After swapping a major manufacturer string inverter 4 times over a two year period, and not knowing why, I can say unequivocally that I don't want to deal with that again. Talk about customer frustration... At least in a micro installation, the system remains functional when one microinverter goes down, and as you mentioned, people want to know what's going on!
One other factor is permitting and inspection. AHJ's seem much more comfortable dealing with AC branch circuits. Calculating voltage drops (although still important for the installer in an AC micro installation) is far less important than DC voltage drop issues in the mind of the plan reviewer. The major factors AHJs look at in a micro installation are string quantities, interconnection wiring and circuit protection, and grounding. I do agree with your smaller roof comment, too. We have mostly hip roofs on newer homes and they are all cut up into small pieces, especially in upscale neighborhoods where people have money to spend on solar energy products. Jason Szumlanski Fafco Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Keith Cronin Sent: Thursday, February 02, 2012 2:00 AM To: RE-Wrenches Subject: [RE-wrenches] String Vs Micro As I look out on the market place here, it must be close to 100 to 1, micro inverter installations vs string on residential systems. Don't know what the primary reason is, but I sense simplicity, as there are less "wrenches" out there, so to speak. The electricians and mechanical type folks I work with seem to get into a groove and just go for it. Sure, sometimes their biggest challenge seems to be interference due to the communications signals, but that appears to be the only hurdle. The more companies I work with or talk to, say the additional cost of micros is worth it, as opposed to training someone on string sizing and the concern for DC wiring mistakes. Perhaps its also due to the fact that we have smaller roofs and the need to be on multiple roofs, where other places around the country can put the system on one roof and be done? The perception of people that have micros seem to be bullish on the ability to know what is going on and when things are or aren't working and receive status. Alot of the leasing companies seem to be shying away from micros and perhaps its cost or the future liability of sending wrenches out to swap devices? What are wrenches seeing elsewhere? Regards, Keith
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