I am in the process of installing a 47 panel system. I did much research, chatted with folks on this board, read books, built spreadsheets, talked to multiple installers, read some more, talked to folks that did have systems in the neighborhood - folks I knew and others I didn't. I am an engineer too I will add.
My observations.
1. Two friends that have sunrun systems, we looked at thier monitoring systems (which sucks btw), both are SolarEdge systems, were not producing anything close to what their contract said. Both called up sunrun and sunrun performed maintenance of some kind on both systems.
2. @J.P.M., I agree with KISS, but I also am very skeptical of installers/dealers or the big companies managing g these systems in the solar panel owners best interest. My opinion.
3. The decision really vame down to SolarEdge or Enphase. I went Solaredge w/optimizers. You can read a thread I started as to why, but to summarize, mostly performance concerns of of microinverter design in very hot climate in Southern Nevada.
4. For me, I do want the detail panel monitoring data. I also want the safety of the optimizer methodology to shutdown /significantly reduce DC power when needed (emergency, or maintenance on roof) and may be required in some jurisdictions. I want the data as I will be writing automation scripts, with AI algorithms, to alert me proactively when performance is lower then expected. I assume I will assume I will have false positives, but that is where my algorithms will adapt over time. I want this as software and automation is also a hobby for me. But I want to maximize my investment. I am also installing the iotawatt monitoring system to monitor many circuits to assist with energy consumption, but I want to add this data to other calculations. Net net, I want to validate vs. trust both the instaer to monitor my system for performance, and NV Energy to provide accurate credits for power sent back to the grid as I get 81% of retail value of energy sent back to them.
I think your cost per kW is very good. Sub $2.50 is very good IMO based on what I saw in my research. I like the Enphase design. Much less complicated to add panels in future than optimizer approach, but may not be an issue if you dont plan or need to add panels in future or you properly design an optimizer based system. I am not a solar expert, but did do my homework on my system choice and design. My system is not online yet, but is working as I have tested.
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You're welcome.
Since you are asking:
If you have little/no shade, the biggest and in some opinions only advantage to either micros or optimizers is not there: The benefit that SOME (but never all BTW) of the solar production lost to shading that would otherwise be lost might be recovered.
The word "SOME" is there because micros or optimizers will not recover energy that was not there in the first place. That's a little factoid most peddlers and micro/optimizer fans seem to be willing to or avoid talking about. A very rough 1st approx. of how much of a panel or string's lost production from shade might be recoverable using micros or optimizers might be 50 % or so and pretty variable depending on the applications and other variables.
Here's the simple deal: String inverters operate much (but not entirely) like the old Christmas light strings wired in series where one bulb burns out and the whole string dies. With a string (central) inverter, if one panel in a string is shaded - even partially - the entire string's output is reduced or otherwise affected. That's a disadvantage. No doubt about it.
The theoretical and probably actual advantage of micros/optimizers is to allow most of the rest of a string's output to be used. That's an advantage. No doubt about it.
But, at what cost. There ain't no free lunch.
As a practical matter, the logic of using micros or optimizers works well until it doesn't. Lots of systems w/micros or optimizers have been running well for years - my HOA is full of them.
But it seems to me, and as I'd suggest a regular reader of this forum may agree, the number of complaints and comments of problems from micro and optimizer equipped system owners seems to far exceed the number of complaints from string inverter equipped systems.
As a retired engineer, I can spout all kinds of technical reasons why the KISS principle has stood the test of time.
Bottom line, more complicated systems have a higher statistical probability of failure and/or problems.
Micro and optimizer equipped systems are more complicated with more stuff to go wrong with most of that stuff located in harsh environments that are usually not easily accessible.
As a practical matter, most folks w/ PV systems on their roof don't give a crap, much less understand why a system more complicated than it needs to be is probably not in a homeowner's best long term interests.
Opinion only, most of those folks are victims of their own solar ignorance.
Besides all that, if the shading is so prominent that the increased probability of system failures and lower reliability that micros and optimizers bring with them is deemed necessary, I'd wonder if the reduced availability of the solar resource at a site from shading is great enough to make the effort economically viable in the first place.
Take what you want of the above. Scrap the rest.
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Thanks for the input. I will ask to see if it would be a hassle to change the install to a string inverter setup. I should also be inquiring about a power optimizer along with string inverter no? Thanks again for all of the help.Leave a comment:
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What you may be missing is information that the vendors usually leave out.
If you have no/little shade, you will be able to benefit from the KISS principle. Central inverter equipped systems are much simpler - meaning a lot less to go wrong - fewer parts, less complication, fewer electronics in largely in accessible places like under a panel on a roof which just happens to be a pretty inhospitable environment for those sensitive electronics. You may learn to appreciate that the first time a micro or an optimizer needs service/replacement and it's on a panel located in the middle of the array and a real hassle to even get at much less fix.
Suit yourself.
BTW, usually, but not always, the novelty of per panel monitoring wears of and gets mundane after a couple of weeks or so. Then, if one micro craps out, the small loss in production may well not be noticed as much as if a string inverter sitting in the garage, and note, FWIW, in a more accessible location, dies.Leave a comment:
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Why are you considering micro-inverters ? There are better ways to solve shade issues (chainsaw for trees, properly locate panels around chimneys) Micros are a last resort.Leave a comment:
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New member from SoCal
Been lurking for a month, reading as much as I can from this site to educate myself on a new turnkey system. Thanks for all the great information from all of the members. Looking to get the following system installed:
6.9kW system size
LG345N1C-V5 NeON 2 Panels x 20
Enphase IQ7-60-x-US-240 Micro-inverters
($16,215) $2.35 ppw
Extras:
- Main Panel upgrade ($2,250)
- 240v EV Charger outlet ($495)
Total: $16,215 + $2,250 + $495 = $18,960 - $4,929.60 (26%) = $14,030.40
How do my numbers look? Am I missing anything that I should get? Thanks!
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