here for the sunshine shenanigans

Category: solarlog

  • “It’s not pushing power to the grid!”

    “It’s not pushing power to the grid!”

    Got a request from someone on TikTok recently about their PV system not working, asking if I can help troubleshoot remotely.

    I like to do these things pro bono if I have the time, and so they proceeded to unpack their frustration with their solar company, which this time, just so happened to be Freedom Forever.

    They said the system was not sending power to the city like it was supposed to. It was making “30-50” but only transmitting “10-15” to the grid, per day. Aside from the ~$200 a month solar bill, they’ve been paying $150-$250 a month in electric costs.

    Couple of possibilities here — the first thing I thought of is voltage drop, a classic (for me) over-thinking of the situation. However, I’ve seen other large companies make similar mistakes. One that comes to mind is a Pink Energy site that didn’t account for voltage drop at all, yet ran AC wires and DC battery wires to the inverters 500 ft away at an outbuilding, reducing the useful output dramatically. However, after looking at the drawing for this customer, I concluded that the short wire runs meant that voltage drop was unlikely.

    There were some possibilities raised by an electrician, hired by this customer to do some independent investigation. The electrician noted that the voltage seemed a bit low for the inverter to produce (only 235v), and that there appeared to be an imbalance on the neutral.

    This illustrated to me that most electricians still have no idea what they’re talking about, either about solar or electricity in general. Most inverters have a wide range of voltage compatibility (I believe SolarEdge inverters can operate in low 210s), and the imbalance on the neutral is simply almost always going to happen if you have any 120v loads in the house at all.

    It was clear I needed to get some history on this site to further evaluate.

    I gained access to their SolarEdge login and checked out the data. Over the course of the last several years, the production had remained very consistent, despite a couple springs where it was down for a couple months while they were trying to get an inverter replaced. The DC array is a bit over 11kW with a 10kW inverter, and given that sizing decision, the array seemed to produce what I’d expect, occasionally peaking at 10kW AC production in May. The inverter was also reporting a similar voltage to what the electrician reported at the main panel, which indicates there are no voltage drop issues.

    The only alternative then, is that there’s simply not enough solar to fully offset the electrical usage of the property.

    Was the customer not informed, or did the customer forget? Well, the customer gave me as many documents about the system as they could. I pored through the contracts and project manager reports, eager to see if Freedom Forever gave the customer any indication about how much the system would produce, vs how much energy they were using.

    Nowhere did I find a single indication that Freedom Forever even asked for an electric bill.

    Maybe they did, and maybe there was some sales documentation that was missed in what was sent to me. But my suspicion is that Freedom never educated the customer at ALL about what their solar would actually do for them. I come from companies that put details in the initial quotes to their customers: how their current usage lined up with what their solar would produce over the course of the next 15-20 YEARS, what percentage would be covered, and how much projected money they would save by switching to solar. Real, reference-able projections about what they could expect from their power bills over the next years. This information was in contract documentation as well as initial estimates.

    Did we still have people misunderstanding how the solar worked? Sure, people will often not read anything you give them. But there was a reasonable effort made. The paperwork that I saw from Freedom was almost negligent in how difficult it was to scan for useful information.

    If you, as a solar company, do not start to educate your customer as best you can on the front end, you are guaranteed to fail your customer on the back end. There will always be customers that don’t listen or don’t understand, but you have to still try.

    If you don’t, your warranty and service team have to re-sell the system you already sold, back to your customer. Not monetarily, but emotionally. They’re frustrated, they’re ready to give you bad reviews on Google, and service ends up doing the work of talking your customer through their electric bill and answering the question, “Why didn’t anyone explain this to me at the beginning?”

    It’s been 4-5 years since this system was installed. Maybe their process is different now. I HOPE their process is different now.

  • Nature Energy Paper: “Durability research is pivotal for perovskite photovoltaics”

  • How To Curve Trace Through Rapid Shutdown

    How To Curve Trace Through Rapid Shutdown

    The general understanding in the solar industry is that it’s impossible to curve trace through module-level rapid shutdown devices, but with the right equipment, it’s 100% possible.

    For this video, I used an APsystems RSD-Start kit for APsmart rapid shutdown devices (not in stock anywhere I could find), and a Fluke SMFT-1000, but you aren’t limited to using these tools to accomplish your task. Any curve tracer should work, as long as you use an appropriate transmitter box to turn on the RSDs first.

    If you want to build your own (affiliate links ahoy), here’s a general shopping list:

    If you want to make the box for a generically rated Sunspec system, I’d honestly just try sticking with the APsystems transmitter, it’ll probably work.

  • Why no SolarEdge or Enphase? – The 3741 Reference

    We’ll sometimes get the question, “Can I use Enphase with UL 3741,” or “why isn’t SolarEdge listed on your website?”

    They are perfectly good questions — SolarEdge themselves have touted being the first to UL 3741 compliance, since they were listed via Intertek in 2021, and Enphase got certified by UL around the same time. Just recently in May of 2025, Generac listed their inverter to UL 3741 compliance through Intertek. So why aren’t these inverters or systems listed on the website?

    Read more at The 3741 Reference…

  • The difference between types of UL 3741 listings – The 3741 Reference

    There are now dozens of solar structures, commonly referred to as racking, that are listed as PV Hazard Control Systems (PVHCS) under UL 3741. As time goes on, we’re seeing some differences in how listing bodies allow structures to be listed.

    Continue reading on The 3741 Reference…

  • The Optimizer Advantage?

    The Optimizer Advantage?

    Updated 01/25/25 with additional detail about the voltage/amperage of the optimizers and panels.

    Can someone explain to me what’s going on here? This is not how I’d expect an optimizer system to work, at least based on how it’s advertised.

    A customer pointed out an interesting situation as his snow is melting off the roof this week. He has one string that is completely unshaded from snow, and one string that is probably about 1/3rd covered with snow. The production on the unshaded modules from the partially covered array are producing at about 1/4 of any module from the unshaded side. See the pictures below.

    Before you start your comment, I took the screencap of the array from the playback view (notice watts instead of watt-hours), so it’s not representative of any snow that may have been present earlier in the day.

    I drew an example of the approximate shading so it’s easier to see on the screencap. Of course I’d expect partially shaded modules to produce way less. But it seems like the difference between module voltage and where the string voltage needs to be is so stark that it’s actively dragging down the ability to produce for most of the string.

    The inverter doesn’t have MPPTs (that I know of), so it’s entirely reliant on the optimizers to create the proper voltage. I’m guessing what’s happening is that the optimizers are boosting the voltage so high that they can no longer run the module at the best voltage for production.

    What’s important here is that if you ask literally anyone about what would happen if half of an optimizer string got covered by snow, most people would say that the rest of the modules/optimizers would produce just fine, no problem. Apparently that’s not the case.

    UPDATE: I got a request to add more details about the optimizers themselves, so below is the opti wattage and voltage, and panel voltage and amperage.

    After some spirited speculation, I think the answer comes down to this comment from Gabriel Chong of Sunspear Energy:

    These are S1201 SolarEdge optimizers, whose minimum string length is 15 optimizers/29 panels. So it turns out, this installation is at the minimum allowed string length. What seems to be happening is that once another optimizer or two gets completely covered and can’t produce energy, the rest of the optimizers can no longer “optimize” for best production and are focusing entirely on meeting the bus voltage, compensating for the MIA optis.

    Such an interesting edge case, and would seem to suggest that aiming for the middle spot between minimum and maximum optimizers is the best design practice.

  • The solarboi shop is now open!

    I’ve had a merch link in the menu of this here website for a long time now, but there was never much to see there, and the types of products available there were pretty limited. That’s changing!

    You can now get the classic “solarboi” t-shirt and beanie at the merch store on THIS website! Not only that, but I’ve added a crop hoodie (which my wife loves), and a cozy embroidered zip-up hoodie. If you’re into UL 3741 stuff, there’s a hat and t-shirt for you, and brand new to the lineup is the “StuckPackets” parody shirt, which I created one evening in blind frustration at a…certain company’s firmware problem.

    There will certainly be more to come in the future, but for now, check it out and see what stands out to you!

  • Sick-Ass Panel Recycling Machine Video

    Terry Ko from PV Circonomy posted a video of the full process from beginning to end of their panel recycling machine. They say they can recycle 99% of the components of the panel. I’m a sucker for this kind of video, go watch it.

  • TikTok’s Ban Won’t Be Delayed

    Looks like TikTok is going to be given zero opportunity to avoid a ban. I’m gaining some traction on YouTube and elsewhere, so losing those followers will ultimately have a small effect, but I’m deeply sad about losing this weird little app.

    I wasn’t expecting to be this sad.

  • Do colored PV cables degrade faster than black?

    Do colored PV cables degrade faster than black?

    From Jan Mastny on LinkedIn:

    They didn’t know that these colorful cables held a terrible secret. Beneath their cheerful hues lay a weakness, a vulnerability that only the sun could reveal. For without the protective black cloak, these cables had no defense against the sun’s UV fury. They faded. Cracked. Aged like the lost souls of a haunted forest.

    What about UV resistance testing? Surely, colored cables are tested, right? Yes, but there’s a twist. The most common standards for UV testing last only 720 hours (about 30 days).

    Colored cable might seem fine under these limited tests. Simply no way to be sure it will hold up over decades.

    I want to be clear, I got nothing against the cheesy, Halloween-themed part of the article. We gotta have fun where we can.

    Aside from that, these claims smell like bullshit to me.

    There is no source cited in this article. Would be nice if there was some evidence of these claims, aside from speculating, “Eh, just because they were tested this way doesn’t mean they’ll actually hold up.”

    I don’t think I’ve ever seen PV cable crack and degrade like Jan’s talking about here, at least under normal UV stress. Any cracked PV cables I’ve seen are from heat within the wires, like in the case of an arc fault, or too much current. And I’ve never seen white or red cables degrade faster than black cables, aside from the color fading (which, by the way, absolutely happens to black cables as well!).

    It IS possible I may be in the wrong climate for this. If I take these assertions charitably, maybe there are hotter, more humid climates that expedite cable degradation, highlighting the differences in colored cable.

    But I’d like some actual evidence for it, please. There’s not even any pictures of this supposed phenomenon in the article. Seems like that would be low-hanging fruit if this was truly a common phenomenon.

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