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Solar pv ground mount panel angles

  • 08-10-2020 4:02pm
    Registered Users Posts: 125 ✭✭ Ballylad

    Hi, Is it worth putting up a ground mount solar pv array that can be adjusted for tilt angles in winter and summer, ie, lower tilt angle in summer and higher in winter or would it make much difference, Any websites that can calculate best angle tilt for location?,array will be facing south. Any suggestions appreciated.


  • Registered Users Posts: 1,627 ✭✭✭ quentingargan

    Simulation software shows 30 degrees to be 5.8% less efficient than 65 degrees for winter months Oct to March. December / January would probably be a good bit more than that. For summer, 65 degrees is 7.9% less efficient than 30 degrees.

  • Registered Users Posts: 2,820 ✭✭✭ air

    It's not really worth putting the money into a tilt mechanism any longer in my opinion unless you are really caught for space.

    It's more effective to spend the money you would have spent on the tilt function on more panels.

    I'm a fan of steeply mounted panels for Ireland, especially if facing South.

    You will get some extra production in mid winter when you really need it.
    In summer your output will be reduced slightly but chances are good you will already have more than you need at that time of year.

    60 degrees would be my peferred angle but your particular circumstances might change this.

  • Posts: 0 [Deleted User]

    I'm a fan of shallow mounting (15°): all day power. They perform very poorly in the Winter though.

  • Registered Users Posts: 2,820 ✭✭✭ air

    Well it's all a balancing act really & there is no one size fits all answer, but the majority of people are on grid without a FIT,
    In those circumstances I believe it makes more sense to optimise a little more for winter than summer.
    Overall production will be reduced but (all else being equal) the number of solar units consumed will be higher (which is all that matters).

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  • Posts: 0 [Deleted User]

    Tehehe...true that, and the more panels rather than complications philosophy is gold. I prefer the low angle for the same reason. I don't want peaks I end up exporting power with. A little all day has a lower on paper generation figure but a higher offset overall.

    Still not much good in the Winter having said that...I may change tactic. More of not a lot is not much van life has thought me. I might revisit it...more pressing matters to consider before I bother though.

  • Registered Users Posts: 2,820 ✭✭✭ air

    Sure, a shallow angle might be a good option for a summer home for example.

    You could get by with a very small array at 30 degrees if only using it 6 months of the year perhaps.

    Another option is a bit of both shallow & steep, split the array into two strings.

  • Posts: 0 [Deleted User]

    Or a Spring and Autumn home.

    They perform better in overcast and clouds too when light is diffused. Winter losses are not that much.

  • Registered Users Posts: 2,820 ✭✭✭ air

    They're not that much in terms of a percentage of annual consumption but it's significant in winter.
    A 70 degree array will outperform a 30 degree one by 34% in December per the EU calculator.
    This could be very significant if you were off grid and relying on diesel backup for example.

    Anyway I think we've said enough to illustrate the pros and cons of either angle :)

  • Moderators, Sports Moderators Posts: 15,992 Mod ✭✭✭✭ slave1

    If ye guys are ground mounting is it not possible to create a lazy Susan type base to track the sun?

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  • Registered Users Posts: 2,820 ✭✭✭ air

    Anything is possible but it just doesn't make sense economically.
    You've a lot more steelwork, hardware and complication which all add cost.
    2 axis active tracking will increase annual output by about 30% in Ireland but a tracking system will cost a hell of a lot more than 30% of the cost of the panels, therefore it's pointless in almost all circumstances.

  • Posts: 0 [Deleted User]

    I put a tilting rack on a van. 30% of 10 watts is 3watts extra.

    It did make a big difference when the sun was actually shining with cold temp uprating.
    I got a bigger panel after that and bolted it.

  • Posts: 0 [Deleted User]

    Couldn't resist! :pac: