Top Pole Mount system Foundation question.

ROTTEN · April 2016

hello friends.

I just purchased 6x
235watt panels
that are
45lbs
40inch x 66inch

my total square footage of the panel area is 110 sq ft.
So thats what will be pushed by wind.
My climate is pretty mild, northern Ohio.
Rarely see 40-50mph winds
ground is clay.
frost line is 36-42inches.

I want to purchase a top of pole mount tracker setup and I needa know what kinda
foundation im looking at for this setup with room to expand, add at least another 6panels down the road...

Anyone experienced in installing top of pole mounted systems?

or anyone that might have some calculators I could use or some math i can go over in order to figure out what
i need.

So far from what I read.

a schedule 40 steel pipe 6inch diameter and 11 feet long.

dig a whole that is 5ft deep and 32inches wide

put pipe in ground, back fill 1ft with soil/clay (im going to use the pipe as a ground also)
then the rest of the 4ft fill in with concrete(ill be running 2-3 bolts throw the pipe so that
it locks in with the concrete and cant slide)

this will leave the pole 6ft of pole out of the ground with the panels clearing the ground
by around 3ft.

would like input from anyone please.

thanks for your time.

vtmaps · April 2016

It sounds OK for 6 of those panels, but I doubt you can add 6 more on a 6" pipe... maybe an 8" pipe. Do a search on this site for "top of pole mount"... there are lots of good pictures and some links to a two-part Home Power article.

Are you in snow country? If so, you might want to consider a mount that goes all the way to vertical.

--vtMaps

Hill_Country · April 2016

Hi Rotten,

I can lend you my experience for my setup, but it may not be pertinent for yours. I purchased two UPM-6X top of pole mounts from General Specialties Inc. that are each capable of holding 4 60-cell PV panels (fyi...we have 8 Solarworld 275 watt 60-cell PV panels so we bought two of their UPM-6x's). I followed their foundation recommendations for the depth of pole, as well as the amount and dimensions of concrete that is necessary for their pole mounts. Please see: http://www.generalspecialtiesmfg.com/page/10784/Assembly-Instructions for more info.

My suggestion would be to go to their site (or any other pole mount site) and find a single pole mount setup (perhaps the UPM-12XHD ?) and see what their foundation requirements are, and then use that as a guide for your setup. I chose to split my 8 panel PV array up into two separate arrays of 4 panels that are supported on two separate pole mounts (i.e. I bought two UPM-6x's). I figured it was slightly cheaper and MUCH easier to install as the metal pole doesn't have to be as big/thick, nor do you have dig as deep! Little things like depth of hole and amount of concrete can really vary and can affect the overall cost of the project...so keep those in mind.

Hope this helps!!

ROTTEN · April 2016

great, thanks for the replies.

I have been doing some reason and searching around the site, just wanted to start
some dialog with some folks.

I'll be reading and will post back when I get things a lil more dialed down.

ROTTEN · May 2016

Ok so after some more searching and talking to some peeps this is what Im thinking about going with.

In the future I want to add another 6 panels to my system, doubling the size.
So I want to make sure that the pole, footer and tracker system can handle that kinda weight,
which would be roughly 1000lbs on the HEAVY END.

12 panels would weight only 540lbs, so maybe another 200 for the hardware and rails.

this is the tracker im looking at picking up, should
be big enough to be able to add the additional 6 panels in the future.
http://www.ebay.com/itm/291602807889?euid=0ee765dab88d41cb82c34559c0c38039&cp=1&exe=11473&ext=27979&sojTags=exe=exe,ext=ext

so with that...
Going to do a
12ft long
8inch diameter
sch40 thickness galvanized steel pipe.

with a 36inch x 48inch deep footer

so the pole will be about 8ft off the ground... which I think its pushing the limit, it might need to be longer...

but I wanna figure out how the panels will be arranged... because
im planning on running them horizontally on the mount, so then they can be 3 wide and 4 high making
it roughly 15ft wide 13ft long

mike95490 · May 2016

Why the tracker ? If you have the space, split the array into 2, and use small poles. One array will require a Large pole set deep into concrete.
I have 3Kw on a single pole, 10' deep in a 24" hole of concrete and rebar. My 2Kw array is on a larger di and taller pole, also 10' into concrete, The soil test is so the mount will be stable when the clay is wet and the wind blows, so the rig does not tilt in the ooze.

ROTTEN · May 2016

mike95490 said:

Why the tracker ? If you have the space, split the array into 2, and use small poles. One array will require a Large pole set deep into concrete.
I have 3Kw on a single pole, 10' deep in a 24" hole of concrete and rebar. My 2Kw array is on a larger di and taller pole, also 10' into concrete, The soil test is so the mount will be stable when the clay is wet and the wind blows, so the rig does not tilt in the ooze.

holy shit.... 10 FEET deep thats intense lol very expensive pole, i take it you have high winds though??
but according to how much concrete that is, roughly 1.5 cubic yards NOT including the space the pipe
takes up, you filled the pipe with concrete??

Its not that windy here, average yearly is 10mph winds, with gusts maybe in the high 20s.

I want the tracker to follow the sun, only makes sense to add a tracker if it only cost about 400 bucks more.

The dude with the tracker tells me to dig at least a 2 cubic yard hole for the pole, I figure ill go below the frost layer
and dig out a nice square at the bottom of the hole so prevent spinning, then of course ill add
the rebar thru the pipe before I pour the concrete. Pretty much what @vtmaps did in his project.

I just wish I can flipping find my counties codes regarding solar installations...
I know im well above whats needed for construction code with frost line and what not.

nonetheless, I think I'll be in the clear if i go with...

8inch steel pipe, schedule 40 thickness
now just debating on what length I need or should get...
either a 16 or 14ft long pipe... both will in ground same amount, 6ft.
Its either ill have 8 ft or 10 ft of pipe sticking out of the ground.

here is the final layout that I plan on using when I expand the system.. from 6 panels to 12 panels.
So of course I gotta size this mount accordingly. 12 panels is probably plenty large for what I need...
and it will be quite the statement in my area haha people will admire it

Image: http://i.ebayimg.com/00/s/NTY3WDc4OA==/z/zHEAAOSw~oFXJqG3/$_12.JPG?set_id=2

From the center of this array to any corner is roughly 10.5ft

shit... looks like Im going to have to go with the 16ft pipe... Meh lol rack um up Johnny $$$ lol
Damn this foundation mount, This was the only aspect I underestimated on this entire system
im building and its ending up costing me around an extra 600-700 bucks. BUt its gotta be done right.

really appreciate the feedback I have been getting here though. Thanks for
pointing some direction, thats all i ask, I can read and research just fine

and if anyone has any resources or links to some county or state codes and ordances for
Cleveland Ohio area, Chicago... PA.. we all got pretty similar soil, im working with straight YELLOW CLAY.

sweet site dude from ebay sent me.
http://www.solarelectricityhandbook.com/solar-angle-calculator.html

ROTTEN · May 2016

Hill_Country said:

Hi Rotten,

I can lend you my experience for my setup, but it may not be pertinent for yours. I purchased two UPM-6X top of pole mounts from General Specialties Inc. that are each capable of holding 4 60-cell PV panels (fyi...we have 8 Solarworld 275 watt 60-cell PV panels so we bought two of their UPM-6x's). I followed their foundation recommendations for the depth of pole, as well as the amount and dimensions of concrete that is necessary for their pole mounts. Please see: http://www.generalspecialtiesmfg.com/page/10784/Assembly-Instructions for more info.

My suggestion would be to go to their site (or any other pole mount site) and find a single pole mount setup (perhaps the UPM-12XHD ?) and see what their foundation requirements are, and then use that as a guide for your setup. I chose to split my 8 panel PV array up into two separate arrays of 4 panels that are supported on two separate pole mounts (i.e. I bought two UPM-6x's). I figured it was slightly cheaper and MUCH easier to install as the metal pole doesn't have to be as big/thick, nor do you have dig as deep! Little things like depth of hole and amount of concrete can really vary and can affect the overall cost of the project...so keep those in mind.

Hope this helps!!

Thanks for the link, I checked it out and pretty much I'll be going with just about what they recommend.
They are also having a warranty on those mounts as long as you get things inspected as you install, pretty slick.
There mounts are really impressive.

I'm pretty comfy with being damn near their specs.

Here are some sheets I have been looking at.
http://www.homepower.com/article/?file=HP108_pg28_Schwartz

http://dpwsolar.com/images/UTPMPricingSelectionGuide_SL-PL-1008-1.pdf

vtmaps · May 2016

ROTTEN said:

according to how much concrete that is, roughly 1.5 cubic yards NOT including the space the pipe
takes up, you filled the pipe with concrete??

Do NOT fill the pipe with concrete... that will make it a Lally Column. Lally columns are good for supporting great weight, but not good for bending forces such as panels in the wind. If you fill the pipe with concrete it will snap off at the foundation.

--vtMaps

ROTTEN · May 2016

vtmaps said:

ROTTEN said:

according to how much concrete that is, roughly 1.5 cubic yards NOT including the space the pipe
takes up, you filled the pipe with concrete??

Do NOT fill the pipe with concrete... that will make it a Lally Column. Lally columns are good for supporting great weight, but not good for bending forces such as panels in the wind. If you fill the pipe with concrete it will snap off at the foundation.

--vtMaps

thanks for clearing that up.

It makes sense that you want the pipe to bend and give as it gets hit with gusts of wind.

mike95490 · May 2016

Just filled to ground level for ballast, no rebar, not vibrated in. Rebar cage was installed between pipe and hole, filled with concrete and vibrated in to fill voids. Winds 30-50mph in storms, but not enough for a turbine to be useful. The array and pole really creak in the wind when it blows, been holding up so far (crosses fingers and eyes)

ROTTEN · May 2016

MEH...

I cant find any damn 8inch pipe for the life of me in my area.. WTF lol...

one place said they not getting a new pipe shipment in until middle summer....
Im like... WHAT!!!..

westbranch · May 2016

Check to see what the well drillers carry..... they use 8 inch a lot up here, and bigger if needed..

solar_dave · May 2016

Isn't it just easier and cheaper to buy more panels on fixed mounts (or perhaps tillable mounts for the seasons) and forget the trackers these days?

Hill_Country · May 2016

Rotten...the difficulty in finding the larger size metal pipe is one of the many reasons I chose to do two separate top pole mount installations instead of one big one. The metal pipe size can be smaller, the depth of the foundation and requisite hole can be smaller, plus the smaller top of pole mounts are easier to move around/adjust if you decide not to do the tracker thing. Just my 2 cents...

I'm glad you're investigating this thoroughly BEFORE you install the top of pole mounts...awesome!

ROTTEN · May 2016

I found the pipe.
Normal steel 8inch 16ft sch40 thickness $250
Might be able to get it in galvanized for $500.

I talked with the guy that I got the solar stuff from and he mentioned that abut the stationary mounts.

I got a lot more math and figuring to do before I finalize my plan.

Right now I'll be able to get a tracker mount that will fit the 8inch pipe and handle 12x 60cell 45lb panels, supposedly. I got a lot more questions for the seller to determine if I'll buy it or not.
But the cost for the tracker and mount will be about 800 bucks.

Dave Angelini · May 2016

8 inch pipe is too heavy for me without a back-hoe. Multiple 6 inch arrays are the way to go in my opinion for many reasons.
Who is the tracker manufacturer please?

mike95490 · May 2016

Better look up the corrosion specs of galvanized steel in concrete, I think the caustic concrete eats the zinc right off and you end up with a gap in the pipe-concrete interface where the zinc was, that funnels rain water in. get sch 80 and never worry about rust eating thru it. Have an engineer wet stamp the plans (another $500)

Dave Angelini · May 2016

Galvanized is really only for coastal or near salt water locations. Probably the biggest corrosion problem is from someone who uses rebar and does not properly float the rebar off the dirt. It should be completely encased in cement. Some soils do not attack the metal and that is why commercial solar often does not use cement and a pile driver is used. A coat of paint every 5 years or so and schedule 40 is more than enough. If you can get 80 for a decent price why not?

What kind of tracker?

ROTTEN · May 2016

Dave Angelini said:

8 inch pipe is too heavy for me without a back-hoe. Multiple 6 inch arrays are the way to go in my opinion for many reasons.
Who is the tracker manufacturer please?

mike95490 said:

Better look up the corrosion specs of galvanized steel in concrete, I think the caustic concrete eats the zinc right off and you end up with a gap in the pipe-concrete interface where the zinc was, that funnels rain water in. get sch 80 and never worry about rust eating thru it. Have an engineer wet stamp the plans (another $500)

Dave Angelini said:

Galvanized is really only for coastal or near salt water locations. Probably the biggest corrosion problem is from someone who uses rebar and does not properly float the rebar off the dirt. It should be completely encased in cement. Some soils do not attack the metal and that is why commercial solar often does not use cement and a pile driver is used. A coat of paint every 5 years or so and schedule 40 is more than enough. If you can get 80 for a decent price why not?

What kind of tracker?

yea, Ive decided to just use the sch40 and paint it.
Thanks for the comment about making sure the rebar is encased.

after some more talk with my local solar guy, he has me second guessing this tracker.
Here is the link its on ebay.
http://www.ebay.com/itm/291602807889?euid=cc856f65b16248f3addb6b70a83e94a8&cp=1&exe=11473&ext=27979&sojTags=exe=exe,ext=ext

Pretty intense mount if it can handle 18 panels...
Im only going to max it to 12 panels..

The cost comparison between just buying more panels with additional mounting and
adding the tracker comes to around... 200-300 bucks MORE when using 25% as a mark up of
additional power created.

I guess thats a pretty good deal because usually its worth it to just buy more panels instead
of adding a tracker.

one of the main things I need to haev though is to haev these panels a god 4-5 ft OFF the ground.
This way I can still plant plants under the panels, lettuces and shade liking crops.

Im stilling more work and research.
I plan on doing some more math and I wanna post that work here so you all can see it, you know
share my work

Again really appreciate the feed back everyone, really helping me out making decisions.
Not trying to just spend money needlessly.

Dave Angelini · May 2016

Drop me an e-mail. I think you are wise to keep looking. I would doubt that tracker design also. No matter how much american steel is in it, the design is suspect to me from my experience. If you are offgrid, you should go for the best unless you have time to play around with this. When it is done right, there should be very little to do for power.

ROTTEN · May 2016

Picking up the pipe today. 8inch sch40 thickness 16ft long.

ROTTEN · May 2016

after chatting with the eBay guy about his mount and how its constructed with what metals, I decided on
going with that mount and see how it rolls.

making teh order tonight, should haev the mount within 2 weeks.

Top Pole Mount system Foundation question.

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