Expanding system size & SDGE limit's 1kw system limit

[inspron]

I have a 5.5kw DC system with a 5kw Solaredge inverter. On ideal cool summer days, I hit 4.2kw peak production rate. I am thinking about adding more panels.

SDGE allows for 1kw expansion to the system without going through another application process. But my question is what is the 1kw limit on - panels (DC) or inverter output (AC)?

If I were to add 1.5kw more of panels (shading issues) am I over the limit or are they strictly looking at the AC side so I could potentially go with a 6kw inverter?

[sensij]

I have a 5.5kw DC system with a 5kw Solaredge inverter. On ideal cool summer days, I hit 4.2kw peak production rate. I am thinking about adding more panels.

SDGE allows for 1kw expansion to the system without going through another application process. But my question is what is the 1kw limit on - panels (DC) or inverter output (AC)?

If I were to add 1.5kw more of panels (shading issues) am I over the limit or are they strictly looking at the AC side so I could potentially go with a 6kw inverter?

I don't think I've seen anyone in the forum post first hand experience with this. Based on the interconnect forms, my guess is that the AC rating is the one that matters, but I think you should probably get them from them, not me. The AC size is based on some standard calculations they perform on the array's DC rating, not the inverter's output limit.

For example...

I have a 12 x 260 W system (3120 DC W) with a 3000 W inverter, SDG&E sees it as a 2.797 kW system.
I also have a 28 x 290 W system (8120 W) with a 7600 W inverter, SDG&E sees it as a 7.27 kW system.

The formula they use (from an SDG&E rep, in writing):

The formula is as follows
Number of panels x solar panel rating x inverter efficiency

The solar panel rating is the PTC rating in the CEC equipment database (for modules).
The inverter efficiency is also in the CEC equipment database (for inverters)

[inspron]

You are right, just confirmed the same in the PTO notice, "We want to officially inform you that the 4.893 kW system tied to meter 061XXXX7 at the address noted above meets all of our interconnection requirements."

So AC output is the key determinate. In my case, I can go as high as 5.893kW AC system.

[mchen1]

Inspron, Sensij,

Did either of you ever move to expand your system size? I have a 4.4kW system, and I'm interested in expanding, and adding a Tesla Powerwall. Is it correct I'd be wanting to set up the additional solar with its own inverter, and the PW will be able to handle inputs from two solar sources?

I'm also wondering who would be able to do the expansion, so any referrals for companies would be great. I had Baker do my original solar system, but I'm not sure if they'd be interested in adding just 1kW of solar to my house.

[J.P.M.]

Inspron, Sensij,

Did either of you ever move to expand your system size? I have a 4.4kW system, and I'm interested in expanding, and adding a Tesla Powerwall. Is it correct I'd be wanting to set up the additional solar with its own inverter, and the PW will be able to handle inputs from two solar sources?

I'm also wondering who would be able to do the expansion, so any referrals for companies would be great. I had Baker do my original solar system, but I'm not sure if they'd be interested in adding just 1kW of solar to my house.

The system add-on limits that Sensij posted with respect to size have not changed in that time.
You can add storage but know that the STC system size limits still apply and a county inspection for the new equipment will be required.
A simple call to SDG & E will confirm.

[mchen1]

Thanks, I did call SDG&E, and they confirmed the 1kW limit, and also confirmed adding battery storage wouldn’t impact NEM1.0.

Google brought me to this old thread; I’m wondering if there was work done here, and if I could find out who did that work for them.

[J.P.M.]

Thanks, I did call SDG&E, and they confirmed the 1kW limit, and also confirmed adding battery storage wouldn’t impact NEM1.0.

Google brought me to this old thread; I’m wondering if there was work done here, and if I could find out who did that work for them.

FWIW, Baker (your original installer) is still peddling PV. Your best bet will be to go with the original installer of the equipment already installed.
A lot of vendors don't/won't want to mess/interface with equipment and systems done by other vendors.