This will chronicle my search for the most cost effective self installed PV.
About 2010 or 2011, Jean and I bought a Sprinter RV conversion anticipating doing some travel while she had the time. Though her time was shorter than we planned. I had a building put up to store and protect the Sprinter conversion. I had the building oriented with a due south facing roof anticipating installing PV panels. For a few years, neighbor Ray had been experimenting with PV and keeping the subject in my consciousness. I bought a four panel kit from an eBay seller. I fondly remember Jean and I taking our new 2011 Leaf to a north side of Austin freight terminal to pick up the kit. The packaged panels would not fit in the Leaf and we had to unpack in order to load the panels. I don't recall the cost but probably less than $2k. I eventually had Steve Clunn of Green Shed Conversions in Florida install the four panels on a structure cantilevered off the south shed of the RV building. That was Steve's first experience with PV; he went on to install quite a lot of PV at his Florida home. Those four panels are still producing but the initial plan to expand along the length of the shed were never fulfilled. I later had Longhorn Solar do a roof top install on that building; that must have been 2012 or 2013. Cost was high. Even with a 30% income tax credit, the expected pay back period was around 20 years. That system has now about half paid for itself.
My next self install experience was a wood frame mounted on a 16' flat bed trailer deal. The first pictures of the album. That system produced only a couple of years before high wind and new ideas hastened it's demise. 2016-2017 era. I believe the panels cost around $100 each and the chinese micro inverters were around $80 each. The wood frame was insufficiently durable and cost around $50/panel. While the trailer system was still producing, I experimented with two much more substantial six panel two post mounts. Those are about the most durable and maintenance free mounts that I have done. Sadly, too expensive, around $100/panel. I went on to panels leaning on pipe rails and resting on the ground. Far cheaper at less than $50/panel. Difficulties are ongoing maintenance for weed/grass control and restraining against wind forces.
Somewhere along about this period, I came to the realization that I could become a professional power producer. Selling power to my utility with attractive economics. I decided I might get my costs low enough that my pay back period might be as short as about five years. Even with the wholesale prices the utility is willing to pay.
I put in quite a few low rails with leaning panels over a year or so. I early became aware that pointing direction was not crucial. Most panel orientations will produce about 90% as much energy as optimally pointed panels. So, I placed rails that mainly just avoided pointing toward shade. In the search for lower cost, Ray suggested north/south rails with panels on both sides pointed east and west. The disadvantage was lack of access to the back sides of the panels where micro inverters were dangling. The high reliability of the Enphase micro inverters then being used persuaded me that maintenance access was not so important. So, I started installing "two face rails" with steeper panel slopes. These were more wind resistant than the "one face rails". After getting several of those two face rails installed and producing with one micro inverter for each panel, I realized that a single micro inverter might serve one east facing panel and one west facing panel. Testing revealed that that was the case with only a small loss of total energy produced. So, all new rails are two faced with half the number of inverters as panels. Old two face rails are slated to be reconfigured. Cost per installed and producing panels are now down around $75-$80. I've spent quite a bit experimenting with string inverters; they have the potential to bring cost down to about $60-$70 per panel. I've had good success getting my low cost panels to work with older design string inverters. But, the older string inverters are generally no longer available and I've failed to get more modern string inverters to work with the low cost panels.
My concentration on east and west facing panels has, as a primary benefit, spreading production over a much wider time period than optimal south facing only. My daily periods of good production may be 3-4 hours longer than for south facing only. It also maximizes the utilization of my grid connections. The size of transformers limits peak power of production; when that peak is smeared out over time, more energy can be pushed to the grid.
Included in the photo album is a photo of a neighbor's very nice rail system with the lower portion of the panels elevated. But the cost is high, about $100/panel just for the mount. Neighbor Ray also holds his rail panels up off the ground. His system is a bit expensive and also retains obstruction to mowing. He uses inverted plastic feed tubs which are not available cheaply in volume.
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