Panel tilting advice, please...

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paulskirocks
paulskirocks Solar Expert Posts: 84 ✭✭✭✭
OK, according to whatever website I checked, the optimal south facing angle for the panels in Topanga, CA is 39 degrees... Well, the roof of my cabin faces southwest, and my roof angle is 27 degrees... The roof gets direct sun from around 10 am to 4 pm this time of year, and even in summer, the cabin is shaded until mid morning... So, I am wondering if I should tilt the panels more... My setup is like this:

Attachment not found.

So, most of my sun is in the second half of the day, so southwest facing seems good... The question is, should I tilt them at all, and, if so, do I increase the tilt towards the southwest, OR, since I have 18" between the two strings, I could tilt each string towards the southeast without one string shading another...

As usual, your sage advice is greatly appreciated...

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  • paulskirocks
    paulskirocks Solar Expert Posts: 84 ✭✭✭✭
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    Re: Panel tilting advice, please...

    Well, as is often the case, I kind of answered my own question by plugging various figures into PVWatts and checking it on the hourly performance data, it seems that due to my shading in the morning, I'm setup as optimal as I can...
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
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    Re: Panel tilting advice, please...

    Yep--Playing with PV Watts can answer many of these types of questions... Also, just looking outside can too (get morning marine layer--don't bias panels east. Get evening thunder storms and/or hot weather, don't bias panels west. Grid Tied power with summer after noon power charges--summer afternoons maximize generation. Off grid and need power in winter, look at optimizing for winter or add a winter near vertical tilt to shed snow, etc.).

    No one right answer here. Depends on your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • newl
    newl Solar Expert Posts: 53 ✭✭✭✭
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    Re: Panel tilting advice, please...

    Something else to keep in mind too is that tilt kits typically costs more than it would cost to get additional panels to compensate. The only time that this would not be a possibility is if you're out of roof space.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Panel tilting advice, please...

    i didn't look back at your other posts to reread what type of setup you have, but it would depend if you are gt going for max overall yearly production or if it's more like an off grid thing and winter production becomes more important in the mix, all with going with 1 fixed angle year round. if the latter then bring the pv angles up as much as possible without causing shade issues at the worst case being the winter solstice. normally it would be around lat +15 degrees as a nominal point, but being you are aimed off of south the sun will be at a lower point to the horizon and another 5-10 degrees could be in the mix for it.

    in general, being you obviously have adjustibility, i would do for both parallel to the roof in the summer and higher angles in the winter to optimize overall productivity no matter which method you employ, gt or off grid.