Tips and tricks for pole mounts?

Hey all,

As an alternative to a 6x6 post mount, also contemplating doing a top of pole mount.

What are the tips and tricks of doing a pole mount? We want to get the panels high enough to deter theft -- so roughly 12-15' off the ground. Means working on ladders or scaffold to install the panels. Anyone have any good tricks to share? Do you install the panel mount (not the panels themselves) on the ground before raising and cementing the pole or do it after?

How about tricks for securing the base of the pole itself so it's permanent? Do you simply cement the pole into the ground or is there a better way?

Tried doing some searches on the site here, but there wasn't much to find...

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Tips and tricks for pole mounts?

    see my sig
    http://tinyurl.com/LMR-Solar
    10' deep hole, 24" di, cement & rebar.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • TenMile
    TenMile Solar Expert Posts: 62 ✭✭
    Re: Tips and tricks for pole mounts?

    Stumbled across a great article last night: http://homepower.com/view/?file=HP108_pg28_Schwartz&pdf=1
  • HuckMeat
    HuckMeat Registered Users Posts: 24
    Re: Tips and tricks for pole mounts?

    I mounted all my poles in 3' diameter concrete holes 8' deep (high wind), with a pole height of about 8.5' (I'm not worred about theft).

    I mounted the poles first, then assembled the rackmount strongback and pole top head on the ground, then lifted it up and set it on the pole using my tractor.

    I then used the tractor bucket to lift the panels up by the array, and a scaffold to work on and bolted each one into place. Put the mount as level as possible when you are bolting the panels on, it makes it much easier.
  • samuel
    samuel Solar Expert Posts: 80 ✭✭✭✭
    Re: Tips and tricks for pole mounts?

    Scaffolding. 100% the way to go. It's way safer than a ladder and relatively cheap to rent. I put in a 6x8 array with my Dad. For the details here are some links to a few of my blog posts

    part 1
    part 2
    part 3

    I would recommend using heavy equipment unless someone else is going to dig the hole. The panels I put in have had no trouble surviving the infamous 30-year wind storm we got hit with this winter so we're fairly confidant it will hold up long term. We also mixed our own concrete and went a little heavy on the cement for our mix. Our ground is real heavy clay and the pole had steel bar welded in a 'X' shape to prevent the possible spinning in the wind. We tapered the concrete away from the pole in order to prevent water working its way down between the pole and concrete.

    Your soil type will vary and it's seldom a bad idea to err on the side of caution when choosing hole size and rebar use.
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Tips and tricks for pole mounts?
    TenMile wrote: »
    Hey all,

    As an alternative to a 6x6 post mount, also contemplating doing a top of pole mount.

    What are the tips and tricks of doing a pole mount? We want to get the panels high enough to deter theft -- so roughly 12-15' off the ground. Means working on ladders or scaffold to install the panels. Anyone have any good tricks to share? Do you install the panel mount (not the panels themselves) on the ground before raising and cementing the pole or do it after?

    How about tricks for securing the base of the pole itself so it's permanent? Do you simply cement the pole into the ground or is there a better way?

    Tried doing some searches on the site here, but there wasn't much to find...

    The taller the pole, the deeper the concrete needs to be. General rule of thumb is the part of the pole in the ground needs to be 1/2 as long as the part sticking out of the ground (1/3 of total length in concrete)

    Concrete footing needs to be at least 2 foot in diameter. If your array is more than about 120 sq feet, you'll need a bigger hole.

    15' off the ground is a DEEP hole. 8 to 10 feet tall and nobody is stealing anything without a ladder. Remember you have to MOUNT the panels too, 15 foot high will be a challenge unless you have a cherry picker, etc.

    When I set my poles I had a neighbor come over with a backhoe and dig a trench. He made the trench deeper and wider where the poles were. I finished digging the holes by hand (needed to be another 18" deeper) and used 2' sonotube then backfilled around the tube before filling them with concrete. The trench was used to run conduit between the poles and the house.

    I used lengths of 2x4 to hold the poles upright before pouring the concrete, after the concrete is in you can adjust the poles for plumb and the concrete will keep them from wandering.

    trench1.jpgBraced.jpg
    lined_up.jpgConcrete.jpg
    Panels_Install.jpg
  • TenMile
    TenMile Solar Expert Posts: 62 ✭✭
    Re: Tips and tricks for pole mounts?

    I'm fortunate I guess in that my installation is MUCH smaller than the ones shared. I've only got 3 panels -- total area is about 30sqft. Lets me get away with a skinnier pole (3" according to the mount manufacturers).

    Thanks for sharing the tips guys. Your guidance plus that article I posted are all very useful.
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Tips and tricks for pole mounts?

    Peter V,

    You have an impressive installation and you get an
    excellent harvest from it. I had a few pure curiousity
    questions for you:

    1. Why did you put gaps between the panels? Is that
    to allow an escape path for wind, i.e., lessen the wind
    load?
    2. Do you have a sense for how much wind load your pole
    mounted panels can sustain?
    3. Why did you do a maximum of six panels/pole versus,
    say, two poles with eight panels each?
    4. Why did you do pole mounting instead of a roof mount?
    It's true that you can't do tracking with a roof mount,
    but classically, people compensate for that by being
    able to buy additional PV panels with the money not
    spent on tracking hardware.

    John
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Tips and tricks for pole mounts?
    jcgee88 wrote: »
    Peter V,

    You have an impressive installation and you get an
    excellent harvest from it. I had a few pure curiousity
    questions for you:

    1. Why did you put gaps between the panels? Is that
    to allow an escape path for wind, i.e., lessen the wind
    load?
    2. Do you have a sense for how much wind load your pole
    mounted panels can sustain?
    3. Why did you do a maximum of six panels/pole versus,
    say, two poles with eight panels each?
    4. Why did you do pole mounting instead of a roof mount?
    It's true that you can't do tracking with a roof mount,
    but classically, people compensate for that by being
    able to buy additional PV panels with the money not
    spent on tracking hardware.

    John

    They are on Zomeworks trackers. The pivot axle (part connected to the pole) sits above the main frame in order to get the COG as low as possible. This makes the tracker more stable in wind, etc.
    Because of this the center panels have to be raised so they don't hit the axle. So the spacing is to keep the raised center panels from shading the edge panels in the early morning/ late evening.

    The tracker is passive, no electronics or motors. It works by using a low boiling point fluid and the heat from the sun makes the fluid boil and the gas pressure moves the fluid from one side to the other, which changes the balance on the tracker so it tips and follows the sun.
    The tracker only tips a total of 90 degrees, from 45 degrees one side to 45 the other. Hence the issue with possible shading in the morning/evening

    The trackers are designed to handle a maximum of 120 sq feet, roughly 10 ft x 12 ft. 6 panels are all that fit within the limits of the trackers.
    The small tracker is home made.

    The trackers I bought, UTRF-120s, cost me about $1600 each last year. The next size up, UTRF-168 cost almost $1,000 more but only hold 2 more panels. The 168 needs a larger diameter pole, which has to be at least 4 feet taller and therefor deeper, and the footer had to be 3' foot diameter instead of only 2'
    All and all the larger tracker was a lot more expensive.
    So it was cheaper to buy two of the 120s and build a tracker than can handle 3-4 panels. I'm willing to gamble 3 panels on my DIY skills, but not 15 panels.

    My roof faces southwest so that the house has a nice view of the nearby mountains. That coupled with the slope of the roof means that I would need approx 5 kw worth of roof mounted panels to equal my 3.4kw of pole top mounts. Either that or a fairly complicated (read expensive) adjustable angled roof mount with a bit over 4kw worth of panels.
    The larger roof mounted array would actually cost more than the tracker mounted array.

    Plus I'm not keen on roof mounts. Aside from the possibility(probability?) of leaks there is the whole issue of eventually having to replace the roofing tiles and having to pull off the array to facilitate that. Plus it's a hassle to climb up on the roof several times a year to clean the panels (it can get really dusty around here)

    Finally I just think trackers are cool!
  • henry1
    henry1 Solar Expert Posts: 51 ✭✭✭✭
    Re: Tips and tricks for pole mounts?

    a nice set up there sir and i can see your in loveing southern border area ..your solar put must be crazy most of the time ..
  • bobdog
    bobdog Solar Expert Posts: 192 ✭✭
    Re: Tips and tricks for pole mounts?

    For mine, a small 3 panel install, I use schedule 20 steel pipe, buried 4' and in a hole 3' in diameter. The pole is 12' so 8' above ground. I "rebared" the hole in many directions to keep it from spinning and for strength AND pounded in the grounding rod next to the pole. I used sacrete style concrete and filled the hole plus some. Currently have 2 panels on the mount. going to add the 3rd this summer. We have some serious winds/gusts (60+mph) and the unit doesn't seem to move. No problems after 3 winters and summers.
  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    Re: Tips and tricks for pole mounts?

    Here is my pole mount arrangement. I used unistrut for the panel racking. The tubes are 1/4 wall structural tubes that were poured into the concrete block. I bolted some spare unistrut at 90 degree angles about 6" up from the bottom of the pour. Due to potential frost issues, the base of the block is about 6' deep. There are three unistrut rails, one between the the tubes and one outboard of the tubes that pivot on a 5/8" rod. When I installed the panels I mounted four on one side with the panel rack vertical and pivoted the rack 180 degrees so I could mount the top row from a vertical position and then kept alternating until the racks were full. I used flexible conduit between the top of the pole and the rack so I can still tilt it up so that it sits flat (90 degrees from the pole) so I can get at all the wiring easily. Normally I adjust the tilt for the seasons. It takes me longer to go get the socket and walk out to the panels then to adjust them. The stainless hex nuts next to the conduit correspond with summer, spring/fall and winter.

    By the way the panel surface is slightly curved especially at the sides, I added 4 panels after the orginal design, so the main unitstrut does support the ouboard panels. Rather then repalce them I used some half height unistrut outriggers.

    Realize that as the pole gets taller the overturning load goes up substantially which means much larger diameter pole and much larger concrete block.

    By the way, I did the entire project solo with the exception of the excavation and backfill. I dont recomend hand mixing and pouring 60 bags of sakcrete. ;)
  • dancour
    dancour Registered Users Posts: 9
    Re: Tips and tricks for pole mounts?

    My 10 panel pole mount sits on a guyed, cut-off used street light post. Assembled on the ground and lifted into place by R.W.Electric.