Does Sunpower + Solarbridge Microinverters = World’s Best Performing Solar System?

sunpower and solarbridge logos

Sunpower & Solarbridge sitting in a tree K-I-S-S-I-N-G

A lot of Aussie solar installers really dislike microinverters. In fact many refuse to install them.

The main reason is a fear of inverter failure. The reasoning goes something like this:

  • If a solar system component is going to fail early – it will usually be the inverter.
  • One thing that causes inverters to fail prematurely is heat, so your inverter should always be in a shaded position, ideally a cool garage.
  • Microinverters sit under the solar panels where they can get extremely hot, over 80°C in summer in Australia.
  • There is usually 1 microinverter per panel.
  • For a 5kW system that is 20 microinverters sitting on a roof waiting to fail.
  • If a microinverter fails, you need to get on the roof and remove the solar panel to fix it.
  • If only 1 microinverter fails on an installation, the cost of replacing it can wipe out the profit on the system.

To reinforce this fear, back in 2012 a lot of microinverters were failing (mostly cheap Chinese ones) and some installers were put off them for good.

So why does anyone install microinverters at all. And why do I have 24 of them on my roof?

All new technology has teething problems. Microinverters are no exception. But in the last 2 years, microinverters have actually become very reliable. But even the cheaper Chinese brands like APS have worked really hard over the last 2 years to make their inverters more reliable. APS have told me that their failure rates are down to 0.77% in the last 24 months from thousands of Aussie installations.

The way I see it is this. We’re in the is the 21st Century. If we can land a spacecraft on a comet, we can certainly make power electronics that can cope with extreme heat. There are millions of microinverters out in the field already. Most of them are reporting their temperature and output every few seconds back to the manufacturer via the web. This feedback loop has already enabled manufacturers to quickly identify the weakest links in their designs.  They are continuously improving the reliability and have made great leaps in only a few years. In fact I expect good microinverters to now outlast central inverters. The manufacturers believe this too, putting their money where their mouth is.  Twenty five year warranties have become standard for most microinverters compared to 5-10 year warranties on a typical central inverter.

Getting back to Sunpower

Last week the manufacturer of the world’s highest efficiency solar panels, Sunpower, acquired the manufacturer of one of the world’s best microinverters, Solarbridge.

This has to be a huge vote of confidence in microinverters from arguably the world’s best solar panel manufacturer.

Sunpower panels are the world’s most efficient at 20.4% panel efficiency. From what I’ve seen you can expect them to produce about 8% more power per rated Watt than other brands.

If you stick a microinverter on the back of one of these panels, then on an unshaded roof, you can expect to get a further 8% power increase because of the panel-level optimisation.

So a solar system made of Sunpower + Solarbridge should give you a 16.6% power advantage.

Pretty impressive!

But will everyone be rushing out to buy a Sunpower + Solarbridge system now?

Unfortunately not!

Why? Because Sunpower make the most expensive panels in the world, and Solarbridge make the most expensive inverters! So if you want the Ferrari performance, expect to pay for it.

As I have written before, buying the most efficient solar system on the market is not necessarily the best option, as the extra energy produced may not compensate for the extra ticket price. For example you could easily pay 30-40% more for one of these systems compared to a regular “Tier 1” DC solar system.

But if you have limited roof space, want a system with a proper 25 year warranty on every major component or simply want to own the best, the Sunpower Solarbridge option is definitely worth considering.

About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of SolarQuotes.com.au. My last "real job" was working for the CSIRO in their renewable energy division.

Comments

  1. A good summary of the current situation…however there is hidden issue with micro inverters from our practical testing here, and that is the amount of EMI that each and every single micro inverter radiates…the problem being that central inverters have much more physical room to apply 1st class filter components whereas with all the micros we have pulled apart…filtering components are generally thin on the ground. Amateur radio enthusiasts in the US have been quick to point out the problem…which is not helped when you have numerous micro inverters in aluminium ( no RFI shielding) cases all sitting well above ground with plenty of copper wire acting as super radiating antennae…

    • Hi Bruce,

      Thanks for the observation! Have you had any troubles with RFI from microinverters? I’ve never had an issue with mine.

      If so is it only AM radio reception or does it cause other issues?

      Finn

      • Hi Finn.
        Allow me to butt in here ~ off topic ~ because I don’t know how work the system:- I’m more than five years old, so often get lost in cyberspace.

        Sent you an email this morning ~ which just bounced back ~ including a link I discovered accidentally but which I thought some of your bloggers (particularly over on a different thread) might find most useful. Well worth exploring in re. the buying of components from ebay and the like, and might spare more inexperienced people some frustration and some cash.:-

        http://www.scamadviser.com/check-website/importerdeals.com

      • Tom Morley says

        Hi Finn

        Back on the EMI topic; In early 2015 Solarquotes kindly helped us choose an installer for a solar system on my mothers house and she purchased a 3 kW system that uses 6 APS YC500 micro inverters.
        In full sunshine the system seems to produce EMI that interferes with the TV signal in the house. The TV signal is normal when the solar system is switched off or operating in low light and at night. But if the household wants to watch TV when the sun is out then the solar system gets switched off (and sometimes they forget to switch it back on for days).
        I’m trying to find a solution for this EMI problem. Do you know if a ferrite choke (or several chokes) might be be able to be used. On which cable or cables might they be placed? Will they have any affect of system output or adversely affect the system in any way?
        We had an antenna guy out to try to improve the TV signal but he didn’t seem to be able to.
        Any other suggestions would be greatly appreciated

    • You point might be valid if these micro inverters produced the amount of current that string inverters do. I have 118 micro inverters on my roof and a ham antenna within16 feet of the inverters. I have no problems whatsoever.

      • Tom Morley says

        Hi Mark, Thanks for your comment.
        I’m still interested in finding a cheap and easy solution to the interference that my mum’s solar system (3 kW, 6 x APS YC500 micro inverters) causes to her TV signal. The solar system is the problem (the interference to TV signal is absent when the solar system is switched off) and I strongly suspect that the micro inverters are involved.
        Any suggestions (other than replacing the inverters) would be great to hear.

  2. Perhaps “the Sunpower Solarbridge option is definitely worth considering.”
    But the initial argument stands: IF something goes wrong ~ and sooner or later it WILL ~ it’s a major (and more expensive, Ferrari-wise) job to fix it.

    When my inverter, hanging on the wall had a problem I installed the replacement unit in less than five minutes and never even considered getting up on the roof (let alone fulfilling legal requirements like harness/scaffolding/whatever) and stuffing around with removing a (or ALL) panel/s (aka ‘aerofoil’ (!) to find the faulty one, turning it over and piddling around with pliers,screwdrivers, whatever, dropping bits and maybe breaking a couple of tiles I can no longer replace —> and so on.

    Though I’m usually in favour of many small non-interdependent constructs, on this issue I’m firmly in KISS group.
    For usefulness, reliability, durability, strength and simplicity ~ not to mention price ~ an International truck beats a Ferrari every time.

    • There’s no need to remove all panels to find the at fault inverter – they report their status back to the control unit, so the sparky just goes to the correct panel, unscrews it, unplugs the micro-inverter and plugs in a new one.

      We had one go recently, and it was a 20 minute job for the sparky to replace it.

  3. nb…. Never forget Murphy’s Law:- Anything that CAN go Wrong WILL go wrong.
    (Though I’m more in tune with McCafferty: Murphy was an optimist.

  4. nbb. That “16.6% power advantage.” can be more than compensated for by adding another ~ dirt cheap ~ panel.

    • very true!

      • if you have roof space, which was the other point i guess 😉

        • True enough. But roof-mounting is one option of several; even assuming a roof that faces north, you’d still need to accept non-adjustability for seasonal variations and other considerations, like painting or sealing your roof.
          A purpose-designed and cheap/simple alternative I’ve used is building a simple and cheap pergola/potting-shed/carport sort of thing, and can incorporate easy ways of adjusting the angle of the array. A bit of thought about positioning means you can have the whole thing nearer the ground ~ not only useful but safer in a serious storm
          Of course that requires sufficient space in the yard; but even that has options. I’ll post again a frame one of my friends set up for her own convenience, even though she has acreage.
          :- https://open.abc.net.au/explore/82086

  5. Mario Azzopardi says

    Hi can you please tell me what you think about phono panels ?

  6. I have been quoted $5,900 for a 4kW system consisting of Topsola panels and 4.4kW Solax inverter with Dual tracking capability. This is being installed in a north facing 2nd level and a 1st level West facing tiled roof with an option of upgrading to Jinko panels for an extra $350 and Tigo optimisers for an extra $1,000. Is this a good solution. I can only fit 3kW on north facing roof and I suspect that my daytime useage is about 7kW.

    • I know some installers that really like Topsola, but I’d pay the extra $350 for Tier 1 panels. Jinko is a much bigger manufacturer.

      The optimisers would give you about 8% more power, assuming the roof is unshaded, more if there is any shade.

      That sounds like a good size for a 7kWh daytime usage.

  7. The issue I have is living in Australia and NQLD, sourcing Solar panels is becoming a logistic nightmare. I refuse to be buy panels and inverters only the installers supply rather than being in control and paying for a system I want. I keep changing from enphase to SMA every day but want panels which are aesthetically pleasing to the eye as well as bloody good. For that I want Sunpower X21 in black or wait until sunpower/solar bridge technology eventually makes it way to sunny QLD… Any ideas 🙂

  8. How do you feel about Solarworld, LG, Hyundai, Qcell panels?

  9. It appears that Mr. Peacock never installed any quantity of Enphase 190s or 210s. ESPECIALLY the 190s, but both inverters…were terrible. So many of the 190s had to be replaced that large companies that installed PV in Hawaii (especially commercially) at that time started whole departments for Service, to switch out the faulty inverters. (I am speaking to the comment about (Enphase never really having reliability issues.)

    • Hello Mr G,

      May I call you Anthony? – this surname thing seems very formal.

      I absolutely agree with you – that sentence is sloppily worded – Enphase did have reliability problems back in the day with their 1st two generations of micro inverters. I was trying to say that they have not had reliability issues with their new generation micros – i.e in the last 3 years. I’ve update the post to reflect this.

      Cheers,

      Finn

  10. Laurie Mclean says

    Hi I need an extension lead to join one panel to another ,that have Blue line / now Solarbridge Micro Inverters The model no is . SBT-ECMF-10 Part no is 850-00286. Can you help. Thanks Laurie McLean

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