Tag: "solar maintenance"

07/31/21

  02:49:00 am, by Jim Jenal - Founder & CEO   , 811 words  
Categories: Residential Solar, Safety

Rethinking Maintenance for Residential Solar Projects

For a long time the solar industry - particularly the residential solar industry - has portrayed our systems as “maintenance free".  “Clean the panels when they get dirty, but otherwise you are good to go,” is a common conversation between an installer and their client.  And certainly given the ever-improving warranties being offered by top-line manufacturers, that claim didn’t seem so far-fetched.  But lately I’ve seen some things that have caused me to rethink that whole conception of maintenance-free solar systems.  Here’s my take…

Old Thinking…

My old thinking - that these systems really did not require maintenance over a 20-year lifetime - was predicated on more than wishful thinking.  After all, we used only the very best components: LG solar panels, Enphase microinverters, racking from Everest and Unirac, Polaris connectors instead of wire nuts, etc.  We built our systems with care, using well-trained people, including those who were NABCEP certified, and we went above and beyond all code requirements.

What I have discovered recently, in servicing a couple of older systems, is that it isn’t the components people worry about failing like the panels or the microinverters, that cause the problems.  We have never had an LG panel fail, and since Enphase moved to the IQ series of microinverters we have had exactly one microinverter fail - one!

No, that has not been the problem, it is the little stuff that is taking systems down.

What I’ve Seen…

Before I can talk about how things have failed, let me show you how things start out.

Proper j-box

On the right you see a rail-mounted junction box on the roof.  In here we connect the Enphase IQ-cabling from the microinverters to THHN-2 wire for the run from the roof to the building-mounted combiner box.  (If you look to the right, your can see black marks on the racking bolts - we mark them with a sharpie after they have been torqued.)  We have a grounding bushing on the incoming conduit, and all of the connections are made with Polaris connectors instead of outdoor-rated wire nuts.  Why the Polaris?  Because you can do a pull test on your connection: when the wires are screwed in you can pull on them to make certain that they are secure, something you simply cannot do with a wire nut.

Put simply, it is the best connection method of which I’m aware and so that is why we use them, even though they cost 50 times as much as that wire nut.  But here’s the thing - they aren’t foolproof either.

We got an email from the Enphase Enlighten monitoring system alerting us to a client whose system had gone offline.  That system had a fused disconnect and I fully expected to find a blown fuse.  Nope fuses were fine, and the breaker hadn’t tripped either.  Time to go on the roof and check out the junction box - and here’s what I found…

Bad polaris

What on earth?  The Polaris in the foreground has failed completely, but why?  The Polaris behind it looks like the day it was installed, so why did the other one literally melt away?  Mind you, this wasn’t a case of something shorting out - neither the fuses nor the breaker tripped.  There are two wires being joined there, a 12 gauge from the Enphase cable and a 10 gauge for the run off the roof.  The #10 is still securely held in what is left of the Polaris, but the #12 has broke off - which is why the system had failed.  But why?

My best answer - speculative of course because I didn’t see it happen - is that perhaps the #12 was not as securely under the screw as it should have been, and over the course of the nine years that it was in service, with the daily heating and cooling, it continued to loosen, until the resistance of the connection increased, causing it to heat, melting insulation on the wires and on the Polaris, until the wire broke.

What could have prevented this failure?  Well, as mentioned, this system performed just fine for nine years before failing.  What if those connections had been checked around Year 5?  If, as I surmise, the connection was loosening, an inspection might have caught that and a simple re-tightening would have cured the problem before the failure could occur.

Now this is only one failure out of a multitude of systems using the same components, so it is fair to say that this is low-probability event.  But we have seen other, similar issues including a performance meter that failed, and a line-side tap that loosened, over heated, and failed.

The bottom line is that we are re-thinking how we approach maintenance for resi solar.  I would be interested to hear other folks thoughts about this, so please leave us a comment and tell us about your experiences.  Hopefully we can all learn something about how to make our systems better, if not, “maintenance free.”

 

 Permalink

09/09/16

  02:08:00 pm, by Laurel Hamilton   , 432 words  
Categories: All About Solar Power, Residential Solar

Run on Sun PSA: Time to Wash Your Array!

Here in SoCal we are blessed with endless warm sunny days. The down side however is that it can be many months between invaluable air-purifying rain showers. For your solar array, this means there is nothing to wash away the accumulated dust and detritus from nearby trees. In summer months ash from nearby mountain fires adds to the mix. Consider this a Run on Sun PSA…

IT’S TIME TO RINSE OFF YOUR PANELS!! 

Dirty panels

These panels needed to be cleaned just to get the inverter to turn on!

(Didn’t help that the installer put the panels under a tree!)

When discussing solar with new clients often the topic of cleaning comes up. This is because some solar companies use the concept of cleaning your array as a way to convince you you need a leased system with ongoing maintenance. However, we believe this is a bit of a scam. You don’t need to pay someone to get up on your roof with a squeegie every week. Most home owners have the ability to douse dusty panels from the ground with a strong nozzle attached to a garden hose. Really the benefit is nominal unless it has been six months since the last rain, such as the case in Southern California. As for cleaning the panels, rinsing with a hose is fine (though some insist that is heresy and only deionized water should be used). Do it first thing in the morning so there is no thermal shock to the panels.

Check out this recent case study that brought this issue to our attention:

Clean Panels

Shiny new panels at Chandler School

Last week we heard from a client who did some great analysis using the Enphase monitoring on their system before and after he decided to clean his panels. He found there was an 8% improvement in the period after cleaning. Run on Sun’s CEO Jim Jenal compared this to the monitoring on another system (Westridge School) which wasn’t cleaned and had a similarly unshaded southern facing array. Over that time period Westridge School’s daily average production reduced 8.66%. This means that our client actually had an increase of production of 16.6% by cleaning his panels!

Generally, cleaning an array results in an improvement of between 5-10%, so his panels were exceptionally impaired by the fallout from our summer fires! Not surprisingly, given his location in the foothills of the San Gabriel Mountains. However, for anyone in the Los Angeles metro area, early September is a great time to get out and restore the shiny clean sheen to your array. After all, who knows when the first winter rain will come? 

Help Save Rooftop Solar!

California Utilities are trying to kill rooftop solar on your home by gutting net metering - but you can stop them!
Join the fight by signing the petition today!

Sign the Petition!

Search

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.

Ready to Save?

Let’s Get Started!

We're Social!



Follow Run on Sun on Twitter Like Run on Sun on Facebook
Run on Sun helps fight Climate Change
Build your own website!