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Forum Index : Solar : Panels face Nth on W facing roof
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
anyone got any ideas? seems my 10 panels is somewhat of a headache RE High voltages and voltage ratings of Circuit breakers. 10 panels in one string = VOC 440V and CB's required to be 1.2x VOC min meaning a 500V breaker just misses out. hence fix add 4 more panels and go for two strings of 7. but i need to face them North on a west facing roof, and I just cant quite get my head around how it can be done in a pretty (ish) manner Luck favours the well prepared |
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AMACK Senior Member Joined: 31/05/2009 Location: AustraliaPosts: 184 |
Karl, Have you got any photos of the lay out you trying to do. Panels that is. AMACk *Note to self 1. Make it thick 2.Make it heavy. 3.Make it stronger than it should be. 4. Don't rush the first job as the second job will cost more and take mor |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
This is roughly what I had in mind, obviously not sitting them flat but jacking up one side Problems are as follows mounting rails must run with the panels and ~300mm (width of panel is ~1600) in from the sides rows of roof beams (ie screw lines) not well suited to this. in order for the panel to sit roughly flush with the roof at the apex to the NTH face BOTH rails would need to sit up off the roof, complicating it further. as brackets are designed to fit ~90 deg to each other Luck favours the well prepared |
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Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Could you extend the exising mounting rails? Take all the panels off and extend the rails out one or both sides, then mount them all back on with the extra panels down the side. Or what if you monted them all at 90 deg, portrait instead of landscape, short side top and bottom. They might nest together better. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Why place them at the top of the gable and not start down near the gutter and work your way up. It would require some unused rail lengths, but the extra rail area would allow for some fill in panels to be added as they became available in time. I would be doubtful the small difference would make any difference in output when you concider the distance between the roof and the sun. Its not the problem its the way you see it, that gives the solution. Pete. Sometimes it just works |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Glen, i considered that but it involves another yet another $500 in rails and more importantly the batton spacing doesnt allow the two new rows to butt up against one another like they do in landscape, thus loosing more space again. I considered this but as far as anchoring the tops of the rails to the existing screw lines its an absolute nightmare and hanging out in free air is a big looser! Luck favours the well prepared |
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windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Karl, if what Glenn suggests does not work then do not place them as illustrated, place them along the line of screws. one thing in your favor in WA is much of our winter sun is in the afternoon ie wnw. Be careful about exposing panels to the sumer ESE winds and winter westerly's without strong mounts. I don't see your problem, I suspect this is a case where a little knowledge is too much, what is the probability of the breaker operating under fault conditions, close to zero. allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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Jarbar Senior Member Joined: 03/02/2008 Location: AustraliaPosts: 224 |
Hello Karl,if you add the 4 new panels abutting to the left hand end of the North West array shown in previous post and angle them back to more or less match the North facing array.Yes you will need a frame but would look pretty neat I think.If you need a hand let me know.I tried to import a photo from paint but you can guess what happened. Well done on your systems excellent installation. Anthony. "Creativity is detirmined by the way you hold your tounge".My Father "Your generation will have to correct the problems made by mine".My Grandfather. |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
problem is if i cant get the AOK from a sparkie then no rebate! thats worth $8000 (216x $37). I agree the fault condition ie short circuit will not harm the panels and will in fact probably never trip the breaker even if there was a fault, unless the fault was on the inverter side and it punched 16A 240VAC onto the panels, in which case it probably still wouldnt trip the breaker! regs are the regs though! Luck favours the well prepared |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Solved! Expensive but elegant none the less ARRID bits trade money...still EXPENSIVE but hey I look I the bight side that is 740W more panels for the bargain price of $2500 All UP. now I (will) have just under 5.2KW after RECS should be out about $1900 which for 740W is a bargain! ON another note should be seeing lots of SB1100 on the market cheap as no-one can sell them, seen them as low as $1000 also a bargain even if their efficiencies aren't that great Karl Luck favours the well prepared |
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VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Karl Do you have a in line diode to protect from feedback? Why not get into the ceiling and place a dummy batten where the mounts need to go, the pitch looks high enough to get into the roof. Place the panels in landscape 1 - 2 - 3 from the top down, split loads to suit the breaker specs. You worry to much. All the best Bob Foolin Around |
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VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Back again Don't worry about the west facing as it will give you good input in the afternoon as the north ones start to drop off, or make a tracker and mount the whole lot on it once the dust settles. Perfection tomorrow. All the best Bob Foolin Around |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Going to look like sketch 1 in the end pics to follow soon COnsidered the tracker but for 5.2KW (28panels now ) It would be enormous!!! NOthing beats NTH facing except the tracker, nice to have more watts here and there if you're desperate but west typically looses 30% on Nth facing thus I cant in good conscience waste them facing west. Would have been up for about $200 just to mount them flat, good experience too Just come in from the dark now, torch gone flat so calling it a night Karl Luck favours the well prepared |
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