tracker cement

I have a 2x2ft  x 48 inch deep hole. For a 4 panel tracker,homemade. I was going to make it complicated and get steel pipe and stuff
but now am thinking of this... schedule 40 pvc  4 or 5 inch diam. 3 ft in solid cement and rebar and 3 ft out of hole.Another piece of pvc will go over it and rotate. Should I use only schedule 80?? THe piece over it needs to fit snugly but still turn.
4 panels and some windy days but not severe.. what do you think?

Comments

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    I would only do the best way so I can only say No.
     If this is for offgrid then absolutely not. It will fail when you need it the most.
    "we go where power lines don't" Sierra Nevada mountain area
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    E-mail offgridsolar@sti.net

  • MichaelK
    MichaelK Registered Users Posts: 236 ✭✭✭
    Definately go with steel.  That's what I used, and it has been very, very sturdy.  Look at the size of oaks in the background.  My ridge gets winds that have knocked over 18" oaks, but my arrays are still fine.  In my setup, I sunk 3.5" schedule 40 steel pipe in the ground, then the rotating top is made from 4" schedule 40 pipe.  I filled the 3.5" pipe with concrete to increase it's bend resistance.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    >  I filled the 3.5" pipe with concrete to increase it's bend resistance.

    Generally, if there is no rebar bundle inside the pipe, the bend resistance is negligible.  What happens is the concrete eventually cracks inside the pipe, creating a high stress point where the pipe is "bendier" and the pipe eventually fails there.

    For simple ballasting, concrete works to make it heavier, but for making stronger, it needs the rebar inside
    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 ||
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  • MichaelK
    MichaelK Registered Users Posts: 236 ✭✭✭
    mike95490 said:

    For simple ballasting, concrete works to make it heavier, but for making stronger, it needs the rebar inside
    Well, yes.  I inserted rebar both lengthwise and also crosswise in two directions, extending about 12" out of the pipe.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)