SMA String VS Solar Edge with Power Optimizers

[jflorey2]

Can't tell for sure, but the quite high efficiency and limited # of parts implies a non isolated buck or
buck-boost circuit.

Yeah, there are a few reference designs out there for solar optimizers based on the Solaredge products. They are all four switch buck-boosts.

[ButchDeal]

Can't tell for sure, but the quite high efficiency and limited # of parts implies a non isolated buck or
buck-boost circuit. What they don't mention is that the optimizer losses must be added to the supporting
inverter losses, bringing them down to or below micro efficiency. The system design certainly gets more
complex, but in a varying shading or clipping situation, the optimizers should do better.

The current optimizers are 99% efficient and the HDWave inverters are 99% efficient so the combined efficiency is above the micro and most string inverters.
The buck-boost system allows them to have a much wider operating range.

There has been the thought of improvising a home brew optimizer, for a complete string subject
to earlier gradual shading. But so far it has been easier to just cut the tree. Bruce Roe

No shadow outperforms optimized with shadow any day.

[bcroe]

This is older but shows some of the internal components:
https://www.solaredge.com/sites/defa...imizers-na.pdf

Can't tell for sure, but the quite high efficiency and limited # of parts implies a non isolated buck or
buck-boost circuit. What they don't mention is that the optimizer losses must be added to the supporting
inverter losses, bringing them down to or below micro efficiency. The system design certainly gets more
complex, but in a varying shading or clipping situation, the optimizers should do better.

There has been the thought of improvising a home brew optimizer, for a complete string subject
to earlier gradual shading. But so far it has been easier to just cut the tree. Bruce Roe

[ButchDeal]

Any switcher puts an awful strain on electrolytic caps; designing them out should really help. I don't know any
details about optimizers. But if they are a variation of the well known buck converter, they should be FAR simpler
than any inverter. Multiple phase bucks and high frequencies would help. I would avoid them here, with little
shade (where is my chain saw), as they will be another source of radio interference. Bruce Roe

This is older but shows some of the internal components:

https://www.solaredge.com/sites/default/files/technical_comparison_microinverters_power_optimizers-na.pdf

[bcroe]

Actually the optimizers are very reliable. The early versions had lots of electrolytic caps, the current ones have none of those in them.

Any switcher puts an awful strain on electrolytic caps; designing them out should really help. I don't know any
details about optimizers. But if they are a variation of the well known buck converter, they should be FAR simpler
than any inverter. Multiple phase bucks and high frequencies would help. I would avoid them here, with little
shade (where is my chain saw), as they will be another source of radio interference. Bruce Roe

[ButchDeal]

I just do not like the whole serviceability issue with a distributed architecture. What no one seems to think about is that sooner or later, someone will have to go out to replace these optimizers one by one as they croak. Why marry a super reliable solar panel with a chunk of electronics that is less so - in a hard to service location? I was the first guy in Arizona to go whole hog into the SolarEdge mindset and learned first hand (the early versions had a horrible failure rate) that I do not want to be the guy responsible for servicing all these optimizers.

Actually the optimizers are very reliable. The early versions had lots of electolytic caps, the current ones have none of those in them.

[solarix]

I just do not like the whole serviceability issue with a distributed architecture. What no one seems to think about is that sooner or later, someone will have to go out to replace these optimizers one by one as they croak. Why marry a super reliable solar panel with a chunk of electronics that is less so - in a hard to service location? I was the first guy in Arizona to go whole hog into the SolarEdge mindset and learned first hand (the early versions had a horrible failure rate) that I do not want to be the guy responsible for servicing all these optimizers.

[sensij]

SMA has partnered with Tigo, but it looks more like a marketing thing without any actual technical integration. All communication is proprietary to the Tigo system, managed by the Tigo controller. There isn't an open source type system out there to do this, yet.

[lanb]

SWFLA - Thanks for bringing that up, I heard about it as well but has anyone actually installed one yet ? Are they proprietary like SE ?

http://www.sma-america.com/newsroom/current-news/news-details/news/16064-sma-redefines-residential-solar-with-new-power-solution.html

Solarix - Looks like optimizers are here to stay and even SMA is getting into the game. Do you think they would be more reliable than SE ?
To be honest I am more concerned about SE as a company than the technology itself. I wish they weren't proprietary.

[SWFLA]

SMA now has Power+ optimizers. Glad I have no shade...

[solarix]

The SMA system is going to be a lot more reliable than the SolarEdge system. There may be two SMA inverters, but the SolarEdge has 34 boxes that will fail and 32 of them will be located in an environment that is hostile to electronics and hard to service. They put a 25 years warranty on them to try and convince you that they are reliable, full well knowing that they are going to be supplying free ones to you through the years and the installer is going to get screwed having to replace them all one at a time as they fail. Do you really want your solar company to be coming out and dealing with your solar failures time after time? You have a choice between having lots of failures (which you will find out about conveniently through the module level monitoring) or a system that is flat reliable (such that SMA is willing to let you buy the extended warranty just before the initial 10 year warranty runs out).
Also, only the SolarEdge optimizers are warranted for 25 years - the SolarEdge inverters are only 12 years.
Full disclosure: I sell both brands, but I only use SolarEdge when I have unavoidable shady conditions - and we don't have rapid shutdown rules here (yet).

[ericf1]

Just thought I would resurrect this thread since it has been about 2 years for folks who installed the SE optimizers.

How has the reliability been so far ? If you were to do a system today would you go with SE or SMA ? Would you do anything different with hindsight ?

P.S - To make the comparison fair - I am assuming a non-shade installation for both systems

Thanks for all the info sharing.

My SE system was installed in Feb 2015 and has had no failures. Since selecting SE I have not kept up on any changes, but unless things have changed significantly, I would choose SE again.

[ButchDeal]

P.S - To make the comparison fair - I am assuming a non-shade installation for both systems

Not sue why that would be fair. We so rarely ever have completely unshaded roofs. It does make it an easier comparison albeit slanted way from one of SolarEdges strengths.

[sensij]

I used Solaredge for my first system, turned on in April 2015. I was tempted to save a couple bucks and go with SMA for the installation on my new house, but the rapid shutdown stuff is a headache so I'm going with Solaredge on this one too.

[lanb]

Just thought I would resurrect this thread since it has been about 2 years for folks who installed the SE optimizers.

How has the reliability been so far ? If you were to do a system today would you go with SE or SMA ? Would you do anything different with hindsight ?

P.S - To make the comparison fair - I am assuming a non-shade installation for both systems

Thanks for all the info sharing.