pole mount for solar array

Hi All,

I've got to install a pole mount for a solar array. The manufacturer says to use 5" schedule 40 steel pipe (5 9/16" OD). The hole is specified as:

54" deep 30" diameter .81 cubic feet of concrete

Do I need to weld any kind of rebar to the bottom of the pipe?? What kinds of coating would be best before pouring concrete? Of course, I'll be sloping the top of the concrete for water drainage.

I'm assuming that I need the concrete poured under the pipe opening .... so what do I use as a standoff to raise the pipe off the bottom of the hole? Should I cap the end of the pipe encased in concrete?

I was planning on building a 2x4 wood collar above ground, along with diagonal 2x4's for ground support to maintain vertical until the concrete cures.

Any thoughts or recommendations? Thanks!

Reply to
Daniel Carata
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Hi, How big is the arrray? Wind load? weight? When I installed basket ball goal post was similar situation. No rebar, I filled the pipe with concrete about half height, My kids are all grown up now, the pole still stands rock solid. Wife let me install a cross bar so she can hang flower baskets during summer time, LOL!

Reply to
Tony Hwang

That is .81 cubic yards of concrete.

Reply to
gfretwell

Yes; I made a mistake. It's .81 cubic yard. Looks like 2000 to 3000+ pounds.

Reply to
Daniel Carata

Hi,

There will be two pole mount arrays. Each pole will carry (4) 265W panels. I don't know the weight or wind loading calcs as all the engineering was done by the company for a Florida install. The panels are not heavy at all.

I hope my mount is as strong as yours sounds!

Reply to
Daniel Carata

If you have over 3000# of concrete in that hole, you will be plenty strong but I would go ahead and weld a couple pieces of rebar to the pipe to give it a better bite. They don't really have to be very big. You could just drill some holes and poke pieces of just about any metal rod in there. Once the concrete sets around them they are not going anywhere.

Reply to
gfretwell

Using rough numbers like 1kW for 5 hours a day = 5kHh at $.20 per kWh will save you about $1 per day in your electric bill.

How do you justify this expense?

Don't get me wrong, I am all in favor of alternative energy and I would love to install PV but I can't justify the cost vs payback.

Mark

Reply to
makolber

It will take a while to go through this page. It is by a person I know that is into the solar power.

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I have sat in a presentation or two of his at a local ham radio club. The justification of his is about a 8 year payback. At the time he installed his system there was a big tax break, not sure if it is still in effect or not. Then his system starts putting power back into the grid at the same charge as the power company charges. This goes on from the time the sun comes up and goes down.

In other words he uses the power company like a big storage battery. While no one is at home during the day the system runs his power meter backwards most of the day. Then at night he uses the power. That makes most of his power 'free'.

Reply to
Ralph Mowery

I could be totally wrong, but I can't calculate a payback curve for electric power.

How do you calculate for totally corrupt politicians? How do you calculate for coal-fired plants going offline? How do you calculate for nuke power that is looking like a serious threat to humanity?

The media is reporting that electricity is going up. At what point will they start disrupting our lives?

Obama: My Plan Makes Electricity Rates Skyrocket

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Sheesh, discussing politics is a really big no-no. Sorry folks.

Reply to
Daniel Carata

Hi, Even if the actual weight is not much, if the total area of panel is big, the wind load will matter. I used more or less 1 cu. ft. of concrete I mixed and poured for the pole. I have 1.5 Kw array on the roof which was installed with govt. subsidy. Without it, I wouldn't have it installed. I will have never recovered to total cost until I die, LOL! It does not have battery back up, just inverter feeding the grid back and forth. I can monitor what is going on on my computer because the controller is tied to my router. Is it self tracking panels?

Reply to
Tony Hwang

Add this to your formula if you live in Oklahoma,

A solar surcharge bill was just signed by the governor of Oklahoma, which would charge a fee for people who install solar panels on their roofs, and are still attached to the grid. Apparently, utilities in that state feel threatened by the free energy from the sun, and maybe they are afraid that the entire state will turn to solar.

Read more:

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Reply to
Fat-Dumb and Happy

No; this is not a tracking mount. Also, this is an off-grid system and will use batteries for local storage.

If electricity rates skyrocket, your payback date might just change radically.

Reply to
Daniel Carata

You certainly can calculate it, just like you can calculate the payback for trading out an old 75% efficient furnace for a 93% one. You can't predict for sure what all the relevant prices will be in the future, but you can make estimates. Businesses do it every day before making capital investments. With regard to solar, I've yet to see a typical solar installation like you see on houses or businesses that are economically viable without big govt subsidies.

You just make the best estimates of future energy prices. Some of which look pretty certain. There is a huge supply of natural gas and it's increasing, so the price of that is likely to remain moderate for a very long time. And there isn't much indication that Obama and the libs, who's power is waning, are going to be able to drastically screw with future energy.

Much of the media knows less than nothing.

As stated, do you really think Obama is going to get anything passed that makes energy skyrocket? His latest polls are at an all time low, Putin is making a pussy of him, and after Nov, it sure looks like he'll be a lame duck.

Reply to
trader_4

That's interesting, first I've heard of it. But to be fair, they probably have it right. My electric bill is about half for the energy itself, the other half is for distribution. If you put up a solar array, providing most or all of your power, then you're not paying a similar amount to your neighbor, who has no solar array, ie you're not helping to pay for the massive distribution system. And at night, without that distribution system, you'd have no power.

Reply to
trader_4

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