Small Whole House Backup w/ StorEdge?

[JPro]

Is it possible to install a SolarEdge StorEdge / LG Chem RESU10 system on a main distribution panel (MDP) and not a backed up loads panel? The solar PV will be a supply side connection, and we in theory could place a third party ATS downstream of the POI but before the main disconnect to isolate the MDP in backup mode. The battery generation could then tie right into the MDP and back up the whole house. The house has very minimal loads (older row house) not exceeding 5kW or 25A -- It's comparable to an average backed up loads panel with a few extra small loads. I’ve seen similar configurations done with Tesla PW2 and Sonnen Eco/Ecolinx as they have 200A ATS pass throughs that work well for this, but they’re also cost prohibitive and/or hard to get for applications like this. We'd also prefer not to install a redundant subpanel with all of the home's loads. Is this feasible or crazy?

 

[jaggedben]

As long as the MDP isn't the service equipment, or can be easily converted to a sub, I think it's feasible. If it's a meter/combo I don't see it working.

If the customer's calculated load is truly less than 25A then I don't think you even need the ATS. Not likely, but just sayin'

I got as far as discussing something like this on one project and thinking it was going to go forward and then other participants backed out for reasons that didn't have to do with technical feasibility. SolarEdge was consulted and said it should work.

 

[JPro]

As long as the MDP isn't the service equipment, or can be easily converted to a sub, I think it's feasible. If it's a meter/combo I don't see it working.

If the customer's calculated load is truly less than 25A then I don't think you even need the ATS. Not likely, but just sayin'

I got as far as discussing something like this on one project and thinking it was going to go forward and then other participants backed out for reasons that didn't have to do with technical feasibility. SolarEdge was consulted and said it should work.

Thanks. The meter is separate from load center so we should be good on that end. There are a couple of loads we may disable with relays to ensure we stay under 25A but will still likely need to isolate this with ATS to pass inspection

 

[ggunn]

As long as the MDP isn't the service equipment, or can be easily converted to a sub, I think it's feasible. If it's a meter/combo I don't see it working.

If the customer's calculated load is truly less than 25A then I don't think you even need the ATS. Not likely, but just sayin'

I got as far as discussing something like this on one project and thinking it was going to go forward and then other participants backed out for reasons that didn't have to do with technical feasibility. SolarEdge was consulted and said it should work.

Doesn't a StorEdge system come with a gateway that includes an ATS?

 

[jaggedben]

Doesn't a StorEdge system come with a gateway that includes an ATS?

Yes, in the sense that it's built into the inverter like on a Sunny Island. (But unlike a Sunny Island, it's a 240V inverter.)

But it's limited to 25A. So the issue that gets raised here is that someone may want to backup loads that are more than 25A, and may be comfortable with the idea of being limited to 25A if the grid goes down, but not during normal day-to-day with the grid. So they want an ATS to transfer between, say, a 100A 'normal' feeder and the StorEdge backup feed.

BTW, I don't like the term ATS for a gateway because there is no 'transfer' to another source circuit. It's just a disconnect (relay) and then the inverter, which is always connected to the backup loads, has both interactive and off-grid modes. There's actually a code definition for this now in 705: "Micro-grid Interconnect Device". So let's start calling them MIDs. I think the term applies equally to where the capability is built into another device (StorEdge) or where it stands on its own (Powerwall Gateway).

OP is talking about adding an actual ATS down the line from the backup loads output.