Micro inverter, Optimizer, or Neither??

[mattyg18]

Hello all. After spending about 3 hours last night researching on this forum I finally took the plunge and signed up. I purchased a Sunpower System for my old house about 10 years ago. We just moved into a new house a few months ago and are starting all over again. Had no idea how much the technology has come and all I can say is wow.

After meeting with a few local vendors and being told three different things i'm completely confused now. Was hoping to get some clarification so I called Sunpower directly and they really weren't too much of a help. I'm hoping someone can help me make a decision on this as i'm not sure what I need.

The rear of my roof is south facing and I have little or no shading issues. I'm interested in Sunpower Panels again primarily because of their warranty, longevity in the arena, and the fact that i've had them already on my previous home. I met with three different local Sunpower dealers. They are either proposing the e20(327) or x21(345) panels. One dealer with the x21 panels is recommending micro inverters (not sure of the brand) and the other dealer with the x21's is recommending power optimizers by solar edge. Each dealer is has their reasoning as to why theirs is better. On the other hand, the dealer with the e20 panels is telling me that I do not need either power optimizers or micro inverters because I really do not have a shading issue. He is only recommending a string inverter. In addition, he is also telling me that the less I have on my roof the better and the less to go wrong. Seems to make sense to me. On the other hand I do not want to make the mistake and not install micro inverters or power optimizers now and have to install them in a few years. In my other house I do recall on several occasions when we had snow and it was very sunny out my system was doing nothing. I never realize why until now. If there is snow on any of the panels then the system shuts down until they are cleared off. I can't tell you how many days we lost the ability to make electric because of this.

The system that is being proposed is about an 8k system for either of the three companies with 24 panels. The cost is about the same for the x21's (micro inverters or power optimizers) and a little less for the e20's. I realize that the e20's are supposedly a little less efficient and also produce a little less electric. Not a huge deal though.

After calling Sunpower directly and telling them the situation they really couldn't make a recommendation other than different dealers have different ways they do business, and that they recommend micro inverters over optomizers. I was a little surprised with that response. The person I spoke to was also clearly reading off a cheat sheet giving me the benefits of using micro inverters (which had no benefit to me).

So in a nutshell thats my scenario.

If anyone has any advice on this it would be greatly appreciated as i'm now sure what to do at this point.

[wes@SH]

There has been a bunch of conversation about this in a recent forum here: https://www.solarpaneltalk.com/forum...th-lg315n1c-g4

Ignoring ease of replacement for weakest system part, voltage clipping, cost...I think the most damning thing is that SE outperforms microinverters except on very low light days. The only reason I would pick Enphase is if I were putting up less than 8 panels. I'll post this link again to two public systems that are within a mile of each other that have the same panels, one with SE and one with Enphase. If you use PVwatts to predict expected output based off orientation, the SolarEdge system has one less panel production wise, and numerically it has 2 less. As a potential buyer, I think it is also important to look at the two interfaces you will use to monitor your system....I have a preference for one of those as well. If all things are equal production wise, something like that could be a deciding factor.

http://www.redstonecleanenergy.com/enphase-vs-solaredge/

[J.P.M.]

Hello all. After spending about 3 hours last night researching on this forum I finally took the plunge and signed up. I purchased a Sunpower System for my old house about 10 years ago. We just moved into a new house a few months ago and are starting all over again. Had no idea how much the technology has come and all I can say is wow.

If anyone has any advice on this it would be greatly appreciated as i'm now sure what to do at this point.

I'd agree with you - things have changed a lot in 10 years.

Other than that, be careful what you ask for in the way of advice.

I'd suggest you might benefit from spending a bit more time around here reading how and why some posters think Sunpower, while good quality stuff, is way overpriced for what you get.

Depending on where you are, S.P. equipment will probably cost you about 20% or more $$ upfront and produce not much if any additional annual output for that premium for as long as you're likely to own any system. If you want bragging rights, buy S.P. and pay something like $4.25- $4.50/Watt, or buy equally fit for purpose equipment for about $3.50/Watt or so. If you want to spend a few extra $$, spend it on a good installer and negotiate tough but fair. You're afte

As for S.P's bullet proof, super duper, bumper to bumper warranty: If the stuff is so good, why is such a warranty needed ? A good installer is the best assurance you have of a trouble free system. Still not convinced ? Use a quality installer and buy one of those rip off extended warranties - I'm not recommending them but that may ease your mind for a lot less $$ up front.

Download free from the net and read "Solar Power Your Home for Dummies" Knowledge is power.

Study and understand how tour POwer Company (POCO) charges you for electricity. Assuming the purpose of the solar exercise is to lower your electric bill in the most cost effective way possible, knowing how you pay for power and tariff options available to you are essential knowledge tools for meeting the cost effective goals.

After that (and not before), get more quotes for some non Sunpower equipment. Ask vendors questions you already know the answers to. You'll separate the wheat from the chaff a lot quicker and knowledgeable vendors will know you are not a rube simply running from a high electric bill. Larry with a ladder type peddlers will either run or try to B.S. their way through the sales call - which you'll know - and eliminate himself.

Take what you want of the above. Scrap the rest.

BTW, welcome to the neighborhood.

[Mike90250]

Having had 30 years of experience in electronics in hostile environments, I would suggest the simple string inverter, in a sheltered indoor area. I just can't imagine how 20 rooftop gizmos are going to be trouble free for 20 -30 years. String inverters are good for about 10 years, and then easy replacement. If you do reasonable daily monitoring, you can quickly detect a problem.
If you had shade issues, then I would look at the other alternatives of per-panel gadgets on the roof.

[silversaver]

String inverter. It is ground level service that take less than 30 min for the job. (I saw them switch out my inverter - TWICE). If the inverter out of warranty, you can always buy a new one and labor will be less than $200

[wes@SH]

Like people have said here, a lot has changed in 10 years...spending 20k on electronics and not having interactive feedback via your phone half a world away is slightly off-putting. Even if I had an older system or wanted to buy USA made products only, I would probably look at Tigo as an addition for individual panel performance.

A string of SE is 8-16 volts DC when it is disconnected from the inverter. Having the data of which optimizer is down, a part they will replace for 25 years, and a ladder; it is not an overwhelming or risky task for a homeowner to self service. It is probably more daunting to clean your gutters or replace your car battery. That is one of the coolest things about SolarEdge.

[mattyg18]

Thanks fellas. My lean was to go with the string inverter and not either of the micro inverters or optimizers at this point and you guys just helped me make that decision. After reading all of these posts I think i'm going to look into other brand panels now. One dealer recommended LG in addition to the SP and said they were also Tier 1 panels. He then, in a round about way, bashed LG by saying that the warranty is only 10 years. Funny. The LG they recommended was the LG365N2W-B3 which seems to have great reviews and also happens to be the most powerful panel i've seen so far. Another company recommended a Hyundai panel which I couldn't find much info on. I would definitely consider other panels however have no idea which one.

As far as replacing the String Inverters, i've also hear they typically last 7-10 years. One of the dealers told me they cost around $4000 to replace. I know it depends on the size inverter but does that sound correct for a 8k system? Seems like a lot if i'd have to replace one every 10 years or so.

I found two area dealers that have great reviews and i'm comfortable using either for the install. At this point I just need to decide what equipment I would like and see if they are willing to install that. I sorta get the feeling that one of the companies is more "cookie-cutter" and offer you their package and thats it. It includes the panels and optimizers. But i'm going to wait until I decide on what it is I want before I go back to them with the question.

If anyone has any recommendations on panels that are up there with the SP panels in the 325-350 range I would appreciate it. I know there are so many to choose from and its hard to decide.

Thanks again!

[jflorey2]

As far as replacing the String Inverters, i've also hear they typically last 7-10 years. One of the dealers told me they cost around $4000 to replace. I know it depends on the size inverter but does that sound correct for a 8k system? Seems like a lot if i'd have to replace one every 10 years or so.

You most likely will not. The inverter on my older house (Sunnyboy 6000 watt) is now 16 years old and going strong. And it is in a fairly poor mounting location - on the east side of the house where it is in full sun for several hours a day. If I do have to replace it, it will probably be due to yellowing of the display cover rather than a functional problem. The inverters on my newer house are a very old design (Sunpower SPR-5200 and SPR-3500) and have had no problems in 13 years.

Older inverters often failed due to electrolytic capacitor dryout. Newer designs do not use electrolytic caps.

[ButchDeal]

they also don't cost anywhere near that much, and some have warranties longer than that. SolarEdge inverter for example comes with a 12 year warranty that can be extended to 20 or 25 years.

[ncs55]

SMA offers extended warranty also. It costs a little more than the standard warranty.

[J.P.M.]

Thanks fellas. My lean was to go with the string inverter and not either of the micro inverters or optimizers at this point and you guys just helped me make that decision. After reading all of these posts I think i'm going to look into other brand panels now. One dealer recommended LG in addition to the SP and said they were also Tier 1 panels. He then, in a round about way, bashed LG by saying that the warranty is only 10 years. Funny. The LG they recommended was the LG365N2W-B3 which seems to have great reviews and also happens to be the most powerful panel i've seen so far. Another company recommended a Hyundai panel which I couldn't find much info on. I would definitely consider other panels however have no idea which one.

As far as replacing the String Inverters, i've also hear they typically last 7-10 years. One of the dealers told me they cost around $4000 to replace. I know it depends on the size inverter but does that sound correct for a 8k system? Seems like a lot if i'd have to replace one every 10 years or so.

I found two area dealers that have great reviews and i'm comfortable using either for the install. At this point I just need to decide what equipment I would like and see if they are willing to install that. I sorta get the feeling that one of the companies is more "cookie-cutter" and offer you their package and thats it. It includes the panels and optimizers. But i'm going to wait until I decide on what it is I want before I go back to them with the question.

If anyone has any recommendations on panels that are up there with the SP panels in the 325-350 range I would appreciate it. I know there are so many to choose from and its hard to decide.

Thanks again!

For anything I contributed, you're welcome.

It's not the panel Wattage that is important. It's the system size. Often, lower Wattage panels from the same mfg. are a bargain with the same quality, something like buying a new car that's last yrs. model.
Whoever told you $4K on an inverter replacement is wrong, by about a factor of 2 or so, unless it's for multiple inverters on a large system. Most string inverters seem to be lasting more than 7-10 yrs.
On the warranty of 10 yrs., see my prior post. BTW, panels do not all fail or expire the day after the warranty expires.
As others suggest, and throwing an attaboy on your decision, with no shade, I'd skip the micros too.
I'd not use vendors as my first source of information. Unscrupulous peddlers use (customer's solar) ignorance and their natural tendency toward laziness to not get their own answers to screw people. Read the book, get answers to any questions raised by reading here or from other sources with no skin in the game. Question everything everyone says, including me.

[rsilvers]

As far as replacing the String Inverters, i've also hear they typically last 7-10 years. One of the dealers told me they cost around $4000 to replace. I know it depends on the size inverter but does that sound correct for a 8k system? Seems like a lot if i'd have to replace one every 10 years or so.

More like $2500 to $3200 if you order it yourself and pay for an electrician to swap it. No doubt someone would charge you $4000 if you just pay full MSRP.

[DaveDE2]

For a point of reference, I just bought two of the new Sunny Boy 6.0's (6kW) inverters for $1910 each. They are designed such that replacement is easy without having to fuss with the dc or ac disconnect part of it or any conduit refitting, etc. I could unbolt the top half (sans dc/ac disconnect) and put a new one in in about 30-60 minutes.

SMA just relaesed their new 5.0 and 6.0 inverters. They tell me that all of the other TL series inverters will be replaced soon, so an 8kW unit is apparently in the works.

[silversaver]

Most of the warranty on string inverter up to 20 yrs in less than $1000