A year ago I installed a 4 kilowatt solar fence. I'm revisiting it this Sun Day, to share the design, now that I have prooved it out.

The solar fence and some other ground and pole mount solar panels, seen through leaves.

Solar fencing manufacturers have some good simple designs, but it's hard to buy for a small installation. They are selling to utility scale solar mostly. And those are installed by driving metal beams into the ground, which requires heavy machinery.

Since I have experience with Ironridge rails for roof mount solar, I decided to adapt that system for a vertical mount. Which is something it was not designed for. I combined the Ironridge hardware with regular parts from the hardware store.

The cost of mounting solar panels nowadays is often higher than the cost of the panels. I hoped to match the cost, and I nearly did. The solar panels cost $100 each, and the fence cost $110 per solar panel. This fence was significantly cheaper than conventional ground mount arrays that I considered as alternatives, and made a better use of a difficult hillside location.

I used 7 foot long Ironridge XR-10 rails, which fit 2 solar panels per rail. (Longer rails would need a center post anyway, and the 7 foot long rails have cheaper shipping, since they do not need to be shipped freight.)

For the fence posts, I used regular 4x4" treated posts. 12 foot long, set in 3 foot deep post holes, with 3x 50 lb bags of concrete per hole and 6 inches of gravel on the bottom.

detail of how the rails are mounted to the posts, and the panels to the rails

To connect the Ironridge rails to the fence posts, I used the Ironridge LFT-03-M1 slotted L-foot bracket. Screwed into the post with a 5/8” x 3 inch hot-dipped galvanized lag screw. Since a treated post can react badly with an aluminum bracket, there needs to be some flashing between the post and bracket. I used Shurtape PW-100 tape for that. I see no sign of corrosion after 1 year.

The rest of the Ironridge system is a T-bolt that connects the rail to the L-foot (part BHW-SQ-02-A1), and Ironridge solar panel fasteners (UFO-CL-01-A1 and UFO-STP-40MM-M1). Also XR-10 end caps and wire clips.

Since the Ironridge hardware is not designed to hold a solar panel at a 90 degree angle, I was concerned that the panels might slide downward over time. To help prevent that, I added some additional support brackets under the bottom of the panels. So far, that does not seem to have been a problem though.

I installed Aptos 370 watt solar panels on the fence. They are bifacial, and while the posts block the back partially, there is still bifacial gain on cloudy days. I left enough space under the solar panels to be able to run a push mower under them.

Me standing in front of the solar fence at end of construction

I put pairs of posts next to one-another, so each 7 foot segment of fence had its own 2 posts. This is the least elegant part of this design, but fitting 2 brackets next to one-another on a single post isn't feasible. I bolted the pairs of posts together with some spacers. A side benefit of doing it this way is that treated lumber can warp as it dries, and this prevented much twisting of the posts.

Using separate posts for each segment also means that the fence can traverse a hill easily. And it does not need to be perfectly straight. In fact, my fence has a 30 degree bend in the middle. This means it has both south facing and south-west facing panels, so can catch the light for longer during the day.

After building the fence, I noticed there was a slight bit of sway at the top, since 9 feet of wooden post is not entirely rigid. My worry was that a gusty wind could rattle the solar panels. While I did not actually observe that happening, I added some diagonal back bracing for peace of mind.

view of rear upper corner of solar fence, showing back bracing connection

Inspecting the fence today, I find no problems after the first year. I hope it will last 30 years, with the lifespan of the treated lumber being the likely determining factor.

As part of my larger (and still ongoing) ground mount solar install, the solar fence has consistently provided great power. The vertical orientation works well at latitude 36. It also turned out that the back of the fence was useful to hang conduit and wiring and solar equipment, and so it turned into the electrical backbone of my whole solar field. But that's another story..

solar fence parts list

$1100 total

(Does not include cost of panels, wiring, or electrical hardware.)