Enphase Micro inverters vs. central SMA Xantrex etc

thehardway
thehardway Solar Expert Posts: 56 ✭✭✭✭
I wouldlike to hear some opinions.

I am seeing a lot of statements that single inverter systems have a rather short life cylce (10-15yrs.)

Enphase is claiming a life expectancy of over 25yrs and a MTBF of 331 years. Sunnyboy and Xantrex say "built for more than 20 yrs under the right conditions" and there are reports http://ecmweb.com/ops_maintenance/photovoltaic-module-maintenance/

that say 5-10yrs. is the usual time before replacement

At approx 10-20% of the systems initial cost it seems the invertor should last at least as long as the panels. If it fails it becomes more than 40% of system cost which severely hampers the payback and ROI numbers.

I am inclined to go with the Enphase micro invertors as they will also allow me to expand modularly in the future as panel and invertor prices drop. I don;t see a huge difference in the cost.

Why would I want to go with a single central inverter and why are all of the installers quoting systems with the SMA vs. the Enphase.

I see a lot of you listing Enphase invertors in your systems. What is your experience? Any regrets?
«1

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Do a forum search for Enphase and you'll find this has been discussed here be for. Ad naseum.
    They haven't been around long enough to prove their warranty claims, and there's really no reason to believe they will outlast other systems as all are made from the same components so would have the same expected lifespan. So don't base your decision to buy on warranty length/expected lifespan.

    We are not going to start that argument again, either. Just a friendly little advance warning.

    Rather look at the other advantages/disadvantages. The Enphase (or other micro inverter) is better for dealing with varying shading conditions throughout the day. It is simpler to install because of there being practically no DC side wiring. It is easier to expand. On the other hand they tend to cost more per Watt and have more AC wiring - especially when you get up into the typical 3-5 kW system size.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Here are a couple threads:

    Enphase
    Enphase inverter MTBF calculation thread
    9.87 kW Enphase installation - Roof penetration questions
    Micro grid tied inverters on E-bay

    And easy way to search the forum is to use Google and the "site:" tag:
    • enphase reliability site:wind-sun.com
    I am becoming more agnostic over the central/micro inverter choice...

    Just have had my entire solar array replaced under warranty (took awhile, but the vendor did come through). And my central inverter was also replaced at the same time as part of a replacement program (also yesterday when the panels were replaced) even though my inverter/system was just out of 5 year warranty (at the time, before the mfg. went to 10 year for their GT inverters).

    So, my system is basically back to new for $500 cost on my part (panel vendor did not cover 100% of installer's labor costs).

    I am the guy that is pushing the ~10 year inverter hardware replacement meme (and possible 5 year / mid life repair trip back to the vendor).

    I am doing this to ensure that people have money set aside and plans for backup power "IF" they have problems with their system. Building your own power station is not cheap and comes with responsibilities that grid power does not have.

    In my case, I am somewhat lucky that both my vendors are still in business and providing support for their product (and even went beyond warranty terms). I still was ~4 months without solar panels while waiting for vendor to accept the claim and ship out new product.

    I am on grid power, so I only had higher power bills during the time my system was not operating. For an off-grid person--that would probably have been unacceptable for the typical cabin/home. Then what--run a genset for 4 months, buy new (temporary) hardware until the parts are back in...

    Hopefully, my stsyem will have a good long run before the next repair/replacement because the vendors have learned from their earlier products. And in my case the solar panels are the same (foot print, electrical specs.) and the central inverter was almost identical (new is ~6 inches taller, so some installations may have some remounting to do).

    What will happen in another 10-15 years? Don't know...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    BB. wrote: »
    Just have had my entire solar array replaced... And my central inverter was
    also replaced ...even though my inverter/system was just out of 5 year warranty...
    -Bill

    Curious...what would cause you to replace an entire solar array
    system after only 5 years? Storm damage? Premature failure
    of the components? I am especially surprised that you would
    need every panel replaced, as PV panels are definitely durable.

    John
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    They where BP 4175 (possibly 4175A) panels.

    They failed pretty quickly as near as I can tell... I generally take a few quick looks during the day and see how my power is going... And write down the kWH per day at night.

    Over ~2 days, my system went from roughly normal production to roughly 1/2 production.

    Called my installer, he came out the next day, pulled the panels and did a visual/electrical quick check. The warranty rules from BP (as I understand) is they will replace all panels if 1) three separate trips to replace 1 or more failing panels or 2) more than 20% of the panels have failed.

    In my case, >20% had reduced output and had visual signs of failure/impending failure. My panels are a "black" frame and interior components. Above the small junction box (pig tails to MC3 connectors) there is a thin metal plate. At and around the plate, there was a light brown coffee colored stain (looked like rust haze, but my guess it was heat). And some of the panels got enough heat that there was obvious delamination (streaks of air pockets) emanating from the junction box area.

    My installer charged me, probably, around $20 a man hour for labor to R&R the panels. BP would pay him partial money for R&R labor.

    Installer submitted a claim with BP and installer told me that it would take around 3 months to get new panels (BP was also going through a re-org, I was told, in that department at the time too, which did not help).

    I did not give anyone a hard time--just called my installer once a month and at 3.x months called BP warranty claim person... At that time found that my panels were getting ready to ship to my installer.

    Installer came out about 2 weeks later to install (scheduling and weather delays).

    I will say, this failure of the BP-4175 panels appears to not be rare.

    At the same time, we had the Xantrex Capacitor Recall--which was not done on my inverter since the array was out of service. And, for older Xantrex GT 3.0 inverters, there is (apparently) a voluntary replacement because of a factory soldering issue (don't know details). Even though my GT was sold with a 5 year warranty and my 5+ year old inverter was working fine, Xantrex/Schneider did R&R with a brand new current production GT inverter (with new, massive 3 bladed knife w/ spring assisted, disconnect that made the inverter about 4-6 inches taller). Xantrex did pay my installer to R&R the inverter.

    Everything worked out OK for me. $500 for labor (and new MC4 connections) was not bad. No other maintenance (wiring/conduit changes) required.

    From my installer's point of view--He really likes Sanyo HIT panels. Not not one failure.

    BP was slow but honored the warranty and did kick some money for R&R. His experience was BP was one of the few that helped with R&R.

    BP replaced with current production BP4175B panels (made in China). Panels appear to use thicker glass and heavier aluminum frame. Cannot tell if there are any changes to the junction box.

    Right now, the inverters he has the least amount of problems with are Fronius and SMA. Personally, he installed a Enphase system on his home.

    And if you have rats/squirrels living under your panels, you probably should screen around the panels to exclude them. He just finished rewiring/replacing hardware on a large install with rats nests (rats only chewed on black/positive leads--for what that's worth).

    Pretty much all I know and what happened with my home.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    thehardway wrote: »
    that say 5-10yrs. is the usual time before replacement
    I think all the major manufacturers have a 10-year warranty at this point in time. If a significant number are failing in warranty - those manufacturers won't last. Fronius and SMA are 2 big players as BB's installer noted - Haven't heard of any significant issues with those.

    That said - over 20 years most people do expect to have to replace a central inverter once. I know that SMA will extend your warranty to 15 years if you pay a bit more.

    Enphase has a 15 year warranty nice thing is that an inverter failure will only take out one panel (possibly 2 if you are using their D380 inverter depending on where the failure is internally). I have only heard of one Enphase failure and this was one of their 1st gen inverters. But I don't have a large enough sample size to determine any failure rates. Would need an installer to chime in here.
    thehardway wrote: »
    I am inclined to go with the Enphase micro invertors as they will also allow me to expand modularly in the future as panel and invertor prices drop. I don;t see a huge difference in the cost.
    Expandability is definitely a plus w/Enphase. I will likely add another 6-8 panels to my system in the next couple years.
    thehardway wrote: »
    Why would I want to go with a single central inverter and why are all of the installers quoting systems with the SMA vs. the Enphase.
    Enphase is the biggest micro inverter company and SMA is the biggest central inverter company.
    thehardway wrote: »
    I see a lot of you listing Enphase invertors in your systems. What is your experience? Any regrets?
    I would have tried harder to get bigger panels. Instead of the 180W panels I would now opt for 220-230W panels or so as this would have gotten me ~4 fewer inverters. But at the time the panels I got were so much cheaper than larger panels it didn't seem to be cost effective.

    The online monitoring is great - but I do wish it were possible to get the same level of information w/o having to subscribe to their monitoring service.
  • thehardway
    thehardway Solar Expert Posts: 56 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Have been reading back through the posts on micro vs. central and it seems to be a lot of salesmanship which I am not that interested in. Lot's of argueing and speculation about what might happen. I am more interested in real world experience. I realize the Enphase inverters may not have been around long enough to have the track record I am looking for. My electronicas experience has been it usually will fail within 2 days of removing it from the box or within 2 days of the warranty. If you get past those two points and don't drown it or get hit by ligthning you'll probably be OK. So far based on reports of real world feedback from owners it seems there are quite a few a lot of Xantrex inverters being recalled/replaced for potentially exploding. SMA's seem to fail toward end of warranty or shortly thereafter unless treated with kid gloves. Does anyone have or know of an SMA unti that is successfully through the warranty period and still going strong?

    Outbacks seem more expensive than either SMA, Xantrex or Enphase.

    Enphase appears to run about .30 per watt more than the SMA central inverter.

    Cost difference on a 15 panel 3000kW install would be about $900.00 Is there any hidden cost I am missing? What all is needed to grid tie the Enphase inverters? Just a 240v 15A Double pole breaker for each string of 15?

    Panels will be ground mounted and inverters easily accessed under panel. I can easily protect from rain/sun heat/cold in my application.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    I recommend the new SolarEdge system as being the best system solution for harvesting sunshine. There is an old thread on that as well. My opinion is that I do not trust the Emphase reliability because they have electrolytic caps in a rooftop application, and as a dealer, I don't want to be pulling modules in the middle of rooftop arrays trying to fix dead AC inverters.
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    thehardway wrote: »

    Enphase appears to run about .30 per watt more than the SMA central inverter.

    Cost difference on a 15 panel 3000kW install would be about $900.00 Is there any hidden cost I am missing? What all is needed to grid tie the Enphase inverters? Just a 240v 15A Double pole breaker for each string of 15?

    Panels will be ground mounted and inverters easily accessed under panel. I can easily protect from rain/sun heat/cold in my application.

    For the SMA inverter did you account for DC combiner boxes (if needed), DC wiring, DC fuses/breakers, DC disconnect, etc.? Some of these are pretty expensive (price a high voltage DC circuit breaker and breaker box)

    You are mostly correct for the Enphase. In addition to the circuit breaker you'll also need a AC interconnect cable to go from the last Enphase in the daisy chain to your AC wiring.
    Depending on your power company requirements you might need a lockable AC disconnect, but you'd need this with any grid-tied inverter.
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    For home use, Enphase hands down over large inverter. Installation is way easier.
    I'm an engineer and I've looked at the reliability numbers. Look at the failure modes and how easy it is to fix. Did an FMEA - Enphase won out over a central inverter. Did a QFD - Enphase again won hands down. Shading, even a slight shading issue your ONLY solution is Enphase.
    Need to split small arrays like three of four, your ONLY solution is Enphase.

    Well that about settles it.
  • thehardway
    thehardway Solar Expert Posts: 56 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Mr.Radon,

    This is the kind of info I am looking for. How long have you had your installation in place and running?

    Yes, my .30 per watt numbers were based strictly on the cost of the inverters. I guess I am hearing that there are more costs in extras with the central inverter setup so the cost may not be more equal?

    One other thing I am not clear on. Why is the recommended input on the M190 inverter 230w and the max output 190w? This doesn't add up to the 95% efficiency claimed. What am I missing?

    That's a monster array you have.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Here's a question to ponder. If you were designing a EV, would you choose a single motor design or or multi-motored in-wheel design. We know the single motor design works, we've done it for 100 years with gears and transmissions. On the other hand the Multi-motored design offers all the simplicity and flexibility we don't like about a single motor design. I guess it's a personal decision on the one to choose, I chose the Enphase because I thought it was a step forward and offered the simplicity and flexibility that a central Inverter didn't.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    thehardway wrote: »
    Yes, my .30 per watt numbers were based strictly on the cost of the inverters. I guess I am hearing that there are more costs in extras with the central inverter setup so the cost may not be more equal?

    Yes; if you're paying for the install rather than doing it yourself, the micro inverters may be cheaper because they are simpler to install.
    One other thing I am not clear on. Why is the recommended input on the M190 inverter 230w and the max output 190w? This doesn't add up to the 95% efficiency claimed. What am I missing?

    Panels don't put out their "nameplate" rating. Over the course of the day they put out an average which is less than maximum. To keep the inverter at its maximum output (and thus derive the most benefit) arrays are often over-sized. So a 230W panel operating at an average of 82% = 188 Watts over 4 hours of "equivalent good sun". Any peaks above 190 Watts will not be harvested, but over-all it give you more total output through the day than with a 190 W panel on a 190 W inverter.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    There so many " Variables " with each installation that it's hard to come up pinpoint data. With the public data that owners share you can get a idea of what they have and it's output.

    The one below is a idea of what a system does and you have to be able it interpret it with a little estimation. Enphase Inverter " Clipping " on the 190 occurs at 198-199 watts. If your seeing clipping you have to assume that the panel's are 200-230 + watts because they do not list the panel size.

    When you click on the past 7 days, the graph at the bottom that have flat tops on the output curves are where clipping has occurred. On your pointer you see the max output, if you look on the panel display you'll see the what each panel was producing. Even if the output looks flat if you slide the pointer along you can see the variations in the output during the day in watts.

    https://enlighten.enphaseenergy.com/public/systems/yhtP8606

    I have 100's of these links, if this is a posters system here, it's not my intention to upstage you. I think anyone with PV solar realizes it's all about averages and not about trying to pinpoint something at some given time.
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    thehardway wrote: »
    One other thing I am not clear on. Why is the recommended input on the M190 inverter 230w and the max output 190w? This doesn't add up to the 95% efficiency claimed. What am I missing?

    That's a monster array you have.

    Panels only produce their nameplate rated power under ideal conditions, clear sky, cold weather, panel pointed directly at the sun.

    If the weather is hot, say middle of June, even with the panel pointed directly at the sun a 230W panel will only produce maybe 200-205 watts.

    If you have your panels on a fixed mount (like a rooftop) then they will only be pointed directly at the sun at best for a couple minutes a day and only for a few days twice a year.
    The rest of the day and the rest of the year the panels will NOT be pointing at the sun. This means their output power will drop. The further away from directly at the sun, the more their power drops.

    If you look at the output from a fixed panel throughout the day you will see the typical "Bell curve" Maximum at noon (depending on panel orientation) and then rolling off on the sides.

    So yeah, when it's cold out and the panel is pointing directly at the sun you'll lose energy because the inverter can't keep up with the panel. But the rest of the time the panel's output power is low enough that the inverter works at max efficiency.

    Also, the Enphase inverters are rate at 190 watts, WHEN THEY ARE HOT.
    When they are running cool the inverters can exceed 190 watts, during the winter mine typically run at 199 watts and yesterday a couple of them hit 200 watts.

    You can see an example of what happens when the panel output power exceeds the inverter by looking at the output from My Array
    My trackers manage to keep the panels pointed fairly close to directly at the sun through most of the day and when the weather is cool (like recently) my inverters run at max output (199 watts) I have 230W panels.
    So yeah during the winter I waste a bit of power, but during the summer I typically see my inverters producing 193-194 watts.
  • thehardway
    thehardway Solar Expert Posts: 56 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Thanks to all. Some great answers and info.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    I am not sure where I found this. You can find your location on the " Satellite " map. There is a slider on the time bar and you can follow the sun track for anytime of year by setting the date and moving the time with your pointer.

    http://suncalc.net/#/38.2527,-85.7585,10/2011.02.27/22:14
  • xiphias
    xiphias Solar Expert Posts: 52 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    For shading issues and module-level optimization you might also look at a DC solution like Tigo. That approach also has the advantage of being able to use a central inverter stripped of the MPPT functions, so can be simpler, less expensive.

    NOAA also has a convenient solar calculator at

    http://www.esrl.noaa.gov/gmd/grad/solcalc/
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    i was going to say that google earth should be able to do the different times of day, but this new version is flakier than the previous and i doesn't see either the time slider or the time of day slider.
  • Fatawan
    Fatawan Solar Expert Posts: 71 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    I am just starting my research on a system for my home. I am convinced that Enphase is the way to go, but I will wait until the end of the second quarter for the next generation to come out. I think there will improvements in the design(hopefully soothe the fears of the electrolytic caps folks) and they are upping them to 215W(with 5% built in above that). That will give a much better margin of safety before clipping.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    If the new M 215 commands the same $20.00 per unit up-charge as the M 210 it would take a long time and a whole lot of clipping to justify the cost. If the panels degrade 10 % in 10 years a 230 W panel would be down to 206 w max or so, but some with trackers might justify it.

    Just for Information the M 210 takes 38 V and only Sanyo panels with 84 cells produce that, I guess.
  • Fatawan
    Fatawan Solar Expert Posts: 71 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    If the new M 215 commands the same $20.00 per unit up-charge as the M 210 it would take a long time and a whole lot of clipping to justify the cost. If the panels degrade 10 % in 10 years a 230 W panel would be down to 206 w max or so, but some with trackers might justify it.

    Just for Information the M 210 takes 38 V and only Sanyo panels with 84 cells produce that, I guess.

    They told me "similar $/watt cost as the 190". The new 4th gen version will work with all the same panels on the approved list for the 190W version. The current M210 will still be the only option for the Sanyo panels for the near future.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    By the way, my "new" system is working well--I am seeing ~3,100 watts peak (first clear day since install)... My old system never saw more than ~3,000 watts peak. This new inverter is a 3.3 kW vs the 3.0 kW previous version.

    -Bill :D
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    BB. wrote: »
    By the way, my "new" system is working well--I am seeing ~3,100 watts peak (first clear day since install)... My old system never saw more than ~3,000 watts peak. This new inverter is a 3.3 kW vs the 3.0 kW previous version.

    -Bill :D

    bb,
    do you attribute the extra to the pvs being replaced or because this inverter is not limited to 3kw?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    It is hard to tell... I never saw a warning from the inverter that said it was limiting power... And it was always just bumping at the 2.999 kW rating.

    Today, it was crusing in the 3.0-3.2 kW for multiple minute realm very nicely.

    So, it could be brand spanking new/clean panels (which have tighter specs. than the old ones), a inverter with 300 watt higher peak rating, better MPPT algorithm, 4-5 years of hardware improvement, or a more "optimistic" power meter...

    I have no clue--And it is really too small a number to notice difference in my power bill at the end of the month.

    After a few days, I will get a few clear day kWH readings (right now, we are getting periods of clouds/showers/weather patterns so it will be a while)... Before, I would get maybe two 20 kWH days per year, and a hand full of 19+kWH days.

    But if the readings are 5% optimistic--That is still meaningless (older Xantrex inverters have been reported as being within 1-2% accuracy--Don't know that the new models are any better/worse).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Enphase are actually overpriced due to their substantive monopoly.
    But several new competitors are shipping and have warranties that
    match the panels - 25 years. They also are cheaper than Enphase, making such a system cheaper than any using centralized inverters. That clinches the dominance of micros for residential and small business. They make installation simple even for those not thoroughly versed in electrical systems. They also eliminate the single point of failure in centralized inverters, making failure of a unit no big deal. At this point, I see no valid arguments in favor of central inverters. Interestingly, despite Enphase claims that mean point of failure for their units is well over several hundred years, yet they only offer a 15 or so year warranty. That will change when the competitors arrive in force - they have much more robust capacitors, which are apprently the most likely component to fail.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Capacitors. Unless they use ceramic printed circuit boards, to match the temperature coefficient of the ceramic caps, or use flex ribbons to mount them, the thermal stresses will tear the caps off the boards in a couple of years. Sure it will add to the cost, but so do warranty claims. And there better be a handy way to pull a dead inverter without having to pull a bunch of panels off the racks.

    Still not sold on the microinverter idea
    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 ,

  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Considering it took me and two friends only 5-6 hours to install 45 panels, I don't think it would take more then a half hour to swap out any inverter. Best of all I wouldn't have to kill the entire array, just the branch circuit and two quick connects. Unplug the MC4's and I'm done. Way easier then a single inverter. Best of all I can trouble shoot. Try to find the problem panel in a single array 6 years down the road. I would love someone to explain how they can quickly find the fault within a string of 8 panels? You'd have to rip into each one till you find the problem child. Much easier to know where the problem is before you get on the roof then spend time on the roof localizing the problem.
    Yeah that cost a little more, but I couldn't set up my system without them. Now that I have them and see the issues my sister has with her Sunny Boys and another friend's system I did with Sunny Boy I'm sold on micro inverters. Even the slightest shading on a panel kills the entire array...
    The way I see it in terms of automotive, micro inverters are like ODBII - the car will tell you whats wrong. SunnyBoy is like a non-OBD car, no brains got to roll up the sleeves and check everything to find out where the problem is and then you are just guessing.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    I encourage you to check out the SolarEdge system. Has the distributed advantage of the Enphase with a Powerbox on each PV module that MPPT optimizes each, sending standardized power to a central inverter that performs the AC conversion with its 60hz capacitors in a location much more servicable. The powerboxes are warranted for 25 years because they have only ceramic caps. The system has a string size of up to 25 modules, decreasing wiring. Efficiency is at least 5% better than SMA and much better than that in shady situations. Built in web interface gives module level visibility. The next generation of solar harvesting in my book.
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc

    Just checked it out: http://www.solaredge.com/files/pdfs/se_system_overview.pdf
    I don't see the advantage. Looks like you have to install expensive controllers that just does MPP for each panel but the panel that produces the least current is still the bottle neck. You still have to deal with bringing DC off the roof and mount a large inverter.
    Hopefully in the 20 years when my inverters start to fail technology will have progressed.
  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    Re: Enphase Micro inverters vs. central SMA Xantrex etc
    BB. wrote: »
    By the way, my "new" system is working well--I am seeing ~3,100 watts peak (first clear day since install)... My old system never saw more than ~3,000 watts peak. This new inverter is a 3.3 kW vs the 3.0 kW previous version.

    -Bill :D

    What happened to your old system?