RV solar systems

Brooks
Brooks Registered Users Posts: 1 ✭
in Off Grid Solar & Battery Systems #1
What is the minimum size cc do I need to get to handle 400 watts of solar panels??
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  • Estragon
    Estragon Registered Users Posts: 4,503 ✭✭✭✭✭
    #2
    It depends on system voltage, and to some extent the location, panel specs, and controller. 

    For 12v in very general case, you could use 400w x 75% for warm panels ÷12v = 25a.  A more conservative approach would be 400w STC output ÷11v deep cycled charging plus a bit of room for temp derating = 40a controller.
    Off-grid.  
    Main 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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  • Jeremy
    Jeremy Registered Users Posts: 5 ✭
    #3
    To determine the inverter size we must find the peak load or maximum wattage of your home. If 400 watts, the inverter size is 400 watts. 
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Jeremy said:
    To determine the inverter size we must find the peak load or maximum wattage of your home. If 400 watts, the inverter size is 400 watts. 
    If you want your inverter to last more than a couple months running at 100% capacity, you size it so sustained loads are only 75% of max. and it's surge capacity is larger than any appliances with motor start up surge (fridge, well pump, HVAC blower)
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Estragon
    Estragon Registered Users Posts: 4,503 ✭✭✭✭✭
    #5
    I think the question was controller output capacity, not inverter.
    Off-grid.  
    Main 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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  • fratermus
    fratermus Registered Users Posts: 48 ✭✭
    #6
    Estragon said:
    For 12v in very general case, you could use 400w x 75% for warm panels ÷12v = 25a. 
    Should we specify that this case leverages MPPT's ability to clamp power if we do get more than expected in some conditions? I'd hate to see someone toast their PWM controller
    2017 Promaster 159" offgrid campervan
    750w:100Ah LFP
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  • Estragon
    Estragon Registered Users Posts: 4,503 ✭✭✭✭✭
    #7
    Yes.  As mentioned, the number is a very general case.  OP hasn't even said what bank voltage is, let alone controller, panel specs, etc.
    Off-grid.  
    Main 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

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