Suggestions on choosing an inverter?

[J.P.M.]

Solis also provides a 10-year warranty and is a large enough company to be around 10 years from now. Many inverters sell with a 5-year warranty and not something I would consider when others at the same price have a 10-year warranty.

Last time I checked, any inverter sold into CA needed a 10 year warranty.

[rebelrider.mike]

I will keep Solis in mind. I couldn't find any models that were split phase, but companies come out with new products all the time.

I remade my inverter selection table so it might be easier to read. As each unit hits a "deal breaker" the data stops, in order to reduce visual clutter. As I've learned more about inverters and how they work, I've been able to refine what characteristics I want in one.
InverterTable.png
The Deye is crammed full of features, and is probably worth the higher price. But I won't be using a lot of those extra features. Also, it's only available direct from China. So shipping will be horrendous. And if the unit I bought were to have a problem, I wouldn't be able to afford to send it back.

The EG4 is the one I'd get if I were to buy one today. I think its biggest flaw is the 115W of idle power usage. Not as high as some, but still kind of on the moderately high side.

I'm not going to rule out the other brands yet though. If any come out with an inverter I like better than the EG4, I'd definitely consider it.

[Ampster]

Last time I checked, any inverter sold into CA needed a 10 year warranty.

I guess it depends on how you define "sold into CA"? Do you mean, on the CEC list?
Very few of the Chinese inverters listed on the above list are on the CEC list but you can get them shipped to California from China. I am not taking issue with your statement, just seeking clafification for the benefit of other readers.

[J.P.M.]

I guess it depends on how you define "sold into CA"? Do you mean, on the CEC list?
Very ffew of the Chinese inverters listed are on the CEC list but you can get them shipped to California from China. I am not taking issue with your statement, just seeking clafification.

Well, I use "sold into" to mean used as part of a residential electrical generation system in CA.
If the OP is not in CA or is in CA but not required to be covered by an interconnection agreement, then my statement is possibly incorrect by virtue of some incorrect assumptions.

However, if the OP is in CA and he's stated he will want the ability to feed power to the grid, that will mean an interconnection agreement.
If he's in CA I'd think that would mean NEM 3.0.
Now, NEM 2.0 requires a minimum 10 year inverter warranty.
In my snooping around, I've not been able to locate the specifics of inverter warranty requirements under CA NEM 3.0. However, all the documentation and info I've been able to locate and read that cover changes from NEM 2.0 to NEM 3.0 I've not seen any mention of any changes to equipment warranty requirements.

So, I'm of the opinion that if the OP's system will be in CA and if he wants to sell power back to the grid as he's stated, and if he's either a current or soon to be customer of some CA POCO that requires an NEM agreement, he'll need an inverter or inverters that carry a 10 year or greater warranty in addition to meeting all other requirements imposed my applicable codes in force in the jurisdiction where the equipment is located.

[Ampster]

I thijnk rebelrider.mike said he is not looking to feed power to the grid but would like to use the grid as a backup. He may wish to claify if an interconnection is needed. Howecer, for other readers who are anticipating an interconnection in California, they should have as one of their first rank order criteria the fact that a particular inverter be listed on the CEC site.

The above list would be useless for those readers who want an interconnection since the CEC status is not shown. I do know for a fact that the DEYE is not listed and am pretty sure some of the others are not listed on the CEC site as well. I think it may be implicit in any NEM agreement that the inverter be listed on the CEC site. The CEC site says the list is for any interconnection requests in California without referencing a NEM version. Also the online application for PG&E and SCE have a pulldown menu item that can pull the values for listed inverters into the application form. I do not have any experience with SDG&E.

[J.P.M.]

@ Rebelrider.mike:

Please, if you would, clear a couple of things up for me:
1.) Do you plan to ever send power to the grid for any reason ?
2.) What state (or country) will the generating system be located in ?

Thank you in advance.

J.P.M.

[rebelrider.mike]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage. For me, the whole point of having solar is to be able to use it during an outage. I don't plan to generate enough solar power to have any left over anyway. The sub panel I'm going to install will be powered from solar/battery, as well as either grid or generator as needed. Something like this:
InverterBatterySolar.png
Of course, this diagram changes every time I learn something. So it's really only a snapshot of what I'm thinking today.

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

[J.P.M.]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage. For me, the whole point of having solar is to be able to use it during an outage. I don't plan to generate enough solar power to have any left over anyway. The sub panel I'm going to install will be powered from solar/battery, as well as either grid or generator as needed. Something like this:
InverterBatterySolar.png
Of course, this diagram changes every time I learn something. So it's really only a snapshot of what I'm thinking today.

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

Thank you.

[jflorey2]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage.

But you have drawn a system that can 1) export power, 2) do net-zero if the inverter can use CT's for that purpose and 3) allow solar to function during an outage. So what is the utility preventing you from doing exactly?

[Ampster]

.......... what is the utility preventing you from doing exactly?

Good question. I had the same thought. There are some municipal (public) utility districts in which the building permit authority is the same entity. On the otherhand I am of the opinion that if one has a UL approved transfer switch separate or in an inverter that there should be no reason you cannot generate your own power. That assumes it wojuld comply with building codes.

[Ampster]

..........

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

I read somewhere that 15 states have adopted the California CEC list. Perhaps that is the case in WA as well?

[azdave]

My PUD wouldn't allow solar to function during a grid outage.

I don't quite follow this statement so maybe I'm not understanding your PUD regulations. If your system automatically disconnects from the grid during a grid outage, how would the they know or why would they even care that your panels are being used as a stand-alone system while the outage is occurring? Why would they approve using a gas generator (with a proper grid disconnect switch) but not solar generation with a proper disconnect as well? What am I missing here?

[rebelrider.mike]

Seems I caused some confusion, LOL. I'll see if I can clear it up.

In order to sell power back to the PUD, I'd have to enter an agreement which comes with certain requirements. I don't remember them all, but one that stood out (because I can't agree to it) is that the solar system shuts down in the event of a grid outage. I don't know what would happen if I were to backfeed power to the grid without their permission. I've never tried it. At the very least, I'd be giving power back to the grid for free. The meters here are electronic, but I don't know how "smart" they are.

One would think that an automatic disconnect that mechanically isolates the solar from the grid in the event of a grid outage would be sufficient. It is when using a generator. The PUD disagrees. I've found though that questioning policy doesn't change it. Just have to find a way to work around it. Here is a link to their Solar FAQ page.

The good news is that if I don't want to sell power back to the PUD, I don't have to. I have no legal obligation to do so, as far as I know. And if I don't sell power back to the grid, I don't have to comply with PUD policy. Only local code. I'm still working on that one, but I'm pretty sure keeping my solar/battery system active during a grid outage is allowed as long as it's isolated from the grid. Same as using a generator. Washington uses the 2020 NEC. I don't remember if I mentioned that.

So the inverter I have in my diagram is theoretical, but the idea is that there is an AC input from the grid or generator (some inverters have separate inputs for each) and an output for the load. The idea is that the AC input will be input only. No output. I'm not sure what the correct terminology is, but I want an inverter that can use power from the grid but not send power back. I know that grid-interactive can send power back, and off-grid has no power from the grid. Grid-tied seems to imply grid-interactive. Best I can describe it is that I want a grid-supplemented-but-non-interactive device.

From my studies around the internet, I've found that my PUD is not the only power provider with this sort of policy. There's a popular brand of microinverter called Enphase that designs some of its devices to automatically shut down during a grid outage. It's a hard-wired sort of thing that can't be changed. Some providers actually require these exact products in grid-interactive solar setups. So sayeth some You Tubers anyway.

[Ampster]

If Washington state is on NEC 2020 you will have to pick a UL liste inverter if you want to pass building inspection, Any UL listed inverter will be able to isolate from the grid when the power goes out. In your case, since you want to use the grid but not sell back your criteria needs to include the ability to take grid input and Zero export. that narrows the selection especially if you want to comply with the building codes. You may need to use external CTs to control export depending on how it is wired. Many of the inverters on your list are not UL listed but some of them can be configured for zero export and use grid power to supplement solar or battery. It is my strongly held belief that you do not need to get agreement from your utility if you are not exporting but it is a gray area in the sense that the inverter is connected even though it may be set for zero export.. That said, you always need to comply with the building code.

[rebelrider.mike]

Here is a link to my local L&I page listing different certification laboratories that they accept testing from. From what I've read, any of these labs can certify that a product conforms to UL1741, which I think is the magic number for passing an inspection. This isn't really a response to anyone, just an FYI that I found interesting.

So far as I know, Washington doesn't have a list of specific inverters. Any that are certified by one of the above labs as conforming to UL1741, are fine. I found the CEC inverter/batter/solar list here. I guess I'll start going through the 1,542 devices and see which ones might work and if I can afford them. One thing that bothers me is that these are all "Grid Support" devices. I'm thinking that means that only inverters that can send power back to the grid are listed. Might be faster to just look up the manufacturers and see what they sell. There's no info on the list as to whether each inverter is split phase or not. But there are a lot of manufacturers that I've never heard of. Maybe I'll find something good that I've been overlooking.