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output from solar panels winter vrs summer

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  • output from solar panels winter vrs summer

    Hello,

    I'm fairly new to the solar scene. And my experience with the amount of power genereated from my solar panels is limited to the winter (in CT). My question is whether or not I can expect the amperage (and wattage) of my panels to increase during the summer months? I know the days will get longer, and the hours of sunlight will be more, but will the different angle of the sun amount to an increased level of generation? For example, if I'm reading an average of 5 amps between my 3 panels in the winter, can I expect to see an increase in amerage in the summer? Thanks in advance.

  • #2
    Total output will be more amperage may or may not increase. It will depend on the angle of the sun to the panels and how hot it is outside. Highest amperage is generally spring and fall when the temps are cool but the sun is fairly high in the sky.
    Rich
    WWW.solarsaves.net

    NABCEP certified Technical Sales Professional

    http://www.solarpaneltalk.com/showth...Battery-Design

    http://www.calculator.net/voltage-drop-calculator.html (Voltage drop Calculator among others)

    www.gaisma.com

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    • #3
      Do you know what the tilt of your array is? Amperage is related to irradiance. You get maximum solar exposure if the plane of your array is perpendicular to the sun's rays. So if your array is closer to 56 degrees, then it will have better winter production, and if its closer to 26 degrees then it will have better summer production (since CT is around 41 degree latitude, and the rule of thumb is -15 in summer, +15 in winter).

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      • #4
        Originally posted by andrewc View Post
        Do you know what the tilt of your array is? Amperage is related to irradiance. You get maximum solar exposure if the plane of your array is perpendicular to the sun's rays. So if your array is closer to 56 degrees, then it will have better winter production, and if its closer to 26 degrees then it will have better summer production (since CT is around 41 degree latitude, and the rule of thumb is -15 in summer, +15 in winter).
        My array's at around 40 degrees. I'm going to jack that up to 65, and see the difference. And I'll keep your advice long term, as the summer draws closer. At that time I'll bring it to around 25. I'll keep you posted. Thanks.

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        • #5
          Your panels put out their maximum voltage in winter when its cold out. They also will put out the maximum wattage during cold weather with snow on the ground.Unfortunately there are a lot more hours of daylight in the summer than in the winter. In most areas there are more dyas of clear weather than int he winter but thats highly variable on the location.

          Of course some "rocket scientists" dont plan on shade from trees in the summer so their actual hours of daylight are less than what is availlable . I drive by a high profile DIY system near me that is in the shade in the afternoon during pasrts of the fall due to trees on a neighbors property.

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          • #6
            irradiance/conversion/AR coatings/resistance effect amperage
            Hot/Cold weather effects voltage

            The happy medium is to get a fixed tilt to latitude/azimuth of fall and spring for best results. Or maximize fix tilt for latitude/azimuth of summer solstice. Never do you want a fixed tilt for winter solstice as it lacks the most sun hours within the season even if its colder to increase voltage, if PTC exceeds STC even in short sun hour duration's fuses will just become costly to replace IF by chance exceeding the medium voltage of 600V.
            I personally like fixed tilt for spring/fall conditions although sun hours are 1/3 less than that of summer solstice, there are double the amount of sun hours combined to summer sun hours. everyone has their own preference however.

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            • #7
              Originally posted by solarpowered View Post
              irradiance/conversion/AR coatings/resistance effect amperage
              Hot/Cold weather effects voltage - - - - - - there are double the amount of sun hours combined to summer sun hours. everyone has their own preference however.
              To avoid confusion for any newby reading - when people use the term sun hours they really mean taking the daily insolation and dividing it by 1000. Insolation being the amount of watts received per square meter per day. It is a funny usage apparently dumbing the insolation number down for solar salesmen.

              An insolation of 4,500 watts per m2 = 4.5 sun hours.

              Approximate insolation for your location can be learned from PV Watts http://mapserve3.nrel.gov/PVWatts_Viewer/index.html
              Last edited by russ; 02-24-2012, 01:48 PM. Reason: spelling
              [SIGPIC][/SIGPIC]

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              • #8
                Changing tilt on collectors is IMHO probably not worth it. The increased output is only about 3 or 4%
                If you tell me your zip and azumuth (true direction) I can run a tilt optimizer to tell you what fixed tilt is best.
                Rich
                WWW.solarsaves.net

                NABCEP certified Technical Sales Professional

                http://www.solarpaneltalk.com/showth...Battery-Design

                http://www.calculator.net/voltage-drop-calculator.html (Voltage drop Calculator among others)

                www.gaisma.com

                Comment


                • #9
                  re tilt optimizing.

                  I'm off-grid, and have my tilt set for winter (nov-feb) because I need every bit of sun in the short days. Summer, with the longer sun days, it's not much of a loss.

                  Also, the steeper tilt, allows for a bit more "self cleaning" of the panels. I've got no snow, so I can't gain from any reflections.

                  Looking through my charge controller logs, on several really cloudy days, my 3KW array put out about 150 watts peak ! Clouds are bad for harvest.
                  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

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                  • #10
                    PV Watts mentioned above will tell you the story.

                    I'm amazed at how fast production increases in the spring.
                    I will go from a best day in December of ~32 Kwhr to hitting almost 70 in mid-march which is pretty much the peak because the heat kicks in and makes the panels less efficient.

                    I think I'm about 29 degree pitch
                    10Kw solar PV
                    GSHP (6-2011)
                    Solar hot water 2x SPP-30
                    Meter has been going backwards since May 20th :julie:
                    Anyone wanna buy some SREC credits? (cheap!):Cry:

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