price takes a fair jump. 6 x 350 watt panels would be just over 2,000 watts, and push about 40 amps into my "48 volt" battery bank. I will get a 60 or even 75 amp charge controller in case I decide to add another parallel group string of 3 panels up on the wall, or instead of the microinverters on the bottom row. Whatever panels I get, I will likely buy a few extra that I could just lay against the wall and wire in for winter. I still have my BougeRV charge controller that would be perfect for that use.

Bridging between the 8 foot and 11 foot posts, I will have a 16 foot 2x8 that end up tilted 16 degrees towards my house. Due to the angle, it will extend less than 3 feet past the posts. I may also add a few braces of 1x4 between the level 2x6 and the long tilted 2x8. There will also be 6 2x4s between the long tilted 2x8s where the 6 Iron Ridge rails will go across. I was hoping to get away with the 11 foot rails, but that depends on which panels I get. The 375 watt panels I am looking at are listed at 41.34 inches wide. Put 3 of them against each other and that is 10 foot 4 inches. So I would have 8 inches to allow for 1 inch between panels and a couple inches for end clamps. But if I go with the 430 watt panels, they grow to 44.6 inches wide, and just the panels alone is then 11 feet and nearly 2 more inches, even with no space between the panels, OOPS!! I can't find anyone who sells 12 foot rails, they jump to 14 foot. The price difference is not huge, so I may go with the longer rials so I can go with larger panels later if I decide I need more power. I really would like 400 watt panels.

I had thought about also tipping it a bit more west for evening sun, but the heading of my house is already about 25 degrees west, and I think that is plenty far as I watched the sun set today. So the other pair of posts are exactly the same as the first pair. The solar panel roof will just be leaning towards the house. The low end does go a little lower than the edge of the house roof, but it is over 10 feet away. Even on the winter solstice, the sun was on the closer 8 foot post for over 5 hours. It gets better sun than the panels on the garage roof. All the panels I am looking at are the "Half Cut" type, so on that bottom row, even if the sun blocks the lower half, the top half will still produce well. The upper end of the lowest panels will still above and north of the lower posts. The 375 watt panels are just 70 inches long, less than 6 feet. So the gap between the first and second row of panels will be 2 feet inside of the space between the 2 posts standing in the pics.

 

[dougbert]

sweet, looking forward to your report AND lots of pics (lol). I also want to build a pergola and do some 3400 watts. Looking forward to learn from you on the build

My house in Cucamonga years ago, had a terraced backyard just like yours

Did you consider moving the pergola so the north 4x4s would be on the terrace? or is not possible?

I just ordered my 2nd XW Pro from SS for $1255 - I think they are serious of EOL'ing the line in the near future. SS is following NAZ on stock reduction, IMHO

 

[hwy17]

Thanks for documenting and sharing it, I might copy it some time.

First note to myself: Pier blocks look a lot better partially buried rather than just resting on the ground like I always used them.

 

[GXMnow]

sweet, looking forward to your report AND lots of pics (lol). I also want to build a pergola and do some 3400 watts. Looking forward to learn from you on the build

I just ordered my 2nd XW Pro from SS for $1255 - I think they are serious of EOL'ing the line in the near future. SS is following NAZ on stock reduction, IMHO

Thanks for the positive feedback. I am sure I am going to get several structural comments. I am using a book on Deck Design for the stress. It is a bit too weak for people walking on top, but it only has to hold up the solar panels. I am sure it is plenty strong.

I have no doubts my XW-Pro is going to live pasts it's warranty. It is a work horse that has been rock solid. If they do end of life it, I am not too worried. If it fails in another 6 years, I am sure there will be a nicer "All in One" I can replace it with. My brother is looking to add battery storage, so we have been looking at a few units. He might be getting an EG4 8K or 12K-PV. The 18K is way overkill for his setup. The main thing he wants is to stor up enough during the day to charge his EV each night. Right now, he has to use the SCE EV rate plan where they credit him next to nothing but her gets a slightly cheaper overnight rate for E charging but also has to pay something like $30 a month fixed charge for the EV plan.

First note to myself: Pier blocks look a lot better partially buried rather than just resting on the ground like I always used them.

It also makes them far stronger and more stable. Sitting on the ground, they don't resist lifting at all, and they even tip over quite easy with an 11 foot tall post on top of it.

Another reason I left them as far out of the ground as I did was for trimming the grass around them. I want the weed whacker only hitting the concrete, not the wood posts. That nylon line actually cuts into the wood. I also spaced it off the wall to fit my lawnmower around all the posts.

 

[Siamac]

I was thinking of doing the same thing. But it's a lot of work and you can buy some from Walmart or backyarddiscovery for a few hundred to a few thousand dollars. The discovery one comes with assembly for a thousand more. I'll probably end up doing it by myself just because I want it a particular size and shape.

Thanks for sharing the pics. Very helpful

 

[GXMnow]

I am doing this thread for a couple reasons. Hopefully it does help others, but I also will likely be asking for some help in this thread. One thing that entered my mind is that I am using the same basic materials as we did when I had built a swing set for my kids. Those yellow handles in some of the pics are from that old swing set. While it did not truly fail, it was certainly showing signs of weakness after 8 years. I am guessing the wood structure is going to have a shorter life than the PV panels.

I had thought of putting solar panels tilted against that back wall, but here is the reason that has not happened.



That tree casts huge shadows across the wall from sunrise to sunset. To the right of the tree, I might get 2 hours of morning sun, and to the left of the tree maybe 2 to 3 hours of evening sun. Even at the winter solstice, I should see 5 hours of unshaded sun on most of the pergola roof. I had hoped to stand up the other two posts today, but it started raining. Oh well.

I also need to find a way to get a few longer boards back here. I don't want to rent a truck more than once. Was hoping to be picking up the panels but still no reply from Greentech.

 

[GXMnow]

I spent a couple hours in the yard for Christmas.
Here are a few picture updates.

Getting the third post up was easy. Laying out the 4th post got a bit more difficult to make sure I was plumb as well as square to the other 3 posts. The concrete piers are certainly not perfect. The steel straps are not well centered in the block. I did my best to get that dead centered where I wanted the posts, and I got it within about 1/4 inch. Here is the 4th post finally up in place.

I added the pair of 2x6 cross braces. The bottom of those are at 7 feet above the ground. I figured that was a good height to walk under with no worries of hitting your head. I have everything level and square within less than 1/4 inch at this point. In this shot you can see how close to parallel the two cross beams ended up. Hopefully, I got the piers in deep enough that they won't settle from here. Those are 6 foot and 8 foot ladders. I don't have the 10 foot 2x6s yet, but I did put a pair of 10 foot 1x2 between the short and tall posts. The top of them are at the 7 foot height, so when I get the 2x6s, I can just set them on top of the 1x2s and screw then into the posts. I still have most of the braces holding the posts vertical. I don't want to remove the rest until I have the 45 degree corner braces all installed. I am probably going to just use 2x4 for the angled braces. It is already quite strong with 5 screws through the 2x6s into the 4x4 posts. I am thinking just 18 to 24 inch long 45 degree 2x4s on each corner will make it rock solid. There will be a total of 12 of them. I will brace both ends of all 4 beams to the posts for 8, and then from the top, I will also bracr the corners between the North-South and East-West beams at all 4 corners to hold the whole structure square. Then I can certainly remove my temp braces to the stakes in the ground.

Here are 3 more pics. I end spliced a pair of my 8 foor 2x6s into a 16 foot beam. It is not quite at the right height or angle, but I clamped it up to get a better visual of where the panels are going to sit.

If I do end up getting the 375 watt panels, the 3x3 array will extend a little over a foot past each end of the 16 foot angled beam. But the last rails are right at the ends of that 16 foot. The top of the angled beams will be raised up so it is above the ends of the posts, about 10 inches higher than in these pics. I think I will end up with 4 additional vertical braces between the level 10 foot beam and the angled 16 foot beam. That places a support every 2 feet. Should I also add an angled brace to the part that extends past the posts? The other 4 rails will all be between the 10 foot post span. The panels are 70 inches long. The center on will have nearly 2 feet on either side of it to the posts. The mounting rails will be about 40 inches apart. with a 2x4 also going across under each rail. Because of the angle, the span between the mounting points to the posts is actually over 10 foot. It works out to about 10'2" to the center of each post with the 3 foot height difference over the 9'8.5" span from post center to post center. With a rail at each end of the 16 foot beam length, the next rails at 40 inches in from there, puts them at 109.5 inches apart. The center of the posts are at 122 inches apart. So those rails end up at just about 6 inches inside of the posts. I have a very rough CAD drawing of this, but it is on my work computer. I will have to figure out a way to export an image I can post here.

I want to put as few braces across as possible as these are bifacial panels. Grass does not grow worth a crap, maybe the white gravel under the array will look better?

 

[GXMnow]

Too bad I don't have the panels up yet. They would be cranking out some nice power already.

It is only a few days past the winter solstice and already, the shadow from my chimney is clear of where all the panels will be by 11 am. The rest of the day, to sunset will all be full sun on the panel area.

 

[GXMnow]

Just got back from another Lowes trip.

I think I have now hauled more cargo in my C-Max than anyone will ever haul in a CyberTruck.
Today's load was 9 6 foot 2x4s and a pair of 10 foot 2x6s. And yes, it all fit inside my C-Max with the hatch fully closed and nothing sticking out of the windows either. I had to be careful, both loading and driving it home as I didn't want to re-create the SafeLight Auto Glass commercial. The 10 footers were literally from the windshield to the back hatch. I had a sheet of dense foam from one of my solar panel shipping boxes between the wood and the windshield.

Now I have all the lumber needed to complete the structure. Tomorrow should be a fun day. I may enlist my brother to help hold beams in place as I put in a few bolts. I did not get the wood for the braces between the straight 2x6's and the tilted deck. They really are not needed for the strength, but I will put them in to just stiffen it up a bit before the solar panels go on. I would hate for a strong wind to flex it enough to crack a solar panel.

Now I really need to order the solar panels and six 11 foot sections of Iron Ridge rails. I made a little drawing and figured, even if I get wider panels, I could cut the 11 foot rails in the middle, and extend them out to have room for end clamps on 3 panels up to over 50 inches wide. The center panel would bridge across the split rail and I would use some aluminum angle to bolt across the gap in the rails to make sure they stay straight and aligned. I don't have to do that with the 375 watt panels, as I have 4 inches to spare, but most of the 400+ watt panels are 4 inches wider EACH for another foot of span.

I think I am going to go with a 250 volt Victron charge controller. The wire run is going to be nearly 200 feet. I can put 5 panels in series (again with the 375 watt panels). The VOC is 41.1 volts per panel, times 5 is 205.5 volts. And add 20% it is 246.6 volts. We rarely ever get down to freezing here, and the V Temp. Coef. is just 0.27% per degree. So just a 6.75% V rise, so I am safe. With 5 x 375 watts, I am at just 1,875 watts total. Into a 48 volt battery, that would be just under 40 amps. The smallest 250 volt they sell looks to be a 60 amp. It's only $60 more to go to 70 amp. I might do that, because I can also wire the array as 3S3P and put all 9 panels on the Victron. But at 3 times the current, the wire losses will be crazy. But 9 x 375 = 3,375 watts and 70 amps peak.

That takes the top 5 panel, and then I was thinking of putting the lower 4 panels will on a 1,400 watt 4 channel microinverter. In real world conditions, it will typically top out around 1,200 watts. My house in idle almost consumes that, so it will basically just zero the meter when we are doing nothing. I'm not worried about that much power causing an issue with my 16 amp maximum back feed. I may drop it to just 3 panels or 900 watts to be safe. Then the new Victron would see 8 panels in a 4S2P setup.

If I am only running 100 volts at VMP, is there any drawback to running the 250 volt controller vs the 150 volt controller? I know it costs more, but it is less efficient, or have more static losses? Both seem to only need 5 volts over battery to turn on. Oops. I did find one drawback. The input maximum current is lower on the 250 volt vs the 150 volt. But I think I am still okay with the 375 watt panels. The ISC current is 11.65 per panel. The maximum input current on the 150 volt 60 or 70 amp units is 50 amps. No problem at all running 3P at 34.95 amps. And the 250 volt units are 35 amps maximum, right at the limit, but not over. Maybe I can stuff in a 4th panel on the center row and go 5S2P?? The middle rails would then need to be 14 foot.

 

[GXMnow]

I had a few hours free today, so I spent it cutting all the 45 degree braces and I got all but 2 of them installed.

I found I could get 2 braces out of each 8 foot 2x4 if I made the long side 26 inches. All 12 are this length, but they look different lengths due to how they sit against the other boards. I was very careful to make sure I had the structure all square as I bolted on each brace. It is very easy to pull it out of square. I had to keep checked and I managed to get it locked down tight and still all well within 1/4 inch of perfect. Most of it is still well within 1/8 inch, and the posts are still perfectly plumb on my old 4 foot level.

It is truly amazing how much more rigid the whole structure is with those corner braces. I took off all 8 of the temp boards that were holding the posts straight, and it is far more rigid to shake than it was with all those temp braces in place. To get good straight lumber, I had to get interior grade wall stud material. All the pressure treated stuff was too warped and twisted. I need to get a good water seal on that wood to protect it now. I think I am going to go with a very light color due to the bifacial solar panel. It might not help much, but it shouldn't hurt either.

I made a jig to drill the cross hole at the top of each of the posts. It will have a 3/8 inch bolt going through and then probably 4 more wood screws around that. I only drilled one post so far, and it was not easy. That pressure treated 4x4 wants to grab the bit. I drilled it 1/64th inch over, and the bolt still won't slide in. Each time I run the drill in, it cuts out more wood chips. The bolt fits for a second then locks again. The wood seems to be swelling into the hole. I might have to go up another 1/64 inch, but I like the tight fit. The next part of the plan is to assemble the deck that will hold the solar panels. I want to bolt it on at the low post end, and put together all the cross beams. I know how far apart the holes are, so I will have them pre-drilled. Then just jack it up into position and put in the upper end bolts. With it down, I could install all 6 of the rails and even the two lower rows of panels. I can't preinstall all of the top row of panels though as the posts will stick through the outside pair. The middle one could go in, but it might make it harder to lift it up into place.

 

[GXMnow]

I worked on it for a few hours yesterday. I used 1x2 to mock up the layout of the 16 foot beams.

I did use trig and calculated the holes for the mounting bolts should be 10 foot 2 inches and about another 1/10th of an inch apart. On the far side, it was within 1/8th of an inch of that. Yes, I measured it to check before making it, and drilled the hole in the right place and then test fit the stick.

But then I moved the stick to the front side. Wow, it was off over a full inch. Over a 10 foot length, an inch is hardly visible, but it is a problem. Wood is not a very good material. I measure this side, got the exact number, and then drilled the new hole in the mock up stick. This time it fit perfectly, but where is the error coming from? It turns out, the top of that font post has a small twist as well as a warp curving in slightly. Add the two and it is a bit close to the other mounting hole. I drilled the bottom hole in exactly the same place on the second beam, but for the upper hole, it is the inch closer, but also a little higher on the beam to keep the two beams parallel. My 16 foot beams are actually made up of two 8 foot 2x6s. I spent several hours making sure they were as straight as possible as I butted them together and used a 2x4 to splice them as well as a pair of steel connector plates on the top and bottom. I am not too worried about the strength of the joint as the two boards are nearly balanced. The weight between the posts is offset by the weight beyond the posts. The top and bottom panels hang nearly a foot past the ends of those beams. The center panel is 3/4 of the distance between the posts. Here it is with a few of the wood rails in place. It was getting dark last night.

There will be an aluminum PV panel mount rail on top of each cross brace between the two large beams. The pairs for each row of panels are 44 inches center to center. That works great for 70 inch long panels with just 13 inches of panel hanging past each rail. The upper and lower pairs of rails are a little further away than needed for the 70 inch panels, so there will be just about 10 inches past the top and bottom rails, if I put the 3 rows as close together as possible. I did this so it would also work with 75 inch long panels.

I already started a little work this morning and got one more cross rail board installed. But I have reached my ladder height limit. Here is a pic at 10 am, the shadow of my chimney would still be on just one panel, just a week after the winter solstice.

This is why I will have that bottom row of panels on microinverters. The rest of the panels will never have shade issues.
And here is just 40 minutes later.

You can see the shadow is now clear of the whole structure at 10:40 am.
And two more shots before I go buy a 12 foot ladder.

I am placing the order for the aluminum rails today. I found a kit on Amazon that looks pretty good for the money, and the free delivery to my door. At first it seemed a little high, but then I did the math. It comes with the rails, all the "L" feet to mount them to the structure, including the hardware. It then also has all of the end clamps and mid clamps to hold 15 panels (5 per row). And it even has all the WEEB grounding lugs for all the rails included. They have a 2 row kit and a single row kit to make up my 3 rows. Total $530 for all that is not bad.

https://www.amazon.com/gp/product/B0D6RHPF7R/ref=ewc_pr_img_5?smid=A29U7VA6ZG2CDP&th=1

On a bad note.... I blew it on the panels I wanted to get. San Tan solar had a special going and they just seemed too cheap to be any good. So like a fool, I dragged my feet a bit and tried to find out about the panels and see if anyone had tested them etc. They were listed as brand new 375 watt panels for only $63 each. While trying to find info, that sal ended, but the price only went up to $90 per panel. Still a great price, if they are decent. So I put them in my shopping cart on Friday and sent them an email asking about the shipping cost and at what quantity the shipping would be the least per panel on a single pallet. Well, instead of a shipping quote, I got a notice that that panel had sold out and to pick a different model.

So.... I am back to waiting for a quote from GreenTech Renewables. San Tan has a few other options, but the cost per watt is more, unless I go used blemished panels, or much large panels which will tax my structure space limits. The rails I ordered are longer than I need and will hold up to 4 of the larger 400 watt class panels, so I certainly have several options. But I need to watch the VOC voltage. It's the length of 3 of the 400 watt panels that is a real issue. I really want to stay close to the 70 inches per panel if possible.

 

[GXMnow]

Another day and more money spent.
I bought a Little Giant M22 ladder. Collapsed it is only 5'3" long and fit in my car without an issue. In it's tallest "A" frame mode, the top step is over 9 feet up. It is still a little reach to the top end of the beam, but not bad at all. And the adjustable length legs worked great with my wall in the back.

My brother came over for an hour and we got those top two cross boards up in place in no time. The wide angle lens makes it look worse, but that top board is really just about 2 feet over the top of the ladder now. With the new ladder and my old folding 8 foot ladder, I think it will be a breeze putting on the rails and then the panels on them.

I also bought Valspar "Canyon Brown" deck sealer/stain. I started brushing it on and it looks really close to the color of the pressure treated wood posts. Here is a pic where I applied it.

The sun was setting, so I had to pack up for the night. Here are 2 pics from about 4:30 as the sun was falling to the (elevated) horizon. I'm in a valley, and there are mountains to my west.

This will get a lot better as we move away from winter, but you can see the top row is still getting sun from the west. The DC Victron powered panels on the garage were down to just 40 watts out of 2,000 watts of panels. And the Enphase system was at about 100 watts out of 4,800 watts of panels. This is one reason I want to go 3S (or maybe 4S) rows, then parallel the rows. The top 2 rows will go to the DC system. I still think I will put the bottom row on microinverter(s).

Wow, the unstained wood looks so white now next to the stained wood. I will spend most of tomorrow staining the rest of it. But my main job tomorrow is getting in touch with Greentech about the prices on some panels. I don't want to go used from San Tan.

 

[GXMnow]

The first pair of rails from Amazon should be here Sat., Jan. 4th. The other two pairs were set to deliver on Monday, Jan. 7th., but now it says Jan. 10th. next Friday.

Still no word from Greentech. I will try calling them again after 10 am.

If I strike out at Greentech, there are a few other options. I found some new 400 watt panels for just $100 each for 25 cents per watt, before shipping. Another possible option is Aptos 550 watt panels. At $214 each, they are a bit more expensive at 39 cents per watt, but with just 9 of them, that is a solid 4,950 watts on my rack. But the top and bottom panels will extend 3'3" beyond the ends of my wood structure. The panels are HUGE. Width wise, I think it's fine. They are still just 45 inches wide. So 3 across is 11'3" inches of panels and the rails are over 14 feet long. The panels will only be 20 inches past the front and back of the wood. That's the same as the other 400 watt panels, just 1 foot more than even the 350 watt ones. The extra area is all in the height.

Another option is GrapeSolar 370 watt panels. They are just 41 inches wide, so I can fit 4 across my 14 foot rails for a total of 12 panels instead of 9. And they are the shorter 70 inch height so they fit much better along the length. 4,440 watt of panels would be nice.

My Brain Hurts!!

 

[GXMnow]

I didn't get any staining done today. BUT... Greentech Renewables came through.

I called them directly this morning, and he read off a few panels they had in stock. The price was a little more than I was hoping, but I got better panels with a full warranty. I do need to look up how to register them. The cost per panel was $132. That is quite a bit less than I paid for the 200 watt Amazon panels I put on my garage. But these are Hyundai Energy 400 watt 132 half cut cell bifacial panels. It was a 20 mile drive (each way) from home, and I rented the pickup truck at Lowe's to go pick them up.

Here they are in the bed of the truck

Yes, that is 22 panels. I am putting 9 on my pergola. My brother also bought 8. I wanted at least one spare. That brings it to 18 panels. The other 4 I am thinking may go in place of the top 4 panels on my lower roof. At 66 cells, they are just within the safe voltage limit of my iQ7 microinverters. They will produce 33% more power up until the inverter starts to clip. If I was in a colder climate, I might be worried, but I did the math. Safe limit on the iQ7 is 50 volts. VoC at 25C on these panels is 45.3 volts. It has to hit -3C to get up to 50 volts no load.

Here are a few more pics.

I have panels all over the place right now. On Sat. I just get one row of racking. The rest is another week away.
And them I need to run the wires all the way to the opposite corner of my house. And I need another charge controller.

 

[GXMnow]

I couldn't help it.

I am going to wire these in series on my old BougeRV charge controller tomorrow and just see how they do. They will get a ton of passing shadows as they are totally behind all the structure. In perfect sun, it should be 400 x 3 = 1,200 watts. Most of my panels are doing only a little better than 50%. I will be shocked to see these make 600 watts. SO less than 10 amps on the 40 amp charge controller.

 

[SunDave]

Making some good progress!

Had you ever considered putting some boards on top of both retaining walls with masonry screws and building right on that? Looks like that may be roughly the angle you are building. Just a crazy idea.

Could potentially use some unused space.

 

[GXMnow]

Had you ever considered putting some boards on top of both retaining walls with masonry screws and building right on that? Looks like that may be roughly the angle you are building. Just a crazy idea.

Yes, I did look into it. But due to the big tree in the middle of the wall, the wall gets a lot of shade across the day. I would need to bring them way forward, which is essentially what the pergola is doing. The extra panels may end up laying against the wall until I find a place to mount them. Some power is better than having a new panel in my garage doing nothing.

Here is one pic showing the tree issue.

And on the other side is the neighbors wall stepping up as well.

It also helps that I wanted a shaded area in my yard. It gets crazy hot here in the summer.

As I was typing this, Windows decided I didn't need to type any more. I have had this happen a few times in the past, but it was warning me for a few days to reboot to install updates. Finally, it freezes the keyboard. This time, it gave me no warning at all. I typed nearly a full sentence when I looked at the screen and noticed no characters going. Mouse still worked, could move and browse windows etc. I thought, maybe the wireless keyboard batteries died. Replaced them, still nothing. Plugged in a USB keyboard. It said, setting up device "USB keyboard. And that one would not type either. That is a real shitty way of forcing you to reboot your PC. Clicked restart, and everything is back up and I can type again.

 

[SunDave]

Cool. Nice that you will pick up a shaded area. We hung out behind my ground mount just while building it to get out of the sun. Now I happen to have other places on the property to do that, but it was surprisingly nice. Hang out under the solar panels.

 

[GXMnow]

I know this is stupid, but I had a thought just now.

These new panels are "Bifacial" so they produce power from light on the back side as well. Next time I need to weld with my MIG machine, maybe I can do it under the pergola?? Obviously, it won't make even a fraction of the power it is using to run the welder, but that sure is some intense light. They say the arc can be as bright as looking at the sun.

 

[GXMnow]

As I was looking close at the cells, it dawned on me that they looked very similar to the NewPowa half cut cells.
Here is the best close pic I could find of the original 32 cell 100 watt NewPowa panels. Keep in mind the NewPowa panel has a white back sheet. The Hyundai panel has a black sheet between the cells, but clear behind the cell.

NewPowa


Hyundai


The NewPowa was taken in daylight while the Hyundai pic was at night with a flashlight. The light from above really enhanced the bus bars, especially with the black around the cells instead of white. The 9 bus bars, the angle cut corners, the layout of the fingers at the ends of each bus bar on the cell. They use the same mask. Each cell is even the same exact size. I measured a 4 wide by 8 high groups, and it is the same size as the NewPowa panels. Here is where it gets real fun.

These new 400 watt panels are rated at 20% efficient. They do have a 420 watt version rated at 21% efficient as well. They choose the cells and bin them. But my 400 watt panels have a total of 132 cells 400 / 132 = 3.03 watts per cell. The NewPowa panels claimed to be 100 watt, but never quite made it, more like 95 watts compared to my old Sil Fab panels. They only have 32 cells in a 4 x 8 array. 32 cells x 3.03 watts each = 96.97 watts. Hmmm... I really think they are the same cells.

The only real difference is we can't see the back of the NewPowa cells. They have an opaque white back sheet. Here is the back of the new Hyundai cells.

The black striping on the back sheet is blocking some of the cell area as those lines are much thicker than they appear on the front side. I am not expecting much back side power. But these were priced right, and it certainly won't hurt to let light hit an active back cell face. Maybe tomorrow we will see what they do on the old BougeRV charge controller. I may have to setup a few out of any shadows.

 

[dougbert]

future 2nd Pergola possible in front of that tree?

I would love to have that much space for Pergolas - I just have enough space for 1 pergola and have permission of neighbor to trim his tree to the south (red one in upper right of pic below)

you could use the space on the walls for garden, even in the shade

or do some vertical used panels

Will gave me 4 250 watt panels awhile ago that he covered in one of his old videos. I installed them vertically on my WEST fence to get a couple of hours of sun in the afternoon - like you said, better in the sun instead of in the garage

vertical panels on fence

 

[GXMnow]

The shadows under the pergola frame are just too much, so I pulled out 3 more of the new panels and leaned them against the wall on the east side of the yard. Had to wait until after 10:30 for the shadow from the side wall to clear, but even with a shadow on the corner of the panel, they were not doing too bad. I use some old #12 speaker wire to get from the 3 panels in series to my garage. The BougeRV charge controller powered up without an issue and still has my correct charge settings in it. I used #8 wire from there to the battery bus bars. All very temp for a test.

3 panels is 1,200 STC watts. After 11 am, they are already cranking out well over 800 watts. The charge controller is reporting the peak power has now hit 914 watts. In fact, these 3 panels are matching the output of the 2,000 watts of Amazon panels on the Victron charge controller. The live App shows it a hair behind, but when I measure them with my Fluke clamp meter, they are dead on even. The Victron array is turned and closer to flat on to the sun, but at less tilt. As we pass actual noon, the new panels will be at a better angle, and they should go up even more as the old DC array starts to drop off.

Here are a couple pics.

You can see the shadow of the stake in the ground to see we are still well before solar noon.
Here is the Victron app at about the same time.

We do have a few small clouds, so the power is dipping a little now.

On another note, I think I have changed my plan on the panel layout. Thes panels are narrower but taller than the ones I had originally planned on. I was going to place them portrait with 3 across by 3 down for 9 panels. I can almost fit 4 across, but the outer panels end up almost fully past the structure and I don't trust the rails sticking out that far. That would need 6 cross rails to have 2 under each panel. The rail sections I am getting are 88 inches each. They will extend well past the panels left to right and need to be cut off a bit. But check this out.


If I put the rails vertical and turn the panels to landscape, I can fit two columns of 5 now for 10 panels total. The two long wood sticks are about where the mounting rails will be. I don't think the panel overhang will be an issue at that distance. I have a total of 12 of the 88 inch rails coming. Instead of running 6 pairs across, I will run 4 rails up and down that are 3 sections long. It turns out the kit is coming with enough connectors to do that. Each 88 inch rail section also comes with 2 of the "L" mounting feet, I also think it is going to be a lot easier to mount the panels as they can just rest on the lower row until tightened down.

The bottom 4 will go on microinverters and the top six will be 3S-2P on another Victron 150-45 charge controller. 2,400 watts max at 50 volts is 48 amps. Should I go one bigger still? I'll see what the 3 in series peak at.

 

[GXMnow]

I was really hoping to see what the peak power was going to be, but here is why my pergola is way over on the other end of the yard.
This was still a little before the sun was dead in front of the panels at 12:47 pm.

In the summer the shadow of the house will take longer to get this far out. But the face of the panels is about 20-225 degrees west of due south. So as the day goes on from here, the shadow becomes a hug problem. The power at this point was just flirting with 1,000 watts with the peak recorded at 1,006 watts.

I did not plan this, but I took this next pic exactly 1 hour later at 1:47 pm. Look where the shadow is now.

Oops. I missed the peak power output moment before the shadow hit the bottom of the panels. But here is the real shocker. Those 3 x 400 watt panels are still producing 487 watts with that much shadow.

And here it is at 2:40 pm.

The sun is now peaking past the other side of the second floor, but the two right panels are basically useless. But the three panels were still making 95 watts. I would have expected the voltage to drop too low with that much panel covered by shadow, but it was still making some. At the end of the day, the 3 new panels made 3.3 KWHs, and they didn't start making any power until 9:45 am. The 2,000 watt Victron system was making power before 8 am, and didn't die from shadows until after 4:30 pm. Of course, with the far longer useful day, that system did make more energy at 5.15 KWHs. The year total for the panels on the garage came out to 2,757 KWHs.

Should I let it keep counting up, or should I reset the history for the new year??

Each time I went out back to check on the new panels, the entire top of the pergola was covered in sunshine. I get the first rails on Saturday. I should be able to put the 3 panels up on them and get it running in solid sunshine.

 

[Siamac]

Can you build one for me too if i pay you?

Here's some cheap quality panels you can pick up, not too far from you. Maybe we can buy a pallet and split it?

Jinko 540W Bifacial Solar Panel JKM540M-72HL4-TV | eBay

One Jinko JKM540M-72HLV-TV 540W Bifacial Solar Panel. Bifacial Power Gain. Rated Power: 540W. Short circuit current (ISC): 13.87 A. PID Resistance. unless otherwise specified. 25% cancellation fee. Local Pick up.

www.ebay.com

 

[GXMnow]

Can you build one for me too if i pay you?

Where are you located?
I could help with design and some of the work

I already have the panels for mine, and got 4 extra.