How did you decide? Microinverter vs Optimizer & PV Inverter

[sensij]

If I may (using entgegnen's numbering)...

Basing the decision on 5 (clipping) is kind of silly. The other differences between the systems are much more significant. Many people who post in the forum do seem to develop an emotional response to clipping, no matter how many times it is demonstrated that the amount of energy lost is inconsequential.

On 6 - microinverters are more interchangeable, but they make it hard because most use a proprietary trunk cable to make the connections. You can build yourself an adapter, perhaps, but it wouldn't be an off-the-shelf kind of thing. You might also have to give up per-panel monitoring on the replacement micros; I'm not sure you can have two monitoring systems active at one. If you truly want interchangeable inverters, stick with a pure string inverter.

[entgegnen]

Thanks Ltbighorn!

I've honestly gone back and forth - and am currently still leaning towards the SolarEdge product.

1. It does seem that the optimizer is less prone to fail that the micro converter. (recognizing that I would have a larger single point of failure potential with the central inverter). I felt this was addressable thought the extended warranty. This brings me to 25 years on everything, just like Enphase.

2. I do like the apparent storage flexibility of moving to a "StorEdge" product. I just wasn't moved by what I saw on the Enphase side so far. Maybe I am missing something.

3. I did take into consideration the underlying company financials (reading both the SolarEdge and Enphase) annual reports. Frankly, it really looks like SolarEdge is moving to profitability with recent positive quarterly results... whereas Enphase financials did not appear as strong. (keeping in mind that I don't hold stock in either and I am not a financial analyst. This is merely my layman's take away from reading their reports.). But in any event, this would seem to play into things like warranty viability.

4. I do not have the space constraints - so this wasn't really an issue.

5. It seemed that my specific setup would have no "clipping" whatsoever... whereas the micro converters would likely (always?) have a small amount of clipping (I think this was probably a large reason for my preference concerning one over the other... even if we are really talking about rather small volumes of electricity)

6. I certainly do appreciate your comments about being stuck with a brand that is not compatible with other brands. Would this mean that one micro inverter is pretty much interchangeable with the microinverter of any other company? (this argument does have me thinking)

[ltbighorn]

Thanks! I had a lot of time to mull over how I feel about all the options while waiting for my roofer to be available.

[solarix]

Wow, nice to hear a well thought out, rational decision for once! Thanks....

[ltbighorn]

I was debating the same decisions (along with string inverter). For my size array, all options were pretty much a wash cost wise. The reason I ultimately went with the Enphase microinverters:

1. Space is at a premium here in SF, and I didn't want the inverter taking up space in my garage (particularly since it's deeper than anything else I have wall mounted, and thus cuts down on walkable space). Outside isn't a better option as it's a narrow access path to the neighbor's front door, and also very visible from the street (neighbors would be very irritated).
2. Having the inverters within 10 feet of the array removes the need for the external cut-off switch in my area, I believe, so one less box on the exterior wall (especially with all the big red labels now).
3. I personally prefer the safety situation of running AC from the roof rather than DC. Not a big deal though.
4. I can expand without having to make decisions today about how much excess inverter capacity to purchase.
5. Doesn't lock me into SolarEdge -- I haven't pre-purchased extra central inverter capacity that only works with SolarEdge optimizers. With Enphase microinverters, if there's a better product out there in 5 years or whenever I want to add, I can use it without discarding excess pre-purchased capacity. I can feed additional AC on one of the existing branches without modifying or interfering with the Enphase setup.
6. 25-year warranty and expected lifetime is longer than central inverters.
7. I build redundant/reliable systems for a living, and I work very hard to avoid single points of failure. A central inverter is a giant single point of failure. Microinverters are lots of points of partial failure. Optimizers are single point of failure + lots of points of partial failures, worst of both worlds. It just doesn't sit well with me. I realize that the failure rate of the optimizers is likely to be much lower, but there's still the inverter. It may be a wash, but psychologically I'm more comfortable with multiple points of partial failure, given the next two items. Similarly I build arrays of systems, servers, devices, etc. with the expectation that some will fail, but the system as a whole keeps on chugging.
8. With microinverters, the incremental cost to do replacements or maintain spares out-of-warranty is low. With a 25 year warranty, I'm already ahead, but should Enphase go out of business, I can pickup spare micros on ebay quite cheaply. Even if there are failures, I think it unlikely that all the micros would fail early. In the unlikely situation SolarEdge goes out of business (or no longer makes a compatible product), because of the higher cost to keep cold spare inverters, I'm less likely to have one on hand, or have more capital tied up in them. If optimizers fail too, then I'm in a nasty lock-in cycle of having to keep buying more of what's not serving me well, because more money is sunk into replacements that only work with more SolarEdge stuff.
9. My roof is flat and only requires me to climb a 1-story ladder. My panels are being installed in separate rows with a good tilt. Should my installer not be around to honor their 15-year workmanship guarantee, I'm confident that I could do replacements myself without risking life and limb. I can get up there easily in 10 minutes.
10. Allows me to combine house consumption monitoring (Envoy-S Metered) and integrated that into the same dashboard overview as my production data.
11. I can take advantage of the Enphase AC battery should it become cost effective. I feel like Enphase's approach/product is more likely to bear fruit for my approach than Tesla's.

When comparing for yourself, to keep it apples-to-apples, make sure to include the $250 fee for Enlighten Manager access needed for per panel monitoring.

I'm by no means advocating that any particular option is "THE BEST", just sharing what influenced my decision. Hope it helps.

EDIT: I should also add, I live in cool sometimes foggy climate, where no one has AC. So with good ventilation on the tilts, I think the microinverter reliability can only benefit from the milder conditions vs say, someone in Phoenix AZ.

[nomadh]

I had the same situation. I have a bit of shading late in the day and loved the idea of micro inverters. But I also just replaced electrolytic caps in nearly all 100 of my lcd monitors at work after 3 years to keep them going. Not a fan of the concept of all those caps up on the rook even though I know a few people who have had them for almost 10 years without problems. Well a bout 2 problems. 1 failed and 1 needed a reboot of types. So I lean towards optimizers and solar edge looks to be a stronger company than enphase.
But what I actually did when it got down to it was a sunnyboy with sps. Long term I just dont trust the grid or the political climate. Looking at the upcoming political choices I think we all have to admit we just are not a serious country anymore. So even though I am taking a hit on output in the afternoon I have a system that I can get some use out of if something really goes wrong with no extra cost. If that security isnt on your list or you can afford more security I'd lean towards solar edge. I'm betting that there will be add on optimizers for my system in a few years.

[entgegnen]

Thanks for everyone's comments and suggestions. I've sent a quick email to the contractors to make sure nothing has been left out from the quote (e.g. that Envoy thing for monitoring) and as soon as I get confirmation on the quotes, I will proceed with a coin toss since I no longer can decide which type of system I prefer. But in light of arguments made by ButchDeal, I am now leaning towards SolarEdge.... (having gone so far this afternoon as to read their financials and compare them to Enphase)

[ButchDeal]

1) simpler device and solaredge is all ceramic inside. It has a much higher temperature range.
3) not much but you would be paying for the S280 than SolarEdge (or should be as solaredge is cheaper )
5) deffinitly in the range.

[huge]

Thanks for correcting me Sensij. That would be better

[huge]

Only 15 minutes? It would probably take me 15 minutes just to get the screws off

[solarix]

Changeout of a wall mounted inverter takes about 15 minutes and is easy. They all use a 2 piece design where the disconnect switch with its HVdc connections are isolated so no voltages are present to the inverter during servicing.

[sensij]

Post links to the installer's solarreviews.com page, if it exists.

[huge]

Those costs are reasonable for Southern California. Which companies are they? Can't post links, just give names.

[entgegnen]

Thanks ButchDeal-

1. Ok, the optimizer is a much simpler device. Perhaps much less likely to fail. But if it did, I'd be on the roof exactly like the micro inverter. So same labor, albeit perhaps different likelihood of repair need.
2. Thanks, yes, I confused SMA and
3. Would the S280 clip a lot?
4. I'll check out the 315
5. Do those costs per watt seem reasonable for southern ca? 3.28 - 3.36

[ButchDeal]

1) optimizers are much simpler devices and in general one fails you should not lose more than the one modules output. There are some strange situations like a minimal string length and losing one.
2) it sounds like you are talking about the SMA Secure Power source which SolarEdge does not have, BUT solaredge can be expanded to support a battery and give full backup capabilities.
3) the SE 7600 will not clip at all with your size system. The micros would. You would need a lot more solar to justify the SE10000 unit. you have listed a 7.68kw system above and the SE7600 is capable of outputing 8.35kw AC. 7.68kw DC is never going to clip.
4) if you can fit 24 or more 315w modules it will be cheaper. Think of buying solar by the watt not by the module (or panel in layman terms)
5) thats what is important.