Snow vs. panel orientation

softdown
softdown Solar Expert Posts: 4,053 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
When I joined this board there was frequent mention of dealing with snow covered panels. Much of the reason that I settled on ~45 degrees. It worked - any snow is almost always shed by 11am.

During today's hike I noticed just how big of a difference it makes. My panels were 100% clear of snow. My goal was a local hill with a radio stations antennae tower at the top. The antennae station is powered by solar. 

Their panels are mounted at, guessing here, ~30 degrees. They were ~80% covered with snow at 2pm. Mine were 100% clear several hours earlier. Being 80% covered with snow at 2pm means those panels will be largely useless until it warms up considerably. That can take many days at this location.

Darker the panel the better. I have some panels with ~ 10% silver coloring instead of black. They don’t shed snow as well.

FWIW
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Miller_Ranch
    Miller_Ranch Registered Users Posts: 54 ✭✭
    #2
    54 degrees



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  • softdown
    softdown Solar Expert Posts: 4,053 ✭✭✭✭
    #3
    What is the time of day? Mine also look like that until at least 10am - following snow. I also have dry snow and unusually bright sunshine. 

    You also have significant shade.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • JRHill
    JRHill Registered Users Posts: 490 ✭✭✭✭
    #4
    I don't really have a choice in the matter because of a poor decision in siting the off grid house we built for retirement. So the frames that I built from 1.5x1.5x.19" 6061 just follow the 10/12 roof pitch (~40d). We're on the north facing side of a steep canyon. If I had exchanged the location of the house to where the garden is located (125') I would've gained a few weeks before and after our solstice 'black out' but it would still last ~8 weeks. And ya know? Those darn trees at the top of the canyon keep getting a bit taller each year.

    But also during this PNW time of the year I could triple the amount of panels for little gain because if the clouds are in the way I can't get much gain from so little sun except for refraction. I just have to count my blessings for 9.5 months of the year for very rarely needing a generator.

    So my 3kW of aging 2010 panels still do a fine job, considering. With all the handwringing about utility prices, shortages and aging infrastructure I spend little time having missed the mark of perfection and instead the blessings which I now consider providential.
    Off Grid. Two systems: 1) 2925w panels, OB VFXR3648, FM80, FNDC, Victron BMV-712, Mate3s, 240 xformer, four SimpliPHI 3.8; 2) 780w, Morningstar 30a, Grundfos switch, controller and AC/DC pump, 8 T105. Honda EU7000is w/AGS. Champion 3100. HF 4550, Miller Bobcat.
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