Micro inverters

JESSICA
JESSICA Solar Expert Posts: 289 ✭✭
Can anyone here give me a simple explanation about "micro inverters", and whether they are more efficient and cost-effective than regular inverters?
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Comments

  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Re: Micro inverters

    Each panel (or pair) has its own inverter and the AC is then wired onto a common feed.

    From what I can tell it is more expensive than a central inverter but it has advantages of separating any shading issues to only those panels instead of affecting a whole string of panels. It also allows for per panel monitoring.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Micro inverters

    A micro inverter is a grid tied inverter that can run 150-250 watts which can be connected to the back of a single PV panel and inject power directly into grid. In this way every panel is operated independently.

    As to more cost effective and efficient the answer 'all depends'. Generally I would say the answer is no on both counts but if you have a long wire run from panel to central inverter there may be less wire loss on a micro inverter system with wiring running at 240 vac then lower voltage DC for a central inverter. They also make PV panel independent for shading of some panels.

    One of the controversy is the heat that the inverter will be subject to sitting on the back of a panel in the sun. Heat adds stress to the electronics, in particular a single type of component used in these inverters.

    Supplying power to a single phase grid has power pulses inline with the grid sine wave voltage. The current is 120 Hz similar in shape to a full wave rectified sinewave.

    For a panel to operate efficiently, and a maximum power point algorythm to work, there needs to be a smooth DC current load on panel. This requires a sizable storage element to smooth the AC power pulse out. In the micro inverter these are a bank of electrolytic capacitors.

    Electrolytic capacitors lifetime are effected by heat. Generally, the higher the heat the shorter their lifetime.
  • JESSICA
    JESSICA Solar Expert Posts: 289 ✭✭
    Re: Micro inverters

    So, they need to be mounted on the roof, close to the panels?
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Micro inverters
    JESSICA wrote: »
    So, they need to be mounted on the roof, close to the panels?

    That is generally the idea but they don't have to be. Since micro inverters are designed to work with a single PV panel they are designed for lower DC voltage then a central inverter. If you run long wires from PV panel to a micro inverter you will have higher wire loss.
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Micro inverters

    The micro inverters do have to be mounted at the panel due to the NEC ground fault protect/detection requirements. If you mount the anywhere else, then you need a appropriately rated GFP system for each and every inverter, near the cost of the actual inverter itself
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Micro inverters
    JESSICA wrote: »
    So, they need to be mounted on the roof, close to the panels?

    My Enphase micro-inverters are mounted underneath
    each PV panel, actually the lowest edge of each panel.
    I've attached a photo of one as it was being installed.

    --

    With regard to the "heat issue"...theory vs reality comes into
    play here. Micro-inverters are more weather exposed, true, but
    they also deal with much lower (=cooler) power input than a
    central inverter does. Which has the more risk? Enphase
    warrants its micro-inverters for 15 years, whereas Fronius, an
    industry standard central inverter vendor, warrants for 10 years.
    That 50% difference in warranty suggests to me that the heat
    issue is a red herring for micro-inverters (time will tell).

    --

    There are other pluses/minuses that I am sure will be brought
    up in response to your question, so I will not elaborate on them.
    But, I would like to bring up one of the more subtle micro-
    inverter benefits.

    One big advantage I see to Enphase in particular is that it
    is web-enabled, and you can do complete monitoring of
    your PV array, down to the panel level, using their software.
    For example, I was monitoring my array's performance from
    my cell phone while I was vacation in Hawaii earlier this
    month! The panel level monitor enables you to see - and
    fix - problems on a specific panel that affect an entire
    string. That is a very powerful tool (click on my link below
    to see what I mean).

    John
  • nsaspook
    nsaspook Solar Expert Posts: 396 ✭✭✭
    Re: Micro inverters
    RCinFLA wrote: »
    A micro inverter is a grid tied inverter that can run 150-250 watts which can be connected to the back of a single PV panel and inject power directly into grid. In this way every panel is operated independently.

    As to more cost effective and efficient the answer 'all depends'. Generally I would say the answer is no on both counts but if you have a long wire run from panel to central inverter there may be less wire loss on a micro inverter system with wiring running at 240 vac then lower voltage DC for a central inverter. They also make PV panel independent for shading of some panels.

    One of the controversy is the heat that the inverter will be subject to sitting on the back of a panel in the sun. Heat adds stress to the electronics, in particular a single type of component used in these inverters.

    Supplying power to a single phase grid has power pulses inline with the grid sine wave voltage. The current is 120 Hz similar in shape to a full wave rectified sinewave.

    For a panel to operate efficiently, and a maximum power point algorythm to work, there needs to be a smooth DC current load on panel. This requires a sizable storage element to smooth the AC power pulse out. In the micro inverter these are a bank of electrolytic capacitors.

    Electrolytic capacitors lifetime are effected by heat. Generally, the higher the heat the shorter their lifetime.

    Their take on lifetime. http://www.enphaseenergy.com/downloads/ElectolyticCapacitorLife092908.pdf

    Most of the lifetime figures seem very optimistic. 15 years might be at the edge of true service-life in a harsh environment with high quality components (non-Chinese junk).

    There are caps that could last 20 years but like most things you get what you pay for.
    http://www.cde.com/catalogs/330.pdf
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Micro inverters

    Regarding which is cheaper--I would guess that systems that are smaller than 3,000 watts probably can be equal or even less expensive in costs for micro inverters... But, in the end, price/quote out both systems and see what works out best for your situation.

    If you have a long wiring run from the panels to the street--I would look very closely at your line voltage an voltage drop from a panel mounted inverter to your utility meter/pole transformer.

    All thing being equal (which it never is), I would prefer to make very long wiring runs using the solar array to GT Inverter run vs GT inverter to main panel run...

    A GT inverter will run somewhere between 200-600 volts on the input.

    The line side only runs between ~210-264 volts (+/-) and the set point not only depends on the voltage drop/increase from local current--it depends on where your utility sets it voltage at the pole (out of voltage line will kick off GT inverter). If you utility line voltage is too high and you add the voltage increase from generating your own power--it is not difficult to hit the ~264 VAC set point.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JESSICA
    JESSICA Solar Expert Posts: 289 ✭✭
    Re: Micro inverters

    Thanks to all.

    The info is for a neighbor who – knowing I have a pv system – asked for my help (Oh boy! Did he come to the wrong person!)

    His potential contractor suggested one of two things: 10 micro-inverters (guess they are Emphase) or a Sunny Boy 5,000. I think there would be a total of 10 235 watts panels.

    Since the only inverters I know from experience are the exeltechs and the Go Power (junk), I needed the info to help him.

    P.S.: I suggested he suscribes to this forum.
  • michelb
    michelb Registered Users Posts: 9
    Re: Micro inverters

    There are a few other benefits of micro-inverters. They are much more modular; you want to add another 5 panels, buy another 5 panels (don't need to match the others) and 5 micro-inverter and you the connection is pretty straight-forward. Similarly, if part of your array is damaged (e.g. branch falls), you can either replace (and it doesn't have to be similar to the other panels) or remove without affecting the rest of the array. It also removes the 'single point of failure' from your system. Inverters do die and when they do, if you're on a central inverter, your whole system goes down with it. With micro-inverters, if one dies, the rest of your array keeps working.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Micro inverters
    It also removes the 'single point of failure' from your system. Inverters do die and when they do, if you're on a central inverter, your whole system goes down with it.

    And if your micro inverters get struck by lightning ...

    A fairly fatuous argument, in my opinion. As are a lot of the "pro-Enphase" statements.

    Yet I have nothing against micro-inverters. They are a viable solution under some conditions, which have been mentioned. There is no "this is better than that" unless you have the specifics of the application.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    Re: Micro inverters

    I maintain that Emphase microinverters will have a bad failure rate due to thermal degradation of electrolytic caps - at least in our hot climate. As a dealer, I do not want to risk regularly replacing under module u-inverters out in the middle of on-roof arrays. There are other distributed type inverters like Solaredge I do use however. Plus, with Emphase there is no way to monitor the system without a web connection which many people do not have or want to pay for.
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Micro inverters
    solarix wrote: »
    I maintain that Emphase microinverters will have a bad failure rate due to thermal degradation of electrolytic caps - at least in our hot climate.

    To be fair to Enphase, you should tell us your reasoning. Do
    you have any data, testing, or product failure experience that
    caused you to arrive at this conclusion?

    Enphase's simulations and empirical testing indicate a 50-year
    life for the capacitors themselves. Their testing was done at
    full input specification in a high temperature location (a
    desert). In actual operation, the capacitors are being charged
    at only 1/3 to 1/2 of max input, which means the 50-years is
    conservative.

    solarix wrote: »
    Plus, with Emphase there is no way to monitor the system without a web connection which many people do not have or want to pay for.

    [Edit: I am revising my remarks here because I realize that
    your comment refers to the ISP monthly cost, not Enphase's
    modest management software subscription fee.]

    Those who don't want to pay for high speed internet access,
    say, $30/month, are kind of punching themselves in the
    nose. I save so much money from my Internet access that
    the ISP fee pales in comparison. For example, I found and
    bought a car earlier this year via the Internet, and I estimate
    that I saved $2000 over what my local dealer wanted for his
    similar car. That being said, I agree that there are those who
    won't pay for it, or are in situations where it is not available.

    By the way, it's not strictly true that you can't manage
    Enphase inverters without a web connection. The Enphase
    control module shows stats on its LCD display. In other
    words, that is similar to central inverters that are not
    web-enabled.

    John
  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    Re: Micro inverters
    solarix wrote: »
    Plus, with Emphase there is no way to monitor the system without a web connection which many people do not have or want to pay for.
    While you don't get the detail of their web based monitoring system, the monitoring box will let you know if any inverters/panels are non-functional if you plug a computer in to it. I will admit that it definitely could be better and more informative with just a bit of work on their part (have a look at the Enphase data access thread on the board).
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Micro inverters
    Enphase's simulations and empirical testing indicate a 50-year
    life for the capacitors themselves. Their testing was done at
    full input specification in a high temperature location (a
    desert). In actual operation, the capacitors are being charged
    at only 1/3 to 1/2 of max input, which means the 50-years is
    conservative.

    I'm an electronics engineer, in the satellite industry, and anyone expecting a 50 year design life from electrolytic caps, is dreaming. Their shelf life is not even that long. The aluminum case will, by it's porous nature, eventually allow the electrolyte inside to dry out. You know how hard it is to seal a solar panel from water vapor, it's just as hard to seal it (water) inside something.
    Add rooftop heat, cold and voltage, and I'd be surprised to see 10 years. Daily 60F temp swings, from noon sun, to pre-dawn cold, I'm actually surprised PV panels manage to get 20-30 years on the glass.

    Simulation = BS
    Empirical = BS
    1. derived from or guided by experience or experiment.
    2. depending upon experience or observation alone, without using scientific method or theory, esp. as in medicine.
    3. provable or verifiable by experience or experiment.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Micro inverters

    We have had this discussion before on other Enphase threads... Without one taken apart in our hands--we are pretty much speculating.

    However, if there are electrolytic caps in the inverter--I too would doubt much more than a 10-15 year life.

    Add large daily (or more often) thermal cycling swings--it is not unusual for components to crack solder joints.

    I have wondered if they fell into the mistake of predicting failure rates and converting that into "life".

    For example, I have 4 tires on a car that go 40 thousand miles until the first flat. 4 tires*40k miles = 160,000 miles Mean Time Between Failures <> 160,000 miles of predicted life as we all know that tread life is pretty much gone by 40-50k for most tires (mean time between failures vs wear-out).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Micro inverters
    mike90045 wrote: »
    I'm an electronics engineer, in the satellite industry, and anyone expecting a 50 year design life from electrolytic caps, is dreaming. Their shelf life is not even that long....Add rooftop heat, cold and voltage, and I'd be surprised to see 10 years. Daily 60F temp swings, from noon sun, to pre-dawn cold, I'm actually surprised PV panels manage to get 20-30 years on the glass.

    Simulation = BS
    Empirical = BS
    1. derived from or guided by experience or experiment.
    2. depending upon experience or observation alone, without using scientific method or theory, esp. as in medicine.
    3. provable or verifiable by experience or experiment.

    Mike,

    Enphase published a study which, as I read it, involved
    testing candidate capacitors at a Palm Springs location. It
    is this actual testing that I was referring to as "empirical
    data." The below link describes their methodology and results:

    http://www.enphaseenergy.com/downloads/ElectolyticCapacitorLife092908.pdf

    I am not an electrical engineer, so it would be foolish
    for me to debate you on EE topics, heck, I barely passed
    EE back in school. Your background as an EE in the
    satellite industry does not necessarily give you more
    insight to the issue than Enphase's inverter-specific
    design engineers. They have access to the part
    numbers, the product design, the test results, the
    thermals, etc. I'd accept that your background
    enables you to read and fully understand their study.
    Why don't you look at it, and if you think their
    analysis or product design is flawed, tell us why.

    Common sense does suggest that no single electronic
    component of any type will last 50 years. What
    if, though, Enphase selected a component type that has
    four times the quality rating of a standard-grade component,
    and they built fault-tolerance and redundancy into their
    design? Mightn't that assembly last longer than what you'd
    predict for a single, standard grade capacitor?

    Lastly, while their study suggests a useful life of 50 years,
    which is another way of saying their spec'd capacitor
    degrades 2% a year in the worse case, no one contends
    that the design life is 50 years. My expectation is that
    Enphase products will be reliable or will be replaced for free
    during their 15-year warranty. If Enphase has evidence that
    the underlying major components could last 50 years or more,
    then that gives me more confidence that 15 years is attainable.
    I hope they will last beyond that, up to the full 25-30 year
    expected useful life of a PV array, but only time will tell.

    John
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Micro inverters

    john,
    i think i can state this for most here when it comes to this type of thing. we do hope that they aren't just shoveling bs, but ultimately the proof is in the puddin'. if the company is around for that long term and few of them fail then they were not fooling. we have our doubts here and reasonably so.
    as to any electrical part lasting 50yrs, there are many of them out there and i don't think there were that many for electrolytics. many of those will fail without any hours of use even on them when you are talking a decade. to use them for decades even some of the standard electrolytics may survive that long although most will be compromised. i know i have some pushing 40 years old that may still function, but under harsh conditions with guaranteed usages of at least a few hours every day is highly questionable even with all the bs they state. the bottom line is that it is their warranty and if they are still around when these things fail in the warranty period (this is your risk if they will be here or not), they must replace them.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Micro inverters

    For space, we build to the harshest standards, and hope something last 10 years for us. But there is no way a engineer can compete with a statistician. Ask a statistician for a report, and they will ask, "What do you want it to say" ?
    I read their study, and while it's a good read, it flys in the face of nearly all realistic design expectations.

    We'll all know in 10 years or so.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    Re: Micro inverters

    I've been doing electronics since the 70's and know from personal experience the reliability of electrolytic capacitors. Even worked for a while as a test engineer in the capacitor production department for a well known scope company. I watched for years as the Japanese manufacturers put out power supply after power supply (switchers) using gradually better caps not understanding all that time that electrolytics are not spec'd for frequency of operation and are less reliable the higher you go.
    When a circuit designer makes the choice to use electrolytic capacitors and then try to achieve high-rel through testing and specsmanship, instead of using a design that eliminates this serious problem, I really wonder about them.
  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    Re: Micro inverters

    Enphase seems to be aiming for a 20+ year design life according to their whitepapers. They are backing it up with a 15 year warranty - will they be around for 15 years?

    No one knows for sure, but so far I haven't heard of any failures. I would have expected to have heard of at least a few infant mortality deaths, but it appears that their pre-shipping testing/QA is weeding those out effectively. I know there are a few installers around which use their inverters a lot - would be nice if they chimed in as they probably have some decent volume to back up their data.

    The primary caps used in their design are 4 Nichicon UPW1J222MHD 2200 uF 63V rated at 8000 hours (~4 years) at 105*C.

    The maximum operating temperature of the inverters is 65*C. The inverters are also completely potted which should minimize the effects of electrolyte evaporating which is the primary cause of e-cap failure.

    I guess we'll find out in 10-20 years!

    Rumor has it that their next generation inverter is going to do away with electrolytic caps as they are aiming for a very small (cell phone / pack of cards size), high frequency design - as solarix mentioned above, high frequencies are not friendly to e-caps.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Micro inverters

    Solid tantatlum caps, about 4x as costly as the best wet slug electrolytics, those I could see lasting a long time, but still, thermal stresses will affect the parts. We shall see.
    I'll bet there is some sort of NDA with their installers, there are always failures, and if none, after thousands and a year of installs, something stinks.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    Re: Micro inverters
    mike90045 wrote: »
    I'll bet there is some sort of NDA with their installers, there are always failures, and if none, after thousands and a year of installs, something stinks.
    Anyone can buy their inverters from any of their distributors - and many places sell them online to anyone - so I highly doubt there is anything "stinky" going on. Heck - you could browse all the publically viewable systems on their website to see how many panels/inverters are "offline" at any time.

    Anecdotally I've got 18 of them on my roof and have been in communication with a few other owners with about 50-60 between them with no failures yet. Admittedly, only one of them has had them installed for longer than a year, though he has 14 of the original inverters - the ones they have been selling for over a year now seem to be significantly better.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Micro inverters

    i should point out that how many are offline is not an indicator of anything. it could just be not enough sun due to weather or nightfall. it would also seem web connection problems would be in there somewhere too. i think in a failure, that either the company or the home owner knows about, that it would result in the removal of a redundant dead system occupying space needlessly.
    i don't believe they would reveal their failures, let alone the rates of failures or the numbers of those failures, as that would impact their business no matter if the inverters are worthy of their guarantee or not. i am skeptical, but hopeful all will be ok. i do believe these smaller inverters have a place and i remember saying so years ago here on the forum when we were talking of the ok4u inverters. i don't believe they are suitable up at the pvs or in large systems, but there will always be exceptions and if it proves out i can change my mind.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Micro inverters

    The question is a simple one:

    All companies manufacture their inverters using components sourced from the same suppliers. These components have a maximum expected lifespan of 'X' years. Given that the "ingredients" to every inverter are no better than that, how can (or why does) Enphase expect a longer lifespan than other companies especially given that their units are meant to operate in what can only be considered an environment more detrimental to the internal components?

    Either Enphase is overly-optimistic, or other companies are exceedingly pessimistic. (The matter of "will Enphase still be in business 15 years from now?" is irrelevant, as it doesn't address the expected lifespan issue.)

    I am not saying there's anything wrong with their inverters or that no one should use them. It's just that their warranty doesn't make sense in light of what is known about component longevity. But real-world performance isn't always the key to warranties: sometimes they just gamble on averages and expected "legal outs". In the end, the "come on" of the warranty can be worth more in business profits than the eventual expense of having to make good on warranty claims.

    Example: The company I used to work for sold two different garbage disposals. One warranted for 5 years, the other with a "lifetime" warranty. Actual difference between the two: price. The extra $ bought "insurance" against having to make good on claims. They knew full-well that most people would move, remodel, or even die before the units would give up and thus the number of them that would actually see the warranty through to the end was very small. (Keep in mind that on a disposal there are any number of "legal outs" as it is only warranted against defects in material and workmanship, not against performance or resistance to abuse.)


    Personal update: The sky above my house at 2:00 PM yesterday: http://kaleidopsyche.deviantart.com/#/d2vdn2r That yellow dot is the sun.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Micro inverters

    "(The matter of "will Enphase still be in business 15 years from now?" is irrelevant, as it doesn't address the expected lifespan issue.)"

    actually it does have to do with their expected lifetime claims on the inverters for what if after say 7, 8, or 9 years they purposely go belly up before all of the major failures start rolling in? if the claims are false this is what many shysters do is cut and run with the money.
  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    Re: Micro inverters
    All companies manufacture their inverters using components sourced from the same suppliers. These components have a maximum expected lifespan of 'X' years. Given that the "ingredients" to every inverter are no better than that, how can (or why does) Enphase expect a longer lifespan than other companies especially given that their units are meant to operate in what can only be considered an environment more detrimental to the internal components?
    Enphase has told us specifically what caps they use in their system and their rating (see my earlier post). They have also told us how they calculated their estimated life along with what lab tests they have done to back up those calculations. From my basic research, their claims seem to be fairly accurate and according to industry standard. I highly doubt they would have attracted the VC capital they have unless those VCs have also verified their claims using their own experts - but who knows.

    It seems to be fairly well established that central inverters tend to start failing around 10 years. The question is - what is the nature of those failures - and if related to e-caps - what caps were/are they using and under what environmental conditions? I'm sure that a number of you here should be able to provide that sort of information.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Micro inverters

    Never saw any data that says central inverters die after 10 years. Who made that one up?

    Might as well say that Enphase inverters are perfect, will last forever, and everything else is junk.
    Or that the company is a fly-by-night bunch of scam artists out to grab as much money as possible then run.
    Neither statement is true, but exaggeration seems to take the place of fact on this issue.
    Kind of like the climate change argument.

    It seems everyone is taking Adam Savage's saying as gospel: "I reject your reality and substitute my own."

    I just regret that I, in all likelihood, won't be here to see if Enphase's claims hold true or not.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Micro inverters

    you don't know when you will go and that's a bit of morbid talk as i'm just as apt to go before hand and maybe moreso. who knows?
    anyway i don't want anybody misconstruing what i said before as i don't want it to sound like i am calling them fly by night, but that if (big if) they really are shysters that how long they will be around has lots to do with the inverters they make and the reliability of them. it's difficult to make good on a warranty for something if a company isn't around to do so and you can't force a non existent company to do anything.
    to be very clear here, i am not saying this is the case with enphase if you really read what i've been saying because i don't know that. nor am i implying they are shysters as it is just a way of saying show me and in the meantime i have reason to doubt the product, but time will tell.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Micro inverters

    Niel, that's exactly why I was leaving that bit out of the equation. And then look; stupid me wanders right down the path he was trying to avoid! Sorry. :blush:

    The conclusion I draw is that Enphase is gambling on maximum component life and reflecting this in their warranty in order to address the question we all asked when the units were announced; how well is that inverter going to stand up attached to a panel up on the roof in all kinds of weather extremes?

    I do not think Enphase are any worse than other inverters. I just don't think they're any better either. Not in their construction, and not in their usefulness.

    Quote from Enphase squib on NAWS' own site:
    "Home owners and business owners get more energy, lower costs, and greater control of their solar investment."

    Every part of that statement is debatable. I just wish people would stop declaring any one particular inverter (or any other part of a system for that matter) as being the vastly superior, one-and-only, solution to all situations. 'Tain't so.