Solar attic ventilator

garynappi
garynappi Registered Users Posts: 120 ✭✭
edited October 2019 in General Solar Power Topics #1
I have an AC attic ventilator that has died. I read that a few states no longer allow AC operated attic ventilators but do allow solar. 

My old unit is situated in the eaves immediately above my wall mounted 100 and planned 175 watt panel. I also will have a spare 40 watt that I can connect directly to a "solar" fan which is "designed" to take the output of a solar panel in lieu of going to the CC. This would be cool because it will only work during the daytime if it's possible.

What I need to know is...

The gable mounted fan is located a few feet from where the 40 watt PV will be and the wall is just 1/2" ply with a wood siding on it, what kind of wall mounted box would be correct for the MC4 connectors from the PV? 

I found this one... Any other ideas?

PS, I read all about the controversy involving attic ventilators, in my case, I wholeheartedly disagree.




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Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    In this particular application, I'd probably just cut the mc4 connectors off, and wire into a weatherproof j-box.
    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
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    edited October 2019 #3
    One thing with weather prooflng is to have drip loops.

    Wiring runs down then loops up onto the box. Wires runs that run sideways or down into the box will almost always bring water in, no matter how well you try to seal.

    And, drill a small hole at the lowest point in the box, if water does not come in directly, temperature cycling will condense water inside the box and collect in a puddle and make for a humid interior.

    Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
    Very good tips!
    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
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #5
    garynappi said:
    I have an AC attic ventilator that has died. I read that a few states no longer allow AC operated attic ventilators but do allow solar. 

    My old unit is situated in the eaves immediately above my wall mounted 100 and planned 175 watt panel. I also will have a spare 40 watt that I can connect directly to a "solar" fan which is "designed" to take the output of a solar panel in lieu of going to the CC. This would be cool because it will only work during the daytime if it's possible.

    What I need to know is...

    The gable mounted fan is located a few feet from where the 40 watt PV will be and the wall is just 1/2" ply with a wood siding on it, what kind of wall mounted box would be correct for the MC4 connectors from the PV? 

    I found this one... Any other ideas?

    PS, I read all about the controversy involving attic ventilators, in my case, I wholeheartedly disagree.



    Gary, where did you find that MC-4 entry gland?


    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    #6
    >  the controversy involving attic ventilators

    There is some data indicating that attic ventilators can increase energy use.  But it's a case of taking data involving high powered exhaust fans and then erroneously applying it to the general case (ie, concluding that attic ventilation is always bad). 

    I am available for custom hardware/firmware development

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  • garynappi
    garynappi Registered Users Posts: 120 ✭✭
    #7
    littleharbor2 said:
    garynappi said:
    I have an AC attic ventilator that has died. I read that a few states no longer allow AC operated attic ventilators but do allow solar. 

    My old unit is situated in the eaves immediately above my wall mounted 100 and planned 175 watt panel. I also will have a spare 40 watt that I can connect directly to a "solar" fan which is "designed" to take the output of a solar panel in lieu of going to the CC. This would be cool because it will only work during the daytime if it's possible.

    What I need to know is...

    The gable mounted fan is located a few feet from where the 40 watt PV will be and the wall is just 1/2" ply with a wood siding on it, what kind of wall mounted box would be correct for the MC4 connectors from the PV? 

    I found this one... Any other ideas?

    PS, I read all about the controversy involving attic ventilators, in my case, I wholeheartedly disagree.



    Gary, where did you find that MC-4 entry gland?


    I found it on Ebay item number: 193146853348
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #8
    Thanks!

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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