diy solar

diy solar

Adding storage to my Enphase system

Can't tell from the photo, but it the roof doesn't have another 10 years on it, pressure wash it and then lay down a coat of silicone over it first (possibly look for and fill any voids/hollows if they're big).
 
Whatever direction it slopes (looks like diagonal?) you want water to flow, not be obstructed.
Could stand up 2x4 going that direction or at least orthogonal to rafters if that leaves a reasonable slope. Diagonal to water flow would cause some depth, so not desirable.
Then crosswise boards, tied in to parapets. Then rails to mount panels.
 
I did up a quick drawing in Visio. It's not quite ready to post yet. I got up on a ladder and took some reasonable measurements. The roof is actually a little bigger than I estimated. The outside, including the wall thickness is a full 20 feet wide, and it extends 23 feet from the wall of my second floor out to the end of the garage. The wall is about 7 inches thick, so take off 8 inches all the way around. 18.5 feet wide, and 21.5 feet long. Putting the array with the rails crossing all of the rafters makes the array 3 panels wide x 39.4 inches = 10 feet, plus a bit of rail out the ends. Gives me over 3 feet on both sides. The length is 2 x 78.5 inches = 157 inches, plus a gap between the panels, so let's call it 13.5 feet. So if I leave 3 feet down by the garage door, it is still 5 feet away from the wall to the second floor. The 72 cell panels fit just fine. So... Do I buy the solar panels from San Tan and save about $30 each (maybe $200 total savings), or just get it all from Alt E Store?

Looks like it is time to make up the drawings and talk to the city. If I start putting up this much on my roof, I know someone will call on me if I don't have the permit posted. I should not have to deal with So Cal Edison, since this is an off grid battery charger, with no back feed. Just the basic city electrical inspection should do.
 
I was thinking AltE. Their prices are pretty good and you might save some on shipping since you are already placing an order.

My town has a $500 limit on roof repairs without a permit. So I'm going to install one panel at a time.
 
I am so rusty with Visio. I had not used it in a year, and Microsoft updated it and all my pre made macros are gone and they moved all the tools. I am using this to re-learn it. Here is my rough draft of how the 6 new panels will fit on my garage roof. The page scale was set wrong, but the panels to the roof is properly scaled to each other, but in Visio, it says everything is 4 times the size, Oops. Print it at 8.5 x 11 and it is 1/4 inch = 1 foot.
 

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I'd play around with the locations of the weights. Since the mass prevents an "edge" from getting lift, the ones on edges (or beyond) can make use of "leverage" to hold it down, weights in the center do very little in comparison. That is you get more anti-lifting per pound. I did an example of redistribution in the bottom left diagram (openoffice ;) ).

Also, if the bottom edge represents a higher structure, then you won't have wind from that direction and won't need the downward force. Below is an example drawing demonstrating changing the locations.... but I didn't run the math as the picture in #400 suggests, and in a permit I'm pretty sure you'll have to show that math (you would in my county anyway).

I also illustrated what I think @Hedges was saying (center image, rails attaching to the parapets), which makes great sense since it eliminates the excess weight and no roof punctures. You'd still need some sort of standoff under the rails so water could runoff, but they could be attached to the rails and not through the roof deck. Finally, the right image is a modification of that idea, it has "bars" (2x4s?) over the rail tops to distribute the holding force along the length of the parapet, basically it clamps the rails down.

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Thanks for the input. Always helpful. It will basically act as 2 separate arrays as far as wind is concerned, since each pair of rails are holding 3 panels, and the is only the wiring tying the front and back groups of panels together. Yes, the bottom is the second floor wall sticking up over 7 feet above the flat roof. I agree the rails extending to the parapet walls would be strong, but I would really hate tripping a firefighter in gear trying to walk past the bars in full gear. I do totally get the idea of the weight at the end having more effect. I think I will stick to 5 bricks, but have a close pair at each end, and then one in the middle just to keep the rail from bowing. The more I think about the cost of doing this, I should just spend the extra $300 and use the new Trina 144 half cut cell 400 watt panels. They are the same size, but pack quite a bit more power into the space. The cheap 370's made sense, but since those went out of stock, the 355's at a higher price just does not make sense with the total budget. 6 400 watt panels makes another 50% of the power I am getting now with 6 x 300 watt panels.
 
Ok, having read through this all as it happened I can't remember if this came up. Sorry, I couldn't be bothered to read back through 22 pages ?

Do you have a shot of where you cut the bus bar? I remember reading about how you cut with a step to leave one rivet intact on each side. But, that looks like it would leave a very uneven separation when splitting the pack.

Also, do you remember where you got those bus bars bolted to the front cover for both the + and - distribution with covers? Those look like they would work perfectly for me too. I've searched around a little and haven't come across anything between crazy expensive and over built and cheap, not rated for enough current.
 
I agree the rails extending to the parapet walls would be strong, but I would really hate tripping a firefighter in gear trying to walk past the bars in full gear.

In my area I do not need a 3' path on every side. Just 2 depending on other factors.

What if you pushed the array off to one side (into the wind) and bolted that side to the parapet? Then you would rely on the weight on just one (or 3) sides.
 
I thought I had pics of the buss bar cut, but I can't find them. Next time I have the battery rolled away from the wall, I will try to pop off the cover for a pic, but I also coated the cut area with liquid electrical tape. Man that stuff smells bad when you spread it on.

I never actually split apart the brick. That would likely require the rivets to be removed to allow the buss bar to slide apart as you split between the cells. The odd issue also comes in with the cells being packed as pairs, but wired in triples. Trying to pull off a 4S chunk should work. 4S-3P is 12 cells, so that would be six 2 packs. Then you just have to splice that on the end of the 10S-3P 30 pack, 15 pairs. Total 42 cells = 14S-3P

My big fear on the solar panel placement would be someone putting a ladder up, climbing onto may garage roof, and stepping right on the panels, as they are not really going to be visible from the ground. My current panels up the sloped roof are very obvious. They might not expect there to be 6 more flat on the garage. I do plan on adding the layout over by the disconnect, but that may be too late. They will see the 16 up on the roof and not take the time to see there is another group. So I want 3 feet all the way around the array so as anyone gets on the roof, it is obvious when they get up there. The more I am looking at it though, I think I am going to just skip the rails, and use "Z" brackets to just bolt the panels down to the concrete blocks. This puts the panels much lower to the garage flat roof. That vastly lowers the wind loading as well. Almost no wind will be able to get under them. With the same 20 concrete blocks, each panel will be clamped to 6 blocks. It would take a serious tornado to move them. The edges of the solar panels will only be 2 inches off the existing roofing between the concrete blocks. The ground wire will need to zig zag between the 6 panels and have 6 separate lugs, since they won't be clamped to metal. I will also bolt the Tigo RSD boxes to the concrete blocks under the panels. I have to see if I can use PVC conduit, or if it needs to be in heavy wall metal pipe. I can do either, but the PVC is much easier to deal with.
 
I thought I had pics of the buss bar cut, but I can't find them. Next time I have the battery rolled away from the wall, I will try to pop off the cover for a pic, but I also coated the cut area with liquid electrical tape. Man that stuff smells bad when you spread it on.

I never actually split apart the brick. That would likely require the rivets to be removed to allow the buss bar to slide apart as you split between the cells. The odd issue also comes in with the cells being packed as pairs, but wired in triples. Trying to pull off a 4S chunk should work. 4S-3P is 12 cells, so that would be six 2 packs. Then you just have to splice that on the end of the 10S-3P 30 pack, 15 pairs. Total 42 cells = 14S-3P

My big fear on the solar panel placement would be someone putting a ladder up, climbing onto may garage roof, and stepping right on the panels, as they are not really going to be visible from the ground. My current panels up the sloped roof are very obvious. They might not expect there to be 6 more flat on the garage. I do plan on adding the layout over by the disconnect, but that may be too late. They will see the 16 up on the roof and not take the time to see there is another group. So I want 3 feet all the way around the array so as anyone gets on the roof, it is obvious when they get up there. The more I am looking at it though, I think I am going to just skip the rails, and use "Z" brackets to just bolt the panels down to the concrete blocks. This puts the panels much lower to the garage flat roof. That vastly lowers the wind loading as well. Almost no wind will be able to get under them. With the same 20 concrete blocks, each panel will be clamped to 6 blocks. It would take a serious tornado to move them. The edges of the solar panels will only be 2 inches off the existing roofing between the concrete blocks. The ground wire will need to zig zag between the 6 panels and have 6 separate lugs, since they won't be clamped to metal. I will also bolt the Tigo RSD boxes to the concrete blocks under the panels. I have to see if I can use PVC conduit, or if it needs to be in heavy wall metal pipe. I can do either, but the PVC is much easier to deal with.
You could probably drill holes in the frames and screw the panels right to the blocks.
 
Looking at the edges of the frames on my current panels, the glass looks like it goes to within 1/4 inch of the edge. It would be risking trying to drill down through that. I could drill through the side and use a 90 degree bracket like these.
Then I just drill a hole in the rail of the panel for a screw, or maybe even use a self drilling and tapping screw into the aluminum frame. Iron Ridge uses a self drilling screw for their rail splice. For the bracket to the concrete block, I plan to use "TapCon" screws that thread straight into concrete. I have used them on these concrete blocks before. Several of the blocks with brackets bolted on have been in my back yard for over 10 years and they are still solid. The steel bracket is showing a little rust, but the bolts still look perfect, and they are holding tight.
 
Right, I forgot you left your 8s in one piece. A pic of that isn't needed, now I understand.

Who made the positive and negative bus/distribution bars on the front panel?
I may just make my own out of a copper bar as it seems like they are pricier than I like.
 
I am using these buss bars on the negative side, before and after the BMS.
I should have gotten 2 black, but the set is a red/black pair, I painted the red lid black. They claim 250 amp rating, but I would not run them that hard on a constant basis. A short section of one bar in my setup is fused at 175 amps. The other bar is combining my 2 strings. 125 amp to each end, and the BMS tapped off in the middle.
I then have this buss bar on the positive side now.
I have the 2 strings going in on separate 125 amp MRBF fuses. They are borderline for our systems, 58 volt max rating, so a full on dead short on a full charge might not be completely interrupted. I will never charge to 58 volts, but the battery could run up to 58.8 volts. The common terminal from that buss bar runs to my cut off switch, and then I also have a Class "T" fuse to the main output from the battery bank. The third fuse on the buss bar is a 30 amp going to my utility breakers that feed the 12 and 24 volt buck converters.

I made one mistake on my Class T fuse. I didn't know there was a size change around 200 amps. I got a 225 to 400 amp rated holder, and fused at 175 amps, Oops, didn't fit. I think up to 200 amp is the shorter length and smaller stud. I am sure I did a big NO NO. I drilled out the holes in the fuse a little bigger, slotted it a bit, and used copper washers. It works and I am sure the connection is fine for the 175 amp fuse rating. But next time I work on the system, I should change the fuse mount down to the 200 amp version, or put in a 225 amp fuse. I have tried to find a 175 to 200 amp fuse in the larger size, and it does not exist. Here is the holder I have.
They are not listing the Blue Sea under 200 amp version now.
 
My positive side doesn't have busbar, just a "Y" of cables with lugs to two fuses, then "Y" to two loads each.
Negative side, I bought a copper busbar with plastic standoffs from an eBay vendor. But would have been cheaper to buy a piece and drill it myself. More optimal hole spacing, too.
This post I gave a couple links:



Yes, Class T fuse holder you have to get the right size. Also some plastic covers are hard to remove (I'll try beveling the catch next time it is off.) One model Blue Sea carries has latches holding the cover, better to get that one.
There are also fuse holders which come in two halves. You can mount them spaced for your fuse. They do not have an insulating cover, so needs to be in suitable enclosure. They Some have fins on the terminal as heatsink, might help high amperage applications.
 
Looking at the edges of the frames on my current panels, the glass looks like it goes to within 1/4 inch of the edge. It would be risking trying to drill down through that. I could drill through the side and use a 90 degree bracket like these.
Then I just drill a hole in the rail of the panel for a screw, or maybe even use a self drilling and tapping screw into the aluminum frame. Iron Ridge uses a self drilling screw for their rail splice. For the bracket to the concrete block, I plan to use "TapCon" screws that thread straight into concrete. I have used them on these concrete blocks before. Several of the blocks with brackets bolted on have been in my back yard for over 10 years and they are still solid. The steel bracket is showing a little rust, but the bolts still look perfect, and they are holding tight.
I've been using a bunch of tapcon screws. They are really good.

I didn't like your z bracket idea because I was thinking something could shift.

Your L brackets should help prevent shifting. If you keep the wind from getting under the panel I doubt anything will move.
Hopefully you won't have an earthquake and a hurricane the same day.
 
I am too far inland for a hurricane, but the wind gusts we had were pretty close to a micro burst. I don't know if this area ever had a real tornado, certainly not in the 18 years I have been living here. We have had 4 earthquakes that rocked the house and made it creek, but no damage that needed repair beyond a few things falling over. But before I moved here, this house did live through at least 3 major quakes. The last being the about 7.0 (depends on the report) Northridge quake back in 97 or so. The epicenter was less than 10 miles away and this area certainly shook hard. There are no cracks in my slab, nothing collapsed, just some cracked windows from the flexing and the stucco pulled back next to the garage door. From the reports I have read about quakes around here, the Santa Clarita valley is on it's own small plate. That plate does 2 things. One is that it isolates us from the larger plates that form the mountain ranges around us. And two, it is just not large and heavy enough to store up the stress to make a large quake. The small plate just moves too easy. Every once in a while, you just hear a little creek sound, maybe feel a tiny shake. The stress is relieved all the time. I am certainly no geologist, but from reading and talking to people who have been here a long time, it sure seems like we are pretty safe from the killer quake. When the 6.9 and 7.3 both hit in Searles Valley, we sure felt the house rock around, but nothing even fell over. I was home for the first one, I was at work in Beverly Hills for the second one. Yes the second was a bit stronger, but I was nearly double the distance away from me. It shook harder and sharper down there, than it did up here. 18 years, and I have not bought earthquake insurance. The premiums and deductible are just crazy. Maybe once my mortgage is paid off, so I can possibly afford it.

I am trying to make up a plan set for the 6 panels that might get approved by the city here. What they are asking for is just plain ridiculous. I can see why the installers charge so much for the plan and approval in my area. What a joke. If I bolt to the roof, under 10 KW of solar, does not need a structural review. ALL ballasted systems require a full structural design review by a licensed engineer. That just blows the cost of the system out of reality. The electrical side is simple, but the panel mounting is just crazy. The guy who did my existing Enphase install won't touch a ballasted system. He would just bolt through my flat roof, into the joists, and then seal over the mounts with asphalt and tar. And with that he would only do it if the homeowner (Me) would sign off that there is no leaf free guaranty and the system should be on the sloped roof only. The only ballasted jobs he has done are very large systems on huge industrial buildings where they only had to have a small section design evaluated, and then copy copy copy. That makes it almost cost effective. But even that is very rare here because of the possible wind gusts. I really don't want to do this without a permit, but.....
 
My location, roof mount under 40# per attach point and under 18" high, no structural permit. Ballast requires one.

For you, back to my idea of joists bolted to parapet. In my location we can build a deck (on the ground) < 18" high without a permit.
Fire department says they can step over minor obstacles, walkway on roof doesn't have to be 100% clear.
How about putting deck boards on my suggested joists, so it is a walkway rather than a series of tripping hazards?

Orient the joists from street to house, so not in the walkway? (do periodic cutouts on the bottom to let water pass under.)

Alternatively, glue down panels? Or make standoffs, and glue them down? Glue down deck boards as runners (more area to bond), and screw standoffs or Z-brackets into them?
 
I was going to suggest the deck board over the joists to, @Hedges beat me to it. :cry: Would only take a few boards since there's no reason to deck under the panels.

I don't know that I'd go the glue route given how close the panels are to the parapet edges... (that is it's a small distance, so bolting into the parapet seems both more secure, and less problematic if you ever need to remove them).

I'd bolt beams into the parapet about an inch high (higher if you have leaves or shade from the parapet), put joist hangers onto that beam, put the joists in, then attach the panels to the joists, then decking over the remaining exposed area. You could probably use 2x4s with a "foot" at a few spots underneath each to support loads, but I'd do 2x6"s just so debris won't get hung up on them.

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I wouldn't screw the panel clips directly into the wood; over time with weather they'd weaken. Ideally, the fastemer should be perpendicular to the load so it's the shear strength of the screw/bolt rather than the pull-out force or a screw.
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Possibly bolt the panels to a heavy-duty u-hanger (or unistrut) that saddle the joists as shown above right-most?

Well, that's my contribution! Hope it helps!
 
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