Building a ground mount rack for my panels. Looking for ideas

Fe-Wood

Re: Building a ground mount rack for my panels. Looking for ideas

I believe a tracking system gives 30% more energy than a static one does. I haven't looked what people say the advantage of a tilting system is.

Hydraulics would be cool! I freeze but just a little bit. Not a hard freeze. I have also been pondering the screw mechanism for automatic gate openers.

inetdog

Re: Building a ground mount rack for my panels. Looking for ideas

Fe-Wood wrote: »

I believe a tracking system gives 30% more energy than a static one does. I haven't looked what people say the advantage of a tilting system is.

A single axis tracking system that turns to east and west on an array which is mounted to a compromise elevation angle for your latitude will give your more output per area of panel, but if you have more than one such array, the spacing required to keep them from shading each other in morning and afternoon will require more land area than closer-spaced stationary mounts. If that is not a problem for you fine, but if you have a limited space to install, consider it. You can get accurate estimates of the relative output of fixed and one- or two-axis trackers, customized for your location using PVWatts.

Also, for the most part, unless you are off-grid and depending on getting every possible watt from your panels during winter months, the cost of a tracking system will be more than the cost of additional panels to generate the same amount of energy per day.
A system with a split of east-facing and west-facing panels can give you the longer production hours without requiring a tracker, and allows you to use a smaller inverter or CC for the same total number of panels.

People who use single axis trackers with a vertical axis often incorporate a manual tilt adjustment that they change a few times per year.

H2SO4_guy

Re: Building a ground mount rack for my panels. Looking for ideas

We built a mount from junkyard scrap at about $.30 per pound. It could have easily been adapted for ground mounting, but wanted to keep it safer from damage, theft, and mischief. Here is a link to a description, but if it doesn't work just let me know. Scroll down until you see my post with the picture. The racks are 65 x 150 inches, so larger than they look. [http://forum.solar-electric.com/showthread.php?17881-Automatic-or-manual-method-to-tilt-solar-array


Skip

niel

Re: Building a ground mount rack for my panels. Looking for ideas

do you think you can get a closer in pic from the back so others can actually see it?

inetdog

Re: Building a ground mount rack for my panels. Looking for ideas

H2SO4_guy wrote: »

We built a mount from junkyard scrap at about $.30 per pound. It could have easily been adapted for ground mounting, but wanted to keep it safer from damage, theft, and mischief. Here is a link to a description, but if it doesn't work just let me know. Scroll down until you see my post with the picture. The racks are 65 x 150 inches, so larger than they look. [http://forum.solar-electric.com/showthread.php?17881-Automatic-or-manual-method-to-tilt-solar-array


Skip

Looks impressive in the one picture, but it is so in-your-face that it also looks like a solar McMansion. :-)
I see that this is at the back of the house.

photovoltaic

Re: Building a ground mount rack for my panels. Looking for ideas

Here is my newest ground mount creation . The aluminum wasn't strong enough and sagged in the middle so I needed to prop it up a bit there. But I wanted the panels up high so tall prairie grass in the summer won't shade it. Also I made the center the pivot so it is easy to seasonally change the angle. A steep pitch in the winter lets the snow slide off and no shoveling if it piles up high. I used galvanized chain link fence hardware for the anchor to the wood as a prototype - I will get something stronger welded up some day ( you know how that never comes along and ten years later these will still be up hopefully ). I will be putting one more panel in the center.
Since you are a metal worker you could use this same idea and use steel or aluminum posts instead of wood if you wanted to.
Attachment not found.Attachment not found.

niel

Re: Building a ground mount rack for my panels. Looking for ideas

photovoltaic,
i'm concerned with your arrangement as i fear there will be too much strain on the pvs attached to the pivot point on the posts. this may have been better achieved by another long pipe or even angle iron with pipe attached at the ends so as to distribute the stresses evenly. where it meets the wooden posts can be easily transitioned with something as simple as a pipe strap similar in shape to this below and the pipe can freely turn for adjustment,
http://www.lowes.com/pd_301383-34146-AV301383_0__?productId=3223473&Ntt=pipe+clamps&pl=1&currentURL=%3FNtt%3Dpipe%2Bclamps&facetInfo=

photovoltaic

Re: Building a ground mount rack for my panels. Looking for ideas

niel wrote: »

photowhit,
i'm concerned with your arrangement as i fear there will be too much strain on the pvs attached to the pivot point on the posts. this may have been better achieved by another long pipe or even angle iron with pipe attached at the ends so as to distribute the stresses evenly. where it meets the wooden posts can be easily transitioned with something as simple as a pipe strap similar in shape to this below and the pipe can freely turn for adjustment,
http://www.lowes.com/pd_301383-34146-AV301383_0__?productId=3223473&Ntt=pipe+clamps&pl=1¤tURL=%3FNtt%3Dpipe%2Bclamps&facetInfo=

Yes I agree with you Niel and had thought about doing exactly as you mention using a pipe across the center. I just need to get some pipe and it will be easy to retrofit that. It would as you say give this a lot of much needed support. I put it up the way I did because I just used what I had on hand at the time. I know my mounts are not 100 mph wind rated . (yet !)

Photowhit

Re: Building a ground mount rack for my panels. Looking for ideas

Hi Neil, I think the message got to who you wanted, I'm happy to say my new wood mount survived a gusty 50+ mph wind test a week or so ago, with no problem. Even came out of the North East, my least protected area...

TnAndy

Re: Building a ground mount rack for my panels. Looking for ideas

I've built 3 tracking pole mounts for my previous 3 arrays, but decided with panel pricing in the one buck/watt range, I'd try a fixed mount for array #4. I copied the design of another Tennessee guy, Doug Kalmer: http://www.builditsolar.com/Projects/PV/DougEnphase/DougEnphase.htm

You can see a LOT of detail at the above site.

I did mine similar, except I cranked the tilt angle up to about 50 degrees to make more in the winter sun angle, as that was my weak point on the other three arrays.....two of them are east-west single axis trackers on 37 degrees, and the 3rd array is a dual axis tracker, but the limit on my winter angle is about 45 degrees.

Also, this array is grid tied only, using Enphase 215 inverters.



I used 1 1/2" galvanized pipe, Mig welded together, and 2" galvanized angle across the top of the pipe for racking to attach the inverters and panels.

H2SO4_guy

Re: Building a ground mount rack for my panels. Looking for ideas

It is actually a barn, 100' x 40' wide, which is the south facing side for the solar. We tore off the steel wall and put up another wall with 2x6 stick framing. I'll see if I can get up there with a camera this weekend.

Skip

Pls2400

I own a store that sells structural grade, fiberglass reinforced recycled plastic lumber. In my opinion this is the ultimate solution for ground mount systems. It will never rot or need any maintenance and is contributing to recycling efforts. It is easy to drill and mount and gives ballast, where aluminum doesnt. I have been building these for 20 years, but just as a customer service. I am considering making more of a kit, since solar is continuing to grow and people are looking for easy solutions. www.plasticlumberstore.net

Dave Angelini

To sell this to someone like me you need structural data. You would need a complete design with wind, snow, and wind/snow loading for me to show to an AHJ.

I agree with you that fiberglass has some nice attributes. It also burns quite easily. Hope this helps.

MichaelK

These are the mounts I made out of unistruts.  The center post is 3.5" schedule 40 pipe sunk in concrete.  The T post slipped over it is 4" schedule 40 pipe.  They hold three 300 watt panels.  They can rotate to track the sun.  I am the tracker.

geosierranevada

Michael,
Your pole mounts look sturdy enough, but the pole mount racks seem to be too close to each other in order to turn them in another direction.   George.  Have a nice day

MichaelK

Perhaps it's the angle at which I shot the photo.  I routinely turn the panels east in the morning, and west in the afternoon.  A bit of shading is a problem at about 7:00AM, but I typically am producing enought power by 8:00-8:30am to run my wellpump.

zozomike

Wind wants mass. Earth has it. But 
So does concrete. Put lots of gravel for drainage and a full size slab on grade. Thick at point loads. Bolt to that. I've worked areas which had 170 mph. Structures gone slabs fine.