My panels are patially shaded.

bc buck
bc buck Registered Users Posts: 59 ✭✭
in Solar Beginners Corner #1
I messed up on my install. I fabricated mounts to tilt my panels at 42 degrees. I screwed them down between ribs of roofing material and looks like a clean professional job. Now two of the three Kyocera KD 145sx-ufu in series are 25% shaded from panel in front of it. Dont really want to get on the roof till Spring to remount panels. How much power loss should I expect till Spring.
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #2
    The shaded panels will output near zero useful current during the times they are shaded.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #3
    @BB - assuming the panels are mounted in landscape mode, is it possible he might get around half output, or would all the cells be wired in one series string per panel?
    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
    · Share on Twitter
  • DConlyGuy
    DConlyGuy Registered Users Posts: 80 ✭✭
    #4
    as bill said a shaded panel is pretty much useless, even one shaded cell can bring a panel down 
    600 watts of solar panels,Epever 30 mppt , 2 PWHR12500W4FR battery's in 24 volt setup
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #5
    These cells all are in parallel (it looks like 36 cells in series for Vmp~18 volts). You cannot limit shading to a subset of cells and reduced the effect of the shading.

    Conceivably, you could put the three panels in series with an MPPT charge controller on a 12 or 24 volt battery bank. And if you limit the shading to just once 9 cell vertical (or horizontal) row--That would reduce the panel Vmp to ~13.5 or ~9 volts (bypass diodes, assuming 4 of them, could be just 2 also--you need not open j-box to see). But I suggest that running current through bypass diodes for long periods of time is not great either (diodes get hot, very little cooling in a solar panel J-Box, hot diodes will eventually fail).

    Otherwise, there is nothing you can do that will really help other than "removing the shade".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • bc buck
    bc buck Registered Users Posts: 59 ✭✭
    #6
    BB. said:
    These cells all are in parallel (it looks like 36 cells in series for Vmp~18 volts). You cannot limit shading to a subset of cells and reduced the effect of the shading.

    Conceivably, you could put the three panels in series with an MPPT charge controller on a 12 or 24 volt battery bank. And if you limit the shading to just once 9 cell vertical (or horizontal) row--That would reduce the panel Vmp to ~13.5 or ~9 volts (bypass diodes, assuming 4 of them, could be just 2 also--you need not open j-box to see). But I suggest that running current through bypass diodes for long periods of time is not great either (diodes get hot, very little cooling in a solar panel J-Box, hot diodes will eventually fail).

    Otherwise, there is nothing you can do that will really help other than "removing the shade".

    -Bill
    Bill do you think diodes and panels would be OK till March. I hate to take chance in below freezing weather here in Missouri.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #7
    Are the panels in parallel?

    Is this a 12 volt battery back?

    If yes to both questions, then there should be no problem. The shaded panels just will not supply any useful current.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • bc buck
    bc buck Registered Users Posts: 59 ✭✭
    #8
    BB. said:
    Are the panels in parallel?

    Is this a 12 volt battery back?

    If yes to both questions, then there should be no problem. The shaded panels just will not supply any useful current.

    -Bill


    3pc 12v panels in series using MPPT charger on 12v bank.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #9
    Not my favorite for shade. Cold weather will help the diodes.

    And if any panels fail, there is always the mfg's warranty.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter

Categories