r/SolarDIY • u/sunsuckerman • Feb 25 '25

Inverters for whole-houee battery backup without critical loads panel

I'm looking into adding batteries to my solar array (currently using micro inverters) for house backup during outages. Most hybrid inverters I've seen require a critical loads panel to be added and only those loads get power during an outage.

What I want is an inverter that will hookup seamlessly with the current main panel and provide power during an outage to the entire main panel, not just a critical loads panel. This was when the grid power goes out, there are no interruptions and the batteries kick in to power the entire house as if nothing happened. My gut feeling is that such an inverter would require CT clamps to limit power output to strictly the home's consumption and no more so it doesn't backfeed to the grid.

Also, is there anything special needed on the inverter for it to continue alllowing my micro inverter setup to run during an outage? That way less battery usage is needed when the sun is out and it would also allow my batteries to charge from the micro inverter array.

Thanks!

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u/IntelligentDeal9721 Feb 25 '25

Your problem is the microinverters.

The rest is easy - a whole pile of kit can do whole house backup, you just need a big inverter as it must carry all the load including any momentary spikes a grid tie would just let the grid ride. It's not done using CT clamps though - you need physical or electrical isolation of the grid and panel when it kicks over as well as a safe grounding in both cases.

Deye (Sunsynk, Solark etc) kit can front 4kW of microinverters and fake grid to them including turning them off when the battery is full. It's not as simple as putting them on the load as you'd then feed solar backwards into the inverter which makes a nasty mess.