Best angle for east and west panels?

softdown
softdown Solar Expert Posts: 3,896 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
I'm at 37 N Latitude if that matters. 37 degrees is a "broad rule of thumb" for southerly panels.

I just can't seem to recall the best year around production for east and west panels. PV watts has changed. Think I recall that it used to allow computations for easterly and westerly panels.
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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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #2
    The new NREL PV Watts will allow Azimuth, and Array tilt to be entered. You can run each array independently.

    And, here is some additional reading:
    http://solarpanelsphotovoltaic.net/find-best-solar-panel-angle-tilt-angle/

    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #3
    From the article and right off the bat: "In general a steeper slope is preferable during the summer as the sun will be higher in the sky."
    I think this may be poorly worded.

    Other than that, the article is pretty useful for orientation of south facing panels.

    Last years edition of PV Watts made it real easy to compute angles for east and west panels. I'll give it another look as it may simply be "buried" a bit now.

    EDIT: New edtion of PV Watts is likely better than last years...after you grow accustomed to minor changes.

    For me: Easterly panels should be ~15 degrees.
    Westerly panels should be ~ 35 degrees
    Westerly panels deliver ~15% more energy than Easterly panels

    CONCLUSION: Very worthwhile to do inputs for easterly vs westerly panels. This is somewhat intuitive....just thinking about it.
    Vic wrote: »
    The new NREL PV Watts will allow Azimuth, and Array tilt to be entered. You can run each array independently.

    And, here is some additional reading:
    http://solarpanelsphotovoltaic.net/f...le-tilt-angle/

    Vic
    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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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #4
    softdown wrote: »
    From the article and right off the bat: "In general a steeper slope is preferable during the summer as the sun will be higher in the sky."
    I think this may be poorly worded.

    EDIT: New edtion of PV Watts is likely better than last years...after you grow accustomed to minor changes.
    soft..,
    Sorry about the Link, above ... last night, I did not more than abut 10 seconds to review what was written at that site, did not have the time, then.

    Yes, in general, the "information" could be more clearly written, and the quote that you pulled from there, is simply wrong for most of us on this planet.
    In general, for Summer months, the PV modules should be tilted less -- ie, be more flat. The correct tilt information is stated later in the text.
    There are a number of strategies in choosing the proper tilt for fixed-tilt arrays, based on what time of year one wants/needs the maximum amount of PV production. This tilt preference can easily change, when one discovers Air Conditioning, and so on.
    And, yes the newest PVWatts calculator, is actually somewhat better, in many regards, than was Ver. 2, especially considering the greater precision in Location and WX data, etc.
    Vic


    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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