Advice on two systems to be tied together

[Mattb4]

You mean because the hybrid generally does not follow a grid former? (Microinverters are used this way all the time, I don’t know if it’s explicitly allowed)

And/or because the hybrid generally does not follow on battery power to a grid former?

I know the grid forming side often has a lot of conservative constraints on what is allowed to follow. In terms of kW output of the following inverter. And those are explicitly listed so more likely to be a cause for warranty issues.

It’s not hard to exceed those limits.

At my age my limits start getting exceeded by late afternoon. My brain then shuts down.

An any rate if the OP gets it all up and running it should be interesting.

 

[zanydroid]

Solark touts its ability to accept AC coupling through its gen port or a load side sub panel. This would be through a panel. The only difference is that it would be coming from the downstream inverter’s “grid export” instead of its load output.

SolArk as the one in building A orchestrating everything is fine. My wondering is about the inverter on B.

Gen port I believe has the safety advantage that SolArk can open a relay if the AC coupling has issues.

Unfortunately if AC coupling has a safety relay your B will lose power. Maybe this means you want to consider two separate feeders to B.

One for the AC coupling (maybe subject to safety relay)

The other for loads (always connected)

 

[SilverbackMP]

One reason I can think of to do an inverter in both buildings is to shorten the length/number of DC circuits. Even if the shed with all inverters is exactly in the middle.

OTOH I think the extra back breaking of pulling more cables needs to be traded off against simpler system design and ongoing operations. You don’t need that many brain cells to pull more conductors, and it only needs to be done once.

DC circuits need to be just long enough to go from your batteries to your inverters. You’d be sending AC everywhere from that location. That would be a main panel and everything else would technically be sub panels.

I do send DC to my shed from my solar panels rather than converting to AC at the panels because they are 280 feet away and I can use much smaller wire with less line loss. This requires SCCs or DC/AC inverters (like Sunny Boys) though that can handle higher voltage (12 of my panels will output 450-500 volts Dc on average when in series, just under 600 volts DC on coldest day on record).

But if the panels would have been closer, I would have likely just mounted the Sunny Boys underneath them and converted to AC there.

And I might do that in other locations.

It helps that I have a complete SMA setup, but other inverters are also capable of “AC coupling.”

 

[SilverbackMP]

DC circuits need to be just long enough to go from your batteries to your inverters. You’d be sending AC everywhere from that location. That would be a main panel and everything else would technically be sub panels.

I do send DC to my shed from my solar panels rather than converting to AC at the panels because they are 280 feet away and I can use much smaller wire with less line loss. This requires SCCs or DC/AC inverters (like Sunny Boys) though that can handle higher voltage (12 of my panels will output 450-500 volts Dc on average when in series, just under 600 volts DC on coldest day on record).

But if the panels would have been closer, I would have likely just mounted the Sunny Boys underneath them and converted to AC there.

And I might do that in other locations.

It helps that I have a complete SMA setup, but other inverters are also capable of “AC coupling.”

Actually that’s what you might should look for. A system that’s capable of AC coupling and which can establish a grid. SMA does this by design but there are others than can do it too. (Some Outback and Schneider units I believe).

 

[SilverbackMP]

Yeah I think Sunny Boys are even explicitly listed for/have official system schematics showing how to AC couple to storage? I think putting those in the remote buildings to handle the PV on roof and ground mounts next to it, and then AC coupling back to one place with batteries and grid connection, is a pretty standard approach.

Yeah with SMA Sunny Islands, it’s fairly intuitive. The LiFePo solutions aren’t as intuitive and/or cheap, but not insurmountable.