Tag: "sma"

05/27/14

  06:55:00 am, by Jim Jenal - Founder & CEO   , 1031 words  
Categories: Residential Solar, Safety, Solar Repairs

Solar Repairs Done Right!

Is your solar power system safe?  How can you be sure?

We are receiving more and more inquiries about fixing solar power systems from folks whose system has stopped working and the original installer can no longer be found.  Sometimes a violent act of nature prompts the need for our services, but all too often we are seeing shoddy work that has failed far too soon.

Case in point, we received a call from a true “rocket scientist” the other day who had a solar power system installed about seven years ago, but now he was having a problem.  We learned that the system had been installed by an air conditioning company (you’ve seen their ads), and it had two SMA Sunny Boy 2800 inverters—now well out of warranty—and one of them was displaying the dreaded, ground fault error.  Ground faults occur when a normally ungrounded, current-carrying conductor makes contact with something that is grounded, such as the frame of a solar module, the system racking or even the conduit itself.  Ground faults can be dangerous and are often difficult to locate.

When the solar system owner contacted his installation company, they offered to replace his offline inverter—for $5,000!  Of course, simply replacing the inverter was unlikely to do anything about the ground fault, and it was possible that there was nothing wrong with the inverter at all, apart from being out of warranty.  But in any event, charging $5,000 to simply do a one-for-one inverter replacement was highway robbery, and the system owner was pretty annoyed by the time he got around to calling us.  Since there was no way to properly diagnose the situation over the phone, we agreed to come out and take a look.

Sure enough, one of the inverters was working fine, but the other displayed a ground fault message.  The system owner told us that there was a combiner box on the roof, so we headed there to try and figure out where the fault might be.  Here’s what we found in that “combiner box":

This is NOT a combiner box!

This is so NOT a combiner box!

This is a junction box into which the folks who threw this system together crammed the wires coming from the strings, joined them together (without any fusing to protect the array, to say nothing of the house) and then routed them downstairs to the inverters.

Another problem—the wires coming into this non-combiner box are all THHN, which is fine for a conductor running in conduit, but is no good at all for conductors coming from solar modules in the array.  The insulation here is simply not designed to hold up under years of exposure to sunlight.

This is simply ignorant, shoddy work that has no place in the solar industry.  Sadly, this particular company has not gone out of business, though the world would be a better place if they had.

People can get hurt this way.  Property can be destroyed this way. 

And the solar industry can get a very bad reputation this way.

We broke the bad news to the system owner and explained that what was needed was to replace the box on the roof with a proper combiner box, replace the improper wiring with USE-2 wiring that is designed to last on a roof, and bring the system back online.  We also suggested that given that his existing inverters were out of warranty, he might want to consider upgrading to a single, transformerless inverter that would provide a ten-year warranty, the possibility of online monitoring, and much greater efficiency.  That was the path he decided to take.

We installed an Outback combiner and upgraded the wiring.  In so doing we managed to bring some order out of the previous chaos, take a look:

New, proper combiner box

Now each of the four strings is properly protected by a dedicated, touch-safe fuse, and there is proper stress relief on the USE-2 conductors entering the box from the array. 

We also installed ground lugs on each of the rails—something the air conditioning guys hadn’t bothered to do—and we installed two end clamps that had somehow been overlooked when the install was done.

The cool, new SMA 5000TL inverter allowed us to add monitoring to the system, as well as SMA’s emergency power outlet that provides a nominal amount of power from the array, even if the grid fails.  In the process we were able to clean up the wiring on the ground, get rid of those air conditioning disconnect switches and install a proper disconnect.  Oh, and while we were at it, we even arranged to donate the old inverters to Habitat for Humanity, providing the system owner with a charitable tax deduction!

Most importantly, we were able to restore his confidence in the solar array on his home.  And maybe, even a bit of confidence in the solar industry itself.

Moral of the Story

There are a number of take aways from this experience that we would like to stress:

  • First, if you are in the market for a new solar power system, please, please, please, go with a solar professional.  If you are confused about where to find one, start at the NABCEP website, they have a searchable directory of them.  (Full disclosure, you will find us there as well!)

  • Second, if you have an existing system that is more than five years old, you might want to have someone come out and check it out.  Start with your original installer—they should be happy to swing by and give things a look for a very modest fee.  If they refuse, or are no longer in business, you will want to contact someone else to do that for you.  (Yes, NABCEP again is the proper starting place.)  Insist on getting photos of what is on your roof.

  • Third, if your system components look like the nightmare we found, you should demand that the original installer repair it.  If they are no longer around, you should have it repaired before it causes a major problem.  A reputable solar pro will give you a fair price based on time and materials to bring your system up to code, and leave it safe to operate for a very long time.
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10/18/13

  09:54:00 am, by Jim Jenal - Founder & CEO   , 641 words  
Categories: Ranting, SPI 2013

SPI Preview - What to Look For...

SPI 2013 logoSolar Power International - the largest solar trade show in the U.S. - kicks off next week in Chicago. Here are the top five things to look for at the show.

1 - Venue Verdict

Continuing its (in our view unfortunate) three-year odyssey away from California, SPI 2013 is in Chicago this year for the first time ever.  Wait, what?  Chicago?

This isn’t a wind-turbine convention - you know, Chicago, the “windy city” - this is the show for Solar.  What is it doing in Chicago?  (Hey - no knock on Chi-town, we’ve had some great times there and the people are terrific, but when you think of solar you do not think of Chicago.)

So the question is - will this sortie into the Midwest help or hurt attendance?  We are guessing the latter, but it will be interesting to see what the numbers say.  (And you know that we love us some data!)

2 - Who’s Missing?

Given the location, and the recent trend of some bigger players taking a pass on big booths, who will be the notable “no-shows” at this year’s event (besides us, that is).  Enphase won’t have a booth, but their presence will be felt as they host a plethora of parties and other events during the show.  Interestingly, rumor has it that SMA will also not have a booth - hard to picture the SMA folks partying like their rivals at Enphase but I suppose it could happen.  (Pictures, please!)

But who else gives the exhibit floor a pass?  And better question - why?

3 - Who’s Got the Buzz?

Buzz is sorta the point of having a booth and LG Electronics - poised to have the first shipments of its long-awaited 300-Watt modules hit U.S. shores in the weeks immediately following the show (and yes, we are in that queue, thank you Focused Energy) is going to have a major booth.   Will they capture the buzz?

With neither SMA nor Enphase fronting a booth, who will capture attention in the inverter space?  At Intersolar the robots seemed to have gotten a lot of interest - will they be prowling the floor?

What about on the racking front - always lots of products and manufacturers out there - but not much buzz.  (Except, perhaps, when a major product is phased out.)  Can anyone break through the noise and clutter to make an impression worthy of the booth fees?

And what about the storage sector - will we see more folks now getting it, like Stem?  Or will it be more of the same fumbling to find a rationale for their product offering that has been typical in the past?

4 - Can the Solar Women Steal the Show?

One of solar’s best kept secrets is that there are lots of intelligent, professional women in the industry - will they finally be seen as the force that they need to be at SPI?  We know that our friends Raina Russo and Glenna Wiseman will be there promoting their survey of women’s attitudes about solar marketing.  What other events will feature women prominently in ways that capitalize on their intellectual contributions to the industry?

5 - Will SPI Police the Bad Boys of Solar?

After Intersolar’s debacle with RECOM and its ilk demonstrating that they had no sense beyond that of inebriated frat boys, tremendous pressure was put on the management of SPI to crack down on unseemly displays on the exhibit floor.  How well will that be enforced?  And how will RECOM’s recent effort to recast itself play with the women at the show?  (Interestingly, as to that last point, comments we have received from women are supportive and grateful for our taking a stand whereas those from men are more along the lines of “why are you talking about this?")

So that’s it - a few things to keep in mind as you pack your bags for Chicago - have a swell time and think about us slaving away back home!

08/27/13

  12:48:00 pm, by Jim Jenal - Founder & CEO   , 552 words  
Categories: Residential Solar, Ranting

Try Doing That with a String Inverter!

There is a vigorous debate among solar installers about the relative merits of microinverters, such as those made by Enphase Energy, versus those of string inverters, such as those made by SMA. We can’t claim that we have resolved that debate once and for all, but our experience this past week reaffirms our confidence in the microinverter choice.

Almost exactly a year ago we did a residential installation at a seriously shaded site.  We explained in detail to the homeowners about the reduced yield that any solar power system would provide given just how much shading they had, but they were still eager to press forward.  The shading mandated that we use microinverters, and they were excited to see how their system would perform using the Enlighten monitoring system.

In addition to the shading, there was another limitation - a 150 Amp service meant that we couldn’t install as big a system as they needed.  However, they were about to embark on a six-month renovation of the home and as part of that they were going to upgrade the service.  We decided to build the first half of the system right away and include the additional infrastructure that would be needed for the later addition - down to the standoffs on the roof.

Here’s how the install looked a year ago:

First phase of project completeAs you can see from the photo, there really is substantial shading present - and you can also see our Unirac standoffs waiting for Phase II.  Sitting on top of those Enphase M215’s are LG 250 Watt solar modules - our preferred product at that time.

Fast-forward to this past week.  We are still using M215’s but LG has moved up the curve and the new modules for the second phase of this project are 280 Watts each.  The homeowner wanted the higher power modules incorporated into the existing system, and they wanted them installed not on the open bottom row, but wherever they would be able to get the greatest amount of sun to maximize their return on investment.

The first great advantage of having microinverters on this project then was the ability to combine significantly different power modules into the same array.  But the second goal - placing the new modules in the ideal locations - was one that we could only solve with confidence thanks to the Enphase Enlighten data.  Indeed, all we had to do was go to the monitoring page for this site and request the display of lifetime energy.  Here’s how that looked:

lifetime energyNow isn’t that interesting?  There is a huge difference going from the NW corner down to the SE.  Overall, taking the top row along with the three west-most modules from the second row seemed like our best plan.

Here is how the expanded array looked after we completed the install:

expanded arrayPretty easy to see where the new panels were installed - they are the bright shiny ones!  (The break in the bottom row is to avoid the utility service mast.)

Here is how the new system performed yesterday (after the old panels were cleaned!):

yesterday's energy yieldOur higher power modules are installed in the optimal locations, thanks to the ability to mix and match modules in the array, combined with the ability to know at the module level where are our best performing slots in the array.

Trying doing that with a string inverter!

05/22/13

  07:02:00 am, by Jim Jenal - Founder & CEO   , 661 words  
Categories: Residential Solar, Ranting

SMA for the Save - Well Done!

We often claim that the solar industry is called to be better - more honest, more ethical, more community oriented - than the average business.  One way that can manifest itself is by going out of your way to help when there is nothing in it for you. Today we want to recognize SMA and their marvelous Melody Kenoyer for doing just that.

First some background.  Back in 2010 we were contacted by a lady we’ll call Sophia about a problem that she was having with her solar power system.  Sophia lives in a modest home in Glendale that was built for her by Habitat for Humanity.  The three townhomes in the project were each topped with a 1.6kW solar power system.  Unfortunately, the solar installer who had worked on the project had long since gone out of business and that left Sophia to go searching on the Web to find someone who might help.  She found Run on Sun.  As luck would have it, we were able to fix her system and get her back online without much difficulty.  Sophia was so grateful she sent us an amazing Christmas card that year.

Fast forward to last Friday when Sophia called again.  She had a different problem this time that couldn’t be resolved quite so easily.

Inverter displaying eeprom_d faultTurns out that her long-since out-of-warranty SMA 1800U inverter had stopped working and was displaying an EEPROM_d error message.  We had seen this problem before and we knew that while you could reset the error, there was no way to prevent the problem from happening again without installing an EEPROM upgrade - a task we had performed on another 1800U years earlier.  We reset the inverter and it came back online - Sophia was very relieved to have the unit working again, but concerned that the problem might return.  We promised to contact SMA and see what we could do.

When we called on Monday we reached Ms. Melody Kenoyer at the service support desk.  We explained about the problem and she pointed out that the 1800U was no longer being made and that as they were all outside of their warranty period - an understatement given that they had carried 5-year warranties and they were phased out long ago when the CSI program mandated 10-year warrantied products. Not surprisingly, SMA was no longer servicing them.  They did have an upgrade program for customers who wanted to upgrade to newer units - but that was not going to be a viable option for Sophia.

Ms. Kenoyer checked with her supervisor who confirmed that apart from assisting us in resetting the inverter, there was nothing more that they could do for us.  I told her that we had already done the reset and the system was back online - it was just that we were hoping to be able to give Sophia some greater piece of mind.  Ms. Kenoyer listened, and then promised that she would personally take this to her Manager to see if there wasn’t something else that they might do.  I thanked her for that and hung up, fully expecting that we had played this out as far as it could go.

But then, lo and behold, I received the following email from Ms. Kenoyer:

I spoke with my Manager about the pro bono job you are doing for the single Mom in the Habitat for Humanity home.   We do have some EEPROM chips for special circumstances and my Supervisor will send you some.

Well what do you know about that!

From utility attacks on the one hand to shady behavior by certain solar companies on the other, at times it is hard to cling to our view that solar is special.  But then along comes Ms. Kenoyer, and her Manager, and SMA to help convince us that our view is the right one after all - solar is special.

So a hearty “Thank You” to everyone involved in making this happen - don’t be surprised if Sophia sends you a Christmas card!

03/12/13

  09:45:00 am, by Jim Jenal - Founder & CEO   , 691 words  
Categories: Solar News, Commercial Solar, Residential Solar, Energy Storage

Solar Trends: Storage & Lower Cost

Predicting the future is always fraught with hazards but a recent survey caught our eye with a bold prediction: nearly one-third of solar installers/integrators world wide expect to utilize storage in more than 40% of their installs by 2015!  Oh and they need microinverters to come down in cost by 50% before they are willing to adopt them!!!  Numbers like that beg for some analysis, so stay with us.

Booming Market for Storage

The survey in question was conducted by IMS Research (h/t to SolarIndustryMag.com) and included global installers, integrators and wholesalers.  Among respondents from the U.K., Germany and Italy, the addition of storage capability was cited as the most important requirement for inverters over the next two years.

We aren’t surprised by this result.  As the penetration of PV systems onto local grids increases, grid operators and utilities start to complain about solar undermining grid reliability.  (Well, ok, utilities are actually complaining about losing market share, but that is not the concern of the ISO.) Likewise for many commercial solar clients, PV alone may not be a complete solution if the client’s electric bills fall under a demand-charge rate structure and their peak demand falls outside of the peak output for their PV array.  (Add Feed-in Tariff clients with time-of-delivery factors and you have yet another potential market for cheap storage.)

According to the survey, respondents were looking to add storage for 10-30% additional cost, but is that a realistic expectation?  Not from any of the products we’ve seen so far.  (The survey noted that 30% of respondents were willing to pay even more - which from what we can tell, they will certainly need to do!)

Ultimately, local storage for distributed generation will boom if the economics justify it - whether because net metering becomes less desirable (or even unavailable), or if demand shifting or time-of-delivery factors boost the ROI enough to overcome initial costs.

How Low Can You Go?

SMA's fabled microinverterMeanwhile, we were baffled by the survey’s contention that the “high cost of microinverters” was seriously limiting their growth.  Indeed, according to the report, a majority of survey respondents who are not presently using microinverters said that they would need to see the price drop by over 50% before they would consider using them!  (Interestingly, the illustration that accompanied the article showed the much discussed, but yet-to-be-sold, SMA microinverter instead of the best-selling Enphase product.)

How does such reluctance make sense?  Let’s look at a typical 5kW residential project using either Enphase microinverters or SMA string inverters.  Assume that we are using twenty 250 Watt modules to power both inverter types.  So we would need 20 microinverters and one string inverter.  Enphase cost - around $3,500 for microinverters plus cable.  String inverter cost - about $2,800.  Labor?  Well someone has to hang that SMA 5000 on a wall downstairs (preferably somewhere in the shade!) while someone else is mounting microinverters to the rails on the roof.  Pretty much a push.  (We actually have lower labor rates for microinverters than we do string inverters, but that’s just us.)  Which makes the microinverter about 25% more expensive going in.

So for the installer it might look like they have a better deal with the string inverter, but what about the client?  Our testing shows a 15% improvement in yield and that goes even higher depending on the amount of shading at the site.  Beyond that, the microinverter comes with a 25-year warranty, the string inverter only 10.  Which means for the client, they are going to have to spend an additional $2,800 or so ten years down the road when their string inverter dies (sooner if it is baking in the sun).  All of which argues quite convincingly that the microinverter is the better deal for the installer’s client - which last time we checked was supposed to be the point of the exercise.

We are all for price reductions, but we suspect that folks who say microinverter prices must fall 50% before they will consider using them have already decided that they will never use them.  Of course, installers are entitled to run their business as they see fit, but it certainly isn’t a lack of value to the client that is keeping these installers from taking the plunge with micros.

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Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

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