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  • Unscientific solar panel orientation

    Somebody told me the easiest way to find out where your solar panels should be pointed was to go outside at noon and stick a dowel rod into the ground, adjust it so it cast no shadow, and point your panels in the same direction.

    Or, point them south (for northern hemisphere) and angle them at whatever the longitudinal is line for your location. For example, google earth says I live @ 37N, so I would point them south and tilt them at 37 degrees.

    Which one do you think would work better?

    Do you have another method that doesn't require a degree in mathematics and astronomy?

  • #2
    I went to www.pvwatts.org, and used their website to caculate for an entire year, 4 different panel settings. They use weather data for each area, and I ended up selecting a November/Febuary angle, as that gave me the best overall harvest at 39N, with least generator runtime. Yes, I could have better summer harvest, but then I either have to change the array 2x a year, or lots more generator runtime in winter.
    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

    Comment


    • #3
      Originally posted by Mike90250 View Post
      I went to www.pvwatts.org, and used their website to caculate for an entire year, 4 different panel settings. They use weather data for each area, and I ended up selecting a November/Febuary angle, as that gave me the best overall harvest at 39N, with least generator runtime. Yes, I could have better summer harvest, but then I either have to change the array 2x a year, or lots more generator runtime in winter.
      "the PV Watts Calculator from National Renewable Energy Laboratory (NREL)"

      ....sweet!

      Just a couple of clicks, came up with 35.4 degrees.

      Comment


      • #4
        OK. Last question. So what if I have a hill behind my house that blocks the sun in the evening. It's more like a mountain. I don't have a sunset. It's more like twilight or something where it doesn't get dark until an hour and a half after the sun disappears at the mountain top. Should I flatten it a little to get more direct sunlight earlier in the day?

        The more I think about this, the more I want swivels

        Comment


        • #5
          Originally posted by crxvfr View Post
          OK. Last question. So what if I have a hill behind my house that blocks the sun in the evening.
          keep the bulldozer parked.

          Depending on the hill (is it due west ??) you need to MEASURE what time the sunsets behind it, and calculate out the difference to regular sunset in your area. 40 minutes, 3 hours ??

          Then measure what your array is putting out at Hillset, and see if the extra minutes are worth shaving the top off the hill.
          (Summer, equinox, and winter.) RIGHT now, we are so close to summer solstice, you can measure both summer & winter angles, use the MOON at it's moonset (early morning right now, just past full) and that's the same path the SUN takes in the winter !!

          Unless your panels are aimed to the sunset, the sun angle is likely so low, that you are not getting much power, and 2 more hours of 73 watts is not worth the diesel.

          If the hill is southwest, and blocks several winter hours, it may be worth it.
          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

          solar: http://tinyurl.com/LMR-Solar
          gen: http://tinyurl.com/LMR-Lister

          Comment

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