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Solar System Reliability — The most important factor

Feb 11, 2020

Let’s face it, everything these days is made to break.  Longevity is an elusive concept when it comes to products in the household — computers, AC units, plumbing, ceiling fans, barbecue grills, automobiles, pool pumps, et cetera; these devices, as well as many more, break down, eventually, just like we will, too.

Solar and storage products cannot be excluded from this mortal grouping, for they, too, will break down.

Keeping that in mind, this is where Enphase Energy shines; the core of their energy technology, the microinverter, has the best reliability, safety and longevity track record in the industry.  By not having a single solar inverter power source, but instead having an army of microinverters, reliability is guaranteed, and due to the electrical conversion in low-voltage multiples by each microinverter, safety and longevity are optimized.

As a distributed-generation energy solution, Enphase is superior to any centralized energy solution with a single-point-of-failure, as well as quasi-distributed systems which include optimizers, dual and quad inverters. However, like all electrical components, Enphase’s products, are still susceptible to failure even with their 25-year warranty; however, with an industry-leading Defective Parts Per Million (DPPM), Enphase is best in class; consider that their microinverter has a single part defect in only about 0.2% of one million produced which is very impressive, and their goal is to improve that fourfold!

The beauty of an Enphase solar energy system is that when a failure does occur, most of the energy solution will still continue to operate. As a microcosm of that, my Enphase 85 microinverter, 20,000-Watt system has been operational since ~2013.  I hate admitting it, but I have had a few issues, but because of the decentralized power topology of an Enphase Energy system, the issues were not a crisis, just an annoyance.  If your home refrigerator,  car, or non-Enphase solar system’s central string inverter fail, the situation is a crisis which you have to deal with immediately.  Being put into this grouping is almost impossible for an Enphase Energy system. When a problem does arise with their system, it’s usually something that can be dealt with at your leisure, because 95% of the system, for example, is still working.

To add proof, about a year ago, one of my panels started having an issue which was quickly deduced by checking the status of my solar system with Enphase Enlighten Manager. Using Enphase’s one-step automated warranty replacement process, I did the few minutes of digital paperwork, and by the following week, had received my replacement microinverter. I shut off the circuit breaker for the branch circuit of solar panels with the bad microinverter, waited ten minutes, then swapped in the new microinverter. Within 30 minutes, the problem was resolved, and the system was back online. Note, the other five branch circuits of my system were never shut down, so I can still say that my system has never truly been inoperable due to a hardware failure. I did have to go into Enlighten Manager to finish the warranty replacement process, but it was as easy as generating the warranty replacement.

Another microinverter issue which arose around the same time was also spotted in Enlighten Manager, and the warranty process was repeated. However, when I got up on the roof, I found the microinverter was fine, and that the junction box attached to the actual solar panel with two wire leads coming out, had experienced a short and melted down (see image below), so it was the panel that was the problem, not the microinverter. Interestingly, Renesola, the panel maker was no more in the US, and the best I could do was replace the panel with another brand; so, my 25-year panel warranty was pretty much useless, but it wasn’t a major loss. I pulled the defective 265-Watt panel, swapped in the new 305-Watt one, and the problem was resolved and gave my system more power at a ~$150 cost.

So, those were easy, resolvable issues, but for the superstitious folks out there, things come in three’s, right! About a month ago, I started seeing an entire branch circuit of my six-circuit system start exhibiting a problem; Enlighten Manager notified me that all of the panels in this circuit were not producing energy, labeling all the microinverters with an “AC Voltage Out of Range Issue”.The rest of my system was working fine, still producing energy, but a fair amount of it was being lost by this inoperable branch circuit with 12 solar panels.

I started doing the simple things, checking the sub-panel with the circuit breaker, shutting the breaker off, turning it on, et cetera. The problem didn’t go away, so I got up on the roof. I looked underneath the panels and didn’t see any destructive rodents, but then again, it was almost inconceivable that rodents could do such a fine job of disabling a single branch circuit and not damaging any of the other nearby circuits. So, the next choice was to inspect the junction box where the Enphase Trunk Cable connects with common 12-gauge, twisted-pair, copper wiring which leads to your sub-panel. Inside that junction box was the problem; from just eight years of being on a hot metal roof, with a very unforgiving, brutal Sun, along with torrential rains, hurricanes, humidity, and tropical weather, one of the wire cones used to connect the wiring in that junction box had literally disintegrated; the plastic had crumbled, and the bare wiring had become disconnected. All the wire cones in the junction box were replaced with new ones, and in no time at all, that branch circuit was back up and running. With no moving parts, maintenance is easy.

These homeowner stories may occur in other systems, and if they are non-Enphase, centralized power topologies using string inverters, complete failure is likely. From a service point-of-view, an Enphase Energy system is better. I love my Enphase system because I’m not a certified this or a certified that, but a Do-It-Yourself-er, and I like having the independence of being able to repair my energy system myself. So, for those of you considering solar, or those already part of the Enphase cult, from a service perspective, Enphase’s microinverter-based energy system is the choice to make, especially for reliability et al.

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