Greetings from Tucson, AZ!

[AZRoadrunner]

I've been hanging out over in the Beginners forum, but want to check in here, too. We have rooftop, grid-tied solar which was commercially installed and is doing fine, but is technically useless in the event of a true disaster. I'm building a solar-charged "cart" (a modified AV cart) with two 12v 100ah batteries (Battle Born) and a 2kW inverter. As of today, the two 195-watt panels are up on the back porch roof and the PV lines almost finished being run inside. All the parts for the solar cart are here and I'm fiddling with where to position things in the AV cart for best operation and safety. My plans are attached for the curious. Look forward to all of the interesting and educational discussions on this board!

 

[snoobler]

Didn't remember you had grid-tie.

You may very well have asked this question, and I missed/can't remember it, but have you considered upgrading the cart with an inverter that's compatible with AC coupling? You could then provide your own "grid" and your grid-tie system would operate with the AC coupled inverter.

A "compatible" inverter has the added feature of sensing "surplus" power on the grid and using it to charge the batteries powering the inverter.

 

[AZRoadrunner]

Hi Snoobler. Our grid-tie system was installed and is maintained by Sunrun. Would AC coupling would require modifying anything in their installed system?

 

[snoobler]

I'm not the expert. It basically involves a transfer switch that manually disconnects your house from the grid and attaches it to your off-grid inverter. Then the installed system should see the off-grid inverter as "grid" and function pretty much normally.

Quick overview compliments of @SolarQueen

 

[SolarQueen]

The transfer switch is internal to the off-grid inverter and is all automatic. Installing AC Coupling is pretty much installing a new critical loads panel, moving your critical loads breakers there. Also moving the grid tied breaker there. The new off-grid inverter has the AC Out breaker at the new critical loads panel, and the AC in goes where the old grid tied breaker was. So there is a bit of rewiring around the breaker boxes, but should not be needed by the solar panels.