Sizing panels to controller

mountainman
mountainman Registered Users Posts: 439 ✭✭
edited June 2019 in Caravan, Recreational Vehicle, and Marine Power Systems #1
I currently have 400 watts for camper dc loads. now I have the chance to get 4 310 watt panels. This will be for a 24 volt inverter system.  For television fans phone charger etc. I'll b using a150 volt cc. 4 in series GC batteries. Panels 2 p 2 s . 100 foot on 10 awg remote array 4.52 volt drop but that's what I have. What amp mppt cc would fit. And what amp hr batteries would i need? I realize sizing is normally by loads. But with  my finances this is how i have to do it.
2kw array 6 345 q cells  make sky blue 60 cc
 6 230ah GC @36 volts 
18 amp accusense charger. 3650 champion 
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    1200÷24v=50a minimum, but I'd go bigger. Actual current max would likely be less, but IMHO it's better to go for a bit more capacity to run cooler.

    4 x GC batteries would be ~225ah@24v.  You could maybe do 4 x L16s for ~350ah depending on the application, other charging sources, etc.
    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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  • mountainman
    mountainman Registered Users Posts: 439 ✭✭
    #3
    So you'd suggest a larger than 50 amp cc. Since you suggest a 350 ah Battery bank . I suppose 1240 watts would normally put out 35 amps~?  Thinking ahead.  wouldn't i be able to add 2 more panels with a 80 amp cc? 1860 watts. 1860÷24 =77.5.    Then if I used 8 GC batteries of 208 ahs. 416 x 29÷.77x .12℅ charge rate 1880 watts. 1250 watt hours on 4 day reserve.   Or 4 l16  with out having any in parelel  say 435 ahs that would put at about 11.5℅ charge rate.t hat give me about 1300 watt hours with a 4 day reserve. Am I doing the math right. Thoughts?
    2kw array 6 345 q cells  make sky blue 60 cc
     6 230ah GC @36 volts 
    18 amp accusense charger. 3650 champion 
    · Share on Twitter
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
    Your math looks about right.

    Doing a single string of L16s has advantages (eg fewer cells to check/water), but 2 strings of GC has the advantage of being able to stay somewhat lit if/when a battery goes bad.  GC also tend to be more widely available, easier to lug around, and may be a bit cheaper per WH.
    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

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