AC & DC Coupling Simultaniously

Discussion about adding energy storage to grid-dependent inverters using OutBack Power technology
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Positive Power
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Joined: Thu Jun 10, 2021 6:04 pm

AC & DC Coupling Simultaniously

Post by Positive Power »

Just a quick question that I'm sure I already know the answer to but would love a little confirmation.
One of my recent installations is a DC Coupled (FM100 AFCI) Dual Radian Grid Connected (Net Metering), system with 750Ah of SimpliPhi batteries. The System is working great and the client is happy. So happy in fact she wants to add more solar. Instead of using another FM100, I'd like to AC Couple the new solar array (using Enphase IQ7+) to the Radian's critical load panel. I have installed multiple AC Coupled systems, but just not one on my existing DC Coupled Systems. I see no reason why both cannot work harmoniously, assuming I stay below the 75% of the 16kW output of the dual radians (no more than 12.8kW of Grid Tied input) and the batteries can comfortably handle the added charge current (which they easily can). Does anyone else see any issues with this combining the two different strategies?
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Mike Curran
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Posts: 3288
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof (2007/2017):
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 24 (2x12) 235W Lightways panels with Enphase M215 microinverters plus 6 - 275W Talesun panels, also with M215s, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Trina Solar 270W in series (DC array input to SB inverter/charger), installed 3/5/24 (replaced original 2019 Talesun DC array)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W (manually switched during outages), Enphase M215 microinverters

Battery systems operate in grid-tied, net metering w/backup mode
All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: AC & DC Coupling Simultaniously

Post by Mike Curran »

The Radian has AC-coupling capability. There's no reason this won't work. My system does this with Skybox but the Radian is similarly capable. I'm sure there are others on the forum who are already doing this with their Radian(s).
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
Positive Power
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Posts: 15
Joined: Thu Jun 10, 2021 6:04 pm

Re: AC & DC Coupling Simultaniously

Post by Positive Power »

That’s my thought too. Indeed I have seen others do it as well. Thanks for your feedback.
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