Fixed roof mount optimum angle

HumMichael · February 2017

Hello everyone.
As I am carefully planning my permanently mounted system, I am considering roof mounting my panels.
Based on my latitude, I would like the panel to be set at about 34 degrees, however my roof is 4/12 pitch.
I have tried to design the mounts using design features of Ironridge and Renogy neither of them seem to offer any option in terms getting the desired fixed angle.
Should I be looking at another manufacturer or am I missing something?
Thanks
Michael

mike95490 · February 2017

If this is grid-tie, you want the optimum yearly angle, that gives the greatest harvest over the year.

If off-grid, I chose to mount my arrays at the optimum winter angle, to get the most from the sun on the short days. Summer, I'm in float by noon, and still running 1Kw of pumps, while in float

(winter, I'm still buying diesel for the generator, my harvest today was a grand 1,630 watt hours - off of 5Kw of panels
and that's better than my low of 590wh in Jan ! )

HumMichael · February 2017

Thanks for reply. My question is which roof mount can I possibly use to compensate for my low roof pitch.
There must be way to order the northside mounting legs to be taller rather than keeping panels at equal angle to the roof.

softdown · February 2017

I found a local welder on Craiglist that had reasonable prices on 1/8" angle iron. Angle iron works great but it must be primed then painted. Lag screws are good anchors. Galvanized may be called for.

Panel angle is important.....you seem to be aware of that.

Southern folks that use the A/C a lot should orient for summer production. Most should probably focus on winter production due to the short, cloudy days of winter. Plus spending time indoors using lights and televisions etc.

HumMichael · February 2017

Thanks. I thought for sure name brand roof mounts had way to adjust to a necessity angle. Hard to justify those rails then.

Estragon · February 2017

There are definitely rack systems with adjustable back legs to set panel angle. I use just such a system, bought from NAWS a few years ago. They don't list that particular rack now, but a similar rack is listed under roof/ground mounts on the site.

There are a lot of choices and variable with different panels, slopes, wind/snow loads, etc. , so you might want to contact NAWS to discuss.

softdown · February 2017

Some prefer aluminum. I like iron myself. pvwatts.gov tells you what angle yields what output for a normal month.

dennis461 · February 2017

Depends on how many rows/columns are going on the roof.
Most residential roof mounts simply use the existing tile, in your case around 20 degrees.
Either company should have what you need.
In NJ, my township, an engineering study was needed for roof loading and wind loading which can get complicated with additional tilt.
Seems like all you need are some 14 degree anodized aluminum brackets for the bottom rail, and an extension and 14 degree bracket for top rail on each row.
I mention aluminum to stay compatible with the vendor aluminum.

Iron ridge calls their system Tilt Mount for Flat roofs, you just put the system on your pitched roof, maybe some additional support to keep gravity from tilting it more each day :-)

HumMichael · February 2017

I saw that tilt model for a flat roof as well. Possibly intergrating that feature would be great. I will do mote research. Thanks

Fixed roof mount optimum angle

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