> What goes into a mount that makes it so expensive?
Ground mounts are far more expensive, not only because of how strong they need to be to support the panels under strong winds and snow without deflection, but the anchoring can be complicated depending on the site.
Some people can just hammer spikes into the ground, fill with epoxy, and their array is anchored. For my yard, I have to dig 4-feet down below frost line, through incredibly rocky clay soil, and bury (and concrete) 4x4 posts. On top of those posts goes the (expensive) metal rails to mount the panels. For just 10 solar panels it's gonna cost me ~$1000 in materials and many hours of digging.
The metal U-channel rails I'm looking at using will cost around $40/pp (10-ft), and I need at least 10 of them. In theory a cheaper option could be wooden boards like 2x8/2x10, but they're significantly heavier, bulkier, and would still be difficult to mount to.
This construction lets me build the array however I want, including adjusting angle (I'll have 4 pre-set angles for each season). This design is still cheaper than the cheapest pre-fab ground mounts, which are metal legs which go for ~$110/pp. You need ~2 legs per panel, though in some cases you can share one leg for two panels. For 10 panels you still need at least 11 legs, so at least $1100, before cost to anchor them. And that's a fixed angle. The adjustable angle ones are more like $185/pp.
No, power augers (even hydraulic ones) don't work well in incredibly rocky clay soil. My landlord tried to use one a couple years ago, got about a foot deep, and gave up and grabbed a shovel and digging bar.
I have the privilege of being licensed and insured for such and have a working relationship with the county fire marshall who issues the permits, so I used a rock bar to open a little hole to the right depth and then sprung the hole with a small binary explosive charge. Covered with matting hung from a borrowed tractor's bucket, so no danger of launched projectiles.
Saved a whole lot of backbreaking digging, do recommend.
In my experience, if you’re willing to sacrifice the bit, they can save time in the earth composition you mention vs manual excavation if the driver has enough power (especially if mounted to a skid steer, just drive the bit towards success depth). Thanks for the reply, always curious on improving the speed and efficiency of ground mount installs.
Ground mounts are far more expensive, not only because of how strong they need to be to support the panels under strong winds and snow without deflection, but the anchoring can be complicated depending on the site.
Some people can just hammer spikes into the ground, fill with epoxy, and their array is anchored. For my yard, I have to dig 4-feet down below frost line, through incredibly rocky clay soil, and bury (and concrete) 4x4 posts. On top of those posts goes the (expensive) metal rails to mount the panels. For just 10 solar panels it's gonna cost me ~$1000 in materials and many hours of digging.
The metal U-channel rails I'm looking at using will cost around $40/pp (10-ft), and I need at least 10 of them. In theory a cheaper option could be wooden boards like 2x8/2x10, but they're significantly heavier, bulkier, and would still be difficult to mount to.
This construction lets me build the array however I want, including adjusting angle (I'll have 4 pre-set angles for each season). This design is still cheaper than the cheapest pre-fab ground mounts, which are metal legs which go for ~$110/pp. You need ~2 legs per panel, though in some cases you can share one leg for two panels. For 10 panels you still need at least 11 legs, so at least $1100, before cost to anchor them. And that's a fixed angle. The adjustable angle ones are more like $185/pp.