How did you decide? Microinverter vs Optimizer & PV Inverter

[entgegnen]

Hi everyone,

1. I am really close to pulling the trigger on a home system. At present, I am pretty confident about the panels (22-24) LG320s for 7.04 (10,842 @ 1.54) or 7.68kWh (11,827 @ 1.54) system.
1a. My annual usage is right in-between. I'd probably go with the (24) panel system.
2. My big point of indecisiveness is whether to go with Enphase (S280) or Solaredge (optimizers)
2a. The Micro-converters seem to offer a rather clean install in the existing utility box, no less. But I'm a two story with basically "zero" shading issues. And it seems that I'd need an extra piece of hardware in order to actually monitor things.
2b. The optimizer and Inverter route with Solaredge seems to offer better monitoring (which may not really matter once the novelty wears off?) and does seem to need a space on the wall for the inverter... and perhaps an extended warranty to take it till 25 years... but as I drove the neighborhood today... I saw lots of each type of system...

Is it really a coin flip? I've had two installers out...so far... each has said I could go either way... I suppose that sometimes this is true...

Questions:

1. Would one or the other system require fewer "runs" between the meter and the panels on the roof? Or can multiple runs be in the same line of conduit? Thinking at this point in terms of cosmetic appeal...

2. If I went with the optimizer/inverter route, how do I know if I have enough inverter? E.g. would a 7600 be enough - for either the 22 or the 24 panel version? I am guessing it would be.... Or do I have to jump all the way to the 10000? (with a substantial component cost as well).

Thanks.

Jason

[easye]

1- A good installer wont show anything on your roof other than panels and a bit of rails. Micro vs opti? Either works fine. Neither has a 25 year track record so who really knows? If you have zero shade why do either?
2 - 7600 would be plenty for a system up to 8.5 IMHO.

[jetsurgn]

How much /watt? Any difference on price between the two?

With the Enphase you will need a Envoy to monitor.

I would say both SolarEdge and Enphase both have good monitoring. I think its a draw in imho.

Do you have a nice cool place to locate the solaredge inverter?

[huge]

Wouldn't you get some clipping with the enphase, since you don't have any shade?

You would probably get the same output with the 315 w version and save some money if you choose enphase

[solarix]

I keep saying, when it comes to choosing inverters, the key criteria is reliability. Putting electronics on your roof, especially in hot climates, is fundamentally a reliability problem and when the time comes to have to start replacing electronics on your roof - you'll be sorry. I know they have25 years warranties - that doesn't mean the stuff will last 25 years - just that they will replace them when they fail (and they don't pay for whose ever labor has to do that). Do you really want your installer (if they are still in business) to keep coming back years from now to replace your microinverters one by one as they fail?

[sensij]

Wouldn't you get some clipping with the enphase, since you don't have any shade?

You would probably get the same output with the 315 w version and save some money if you choose enphase

No, this is false. The 320 W panels will outperform 315 W even with clipping at 280 W. The amount of energy lost to clipping is much less than the extra energy produced during every non clipped hour of the day.

[ButchDeal]

The difference would be very modest though ( 320 vs 315 ). Just the slight more production on the curve on the steep parts of the curve before slipping. is the cost difference worth the slight more production??
With shadows there would be a bit more difference.

Of course SolarEdge would be cheaper than enphase and not have the clipping.

[entgegnen]

Thanks everyone!

This is exactly the sort of discussion/debate I was hoping for. I find myself changing my mind a few times here.

1. As to "longevity" on the roof: solaredge vs enphase. I see the incremental labor argument as individual micro inverters fail 10, 15, 20 years from now. But I also see the same argument attaching to the "optimizer," right? And if an optimizer fails, don't I lose more than just a single panel (unlike he micro-optimizer)?

Moreover, while he solaredge inverter might be conveniently located on a garage wall... Isn't a change-out a substantial job for an electrician due to the voltage?

2. I had been attracted to he solaredge type option because I could potentially get an "AC" outlet at the inverter for use during daylight, in emergency situations (ca is earthquake country). Might never use... But would be grateful to have if I needed it.

3. I too had thought about clipping... Hence wondering if I'd need a 10000 unit over a 7600... But it seems that I'd be unlikely to recoup the $1000 difference between the units even if I avoided substantial levels of clipping....

4. The 315 v 320 is a good point. I'll compare the cost between the two. But if I am within a few pennies, I'll probably go 320.

5. My best (2) quotes are 3.28/watt and 3.35/watt... At that point, I'm just working out who I think will do the best job on the roof.

[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.

[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) 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]

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

[sensij]

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

[huge]

Thanks for correcting me Sensij. That would be better

[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.

[huge]

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

[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)

[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.

[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.

[solarix]

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

[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.

[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)

[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.