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Choosing the right inverter query

  • 21-04-2021 1:03pm
    #1
    Registered Users Posts: 125 ✭✭ Ballylad


    Regarding choosing the right inverter, I don’t know what to do:
    I have 18 sunpower 280w panels 5.04kw on a 4 kw sunnyboy inverter, currently installing extra 5.4 kw 390w panels. Thinking something like:
    Option 1:
    Leave old 4kw sunnyboy /280w panels alone,
    Install fronius 6kw inverter with smart meter for export limitation, hoping this will keep export to less than 6kw, by allowing it to alter the fronius output so as total output/export of both to less than 6kw.
    Option 2:
    Keep sunnyboy/old panels alone,
    Install fronius dual MPPT hybrid 6kw inverter with export limitation, have it future proof for battery addition at later date (more expensive inverter)
    Option 3:
    Get a 8.2kw dual MPPT single phase fronius inverter with export limitation, take down sunny boy inverter and add the 18 280w sunpower panels and 14 q cell 390w panels, is this possible with dual MPPT fronius, it’s on midsummer uk website
    I have two Zappi for charging 2evs, heat pump and annual consumption 23000kwh so very little is exported, hoping to add battery next year if prices reduce. Any input appreciated. No grant required.


Comments

  • Moderators, Sports Moderators Posts: 16,081 Mod ✭✭✭✭ slave1


    Ballylad wrote: »
    Option 3:
    Get a 8.2kw dual MPPT single phase fronius inverter with export limitation, take down sunny boy inverter and add the 18 280w sunpower panels and 14 q cell 390w panels, is this possible with dual MPPT fronius, it’s on midsummer uk website

    I would not do this, firstly you got to watch the voltage so you are not overloading your Inverter.
    More importantly, AFAIK your panel's output are limited to the lowest panels so if that's the case your new 390w panels will be limited to 280w.
    The reason I'm not sure is because you are talking about having them on a separate string but again you could be caught anyhow with too much voltage...

    Panels are cheap, have you considered selling your 280's and getting new ones.

    With combined 10.44kWp there may be paperwork involved in getting FIT as ESB limit things to 6kW export.
    Others may expand on this point


  • Registered Users Posts: 125 ✭✭ Ballylad


    slave1 wrote: »
    I would not do this, firstly you got to watch the voltage so you are not overloading your Inverter.
    More importantly, AFAIK your panel's output are limited to the lowest panels so if that's the case your new 390w panels will be limited to 280w.
    The reason I'm not sure is because you are talking about having them on a separate string but again you could be caught anyhow with too much voltage...

    Panels are cheap, have you considered selling your 280's and getting new ones.

    With combined 10.44kWp there may be paperwork involved in getting FIT as ESB limit things to 6kW export.
    Others may expand on this point

    Thanks for reply, pretty certain voltage limit is ok, no intention of going over 6kw limit , not much interest in FIT either, use what you produce best option and that’s what I do at the moment, will be getting electrician to install, just wondering which option is better long term.


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