"Off-grid" solar on home with grid-tied NEM2.0 array to power EG4 Solar AC

[hex4def6]

Like title says.

I'm in the process of installing a 9.45kW / 9.7kW AC array on my house, but I've been bitted by the "more solar" bug. Unfortunately I can't change my current plans or I'll lose the NEM2.0 approval they were submitted under (PG&E).

I'm thinking what might make sense is getting one of these: https://signaturesolar.com/eg4-hybrid-ac-dc-solar-air-conditioner-2-ton/
and running that off the "off grid" array that I'd add.

Any idea if PG&E would take issue with that? That heat pump has a dual AC / DC input mode in which it can supplement it's solar power with AC. That makes me wonder if they'd look at that and say "nope".

 

[Kuma]

Contact PGE solar support. PGE has an NEM 2 engineer team that allowed me to increase kw "if" the "string inverter" label remained the same. Dont know about MI's. In other words, PGE allowed me to over size the inverter another ~1.2kw.

 

[zanydroid]

I'm thinking what might make sense is getting one of these: https://signaturesolar.com/eg4-hybrid-ac-dc-solar-air-conditioner-2-ton/
and running that off the "off grid" array that I'd add.

Any idea if PG&E would take issue with that? That heat pump has a dual AC / DC input mode in which it can supplement it's solar power with AC. That makes me wonder if they'd look at that and say "nope".

In my head canon this is something to negotiate between you and the AHJ and not with PG&E. When I looked at this for an ADU at a property that does not have NEM, the extremely unclear AFCI situation ruled it out.

I think a lot of people prefer to have the solar panels go to a more fungible power setup like an off-grid inverter rather than a single appliance. Also if you feed minisplits from AC you can choose whichever one you want. There are tons of nice ones to choose from that will sell to you as DIY. I think a Gree Sapphire has better specs than the Deye that EG4 uses here.

 

[hex4def6]

In my head canon this is something to negotiate between you and the AHJ and not with PG&E. When I looked at this for an ADU at a property that does not have NEM, the extremely unclear AFCI situation ruled it out.

I think a lot of people prefer to have the solar panels go to a more fungible power setup like an off-grid inverter rather than a single appliance. Also if you feed minisplits from AC you can choose whichever one you want. There are tons of nice ones to choose from that will sell to you as DIY. I think a Gree Sapphire has better specs than the Deye that EG4 uses here.

I know -- this is the mental exercise I have -- off-grid with batteries sounds more universal. But now, instead of 3*400W panels (what, $600?) + $2000 EG4 Heat pump + $400 racking/acc (total of $3000), you're at that, plus another $1000 for the Gree Sapphire, plus $700 for a Growatt, plus $1300 for a rackmount battery... Suddenly you're at $6000, double the price all-in...

It's admittedly a more capable system, but $6k is now not really play money any more. And for about that I could buy myself the Enphase 5P + System controller and put the grid-tied system on load shift, probably netting me better effective use of the existing solar.

 

[zanydroid]

Nothing (reasonably priced) will fix the lack of MPPT-side AFCI though on the EG4.

I think you over-estimated the racking. Drive to CED Greentech/Renvu with a truck and sawzall to cut rails down to size & grab solar panels. I've done it a few times.

Common price: 600 + 400 (solar + rail + wires + RSD hardware, note the RSD hardware scales better with more panels)

EG4: $2000
Sapphire + Growatt + battery: $3000 (+$1000 from EG4)

You can put all of your slow & steady loads like lights, fridge, freezer, home office, on a small Growatt on SBU. Probably everything 120V (including kitchen), since 1 battery can output 5 kW-AC.

You want to check how capable the load shift programming actually is on an Enphase 5P, I don't think it's comparable to a 18kpv or SolArk.