8x 100watt panels vs 2x 400watt panels

lightsky
lightsky Registered Users Posts: 13 ✭✭
edited December 2020 in General Solar Power Topics #1
I have seen many installations with the above setup, I would like to know it benefits before buying my panels.
What are the advantages of using many small wattage of panels against using few higher wattage panels of say 12volt ?
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  • New_Mexico_Will
    New_Mexico_Will Registered Users Posts: 107 ✭✭
    #2
    Take it from someone using 16 x 100 watt panels-get the bigger ones.

    I got mine new for 25 cents a watt, which is why I went that way, but it is a lot of extra wiring (potential failure points), extra work and materials mounting them, etc.

    Even at such a cheap price, I wouldn't do it again.  The only good reasons to use smaller panels are if you physically can't lift the larger panels or have tight space requirements. 


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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    edited December 2020 #3
    lightsky said:
    I have seen many installations with the above setup, I would like to know it benefits before buying my panels.
    What are the advantages of using many small wattage of panels against using few higher wattage panels of say 12volt ?
    I mostly agree with Will. 

    There can be some advantages. 400 watt panels will likely be very high voltage. 

    To use high voltage panels effectively, you will need a MPPT type charge controller.
    You would need a combiner box for 8 panels to meet code. so there is some additional expense there, but they are likely panels designed to charge 12 volt battery bank with a less expensive PWM charge controller.
    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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  • New_Mexico_Will
    New_Mexico_Will Registered Users Posts: 107 ✭✭
    #4
    Just to clarify, Photowit meant an MPPT charge controller, not inverter.

    Great point about the higher voltage.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #5
    Thanks, I corrected it, I was just helping someone with an all in one inverter/charger...
    ...easy to get dizzy these days, going back and forth...
    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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  • MichaelK
    MichaelK Registered Users Posts: 235 ✭✭✭
    #6
    Besides NMW's comments about extra wiring and potential failure points, which is completely correct, your cost per watt for the 400W panels is likely to be substantially less the the cost per watt of 12V panels.  In my own recent purchases the the ratio is about 4:1 in favor of higher voltage grid-tie panels.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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