About me
I’m just a random Torontonian. I work by day, and write by night. It’s a simple existence.
In case you’re curious (and that’s why you’re here), I’m a failed physicist who tries to keep his hand in the biz. I watch the green-power market, and filter it through what I know of the technology side. Hopefully, some of you might find this useful. Let me know!
I do most of my writing on the Wikipedia, and this blog might be considered a counterpoint. The Wiki is all about facts and references, so this is primarily discussion and opinion. I don’t expect this to be a high traffic site, maybe a post or two a month.
If you’d like to email me, its maury.markowitz@gmail.com.
Energy Matters 
I am interested in going solar to offset my electric bill after horrible summer here in Dallas, Texas (2011) and an already hot May 2012. What do you think about the photovoltaic cells that are about one inch by one inch with the solar plastic concentrators. Are they something worthwhile to pursue on a small scale? Basically I am wondering if it would be a good idea to make a larger fresnel array or to just go plain jane solar panels.
TIA
iceberghotspot@gmail.com
I came here initially from a Google search on microinverter comparisons, which led me to your post: The Great Microinverter Debate. After reading that whole post, I spent several hours reading more of your recent content, and was so impressed with the depth and breadth of your knowledge and interests that I felt the need to leave this comment.
Your writing style is well thought-out, easy to read, and to the point. I am thankful that there are people like you who use your spare time to publish content here, and on Wikipedia, where that knowledge can be shared with the world. Keep up the good work!
Wow, thanks! *blushes*
Hi Maury, I thank you so much for your Optimizer article Tigo and Solar Edge. I am still confused as to why Solar Edge are so pedantic about cell numbers. For example, the P700 optimizer is rated for, you guessed it 700W, but also states for use on 2 X 72 cell PV arrays ? Surely this optimizer can be used on one 132 cell 500W PV panel?
Thanks for your reply in advance.
No, its not the same!
Check out, for instance, this 132 cell panel:
https://www.cedgreentech.com/product/canadian-solar-hidm-330w-132-cell-mono-1000v-blkwht-solar-panel-cs1h-330ms
Note the Voc is about 36Vmpp is about 36 and the Voc is around 43. Now check out this traditional 72 cell panel:
https://www.lg.com/us/business/solar-panels/lg-LG400N2W-A5
Vmpp is 40 and Voc is 49. That sounds ok right? Yeah, but when you connect two of those 72-cell panels together they will be in series, so the Vmpp will be 80, not 40. And that is very different indeed from a single 132-cell panel at less than half those values!
Sorry late comer but had to second Lee’s comment with Maple syrup on (sic)!..well done and many thanks again
Ditto from someone who is just starting to navigate their way deciding which solar company to go with here in Hawaii….I, too, came across your great debate somewhere in my quest for knowledge. I appreciate your fluent writing style. As we say here, Mahalo! (Thank you)
I too appreciate the enormous breadth of your knowledge of the industry and the fluid writing style shown in your 2012 Debate
article on Micro inverter technology. It is now almost 2014 and where does the hard data point in terms of reliability and value of micro inverter vs Power Optimizer vs string inverter for a typical 3-5 KW residential installation. Each integrated provider I talk to has a different story
This is the question we all have. Over at the day job the boss was at the Enphase plant and saw rooms filled with returns. But even if there were 50,000 of them, that’s actually in-line with the 0.5% failure rate they quote.
But the question isn’t the failure rate, but the lifetime. So far I’ve had great results with my Enphase kit, and they’re in their 4th year now, pumping out the electrons like no-one’s business. But what happens at year 12?
And if you want to get *some* idea of why this is of interest, simply look here (see section 2-9-3):
Click to access tec2.pdf
This is the actual part in the Enphase, at least the M190s. They use the part in curve 5. So basically it all comes down to temperature. If the operate, as Enphase claims, at only 65 degrees, then they should get 10 years of *continuous* operation. Of course the sun might be “full blast” for only 6 hours a day, so that gets you decades.
So it’s not like Enphase is faking it. But only time will tell!
I’m computer science student and I help manage some IBM PowerPC model 822SL servers in a lab. My colleague and I initially had a rough time provisioning these servers because the graphics cards we were trying to install wouldn’t produce any output. My colleague suggested that since PowerPC runs on a different architecture than the video cards’s chips that that was probably why they weren’t working. So I thought about this and decided to look into it. Well, it turns out you need to know a lot more about architecture than I do, so…I noticed you had contributed to the PowerPC architecture page some on Wikipedia and thought I would reach out, if you wouldn’t mind responding. My question is this: Can a bi-Endian architecture (our server) run a little-Endian video card? If not, why?
Thanks!
Jonas Steinberg
Wow, this is definitely the most OT email I’ve had on this site!
To make a long story short, no, it almost certainly won’t work.
There is no *theoretical* reason for this. Most bus systems from the 1980s on had support for both little- and big-endian systems, and could be built to operate on either. NuBUS and PCI are two examples.
But to make this work, you had to have drivers that worked in both modes, and put drivers in for each platform. And the companies simply didn’t bother. It was far easier to make a single design and then flash the EPROM on the way out the door than make a single card with both drivers on it. I know of VERY few (none?) cards that could actually be plugged into two systems.
Wow! Thanks for getting back, Maury. Your answer makes a lot of sense. Interesting that it won’t work considering PowerPC is supposedly bi-Endian…
Hi Maury! I found your blog while doing some due diligence on micro-inverters. I have been in the solar game for about 6 years. I have three generations of Enphase equipment, but I am close to pulling as many of the M190s out as I can…
I am looking seriously at Chilicon Power. If you check them out before I do stay in touch. I am checking the notify of new comments here.
Ken Clifton – http://www.kenclifton.com
Hey Ken, sorry for the tardy reply, but check out my latest post for the reason. As to Chilcon, I never had the chance for the same reason. Maybe this summer?
Congratulations Maury!
Hello Maury,
I read your explanations about optimizers. I have a question please, if I may.
I have had 40 panels, connected in pairs with 20 optimizers installed . Now I am not sure if this is even possible. The panels are 170Wp each (Solar edge Frontier 170) and the optimizers Solaredge P405.
Could it be that this setup causes the individual optimizers to only deliver half of the production of the two panels they are connected to
Thanks in advance from a “electronic-nitwit” from Holland (Europe).
Mike.
If you connect two panels together you basically make one bigger one. As long as the resulting voltage is inside the optimizer limits your fine. The only other limitation is that the pairs of panels are parallel.
Thanks Maury,
I’m under the impression my whole system is performing on half of it’s capacity. The person installing the system tells me this is because of some shade I have on my roof, but I doubt it a bit, so now I am investigating a bit more. Because I have half the optimizers I suspect this has something to do with the performance, but am not sure yet.
What would be the limitation of the pairs of panels being parallel as you mention?
Thanks again,
Mike
If you have two panels connected in series and they point in different directions or have different shading, the one panel will rob performance before it even gets to the optimizer. But if each pair is co-located on the same surface then that’s typically not the problem. I’d be more suspicious of the voltages, can you email me a spec sheet for the optimizer and the panel? My email is my name with a dot between first and last at gmail.
Hey, wow, I really did not expect such a speedy reply. Thanks so much . I still have a grey area so Ill put values on the table and specifics.
The P700 Solar Edge optimizer, P730(1)
(for 2 x 72-cell PV modules) states Voc 125, MPPT 12.5 to 105 vdc, Isc 11, Max Adc 15, Max Vdc 85, compatible with Three phase inverters SE16K & larger. The P730 has superseded P700 but same characteristics. What Im asking is this optimizer is for two 72 cell PV’s. Can I use this optimizer on one PV. The PV is 500W, 132 half-cut large wafer cell,
Typical Voltage (Vmp): 38.38V
Typical Amperage (Imp): 13.03A
I think I may have a problem with Isc values.
Click to access ART500-120-1500MH_Datasheet.pdf
If the Isc is a problem then I understand. If the Isc was say 10A, will it work as a 132 cell PV with the P700 optimizer.
Thanks very much for your advise. Very helpful.
Maury, could this work better with the P700 optimizer. Im asking cos I already bought 100 of them.
Click to access ART450-144-1500MH_Datasheet.pdf