Misleading Capabilities of Backup Mode?

[BIC1]

Yes, of course, as stated by others.
Somehow, someone misstated what to expect from the system. You cannot just take the panels rating, 320W in your case and multiply by number of panes. That is where your 12.16 kW came from. Will not happen with those inverters.
Also, don't forget that other calculations come into the system design. A 20A circuit has a limited amount of power over it.
A different inverter, large in your case with those panels, most likely would require fewer panels on a 20A breaker and more 20A breakers in the breaker panel. Perhaps the power company in your location may or may not allow producing more than 100% of your annual historical usage. Here in California at least my local power company has a max 110% limit. They just don't want energy production competition from its customers.

And to directly answer your question, yes, they would, at least that YC 600 would. But then, a system redesign is in order. Don't want you to replace those inverters as that would overload the 20A breaker.
Nothing is simple.

While I wouldn't otherwise replace the YC500s, since the installer didn't provide the microinverters as promised, I'm trying to figure the impact of me requesting an exchange for the YC600s. A whole new system design sounds deal-breaking. Looking at the spec sheets, the YC500 says "Maximum Units Per Branch 7 per 20A @ 240V; 6 per 20A @ 208V". I have 19 twin microinvereters (38 panels), not sure how they're broken up. I assume I'm at 240V. There are three 20A branches.

The YC600 specs are not presented the same. It just says, "Maximum Units per Branch 7 (14 PV modules); 6 (12 PV modules)." Could they just replace the YC500 with the YC600? See attached specs & install manual. Thanks.

 

[Ampster]

I think the big issue with the YC500s is they did not provide the same ramp down functionality as the Enphase inverters that were substituted. That is what made your PowerWall possibly less effective in a power outage.

I do also question your installers statement that the cost the same as two Enphase inverters. It is the same number of cable connections but half the micros being fastened to the rail. If it were me I would ask to see some invoices or just go online and compare retail prices to get data on the price if you want to use that as leverage.

If I were the installer I would suggest turning off one or two of the micro inverters branch circuits to solving the Powerwall charging issue. If that wasn't acceptable to you I would offer moving on or two to the main panel.
If that wasn't acceptable I would put in an automatic switch that would disconnect one or two of them during power outage. Those are in order of least expense to the installer and may help inform your strategy. The most expensive fix is to go on the roof and replace all the inverters.

 

[BIC1]

I do also question your installers statement that the cost the same as two Enphase inverters. It is the same number of cable connections but half the micros being fastened to the rail. If it were me I would ask to see some invoices or just go online and compare retail prices to get data on the price if you want to use that as leverage.

It's hard finding pricing online, most places want you to register (as a pro?). After reading this article, I raised the price issue at the time of making the decision (Nov-Dec 2019). Although this article clearly states the YC600 is much less expensive than IQ7+ (at least in June 2018). My installer said not true, they're the same. Where I feel most slighted is when substituting the AP for the IQ7, he gave me YC500 instead of YC600. I called the place in the article, he said now, with the tariffs, pricing is about the same. But we're talking 15 months ago. Thanks.

https://tandem-solar-systems.com/which-is-the-best-micro-inverter/

 

[charlesj]

I am referring to the diagrams in your post # 93
You are comparing apples and oranges when you look at the data on the lower single image. Yes the inverters in the lower diagram are the same size but the panel sizes are different. It is logical that that the same inverter will produce more power if more panel capacity is adaded to it. It will produce more power even if some of it is clipped at the top NOT because it is clipped but because the power curve is wider. It is not logical to compare two different systems and conclude that clipping causes one to have a wider power curve.

What you are referring to is the upper diagram in which BOTH panel size and inverter are the same for each image, but the insolation is different (winter vs summer). That illustrates the logical reason many systems are oversized. It does not support your statement that clipping results in a wider power curve. A wider power curve is a RESULT of a higher DC to AC ratio. @cwied d also explains this above and why system designs vary.
The phrase above that continues to be misleading is, "you have max peak power that inverter is capable of for a much longer time that if it didn't clip". As I said above it is the high DC to AC ratio that causes it to have a wider power curve. Mabe that is nit picking but I think it is important for people to have a better understanding of issues around their system design.

Thanks. No nitpicking you just explained better . And you are absolutely correct that the higher DC to AC ratio is what cause you to have a wider bell curve which is more power production.
As to BIC1, that is what he has, a much higher ratio.

 

[charlesj]

While I wouldn't otherwise replace the YC500s, since the installer didn't provide the microinverters as promised, I'm trying to figure the impact of me requesting an exchange for the YC600s. A whole new system design sounds deal-breaking. Looking at the spec sheets, the YC500 says "Maximum Units Per Branch 7 per 20A @ 240V; 6 per 20A @ 208V". I have 19 twin microinvereters (38 panels), not sure how they're broken up. I assume I'm at 240V. There are three 20A branches.

The YC600 specs are not presented the same. It just says, "Maximum Units per Branch 7 (14 PV modules); 6 (12 PV modules)." Could they just replace the YC500 with the YC600? See attached specs & install manual. Thanks.

It appears that the spec for the 600s implies 7 @240V and 6@ 208V. Yes, you have 240V system.
It seems that the 600 could replace the 500 without changing number of breakers. And, it seems, with 3 circuits you may have 2 with 6 inverters and one with 7.

 

[Ampster]

Thanks. No nitpicking you just explained better . And you are absolutely correct that the higher DC to AC ratio is what cause you to have a wider bell curve which is more power production.
As to BIC1, that is what he has, a much higher ratio.

No worries. I am glad we agree on that.
Speaking of DC to AC ratios, I know a guy on another forum in rural Illinois that has a 2 to 1 DC to AC ratio. Each string has a different orientation and has very little clipping. If one evaluated his DC to AC ratio one might say it is innefficient based on his ratio of annual production to his STC capacity of 1200. However his annual production to inverter capacity is close to 2000 to 1. That guy had plenty of land, access to inexpensive panels and DIY installed his ground mounts. That just illustrates the point of @cwied about every system should be designed around the users goals.