Panel Shade Affect on Entire String

lzhome
lzhome Registered Users Posts: 39 ✭✭
edited October 2017 in Solar Product Reviews & Opinions #1
Today at 4pm on October 18th I have about 3 inches of shade across the bottom of two panels horizontally mounted. These two serial connected 12v 100w panels are parallel connect to 2 more panels for a 24v string of 4 panels. This shade will only be present during the winter months.

 Will this shade have negative effects on the other two panels in the string? I will be installing two more strings in the exact same manner, with same shade.

Oops, put this in the wrong category. can't more so hope a Moderator does it for me.
TriStar MPPT, 8 x 100w PV, MNPV6 Combiner, 4 x 12v 155ah VMAXTanks AGMs and GoPower 2000w PSW Inverter.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,011 ✭✭✭✭✭
    edited October 2017 #2
    Yes, It would be more effective if you can connect the 2 shaded panels in series and 2 sunny panels in series.

    FWIW - I connected mine this way with side by side panels connected and found my early and late day shading comes from the sides, so I should really connect mine up and down...lol.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Raj174
    Raj174 Solar Expert Posts: 795 ✭✭✭✭
    #3
    lzhome,
    The power output will be reduced about one third in a string shaded in this way. If it were shaded across the short side, output on the entire string would be near 0.

    Rick
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #4
    lzhome said:
    Today at 4pm on October 18th I have about 3 inches of shade across the bottom of two panels horizontally mounted. These two serial connected 12v 100w panels are parallel connect to 2 more panels for a 24v string of 4 panels. This shade will only be present during the winter months.

     Will this shade have negative effects on the other two panels in the string? I will be installing two more strings in the exact same manner, with same shade.

    Oops, put this in the wrong category. can't more so hope a Moderator does it for me.
    Is the shade a morning or evening event or during peak hours? 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • lzhome
    lzhome Registered Users Posts: 39 ✭✭
    #5
    Morning and peak hours are fine, this is late afternoon as I mentioned 4pm.
    TriStar MPPT, 8 x 100w PV, MNPV6 Combiner, 4 x 12v 155ah VMAXTanks AGMs and GoPower 2000w PSW Inverter.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #6
    Personally I wouldn't worry about it, the critical time is the peak period, production would be so low at 4pm, it would be negligible. Sorry missed the 4pm in your OP.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #7
    The shadow will move higher and last longer over the next couple of months though. Around here 2pm in a couple of months will look a lot like 4pm now.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • lzhome
    lzhome Registered Users Posts: 39 ✭✭
    #8
    Estragon said:
    The shadow will move higher and last longer over the next couple of months though. Around here 2pm in a couple of months will look a lot like 4pm now.
    @Estragon Good point.
    Kinda related but different question. I've only installed two panels as a proof of concept on mounting panels on top of my metal building. I check the panels several times a day for shade and alignment and here in the South the panels are covered with dew in the morning which takes a while to vaporize. Does anyone use Rainx or other types of glass polish to disperse water more effectively?
    TriStar MPPT, 8 x 100w PV, MNPV6 Combiner, 4 x 12v 155ah VMAXTanks AGMs and GoPower 2000w PSW Inverter.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #9
    I wouldn't worry about dew. If there isn't enough sun to vaporize it, the panels wouldn't be producing much anyway.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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