Optimizers... what are they good for?

[nwdiver]

The optimizers give me 20-25% more energy

For my the Tigo system I have that figure comes with a GIANT grain of salt. There's only one panel with an optimizer yet it's claiming reclaimed energy of ~364kWh. And when you zoom into how that's being calculated it's showing reclaimed energy when the inverter is saturated so there literally cannot be ANY reclaimed energy.

PLUS... look back at my original post, if there actually WAS a ~20 - 25% improvement due to optimizers then why aren't identical panels down the street on a Solar Edge system producing ~20% more than the non-optimized panels next door? There should only be a ~5% penalty to being off-south by 45 degrees.

Non-Optimized vs Optimized

 

[DrSmile]

I was under the impression that micro inverters are also somewhat less efficient compared to strings? Also a few years ago the MI that were available would clip the individual panels, I guess that is now solved with IQ7/8?

My Solaredge inverter has already failed once.

 

[nwdiver]

I was under the impression that micro inverters are also somewhat less efficient compared to strings? Also a few years ago the MI that were available would clip the individual panels, I guess that is now solved with IQ7/8?

My Solaredge inverter has already failed once.

Micro Inverters aren't that much less efficient than string inverters provided the AC runs aren't too long. SolarEdge failures appear to be attributable to a bad batch of components. I have a 11.4kW in the field that has worked flawlessly for ~4 years.

The problem is how these systems are marketed based on misinformation. There's two basic myths that they perpetuate. That shaded panels degrade the performance of unshaded panels in a string and that there's a significant benefit to sharpshooting the MPP for each panel. Both of these are demonstrably false.

These are identical 13 panel strings of 365w panels. One string is on A&B allowing it to be on its MPP while one string is connected to channel C limited to 10A. Because the channels are limited to 10A the string on C is off its MPP by >5%. You can calculate the loss of power due to this for yourself. (5.29A)(357.3v)+(5.29A)(356.6v) = 3776w VS (10A)(376.9v) = 3769w

So... being off the MPP by 5% resulted in a loss of 7w of 3776w. That's 0.2%. Not 20% or even 2% but 0.2%.

 

[pdx_m3s]

I just like the ability to see how each panel is performing from an issue/fault diagnosis standpoint. Plus they came "free" with my Tesla install back in 2020.

 

[CrazyRabbit]

Tesla is most often paralleling strings down to the inverter and then bonding two mpt together which will cause significant losses if there is any shading.
I like micros because they are practically installer prof!

 

[itsc]

Tesla is most often paralleling strings down to the inverter and then bonding two mpt together which will cause significant losses if there is any shading.
I like micros because they are practically installer prof!

It took months to get them to fix it. It literally took a few $ of extra wire going through the same pipe that was already installed.

 

[nwdiver]

practically installer prof!

.... if you need your installs to be 'installer prof' you need to find better installers. I spent the better part of a weekend repairing a poorly installed PV system that hadn't been working for 3 years. I'm guessing the company that hired these guys decided to invest their training budget in 'installer prof' micro inverters. It did not work out well....

I forgot to take a photo of the cooked wire we found that had been terminated improperly but did take some photos of the crap mounting job where the panel blew off the roof and the feet they installed twice and STILL didn't install them correctly. I'm all for using technology as a hedge against incompetence... but there are limits...

 

[nwdiver]

We had our first panel failure. I was able to ID the failure due to each string being on an independent MPP channel and was able to easily spot the bad panel using an IR camera. So the whole argument that you need panel level monitoring to find a failure is also 100% untrue.

These strings happen to be the same length so it was simple to spot but you can also do a little math to ensure Voltage / Panel per string is roughly the same.

Before fix:

After Fix:

 

[sunwarriors]

We had our first panel failure. I was able to ID the failure due to each string being on an independent MPP channel and was able to easily spot the bad panel using an IR camera. So the whole argument that you need panel level monitoring to find a failure is also 100% untrue.

These strings happen to be the same length so it was simple to spot but you can also do a little math to ensure Voltage / Panel per string is roughly the same.

Before fix:

View attachment 1006429

After Fix:

View attachment 1006428

I think looking at an app and seeing a panel all black is braindead easier than using an IR camera (which I don't even have) nor all the math to ensure voltage nor anything about a MPP channel that I know nothing about neither. Your two pics look near the same to me as well so I can't see what's the problem there.

The main thing is from my own purchase, strings again weren't much cheaper in the grand scheme of a project so I still advocate the route of micros if given a choice (that's not an option for some installers of course). And now, we all need batteries under NEM3.0 as well which are far more $$ than the string vs. micros debate.

 

[sorka]

Micros also mean you will never have a complete failure. Far safer for grid defection which is coming in mass.to California.

 

[skepticcyclist]

Micros also mean you will never have a complete failure. Far safer for grid defection which is coming in mass.to California.

Grid defection will not be done in mass as most municipalities require grid connection (you cannot go off grid), and NET 3.0 makes it less feasible.

 

[sorka]

Grid defection will not be done in mass as most municipalities require grid connection (you cannot go off grid), and NET 3.0 makes it less feasible.

False.

 

[sunwarriors]

False.

I think with how California is, it'll be legislated as illegal in probably IOU areas even if some folks are off grid in certain areas now. I believe I read about that in Florida recently. It's not a stretch with how things are going with the CPUC/governor/IOUs that they will prevent defection en masse here. It would be interesting to see if some grass root organizes a turn off export solar day during to really see how dependent the IOUs are with residential solar now.

 

[sorka]

I think with how California is, it'll be legislated as illegal in probably IOU areas even if some folks are off grid in certain areas now. I believe I read about that in Florida recently. It's not a stretch with how things are going with the CPUC/governor/IOUs that they will prevent defection en masse here. It would be interesting to see if some grass root organizes a turn off export solar day during to really see how dependent the IOUs are with residential solar now.

It is technically illegal in Florida but only in local municipalities that legislate it. It still doesn't prevent grid defection but requires jumping through more hoops.

There is currently no california state law preventing it. I already know several, personally who've defected.

 

[nwdiver]

Micros also mean you will never have a complete failure. Far safer for grid defection which is coming in mass.to California.

Lots of other single points of failure. The system I posted about that had been down for over a year was micros; The line side tap got fried. I had a similar breaker issue take down a system for a month. Breakers don’t care if they’re connected to a string or micros.

The cost difference isn’t small. You can buy 3 or 4 thermal cameras with what you’ll save on a string inverter vs micros.

I’m trying to help a customer with micro inverters get a battery so he can have backup. He would have saved ~$10k just going with a hybrid inverter from the start.

 

[sorka]

Lots of other single points of failure. The system I posted about that had been down for over a year was micros; The line side tap got fried. I had a similar breaker issue take down a system for a month. Breakers don’t care if they’re connected to a string or micros.

The cost difference isn’t small. You can buy 3 or 4 thermal cameras with what you’ll save on a string inverter vs micros.

Yea, all those are much easier to fix than acquiring a new inverter and swapping it out.

I will NEVER not have micros or optimizers.

 

[h2ofun]

It is technically illegal in Florida but only in local municipalities that legislate it. It still doesn't prevent grid defection but requires jumping through more hoops.

There is currently no california state law preventing it. I already know several, personally who've defected.

No way with my 100% electric house, with so little solar in the winter, would going 100% off grid every make sense, and I would be shocked it would really work for basically anyone else

 

[sorka]

No way with my 100% electric house, with so little solar in the winter, would going 100% off grid every make sense, and I would be shocked it would really work for basically anyone else

I'm still making more solar than I use in the winter but my winter usage is 1/2 my summer usage without using AC. Still, I'd want a backup generator hooked up to my 500 gallon propane tank as a fallback just in case and will probably go from 3 to 5 Powerwalls.

What is your source of heating?

 

[skepticcyclist]

False.

What did I say that was false? Most municipalities do require grid connection.

 

[nwdiver]

Yea, all those are much easier to fix than acquiring a new inverter and swapping it out.

I will NEVER not have micros or optimizers.

Apparently not for most people. One system was down for over a year and the other for over a month. If you have the skills why not save yourself ~$4k and just go with a string inverter?

Is the tiny bit of redundancy worth ~$4k?