What to do with load outputs of multiple charge controllers to one battery bank?

JimGiblet
JimGiblet Registered Users Posts: 1 ✭
in Advanced Solar Electric Technical Forum #1
I have recently installed a very simple standalone solar sytem at my Mum's house.  There are two 350W PV panels each going through their own indiviual solar charge controllers which are then connected in parallel to the 80AH 12V battery.  The load then goes to the house which has just a few 12v lights and a 12v fan running on a composting toilet system.  My question concerns the load outputs of the solar charge controllers.  Each controller has positive and negative for the panels, the battery, and the load to house(lights ect).  Do I need to connect both controllers' load outputs to the house, or just one set?
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  • FoldPV
    FoldPV Registered Users Posts: 3 ✭
    #2
    Interesting question!
    According to my point of view, (I'm not an expert) and seeing my neighbors, they have installed 1 complete set... 
    I mean, that they put multiple systems and connected everything into one...
    But I can't tell you how much power they have... 
    Let's wait for the experts 🧐 Can you share some images?
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #3
    Having multiple controllers is fine with a single battery as long as the settings are the same or close, the battery voltage will regulate the current needed, the transmission to different stages of charge much differ slightly but generally that is not an issue. 

    The loads are better connected directly to the battery, fused with an appropriately sized fuse or circuit breaker. To retain low battery cut off, or any other features, use a relay driven by the load terminals and run the loads though a normally open contact.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    several quality charging sources can reliably be paralleled into a single battery bank.  Not a problem.   I'd not do it with harbor freight gear though.
    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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