Why are Off-Grid Inverters more than double price of Grid-Tie Inverters?

YSPYSP Registered Users Posts: 1
I find it interesting that MPPT Solar Grid-Tie inverters less than half the price of Off-Grid Inverters. For example, a MPPT SMA 7.0 kw cost about $1,400. While a Schneider Conext xw+ 6.8kw is over $3,000 (Off-Grid), Radian 8kw is $3,800 and even a SMA Sunny Island is $3,600.

I would think without an MPPT mechanism, you have a simple battery voltage range. I would think it would a lot more simpler to make such an inverter instead of one with MPPT plus UL 1741 (Grid Detection) features.

Any ideas that would drive up the price of Battery inverters so much?


  • 706jim706jim Solar Expert Posts: 476 ✭✭✭✭
    Possibly the number of grid tie units compared to stand alone?
    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 29th year.
  • clockmanfranclockmanfran Registered Users Posts: 92 ✭✭✭
    A Grid Tied inverter is a slave to the main supply it is connected to.  ie, it sincs to the HZ and the preset voltage range.

    Also as already mentioned GTI's are made by the thousands in big batches.

    A serious Off Grid inverter has to give a stable HZ and a stable voltage under loads and handle power of say 15kW for short time periods.
    It also has to handle very large surges.

    My Ozinverter has several GTI's connected to it and these back feed through the Inverter, H Bridge design, and charge my batteries.

    If you make your own 6kW OzInverter, then it can cost as little as $700, even less if you scavenge parts and totoids etc.

    Everything is possible, just give me Time.

    The OzInverter man. Normandy France.

    3off Hugh P's 3.7m dia wind turbines, (12 years running).  ... 5kW PV on 3 Trackers, (8 years) .... 14kW PV AC coupled using Used/second hand GTI's, on my OzInverter created Grid, and back charging with the AC Coupling and OzInverter to my 48v 1300ah batteries. 

  • softdownsoftdown Solar Expert Posts: 3,609 ✭✭✭✭
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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