Comments on: Microinverters Are Changing How Grid-Tie Solar Systems Work

By: Certified Solar Pros, Inc.

Certified Solar Pros, Inc. — Mon, 09 Aug 2010 03:45:01 +0000

Very misleading introduction to this article. Today’s top pv modules have a by-pass diode that will drop a panel from the string’s production once that panel’s output drops below a manufacturer’s programmed percentage. If only one cell in the panel is shaded the ouput of the string is reduced very minimally. If an effective shade analysis is applied to the layout then the shade should be only occuring temporarily during sun hours and will have a minimal impact on the total daily kwh. If there is long-term shading on a panel, even with a micro-inverter, where’s the beneficial R.O.I. justification? If the system doesn’t have multiple strings (central inverters can handle up to 12-14 panels on one string) then the effect of a shaded panel is even less.

With regard to wiring; ac wiring still has to be ran from the combiner box on the roof to the service panel and a larger gauge wire allows less line loss because the electricity travels on the outside of the wire so the larger surface provides more efficiency. The wire must still be protected by EMT conduit same as the dc wiring.

With regard to noise from a central inverter; have yet to experience this from SMA, Fronius or PV Powered inverters.

What’s curious to me is that all of the aforementioned inverter manufacturers are in the inverter business, have the engineers, have the distribution network…why haven’t they introduced a line of micro-inverters if these are truly the “way of the future”? And, why would anyone in solar keep buying central inverters if the micro-inverter is the “silver bullet” for kwh output?

I’m a proponent of new and improving technology, but there is a risk to deploying hundreds of these or any other until they have sufficient “in the field” exposure.

By: John Rollins

John Rollins — Mon, 26 Apr 2010 04:46:35 +0000

Home Depot has started offering “solar in a Box Systems” in DFW. These are dual solar panels with the micro-inverters built-in from SunPhase.

By: Craig

Craig — Sat, 20 Feb 2010 20:31:47 +0000

Those are good points Solar Installer. It is always good to do a lot more research than buying when it comes to major investments like going solar. I wonder if there is any way for the micro inverter to be mounted in a more accessible area other than the back side of the panel? That would solve that particular issue. Maybe in the future this will be one of the bugs that gets ironed out of this new technology.

Thanks for your (and everyone’s) input. We love to know you’re reading. Even more than that, we love to learn from you.

By: Solar Installer

Solar Installer — Wed, 17 Feb 2010 01:45:46 +0000

Read the claims carefully. 25% improvement if one of the panels of a string is shaded. No shade during prime solar hours, then little need for micro-inverters.
Second issue is changing these out when they reach end of life. Dismantling the array one panel at a time will be very costly.
real solution is to build the inverter function into the panels directly.

By: Solar Lights Obsessive

Solar Lights Obsessive — Fri, 09 Oct 2009 18:36:42 +0000

Wow…..I loved reading this. I am passionate about solar power and this development sounds fantastic.

If the micro inverter can boost the performance of a photovoltaic panel by up to 25% as claimed, surely this has the potential to bring down the price of mid sized domestic units – This has to be a good thing if it encourages more people to install the technology.