Best GroundMount Racking Solution for 10kw Install

[dvseliteus]

Hi All!
I am interested in installing a Groundmount system in my yard.
I'm looking to install about 36 SolarWorld Plus 280W Mono Black in a 2x18 Portrait Table about 60 feet long.
I have sourced everything but the racking and I'm wondering what the forums thoughts are on the most affordable racking?
Whats easy to install and what systems should I just stay away from completely?
I have installed on a couple of pitched roofs but this will be my first ground mount.
Can anyone share there experience, photo's or costs on some of the options?
Thanks all!

[Rocksteady2R]

Three thoughts:

We install Schletters whenever we do a ground mount. they're simple enough, and cheap enough. I'm sure you can always swing deals and play one manufacturer against teh other to a fair degree.
Shipping will be a serious cost, factor that in too.
and... l havn't used them as such, but Dynoraxx has used their ballasted racking on the ground, as well - if you want to / are able to go that route. I'm not sure what considerations you'd have to factor in to that, aside from prepping and fencing the lot.

[DanS26]

Just a few thoughts:

1. Have you gone to the IronRidge site to design the rack? Lots of helpful information there.

2. The footprint would be somewhat smaller if you designed a 4x9 Landscape array.

3. If you are in a snow prone area, then landscape is a better orientation because of the way panels are manufactured and electrically wired...not a big difference...but if you have a choice then go with the the higher output orientation. As snow melts off the panel (ie top down) it will expose the cell series in such a way as to increase production.

4. If you go the IronRidge route you can use either 2" or 3" galvanized pipe. That pipe can be sourced locally from a plumbing supply house for less cost and large shipping savings.

Good luck.

[DanS26]

If you decide to use galvanized pipe as the supporting structure here is my method of leveling and aligning the posts. IMO this is the hardest concept and construction technique for DIY'ers. Those are 2x4's with 1/2" holes drilled to accept fiberglass electric fence posts that are cut in half. Then small wood counter strips to set proper alignment. Hole depth is adjusted by gravel fill. Use a laser level to align everything. Super easy with the right tools. No need to build those crazy wooden structures you see all over the web.

IMG_0293.JPG

[DanS26]

Here is the finished product. IMG_0355.JPG

[dvseliteus]

Hi Rocksteady2R,
Thank you for the info. Where do you buy Schletter, direct?

Thanks DanS26 for the great images and info. I am in the west coast with no snow. I like the 2 up portrait so I can have the panel j-boxs facing each other for a clear wire route.
I have seen the IronRidge product but I was looking for something more complete than sourcing pipe additionally.

I am also curious about non concrete options... and I am not sure I am a fan of the clamp style mounting. The direct bolt options or slide in designs look a little more sleek in my opinion.
But I haven't been able to find a low cost solution as of yet.

[DanS26]

Hi Rocksteady2R,
Thank you for the info. Where do you buy Schletter, direct?

Thanks DanS26 for the great images and info. I am in the west coast with no snow. I like the 2 up portrait so I can have the panel j-boxs facing each other for a clear wire route.
I have seen the IronRidge product but I was looking for something more complete than sourcing pipe additionally.

I am also curious about non concrete options... and I am not sure I am a fan of the clamp style mounting. The direct bolt options or slide in designs look a little more sleek in my opinion.
But I haven't been able to find a low cost solution as of yet.

I used WEEB's with my panel clamps. That method eliminated running a lot of grounding wire and connections to panel frames. But new grounding methods are being developed and of course your AHJ will have the last say.

I live in a fairly high lightning strike area so I went to the added expense of creating a ground ring around my arrays. Eight grounding electrodes (one on each corner) all bonded together underground. Since using WEEB's the entire metal structure is bonded and then grounded to UFER's in the concrete encased posts. Not much lightning in CA so probably not a concern for you even if you do use non-concrete options.

[JFinch57]

I used Unirac U-LA, which requires standard schedule 40 2" galvanized plumbing pipe. Shot all of the holes with a laser level to the bottom (put a stone in the center with pressure treated fence wood on it) then cut the pipe so that it would be level on top, worked perfectly! It does require concrete and I had 2 choices for footings, 18" X40" or 12" X 50", went with the 18". Should have put bags around the sonotubes as some got wet and collapsed in the 2 weeks it took me to build the frame. It was a real pain to deal with that! The three portrait panels on the end were a custom addition of mine after the ground slope was too much (55" over 60') and I had to put a break in the middle. I eventually added end bracing going down the the end footings, not shown in the pictures, and straps underneath to hold the middle of the panel downward for wind.

[DanS26]

JFinch....thanks for the pics. My biggest concern were twofold....lightning and wind. As I mentioned earlier I created a ground ring to mitigate lightning, but for wind I decide to install 3" galvanized pipe. The pipe below ground had holes which were drilled and I installed horizontal rebar...yes overkill but I know the pressure of wind uplift in a high wind situation...think tornadic winds. If those winds were going to take my arrays then it would have to pull the foundation up by its roots.

The 3" pipe was HEAVY and I would advise any DIY'er that they need the proper equipment to work with that size pipe unless they have lots of friends and a case of Bud.

IMG_0353-001.pdf

[JFinch57]

Do you have two 10KW arrays?

[DanS26]

Do you have two 10KW arrays?

First array built in 2011 has 36 Kyocera black 235 watt panels or 8.46kW and second array built in 2014 has 36 Kyocera blue 245 watt panels or 8.82 kW. Total system size 17.28 kW. Each array feeds a Fronius 7.5 string inverter so max AC output 15 kW.

Since it is a matched set with the exact same orientation characteristics, I get to observe the performance difference between black and blue cells. So far blue cells perform better in low light and hot conditions and the black cells perform better in intense light and cold conditions. It also appears that the black cells are degrading slightly faster than the blue cells.

[J.P.M.]

First array built in 2011 has 36 Kyocera black 235 watt panels or 8.46kW and second array built in 2014 has 36 Kyocera blue 245 watt panels or 8.82 kW. Total system size 17.28 kW. Each array feeds a Fronius 7.5 string inverter so max AC output 15 kW.

Since it is a matched set with the exact same orientation characteristics, I get to observe the performance difference between black and blue cells. So far blue cells perform better in low light and hot conditions and the black cells perform better in intense light and cold conditions. It also appears that the black cells are degrading slightly faster than the blue cells.

Dan: Nice info. How do annual outputs compare ?

Thanx.

[DanS26]

Black array over a four year period has averaged 11,365 kWh per year. The blue array over a two year period has average 11,973 kWh per year. That is a 5.3% difference. Since the blue array is 245 watts vs 235 watts then I would expect at least a 4.2% difference just from power. Then you have to factor in the 1.44% degradation factor since the black array is two years older (ie .72% per year degrade).

Since I have this matched set, I will know immediately if I have a problem in any panel in either array.....the production ratio will change which will cause me to track down the offending panel post haste. I'm watching one black panel with snail trails but it appears to be producing just fine. Kyocera panels are not the highest producing panels out there but the manufacturing quality is outstanding.

[J.P.M.]

Black array over a four year period has averaged 11,365 kWh per year. The blue array over a two year period has average 11,973 kWh per year. That is a 5.3% difference. Since the blue array is 245 watts vs 235 watts then I would expect at least a 4.2% difference just from power. Then you have to factor in the 1.44% degradation factor since the black array is two years older (ie .72% per year degrade).

Since I have this matched set, I will know immediately if I have a problem in any panel in either array.....the production ratio will change which will cause me to track down the offending panel post haste. I'm watching one black panel with snail trails but it appears to be producing just fine. Kyocera panels are not the highest producing panels out there but the manufacturing quality is outstanding.

Dan: Thank you. Sounds (reads) to me like about a wash +/- a tad ?

[Kevin Aylesworth]

Check out Powers Solar Frames. All of there systems are slide in and very durable. The Ballasted box shown here is a flat rate of $145 and holds 5 panels. www.powerssolarframes.com