Panel Angles

Thomas
Thomas Solar Expert Posts: 291 ✭
in Solar Beginners Corner #1
I was just reading some about optimum angles and I wondered if mine were set up good enough.
My mobile home is oriented about 80'E 280' W end to end. I have my panels parallel to the structure for about 10'E of South. 30'27'29'//91'8'25'= My co-ordinates. The :grrpanels themselves are at about 40/60 winter-time angle- more looking out than up. Today was the first day of sun after about a week of rain and I was getting 105%(252w, 20Amps@12.25v)approx. at apogee. Would it be worth it to tune the array better?
Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: Panel Angles

    So do you live in the snow belt?
    Yeah, I know you gave co-ordinates, but I'm not awake enough to investigate.
    If you are in the snow belt, vertical mounting gives often best overall output, as no snow collects on them, and you get reflected light off the snow covered ground, as well as from the sun. Then tip them up for Summer.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Panel Angles

    wayne,
    wow, you must be half asleep as if you look to the upper right of his post it says baton rouge la and that's in the south so no snow belt there. hurricane belt maybe.

    thomas,
    it may be possible to tweak it, but from your results, if it ain't broke why fix it?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #4
    Re: Panel Angles
    niel wrote: »
    wayne, wow, you must be half asleep as if you look to the upper right of his post it says baton rouge la and that's in the south so no snow belt there.

    Hahaha Yes Niel, ya got me good. lol I've been participating in a sleep deprivation study for one (me, by me, and against my will) :cry: Nite all:D
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #5
    Re: Panel Angles

    Just wondering if going out there and adjusting it just that little bit more would be worth the pain. I gather no, not really.

    Any one know about what happened to voltage regulation/management at the panel point. When solar was new it was all the competition. Like speaker Bose bridges etc...Like the smaller Brunton or ICP Global folding cells have on a larger scale. I really think I know that is missing today and could really help out some chargers and inverters. What would happen if Right out of the gates all of ones panels were simply regulated to a common voltage around say 15v, the standard diversion load divert point. One thing is the amps would increase nessisarily...just thinking. I ran across Tigo and solar majic. they seem like expensive and rather sophisticated prep cooks.
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: Panel Angles

    one can always tweak the angle, but it changes constantly throughout the year. many will go with their latitude +15 degrees on average. for the winter you want to make it steeper and in the summer you want to make it flatter. to get it dead on for solar noon is not what you want as the sun spends more time lower in the sky. this isn't too much of a problem in the summer as the sun makes a wider swing across the sky so it will stay in the neighborhood just below the solar noon angle. the farther north one is the less that is true. the winter angle is much steeper and has more time lower in the sky. it is hard to say what may be best for you and it is also weather dependent.

    one point here, if i read you right, is that you aren't aimed due south and the sun is lower in the sky when it is aimed off of due south. lower in the sky equates to a slightly higher tilt angle for the pv. 0 degrees is flat or horizontal just for clarity.

    i think the angles you have are ok, but it's more a question of when is best to change from one to the other for you due to seasonal adjustments.
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #7
    Re: Panel Angles

    You don't really lose much at small angles. The difference a function of the sine of the angle. At 90 degrees you get 100%, at 80 degrees you get about 98%. You don't start getting a drastic falloff until around 60 degrees, which would be around a 15% loss. Actual power produced will fall off somewhat faster, as cell reflectance etc start entering into it, but basically anything less than 10-15 degrees is not worth worrying about much.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #8
    Re: Panel Angles

    I do notice a signifigant decrease in output in the beginning of late afternoon, the panels are situated about 15' off of E-W axis. I did get some Trig in college, one semester, Can I determine my location to a sig. fig. of 15'..oh yeah I can go to Office Depot and get a protractor.....
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #9
    Re: Panel Angles

    Niel, I remember reading somewhere about the Absolute Supremacy of morning sun....if you can neglect the rest...I currently have 5W allocated to it! The article(in a magazine, not a blog) was about battery charging for overnight daily grid-tie use. How long do batteries last is such a function, if one can get it rolling...
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #10
    Re: Panel Angles

    Administrator, I found some trig tables, I no longer have my text. I have forgotten how to use the buttons on my calculator, this may be a new application.:blush: 90 Deg. being square up w/ the sun directly, not relative to horizon/earth. That is the only way I think 1.00% sine is full power, this table shows .86 % @ 60 Deg. to correlate the finding to your statement, or validate it, depends.(on the protractor!):cool:
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #11
    Re: Panel Angles

    Other factors enter into it beside just the angle. Usually in most places their is more dust/cloud/pollution whatever in the afternoon, that can have a significant effect. That is why you will often get better overall performance by aiming the panels 5 to 15 degrees to the East.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #12
    Re: Panel Angles

    I have noticed that I do not notice a constant for the change in my solar performance/output. Pollution and other factors...I know U.V. is a poor indicator/forecaster, and I have read of some panels that can do that, I do not know how true it is. Good day or Bad day, thats all, no reasons really, that is kind of difficult untill a level of performance is reached I guess. I am happy enough w/ out a mechanical MPPT, even if it is hard not to fiddle w/it/them. I have changed the vert/horiz angle only 3-4 times since Aug.
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #13
    Re: Panel Angles

    basically, as both windsun and myself have said, you are probably fine with what you have for angles.

    just to clarify that windsun meant 5 to 15 degrees east of south.

    " I am happy enough w/ out a mechanical MPPT, even if it is hard not to fiddle w/it/them."
    what in the world is a mechanical mppt? if you are referring to an mppt controller, then please do understand that this is not mechanical and is actually sophisticated electronics for the purpose of regulating electric from pvs. if you are referring to a tracker then i agree with you that you don't need it.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #14
    Re: Panel Angles

    mechanical mppt is making sure tha sun angle is at maximun all the time, sun tracking I have heard of, auto-maticallt follows the sun. a mechanical/manual one is me..haha..funny right?
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #15
    Re: Panel Angles

    thomas,
    you are still confused here as mppt is not tracking of the sun. it stands for maximum power point tracking, but it is tracking the most efficient use of a pv electrically and not physically by position. it is not the kind of tracking you are thinking it to be.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #16
    Re: Panel Angles

    I am confused by mppt now, so....I cant afford a mppt or a solar tracker anyway.
    what about solar pre regulation? is raw open circuit electricity good enough? can it be made better, would all chargers be able to benifit? how would the chargers behave? simply altering the pv output at junction up there where they are, from ie 240w 17.7v13.71a to the equivilant @ 14.5 volts240w 16.55aI know this is crude math but we are talking about a 18% decrease in volts and 18% increase in amps, of course the consequenting watts remain the same...so there is no increase in power. I believe that at the charger point the math is the volts at the charger are going to be 17 and the amps are going to be 16.55 for an increase in output from the charger 288 w power out for charging. This may make some part of the line warm, or even stress the charger or panels, if the wire is all that gets warm....anyway I thought i would run this by yall before i tried it.[if i could]
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #17
    Re: Panel Angles

    a controller is a regulator circuit, be it a pwm controller or an mppt controller. go with what you feel is best for you. you won't want pvs that are in odd areas for their vmp when using a pwm style controller. for 12v battery use with a pwm controller the pvs should have a vmp of about 17v to about 18.5v. too little and it may not deliver a charge to the batteries during hot weather and if too high it will just waste power.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #18
    Re: Panel Angles

    Thomas, I'll try to explain MPPT controllers for you. (For simplicity in this explanation, we'll ignore all system losses etc.)
    Lets assume you have a solar panel capable of putting out 5 amps @ 36 volts at it's most efficient point electrically. Now you take that panel and connect it directly to your 12 volt battery (or through a PWM controller). The battery instantly loads down the panels to say 12.7 volts, but the amperage stays at 5 amps. What the panel is CAPABLE of putting out is 5X36=180 watts. But you have reduced that to 12.7X5=63.5 watts. You've just installed a system that's throwing away over 115 watts!
    Now, replace your PWM controller with a MPPT controller and everything changes.
    Your MPPT controller, electronically finds that the Max Power Point of your panels is 36 volts, so it only loads the panels to that voltage. Thus what's going into your MPPT controller, is 36VX5A=180 watts. The MPPT controller, using it's electronics takes that 180 watts, and like an AC transformer, drops the voltage down to the battery voltage of 12.7, and since it has 180 watts to work with, it increases the current going to the battery to over 14 amps, even though the panels are only putting out 5 amps! This is the beauty of the MPPT controller and what it does.
    Hope this helps you grasp the understanding. (Keep in mind that this is a very simplified description, ignoring all system losses etc for simplicity)
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #19
    Re: Panel Angles

    You can zoom this down to a satellite photo and and find your house then you'll know whats happening through the Sun's Path all day.. You can change the date and see it any time of the year. There a slider where the time is and you can move the arc of the sun to any time you want.

    I set it for Baton Rouge for you.

    http://suncalc.net/#/30.4583,-91.1403,11/2011.02.27/22:14
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #20
    Re: Panel Angles

    @ blackcherry; Awesome link. Thanks a lot for sharing!
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #21
    Re: Panel Angles

    It's easy to find the Solar Noon in the box at the left and then look at your output. My solar noon is 12:58, my array peak is at 12: 45 and move the slider time, so I know I couldn't help the azimuth much. I am fixed with that. I can adjust my panel tilt some. When you start playing with the dates , you can find out a lot about what to expect, at different time of the year. There is a arc line that moves as the dates change, as the arc gets smaller the sun moves more overhead.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #22
    Re: Panel Angles

    I try to discover what is best for me all of the time, including Solar Voltaic Technologies, it is very interesting, to say the least, somewhat compelling too.

    Do they make a MPPT accessory for a pwm controllers? You know for budgeteers? That sound like the observation+learned facts=the guess about a line reg/amp booster. Does pretty much the same thing.

    Solar Flex chargers do it differently, would you say a different charge algorithm? I think that is what I am trying to accomplish manually..w lvd/weather

    I have a stick I can use to find my noon and parallel with panels Parallel Motion protractor
    I am all googled out, a little burned ot on satellite imagry right now, I just got off a binge finding everywhere I HAVE EVER BEEN!!
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #23
    Re: Panel Angles

    I am at Latitude 48 degrees and off grid I set my angle for max winter harvest +15 degrees . I know that if you grid tie up here due to the long summer days most people set there angle( if possible )to the -15 degree for max electric production. I don't worry about adjusting my angle, summer brings more KWH then I can use!:D
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #24
    Re: Panel Angles

    thomas,
    they do not make accessories for converting a pwm controller into an mppt and i'm quite sure that if some type of thing ever came to be that it would cost more than the mppt controller in the first place. would you ever ask your car dealer to change your car into a truck? of course not as you buy what you need in the first place. if it costs more to do so, then that can't be helped, otherwise you live within yours means and get what you can pay for.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #25
    Re: Panel Angles
    silvertop wrote: »
    I am at Latitude 48 degrees and off grid I set my angle for max winter harvest +15 degrees . I know that if you grid tie up here due to the long summer days most people set there angle( if possible )to the -15 degree for max electric production. I don't worry about adjusting my angle, summer brings more KWH then I can use!:D

    let me correct you here as lat +15 is NOT the optimal winter setting as it is the equinox optimal setting due to the fact the sun will be at or lower in the sky than the solar noon angle is. the peak height in the sky is not the optimum and you will see that your lat +15 is actually far higher than what the sun will get to during the time of winter solstice.

    for example i am at 40 degrees lat. that is the highest the sun will be in the time of the equinox and during other times of the day the sun is lower to the horizon meaning a higher angle is warranted to take advantage of the other times of day during the equinox. hence, +15 degrees became a good compromise to collect more of the sun at the time of the equinox. now during winter solstice here the addition of another 23.5 degrees will be added to the lat angle for solar noon bringing the solar noon peak angle to 63.5 degrees. the other times during the day the sun is lower to the horizon than that and warrants angles that would be steeper for general collection and this does not include the possible solar reflections that can occur too. now the 63.5 degrees is a worst case peak so you may wish to design for the angle 1 month off of the winter solstice to average it out and not have to change angles often, but it will still be that month's solar noon angle +15 degrees. for me that about 60 degrees to which i would add 15 extra degrees to cover the angles presented during the day the sun is lower to the horizon for about 75 degrees total.

    now for you just add 8 more degrees as you are north of me by that much for 83 degrees optimal. you are now at 63 degrees and are losing power during the winter solstice. obviously if you hit 90 degrees that you can't go any farther than that or you would aim into the ground. if it is a case of the solar noon angle for the winter solstice then you could put it anywhere between 90 degrees (vertical) and the peak angle off of the horizon of 15 degrees (75 degree pv tilt) and still get lots of sun production. most angles are a compromise anyway, but i had to inject that you aren't optimum for winter at all.
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #26
    Re: Panel Angles

    I guess all fixed adjustments are a compromise, adjusting between 75 degree and 90 degree is a bit too much for me I dont want to kill summer production that much. + 15 degree is a very much accepted compromise and the summer is still very long and productive.
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  • Thomas
    Thomas Solar Expert Posts: 291 ✭
    #27
    Re: Panel Angles

    My panels are now flat out[+-15'] for the summer here in Louisiana, I think it is a full 45' change for the winter here.
    Always troubleshoot with adequate sunlight.  Hi Ho Hi Ho
    2.3kW [10] Enecsys SMI-240-60 micro inverters

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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #28
    Re: Panel Angles
    Thomas wrote: »
    My panels are now flat out[+-15'] for the summer here in Louisiana, I think it is a full 45' change for the winter here.
    No matter where you are on the planet, the difference between the sun's apparent altitude at solar noon on the winter solstice and on the summer solstice is 47 degrees, and that range is centered at the angle of your latitude. Of course, closer to the poles than the arctic/antarctic circles, that puts the sun below the horizon at solar noon on one of the solstices.
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  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    #29
    Re: Panel Angles

    My location is supposed to be like 16 for summer, 23 for spring & fall, & 54 for winter..

    The year round number is 26 degrees and I managed to come up with 25-27' for my panels.. I may just set and forget..

    Our winter here in South TX is like maybe a 3" of snow for the entire season..
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #30
    Re: Panel Angles
    ywhic wrote: »
    My location is supposed to be like 16 for summer, 23 for spring & fall, & 54 for winter..

    The year round number is 26 degrees and I managed to come up with 25-27' for my panels.. I may just set and forget..

    Our winter here in South TX is like maybe a 3" of snow for the entire season..
    Why so much more difference between spring/fall and winter (31 degrees) than between spring/fall and summer (7 degrees)?
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  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    #31
    Re: Panel Angles
    ggunn wrote: »
    Why so much more difference between spring/fall and winter (31 degrees) than between spring/fall and summer (7 degrees)?

    Don't know where I got 16 & 54 from sorry.. I may have crossed up my NJ location and TX location numbers..

    Macslab numbers.. for TX property.. (@ 30.XX Lat)
    25.9-26.42 year round fixed tilt
    6.9 for summer
    46.05 for winter (50.7 for max isolation winter numbers)

    Leaving my at fixed tilt of 26 deg angle..
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