Outback GVFX 3648 questions

solarix Solar Expert Posts: 713 ✭✭
I've been trying all morning to figure out the Outback system. Want to put in a 3.8kW array on a Outback GVFX grid-tie inverter that has battery backup. Both the outback website and the catalog I have are real vague as to what is needed. Even though the inverter has a charger I think I get that it needs a FM60 added in order to do MPPT charging - is that right? I guess I should just get the preassembled FLEXware 500 system but it seems like it costs a lot more.

Also, how do these systems connect to the grid? Since they continue to generate during outages, they either need to drive dedicated loads or is a relay needed to disconnect the grid automatically? Here, the local utility is very big on having a disconnect switch to shut you down if needed. How is that accommodated?


  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Outback GVFX 3648 questions


    The OutBack GVFX 3648 product is a grid-interactive inverter/charger. As a “stand-alone” product, it does not include a solar charge controller. An FM60 or an FM80 charge controller would make sense, as either can be networked with the G-inverter for improved U-I performance. For optimal performance, you’ll also need a Hub and a Mate.

    Applications tend to be user-specific. Accordingly, all of the DC components (wiring, circuit breakers, shunts, etc.) must be specified and ordered separately. Similarly, all of the AC components (wiring, breakers, surge protector, etc.) must be specified and ordered separately.

    The FLEXware 500 is a practical integration solution for a two-inverter system, or initially as a single-inverter system with room to grow.

    See: http://www.outbackpower.com/products/integration_hardware/system_enclosures/

    Note that it’s often a delicate balance to spec a PV array that can supply a high enough charging voltage in the summer (hot array = low Vmp) but also not exceed the charge controller’s input voltage limit in the winter (cold array = high Voc). See if you can shoot for an array voltage in the ~87 Vmp STC to ~92 Vmp STC range. You may also need a PV combiner box and circuit breakers.

    See: http://www.outbackpower.com/pdfs/spec_sheets/flexware_pv.pdf

    The inverter/charger is connected to the grid via the bi-directional “AC in” connection. These terminals are typically connected to a breaker in the main power panel. Each GVFX inverter is individually certified to UL 1741, and it automatically disconnects the “AC IN” terminals in the event of a grid failure (“anti-islanding”). Your utility may also require a separate AC disconnect switch.

    However, the inverter will use the battery bank and PV array to continue to power priority loads connected to the inverter’s “AC Out” terminals. See the attached block diagram for a basic functional description.

    Jim / crewzer
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Outback GVFX 3648 questions

    i think you've gotten slightly confused as to the nature of the built-in charger on the inverter. it is basically a 120vac utility connected quality battery charger and you cannot connect pvs to that charger to charge your batteries with. that charger is not a solar charge controller and will not take the place of one, so in order to charge with pvs one needs the charge controller.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    Re: Outback GVFX 3648 questions

    OK, so I need to rearrange my loads so that all the critical ones are dedicated to the inverter's AC OUT. Up to the limit of the inverter's rating of course. Thanks for the help.