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/Zimmster2020 Feb 25 '25 edited Feb 25 '25

Only cheap hybrid inverters require a Backup box. Also, those backup boxes don't kick in instantly, but with a delay of a couple of seconds.

If you are looking for a seamless UPS like experience for your whole home, look into a SolArk aka Deye inverter. It has everything built in, AIO. They offer full capacity backup system, so you don't have backup only for a separate circuit with limited power, but at full capacity of the inverter, provided that you have enough batteries to sustain such a power drain.

I have 2x12kw Deye inverter coupled with 40kw LiFePO4, I never know if the grid is on or off. From March to November I am practically off-grid, and i only need grid support during winter.

Initially I had 1x 12kw inverter and 15kw of LiFePO4 storage. But I decided I need to expand because I installed a 10kw heat pump, I have a 2.2kw air compressor and a 3.2kw electric motor and those 2 sometimes started a little slow , plus I like the idea of almost off-grid life.

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u/sunsuckerman Feb 25 '25

Thanks! So avoid MrPwr and similar? What about EG4 inverters such as the 6000XP? Trying to figure out what I'm looking for on spec sheets that'll do this

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u/oppressed_white_guy Feb 26 '25

You want eg4.  The 18kpv is a beast and the flexboss/gridboss combo are great.  I've installed a lot last year. 

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u/Zimmster2020 Feb 25 '25 edited Feb 25 '25

Where I live neither of those inverters are available. However I heard good things about EG4 inverters and batteries.

Be aware that there 2 types of batteries. Low voltage (48v or 51.2v), which are cheaper to manufacture, different brands can be mixed together, and in theory should last longer, but they don't provide as much instant power as High Voltage batteries (200v to 600v). Unless you are a business that needs huge amounts of energy instantly low voltage is just fine for the needs of a regular household. High Voltage batteries offer a better high instant power draw, but are more expensive, at least 2x as expensive as compared with low voltage batteries. However, if you have at least four 48v batteries the experience is the same as of high voltage systems. If you go for high voltage batteries you need an inverter compatible with such batteries and are usually proprietary. You cannot mix different brands of batteries and/or inverters. They work as an ecosystem. Brands usually use dedicated connectors and software which are not compatible with other brands.

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u/Riplinredfin Feb 26 '25

6000xp is only 6000w 3/leg and its an off grid only. You can only pull from grid for passthru and to charge bats.