Solar System Installation - Advice Needed for PV System Details

I am having following solar system installed in our home by the reputable solar installar listed on the SolarQuotes.

  • 10kW Fronious Symo inverter
  • 31 x Qcell QMaxx 390W panel (20 panels on north facing roof, 11 panels on south facing roof)
  • System size and orientation is not an issue. Due to the limitation with our roof this is the only option.
  • No shading issues

The installation is partially completed and due to be completed on comming Monday.
While reading the documentation left (Your PV Systme Details) by the installer, i found following:

  • MPPT/Input 1: 11 Panels x 2 String
  • MPPT/Input 2: 9 Panels x 1 String

Now, my question is, after reading few articles on google on those solar installation sites, i was under the impression that the solar panels with the same orientation are usually groupped (or Stringed) together, unless this is not physically possible. As we are installing 20 Panels on North facing roof and 11 panels on South facing roof, i was under the impression that the strings would be configured following:

  • MPPT/Input 1: 10 Panels x 2 String
  • MPPT/Input 2: 11 Panels x 1 String

However, based on the configuration shown on the installers document, there will be 2 Strings of 11 Panels which means the panels with the South and North orentation will be on the same String. Google search suggests that this may cause performance issues.

I have asked this question to the solar installer through email, but as its weekend i do not think i will get the answer by Monday. And as the installers are comming back on Monday, i would not have much time to discuss about this issue. So i was wondering if anyone knows if this configuration is normal, or if i should contact them first thing in the monring on Monday, to have the String configuration changed.


The installer responded that the configruation is:

  • MPPT/Input 1: 11 Panels x 2 String (11 South Panels and 11 North Panels)
  • MPPT/Input 2: 9 Panels x 1 String (9 North Panels)

They also commented that 10 + 10 north panels would have been easier for the installers. But 11 + 11 wouldn't impact the efficiency of the north panels as both north and south strings are seperate string. It doesnt really make sense to me… Is this correct?

I asked for an independent professional review of the proposed String arrangements. Then the installer agreed to install the panels 10 + 10 North and 11 South. Installation is now complete.

Thanks for your input guys.

Poll Options

  • 1
    Yes, This is normal. You can sleep now.
  • 3
    No, This is NOT normal. Talk to them first thing in the monrning on Monday.
  • 1



    Pretty sure your assumption is correct and it should be 2x10, 1x11. Likely just a typo/error on the documentation. Though it's a bit useless putting the question on here if you've already posed the question to them. Patience is a virtue (that not many people seem to have).


      Thanks for the tip :D I just wanted to know what is right as i am not an expert with solar system. Just in case the installer gives me the answer that is contrary to my understanding. If what i am understanding is right, i would be able to raise complaint to the installer, so i can discuss with them before the installation is completed. I hope its just error in the documentation too.

  • +1 vote

    It would be a typo as they need an even number to parallel your string on the north.
    But why are you getting south facing panels? Unless they are on tilts


      If they have a north west roof orientation and the north roof is full, south roof mounted panels are better than no panels
      You also don't know where in Aus they are located which makes a difference of the efficiency of south facing panels.