Micro vs. Central Intverter Study

[silverhorsefarm]

This is a little self-serving, since the study was performed by Enphase, but attached is a study concluding that Enphase systems outperform PVWatts projections by 8% whereas tradtional inverters underperform projections by a similar margin.

http://enphase.com/wp-uploads/enphase.com/2011/08/Enphase-Study-Performance-Versus-PVWatts.pdf

[Naptown]

I see you got the newsletter too.
There must be something to the idea of individual MPPT tracking lower DC losses etc.

[Mike90250]

I think they are jsut blowing wind. They only compared the projected PV watts output, to their measured output, they did not do a side by side compare to IDENTICAL panels, feeding modern string based inverters. It's a marketing campaign, not a "scientific study" with a control.

If nothing else, it may show PV watts is biased on the conservative side, to avoid "hey they said I woudl get x watts".

AND, they used 5% shade, which will always foul up real life/estimate, and their panels will shine in mixed shade that would shut down a string inverter.

The energy losses due to resistance in system wiring could not be accurately accounted for in this
study.

Bull. *#^&@. If you have 200' of 10 ga wire, it will have x loss. Every time. it's a law. They just didn't want to be bothered. (or it explained the "advantage")

[silverhorsefarm]

I see you got the newsletter too.
There must be something to the idea of individual MPPT tracking lower DC losses etc.

Yeah, but I saw no harm in passing it on, since it's now public domain. As has been already pointed out, it's not a perfect study.

But I will say this: I have 0% shading, I *still* went with Enphase, and my harvest has outstripped PVWatts handsomely.

[s.xavier]

definitely take these studies with a grain of salt....

you can make a strong case for drinking poison to ward of evil spirits while growing 8ft taller if you really wanted to each solar panel, inverter, charge controller etc must be carefully researched imo

[Sunking]

As a general rule you ignore any studies or Press Releases from a company.

[JERRYG]

As a general rule you ignore any studies or Press Releases from a company.

You take it at face value and then check their sources.. From my research, Enphase has a good thing going with residential sized installs assuming the installer shares some of the reduced labor cost with the consumer. The software monitoring apps definitely have the sex appeal factor too. Plus, nice to know when one of you panels is under producing because a falcon took a dump on it or something.

[Naptown]

Having done many Enphase installs and having a few customers who actually compare the output with the PV Watts calculations that their SREC's are based on The systems are generally producing about 7% more than the initial estimates and certification estimates.

[jjoos99]

I am getting ready to purchase a 3k system and intially priced out a sma 4000 but am wondering if I shouldnt go micro route. I will be doing the install myself and have the paper work approved by my county and local power company. Sounds as if the micros might be a better choice. I am a complete newbie so should I redesign before I get anyfarther with this project? Where can I find a simple line drawing that I can use for an example to submit for system approval if I switch over to the micro route?
thanks
Jeff

[s.xavier]

Take a look at the micro inverter and central inverter comparison

Gives you a good idea of the two technologies. Each solar system will be different. you can make a case for both central and micro so read up on the differences. Myself I bounce back and forth when it comes to micro and central. In general, a micro will be more money but it is easier to manage your home solar system. Central is not that difficult to monitor but a little more trickier.. But then again, the more you play around with something the better you get at it truth in everything we do... except for my case, as much as i dance i still cannot move