DC coupled or AC coupled conundrum
Posted: Fri Oct 03, 2025 3:21 am
I have an existing SolarEdge system with SE6000H inverter and 20 panels with S440 optimisers. I am in NSW, Australia.
The optimisers are important as some panels are partly shaded at different times of the day. Example shown in the attached images where at 10am panel 14 is mostly shaded: But at 2pm, panel 3 is shaded and panel 14 back to full sun.
It's a small roof almost entirely covered, so better placement was not an option.
(although there is potential for another 6 south-facing panels)
I am looking to get am EQ4800 full stack, and most installers have been recommending AC coupling this system and just leaving the Solaredge system as-is, but I feel this would introduce complexities in dealing with 2 inverters and ecosystems, and especially if looking at VPP programs. I am concerned the Fox system would not be fully aware of house consumption, grid production etc as it all just happens on the same AC bus. Would love anyone to expand on whether this is actually the case with correctly placed CT clamps etc. Ideally I'd not want to look at Solaredge system again, except to look at things like panel level production.
The other option some have suggested would be to DC couple the panels, removing the Solaredge inverter and optimisers in the process. I'm concerned this would reduce the panel output due to the shading issues. I have read that Tigo optimisers could be an option here, and it looks like it would be about $2000 AUD to replace the SE optimisers with Tigo ones and remove Solaredge from the equation completely. I'd be willing to pay this for a more optimised and simple system.
I'm wondering what people here would advise - if I went the Tigo route would I get individual panel production in the Fox ESS interface like I have now?
Are my AC coupling concerns unjustified, and am I just shooting myself in the foot removing reliable well performing gear?
Thanks!
The optimisers are important as some panels are partly shaded at different times of the day. Example shown in the attached images where at 10am panel 14 is mostly shaded: But at 2pm, panel 3 is shaded and panel 14 back to full sun.
It's a small roof almost entirely covered, so better placement was not an option.
(although there is potential for another 6 south-facing panels)
I am looking to get am EQ4800 full stack, and most installers have been recommending AC coupling this system and just leaving the Solaredge system as-is, but I feel this would introduce complexities in dealing with 2 inverters and ecosystems, and especially if looking at VPP programs. I am concerned the Fox system would not be fully aware of house consumption, grid production etc as it all just happens on the same AC bus. Would love anyone to expand on whether this is actually the case with correctly placed CT clamps etc. Ideally I'd not want to look at Solaredge system again, except to look at things like panel level production.
The other option some have suggested would be to DC couple the panels, removing the Solaredge inverter and optimisers in the process. I'm concerned this would reduce the panel output due to the shading issues. I have read that Tigo optimisers could be an option here, and it looks like it would be about $2000 AUD to replace the SE optimisers with Tigo ones and remove Solaredge from the equation completely. I'd be willing to pay this for a more optimised and simple system.
I'm wondering what people here would advise - if I went the Tigo route would I get individual panel production in the Fox ESS interface like I have now?
Are my AC coupling concerns unjustified, and am I just shooting myself in the foot removing reliable well performing gear?
Thanks!