Solae panel voltage ?

johna
johna Registered Users Posts: 6 ✭
in Solar Beginners Corner #1
When matching the panels to the inverter do I use the operating voltage or the open circuit voltage ? I am using a sunny boy 8000 and it states 600 volts . my panels are 30 operating volts . I will have 32 250 watt panels . should I have more than two arrays . Thanks
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    Re: Solae panel voltage ?

    Have you tried SMA's design tool?

    Array usually is the word used to describe all the panels feeding one inverter/charge controller, I think you mean strings?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Solae panel voltage ?

    Actually you need to pay attention to both Vmp and Voc.
    The 600 Volts is maximum Voltage on the input, and that means Voc with cold temperature adjustment. In other word never should the array exceed 600 Volts.
    The inverter will have an operating range. This will include a minimum start-up Voltage and a somewhat higher value(s) where the MPPT function works best.

    Using the SMA string sizing tool as Photowhit suggests is your best option.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Solae panel voltage ?

    BTW thirty-two panels isn't going to work out.
    The strings have to have equal numbers of panels, and 32 divides up either as two 16 panel strings which would have too high of a Voc or four 8 panel strings which would have too low of a Vmp.

    Normally central GT inverters use strings of ten or twelve. At three strings of ten you'd be running 300 Volts and that may work best here, leaving only two panels leftover. Or perhaps you could buy four more and run three parallel strings of 12. The 9000 Watts would be more likely to keep the 8kW inverter operating at peak.
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