Adding smaller panel input to combiner??

CVN-71CVN-71 Solar Expert Posts: 54 ✭✭
Have four 24v strings going to combiner box. Panels for this are 205w. Can I add two 60w panels at 24v and feed them into same combiner, or do I need to wire separately to the batteries?


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Adding smaller panel input to combiner??

    It all depends on what the specs of the panels really are.
    If the Vmp of the existing panels is 35 and the Vmp of the 60 Watt ones is 17.5 (two in series adds up to 35) then it will work, providing the 60 Watt panels are fused to protect them from being back-fed current above their Isc rating should something go wrong.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Adding smaller panel input to combiner??

    to make sure you got what coot was saying is that it isn't the wattage you are trying to match, but the voltage at the combiner. coot gave an example, but it doesn't need to be exact either as i often advise to be within 5% and others advise up to 10%. one does have to watch that the voltage does not go too low that it does not function well for 10% of 35v is 3.5v and subtracting 3.5v from 35v (31.5v) would be low functionally speaking for a 24v battery bank.
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