Ok just got off the phone with a former student, now a designer at a significant module manufacturer and I've almost hit my limit discussing this, which now I'll make worse I'm sure.
... I can't believe that Enphase has received as much attention as they have. In my humble opinion, I'm asked way too much about this relatively insignificant industry product. I wish I never discussed the ups and downs of micro-inverters with Raghu and Martin before Enphase was Enphase. Too many downsides to list, there are few niche applications that they can work well within. Small residential is absolutely as far as it goes. Large scale, no way. Their marketing department deserves the MVP for the company, and the psychology of regular people and mostly solar newbie's today, plays right into the "New & Shiny" toy thing. We all know conductor runs benefit from higher voltages, at lower voltages for the same power, systems require larger more expensive conductors, overcurrent protection devices, Yadda Yadda Yadda. They are not less expensive. They are not easier to design with. They are not more reliable. The proof will surely come out. Don't be afraid of string inverters, you can do very short strings, and don't choose to go with the bite size, but still un-satisfying experience of working with them. OK, yes, it may be true that, central inverters are no more reliable than micro-inverters, by the same logic micro-inverters are no more reliable than central inverters. There will always be a small percentage of bad units, a known reality of electronics. So I ask, as you are installing these inverters, do you know if they are good until you have installed the modules, plugged them in and run them? I know I don't, in which case I don't know if I'm burying 1,2,5,10,20, etc of bad units under the modules... in which case, you have to remove the modules, often involving a lot of labor on the roof, requiring getting the harnesses back on, setting up the ladder, replacing the "one-time-only" WEEBS (if you use them) or undoing the equipment ground, cutting and re-bundling wires and zip-ties, etc, etc. The reason they won't be able to get much cheaper will be because of quality control and testing each one extensively before leaving the factory, and support, service and warranty response teams will be busy, busy. If there's a project bigger than one string of 3 typical cSi modules, shortest length I know the Sunny Boy 700U can work on, and you believe Enphase is required due to shading or whatever, then A.) You probably shouldn't be installing PV there, or B) You may need to learn about the existing options and brush up on some other design techniques. A good question recently asked about performance is, "Are the claims of shading performance gains that Enphase provides only good for panels that don't have any bi-pass diodes or just one diode?" - I'm not sure and haven't looked at their literature in a while, nor do I care to, so I would appreciate an education on this one. All I know is that customers don't like to see me back too many times, and I know I've had to replace the same inverter a few times... with micro, it's multiplied. The beauty of central is that it doesn't take much, if any work on the roof, to trade out a Xantrex for an SMA, Fronius, or whoever, but say you get to a point where you do want out of the Enphase family... you'll have to reinstall every single module... I'm nervous for the cool-aid drinkers. Oh, and as for the future, ACPV... none for me thanks either... not for a professional, for similar reasons mentioned above, and not for homeowners. We really don't need a homeowner installing their own ELECTRICAL systems. This can only fuel the counter argument to solar with a likely exacerbated blanket statement of solar being a dangerous fire-hazard on rooftops. Here's a challenge, I will pay someone $150 dollars (same as Enphase inverter replacement reimbursement) to show me a project designed using them, greater than three modules, that I can't redesign using something else, with equal or better cost, time or performance results. Seriously, send me an old or new Enphase design, I'll look it over, and propose an alternative. If a reasonable person won't agree in that alternative, I will send a check. Ryan J. LeBlanc NABCEPT Certified Solar PV Installer Cell: 707.591.1950 Direct: 707.536.9839 [email protected] http://www.NaturalEnergyWorks.com _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
