Solar Array pole size

[mark909]

I am putting in solar panels at my home and using a top of pole mount. I bought an 8 foot alumni pole at the local hardware store with a 2 & 3/8" inch diameter. 3 feet of the pole is in the ground and anchoring by 8 (I think) 80 pounds bags of cement.

I put up a 100 watt panel at first (just to get my feet wet, but am finding solar to be addictive. I want more and more solar power.

I am looking at putting in 250 watt panels on the same pole and just using the 100 watt panel on a ground stand charging a battery to be used for exterior lighting at night.

My question has become how much weight I can put on the 2 3/8" pole and top of pole mount because I have noticed that the 250 watt panels average about 47 pounds per panel. I have read on the Internet estimates of anywhere between 2 panels (500 watts) and 1.2kw.

Does anyone have even a clue as to how I figure this out?

[Mike90250]

This is where you discover what your "Pucker Factor" is. The pole & array is your property, and if a gust of wind blows it off to your neighbors house, they will be looking for you. Local Building codes and the pole mount company, would have suggestions for what is suitable, building department will likely want you to get an engineered plan of pole, hole, and concrete ballast.
I ended up with a deep hole, with rebar and concrete, and huge pole. But I sleep better.

[russ]

Actually the pole you are using is probably too light for even one panel.

[peakbagger]

There is no right size for all conditions, thats where a Professional Engineer makes his living, deciding what factors impact the sizing and what sort of factor of safety should be used. A 2" pole is not going handle much. The tough part is you wont know its too small until the morning after a wind storm when its bent over and a smashed solar panel is on the ground. On most pole mounted arrays, 6" sch 40 is about the minimum and 8" or 10" is not unseen. Where you can really get in trouble is when the unsupported lenth of the pole gets long, just a small increase in length adds a lot more stress ont he pole.

[SunEagle]

You also have to look at soil conditions along with wind loading. I had a project to calculate the size of the footing for lighting fixtures in a parking lot (way back in the 70's). Did all the math for both wind and snow loads but failed to understand the soil contribution. The parking lot had been built over a swampy wet land. What I didn't include in my calculations was the uplift factor from rising water levels. It was pretty sad to see the poles tilting at an angle due to their footings no longer being fully in the ground.

Don't underestimate the power of nature when design something. Check with the local codes and specifications of the equipment you are using. It will save you a lot of headaches.

[FloridaSun]

Actually the pole you are using is probably too light for even one panel.

I agree and as he hasn't stated wall thickness but did say it was from a local hardware store more than likely it is a very thin wall tube used for for a cheap post light. Not nuff for his future plans or present use.

[Naptown]

The last top of pole I did held 9 230W panels
The pole was 6" schedule 80 galvanized pipe.
The pole went 5' in the ground into a concrete foundation that was 6' deep and 3' in diameter and used 3 1/2 yards of concrete.

[mark909]

Actually the pole you are using is probably too light for even one panel.

I have a 100 watt panel sitting up there now.

[mark909]

true

This is where you discover what your "Pucker Factor" is. The pole & array is your property, and if a gust of wind blows it off to your neighbors house, they will be looking for you. Local Building codes and the pole mount company, would have suggestions for what is suitable, building department will likely want you to get an engineered plan of pole, hole, and concrete ballast.
I ended up with a deep hole, with rebar and concrete, and huge pole. But I sleep better.

This much is true to be sur. What can I sleep comfortably with???

[FloridaSun]

This much is true to be sur. What can I sleep comfortably with???

Using your present pole for a bird bath? Not sure your location but hope you don't get any high winds soon.

[mark909]

useful

The last top of pole I did held 9 230W panels
The pole was 6" schedule 80 galvanized pipe.
The pole went 5' in the ground into a concrete foundation that was 6' deep and 3' in diameter and used 3 1/2 yards of concrete.

This is extremely useful knowledge. This is the size that I want to get to. I just want to get there gradually, one or two panels at a time with micro inverters for grid tie while I'm building.

When I get enough panels to power the house, I'll add the house inverter and then an extra breaker.

[Naptown]

This is extremely useful knowledge. This is the size that I want to get to. I just want to get there gradually, one or two panels at a time with micro inverters for grid tie while I'm building.

When I get enough panels to power the house, I'll add the house inverter and then an extra breaker.

that is what was required where I put one in. The engineering on your's will most likely be different due to exposure factor wind loading and soil conditions.

[mark909]

Nevertheless

that is what was required where I put one in. The engineering on your's will most likely be different due to exposure factor wind loading and soil conditions.

Nevertheless, great it's a great guideline. There's much wind here, but ever so rarely, a hurricane comes through. By the time it gets to us, even a cat 4, the wind is down to about 40.

Nevertheless, what you gave is a great guideline. I'm finding the electrical aspect as easy as pie. It's the actual pole mount that's giving me headaches.

[Naptown]

DPW has good mounts and their instructions are pretty detailed