Houston we have problems

[yebbey]

I'm in the Houston area and currently have an Enphase system with IQ8M microinverters. I want to get a battery with all the power outages of late. By my estimate, I need 40 to 50 kwh battery to ensure I can run my house with no interruptions. This would also allow me not to have to draw from the grid at night...almost a fully off grid solution. The Enphase battery is cost prohibitive so I was looking to get the Eg4 18k hybrid inverter along with either the EG4 or Ruixu wall batteries. I'm looking for some advice. Also, if anyone knows if the black start capability would still work outside of the Enphase battery solution. thanks in advance. I've been lurking here for some time, but am a newbie

 

[chrisski]

So, if you are not doing the work yourself, I do not recommend using anything other than what the installer has.

In addition to the battery, you need to figure a Critical Loads Panel, think about 50 amps worth of things, which is a 4 ton AC and a few kitchen devices, Not a single 5 ton AC by itself either. Next you need to get a inverter to AC couple the battery. This probably needs to be planned, permitted, and inspected throughly.

An AC coupled battery is not undoable, just needs a little thought.

I would actually recommend contacting EG4 directly to see their recommendations for an AC coupled system and installer in your area.

 

[yebbey]

thank you. So a little more to think about then. I thought hybrid inverters like the Solark 15k and the EG4 18k would be able to handle the AC coupling. The critical loads panel is to ensure the important things get power if there's not enough left in the battery? Will be contacting EG4. Thanks

 

[chrisski]

thank you. So a little more to think about then. I thought hybrid inverters like the Solark 15k and the EG4 18k would be able to handle the AC coupling.

I went with the Outback, so I don't have specifics on if the two inverters you mention can AC couple. It can be a little more than just hoking the AC in to the generator port. Not sure what those specifics are. outback designed a seperate inverter for this.

The critical loads panel is to ensure the important things get power if there's not enough left in the battery?

The Critical loads panel is

1) What will be powered in case of power outage
2) Can be used for different inverter strategies.
-Where I'm at, the power company lets me use my power I generated for free before I sell to the grid at 1/3rd the rate they charge me.
-Another strategy is to drop the critical loads from the grid so that during peak hours, these loads are ran from the battery. When the battery no longer has enough power, it switches back to the grid. Not sure what happens if the inverter gets overloaded.

There's a bit of thinking that goes in a critical loads panel. I built it for my summer loads where the power consumption is 6 times what it is in the winter. My Critical loads gets nearly full use in the summer with the 4.5 kW 4 ton AC, but in the winter, hardy gets used at all.

Will be contacting EG4. Thanks

This is from the Outback Mojave Manual. I did not go AC Coupled so I did not look at many AC Coupled inverter. If you can do the work yourself with no permitting, than Hybrid may be the way to go, but that would involve disabling the IQ8s.