February 22, 20242 yr Hey all! So just want to run this idea past you guys before I decide to take further steps. I am wanting to add some more panels to my setup, roof space is limited. I have a flat concrete roof, so current panels use A-frame mounts and are held down by concrete ballasts. Since it is a flat roof and panels are tilted, they cast a shadow which further reduces usable space, especially considering there is bunding around my roof - being a flat concrete roof. So I was thinking of trying to add an additional 8 panels to my roof and to help create space and reduce the risk of a string of panels casting a shadow on the panels behind them I was thinking of laying them rather flat, although still elevator off the roof - since I am based in Johannesburg the wind is not as hectic as it is in Cape Town but I do not want my panels to have a chance of flying off if there is a strong gust of wind. I was thinking of keeping it simple, purchase the concrete ballasts and use some drop in anchors and use that to secure the aluminium rail to the ballasts and use multiple ballasts per alu rail for weight and then lay that down on my roof and secure the panels to the rails as per usual. This would also lead to some cost savings as I would not require the A-frame brackets. I think this could work, just looking for some additional feedback - comments are welcome
February 23, 20242 yr Hi Flat panels should give you some extra power during the day,mainly mid-day. Something to concider is that any moisture will just sit on the panels, most of my panels are mounted on a carport with about 5 deg slope and I always get a dust build up on the bottom edge of my panels wich needs to be washed of regularly.From my personel experience I would suggest to rather slope your pannels. I went as far as getting a few of these drainage clips to try and fix the problem. It works, but only so-so. Edited February 23, 20242 yr by Piper
February 23, 20242 yr Author 3 hours ago, Piper said: Hi Flat panels should give you some extra power during the day,mainly mid-day. Something to concider is that any moisture will just sit on the panels, most of my panels are mounted on a carport with about 5 deg slope and I always get a dust build up on the bottom edge of my panels wich needs to be washed of regularly.From my personel experience I would suggest to rather slope your pannels. I went as far as getting a few of these drainage clips to try and fix the problem. It works, but only so-so. Do you have some panels with a better tilt angle which can be used to compare against the relatively flat panels? Like, how much power is being lost due to the lack of tilt angle?
February 23, 20242 yr 38 minutes ago, PsyCLown said: Do you have some panels with a better tilt angle which can be used to compare against the relatively flat panels? Like, how much power is being lost due to the lack of tilt angle? If you are interested I can supply the difference in yields up to 12h daily for you to see between summer and winter. Winter is a killer if you have no tilt.
February 23, 20242 yr 6 minutes ago, Scorp007 said: Winter is a killer if you have no tilt. I agree, I ended up installing additional panels on my house roof (angled) and haven't looked back.
February 23, 20242 yr Author 1 hour ago, Scorp007 said: If you are interested I can supply the difference in yields up to 12h daily for you to see between summer and winter. Winter is a killer if you have no tilt. Yes, please do! Will be nice to have that info available. If it really is that bad with little to no tilt, then I guess I will need to make a plan to tilt them and must double check how many panels I can fit on my roof. Perhaps look at 6 additional panels instead of 8.
February 23, 20242 yr 3 hours ago, PsyCLown said: Yes, please do! Will be nice to have that info available. If it really is that bad with little to no tilt, then I guess I will need to make a plan to tilt them and must double check how many panels I can fit on my roof. Perhaps look at 6 additional panels instead of 8. Ignore after 12h00 as clouds set in on 9 Dec. In winter after 12h15 severe shade from a high side wall where my car port is located next to the house. During winter I used a bracket to lift about 15 degrees and still the peak is only 600W and PV starts 08h00. If string was flat the yield would be even less. During sunshine days in summer the peak is about 1000W and starts 06h00 at zero degrees tilt. Not many full sunshine days. Values are for a 1320W string facing north. As you have a concrete roof and being an expansion to main strings I would make it adjustable to say 3 positions.
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