Help: AC Coupling or Mini Offgrid system with my Micro-Inverters

Braiden
Braiden Registered Users Posts: 3
in Grid Tie and Grid Interactive Systems #1
Hi

I need your advice because I need your help choosing between two systems

I have right now a grid-tie 5KW micro inverter system (Enphase) 20 x 250w.

I want a battery backup in case of a real emergency for many days without power.

Right now I order a Conext SW4024 and a Industrial battery 12-85-13 of 24V 627ah because the price was very good, because I live in Puerto Rico.

I'm thinking two system
1 System: AC Coupling using 2500W of my panels and Conext SW4024 (I know is not tested by many people but it suppose to works) with Diversion Controller and Diversion load.
2 System: Take 6 to 8 of my 250w panels disconnect the enphase and install an Off Grid system with the Conext SW4024 and a Charge Controller

My concerns are
- I don't want to lose too much energy to sell or to use with my devices.
- AC Coupling with SW4024 or any other inverter is new to my installer.
- Question: Is there any other alternative to eliminate the Diversion Controller and use a system that disconnect the micro-inverters when battery is full?

I will appreciate all your comments and help.
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Comments

  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #2
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters

    You live in Puerto Rico so I guess that hurricanes are your biggest threat. What are you going to use to charge your battery if your panels are blown away or damaged ??
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  • Braiden
    Braiden Registered Users Posts: 3
    #3
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters

    Well I hope my panels will not suffer damage but I have also a small gas generator.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #4
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters
    Braiden wrote: »
    Well I hope my panels will not suffer damage but I have also a small gas generator.
    Ok, then set up a mini grid, if you think it is cost effective to include them in your plan. Point is, don't put all your eggs in one basket or all your planning will be for not.

    The last time I had a long term outage the city lost all power to the sewer pumps and it backed up into my house. All I needed was a valve to shut it off, something I didn't have then, something I didn't plan for. I had plenty of electricity. I am sure next time it will be something else.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #5
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters

    Solar PV does not need a diversion load. When the batteries are full, start manually shutting down the PV. It's not an everyday thing, if the grid is down, it's not likely you will be away at work that day.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #6
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters
    Braiden wrote: »
    - Question: Is there any other alternative to eliminate the Diversion Controller and use a system that disconnect the micro-inverters when battery is full?

    Most inverter/chargers have a multifunction relay that can be programmed to come on or off based on different events in the system. I'm guessing that the Conext also has such a relay. So it would just be a matter of programming it to turn the relay off at high battery voltage. Then connect the microinverters' output through this relay. During an outage, once the batteries are charged the relay will be constantly clicking on and off, but it's not a big deal as you won't spend many days in this off-grid charging mode.
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  • Braiden
    Braiden Registered Users Posts: 3
    #7
    Re: Help: AC Coupling or Mini Offgrid system with my Micro-Inverters
    mike95490 wrote: »
    Solar PV does not need a diversion load. When the batteries are full, start manually shutting down the PV. It's not an everyday thing, if the grid is down, it's not likely you will be away at work that day.

    I think the same as you because also the system is connected to a sub-panel that always will be some devices connected as the refrigerator and fans.
    Also the system is only 1.5KW to 2KW.
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