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We bought panels outright with Solar City, end of 2007. Overall, we're satisfied. We didn't get exactly the rig we wanted. As a typical HN reader, I learned mo
by Syzygies 8y ago
We bought panels outright with Solar City, end of 2007. Overall, we're satisfied.
We didn't get exactly the rig we wanted. As a typical HN reader, I learned more about solar than their customer-facing staff, and had to periodically be put on the phone with a techie they usually insulate from customers. One problem was working around a revered shade tree we had no intention of hacking to optimize solar yield in late afternoon. One shaded array in a string is like one bad battery in a flashlight; that string's output crashes. I determined that we wanted two strings on independent converters, so half the panels would be unaffected. I was willing to pay whatever this cost, but they wanted a simple pricing model. They agreed to my request. Studying the wiring after installation, it was clear that the strings couldn't possibly be independent. It took calls to Germany to understand that the converter algorithm was tuned to "fake" two independent strings, like someone learning to walk with a lame leg. As spelled out in the manufacturer manuals, the algorithms claimed to optimize for the better string, even though they only saw the combined output. They lied about what they were actually installing, or more likely, the customer-facing staff were too ignorant to understand the swap being made without my consent.
There was a full-court crush to get our contract signed by the end of the year, ostensibly to have a chance on a limited number of expiring state-sponsored favorable time-of-day rate plans with PG&E. The state office was swamped with a backlog of unprocessed requests, though it strained credulity that SolarCity wouldn't have some idea about our chances. Of course they knew we had no chance; I found out through a back channel that they never filed until January 7th, making us ineligible. This deception speaks for itself.
Our panels cover various roof vents. This is not allowed by code in many locales. One day, a plumber snaking our bathroom sink drain gave up on the new snake his boss was making him use, and said he'd just go up to the roof and snake from there. (This is standard drain geometry in a house.) He came back down mortified: Our panels were blocking his access. He managed with a different snake, then we discovered the cause for his mortification: Our solar was out as of his visit. His original snake had gone up, not down, and shorted a panel. The panel was fine, but some component near the regulator on the side of the house had literally exploded.
SolarCity repaired this promptly, without charge.
- URSpider94 8y agoOne big reason I didn’t go with Solar City is that they install DC systems, where all of the panels are wired in series DC down to a big monolithic inverter. With such a system, shading is a problem, as you mention - one shaded panel will cut current for the whole string. You are also lucky that the plumber didn’t kill himself or burn down your house - DC systems often run hundreds of volts, and DC can sustain an arc with as little as 80V (http://www.acsolarwarehouse.com/news/solar-fires-dc-arc-faults-on-solar-systems/ http://www.acsolarwarehouse.com/news/solar-fires-dc-arc-faul...). AC systems have micro-inverters for each panel or panel cluster, so DC is never transmitted over large distances or at high voltage. Because each panel is independent, shading only affects the output of the shaded panel. You can also replace damaged panels or add to the system later without having to match the characteristics of the existing panels.