xw-mppt60 vs array voltage

Hi all, I have an xw-mppt60 charge controller that I am hooking up to a 12 volt battery bank. I can't find if the array voltage will be more efficient at a higher or lower voltages with this unit in the manual. My two choices are to hook four 11 amp panels in series at 80 volts or series parallel at 40 volts and 22 amps. Which will give me the best efficiency or does it make any difference. The combiner already exists so I can use either 1 or 2 breakers. The wiring distances to the panels from the combiner are within 15-20 feet and the panels have 10 ga wiring with MC connectors.


  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: xw-mppt60 vs array voltage

    for 12v output your better controller efficiency will be with the 40v arrangement, but you may need to address higher voltage drops in the pv wires as these losses will be 4x as high due to the doubling of the current and the halving of the voltage.
  • RCinFLARCinFLA Solar Expert Posts: 1,284 ✭✭✭
    Re: xw-mppt60 vs array voltage

    Other consideration is if you have a shading problem. The higher voltage stack may afford more shaded panels in bypass. If you can squeeze another hour or so a day out of three panels instead of two panels it may more then make up for slightly lower controller power conversion efficiency.
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