Ground mount costs?

icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
I am consulting on a grid tie project on a remote site, as noted earlier.  I am wondering if anyone has a ball park cost difference between “normal” roof mount grid tied systems in the 5-10 kw range, compared to a similar sized ground mount.  I am interested in potential ground mount so that the PV can be easily cleared of snow in the winter.

Tony

Comments

  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    My 5.5kw (22 x 250w) racking, which I mounted on a flat roof, was ~ $2,800.  That was 5yrs ago, but similar racking is about the same these days. 

    Seems to me it's roughly 2x the cost of fixed mount rails on a sloped roof for the racking.  At least some of the extra rack cost would likely be offset by extra labour and materials to deal with roof penetrations, working on a sloped roof, etc.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,303 ✭✭✭✭✭
    edited October 2019 #3
    I feel it is about 30% more after all is said and done for a ground mount. Not much more to have it track which would not be good for you with unattended snow. Just basic handyman skills are required on the ground. Different story up on a roof and liability insurance and all of the other worries that are not there on the ground. So, 30% more for the racking on the ground but much stronger that what a roof mount is with wiring, pipe, cement, and rebar.

    The only time I have done roof mounts is in the jungle/forest where it is too expensive to maintain the growth. Always try and talk offgrid folks out of weakening a roof for solar panels. Other reasons also. Good Luck on this one.....Still seems crazy to me
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • MichaelKMichaelK Registered Users Posts: 228 ✭✭✭
    My latest rotating ground mount design took about 400$ of steel and accessories to build (myself) an array holding four 250W panels.  Mostly unistruts and schedule 40 steel pipe.  Amusingly, I payed 400$ out the door for those panels from Ebay with local pickup.  So the framing for my 400$ worth of panels cost 400$.
    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)
  • 706jim706jim Solar Expert Posts: 494 ✭✭✭✭
    I had roof mounted panels for 24 years. Seemed to make sense at the time (didn't want them stolen).
    I've since changed to ground mounted panels, three against a deck and another three on a 4 x 4 A frame. Cost was couple hundred for the A frame but I couldn't be happier. My newly shingled roof has no holes in it and I don't have to climb up there to clear snow or check connections. So it needn't cost a fortune to put them safely on the ground.
    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 29th year.
  • MichaelKMichaelK Registered Users Posts: 228 ✭✭✭
    Here is a pic of my five V1.5 arrays from the back, which will give you an idea of the construction.  Most of the construction is galvanized steel.  Two points to caution about.  Whenever welding galvanized steel, you need to be careful not to inhale any of the zinc fumes, to prevent zinc poisoning.  Secondly, the steel has to be painted to prevent galvantic corrosion between the zinc surface, and the aluminum frame.  The design is evolving over time, and my newest V4.0 design is being welded together now. 
    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)
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Have you got a picture taken at close to 90-* to the back? It looks like they are 2 dimensional , tilt & rotate manually? 
    So each array is 900W NOMINAL
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • WaterWheelWaterWheel Registered Users Posts: 363 ✭✭✭
    I have to agree with Dave that a ground mount costs about 30-40% more but is much easier to mount the panels and wire up.      In addition a ground mount is easier to inspect, clean, and modify if you ever want to change out the controller input voltage.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭

    About $ 1000.00 worth of steel and sch 80 pipe at today's prices. Alot of cutting, drilling and welding. 20 - 245 watt kyocera panels. Summertime I run all three flat and winter drop them down so the snow will somewhat slide off. I turn and tilt to the South in winter.
    Enjoy Thanksgiving    George
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    George...

    You don’t happen to have any drawing of your design that you would care to share?  PM me if you would if you wish to speak about this.

    Tony
  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭
    Tony,

    I did not draw any thing up, but I will post some views of the framework before panels installed. The first two I built 17 years ago and there are 6 panels on each as you can see. Originally I had 8 BP 120 watt panels on them and there was too much flex on the racks. Cracked 3 panels, reinforced racks and solved the flex issue. BP bought back my 16 panels and now have 20 Kyocera's and built the rack which holds 8 panels. I will take closer pictures of the pivot points when I can ( we are away from home and it just snowed 3 ft in the last 36 hours ).
    These pictures of the rack are all I have for now.  George. Have a nice day
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭

    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭
    That is all I have for now. Everybody have a good rest of the year.  George
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Are the PV racks your own design, or engineered factory racks ?
    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 ,

  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Thanks George...Tony
  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭
    My design, pipes are concreted in, steel is 2" x .25 angle iron, some 2" x 3/16 strap and etc.

    George
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,303 ✭✭✭✭✭
    Looks small on the pipe for that size array. You can't buy one like this because it will not hold the snow and definitely not snow and wind for very many years.
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭
    That rack has had 4 ft snow on it and 70 mph winds - but you are the expert.

    Have a nice day.  George
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,303 ✭✭✭✭✭
    You also.
     If it works for you that is great. Inspector will not let me put more than 125 square feet on a 6 inch pole. Just math, physics and basic engineering.
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • MichaelKMichaelK Registered Users Posts: 228 ✭✭✭
    Have you got a picture taken at close to 90-* to the back? It looks like they are 2 dimensional , tilt & rotate manually? 
    So each array is 900W NOMINAL

    Yes, you are correct, the arrays can track left to right, and are also seasonally adjustable.  They each hold three 300 watt panels.  Here's a pic of the completed array just before adding my panels, about 3 years ago.  When I built the V1.0 design, the flimsyness of the Z axis become apparent, as GSN also mentioned, so I added the trusses on the back side.  I kept on making incremental improvements till I got to the fifth version, pictured here.   They have survived winter storms that have toppled big oaks on my property, like those in the background.

    Next is a pic of my V2.0 design (1000W), which I'm embarressed to show.  It utilized bushings rather than hinges, and although I think it's a robust design, the assembly of the completed array in-situ was just too challenging for me.  I have to say I think the final assembly is crap, though it does in fact act very sturdy.  If you look very closely at pic #2, you can see my finished V3.0 design sitting on the ground in-between V2.0 and my truck.  That fixed angle array is going on top of my little workshop, which is the room on the left side of pic two. It is also designed to hold four grid-tie panels.

    My V4.0 design holds 4 grid-tie panels (1000W), and is made of 4 vertically oriented unistruts.  That's what I'm building now. My V4.0 design is the culmination of all the mistakes I made from V1 through V3.  I getting around all the problems with previous designs by making it more modular.  The major subcomponents, like the trusses, will be bolted on at the last stage, instead of welding.  That way all the subassemblies can be carefully fitted together on my garage floor, then bolted together once the array is being placed into position.  Sorry if that is too verbose.  I'll have pics next spring when I bring this newest array online.  BTW, the V4 design could be scaled up to hold six grid-tie panels, by scaling up pipe diameters and numbers of unistruts.  But since my V4 array will bring my total watts to ~7500, I think I'm done building arrays.



    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)
  • geosierranevadageosierranevada Registered Users Posts: 56 ✭✭✭
    Dave,

    It is a different world up here in the Southern Sierra, the Building Inspector showed up while I was fabricating the last panel rack and he did not want to look it over. The only thing he gave me a hard time about was my lack of having a sign that says electric shutoff. On another note, I was going for a final inspection on my 40 x 60 metal barn, inspection was supposed to be in 3 days ( had the bolt tork guy lined up )
    And Inspector called and told me he was too busy and couldn't come up, said it would be six weeks. I told the inspector where he could go 
    And cancelled inspection because it was not timely ( Fire Marshall passed it ). That is what it is like up here. Sorry I sorta gave you a hard time!

    Have a nice day.        George
    Off grid for 20 years. 5KW panels, Trace sw4024, Bergy XL1 wind generator, 3 EG4 Lifep04 200amphr batteries  3 SQF 2 well pump, 12kw back up gen.  Not easy living in the wilderness but it keeps you busy
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,303 ✭✭✭✭✭
    Hi George,
    I have had my land in the southern Sierra for close to 30 years. We live outside in the foothills near Mariposa. There is a pix link on my web page below.

    I am in business and have well over 200 offgrid homes under my belt. I design to the building code or better, inspected or not.

    I did not mean for my comment to be an issue but rather a source of my experience. It has stopped raining so time to go out for a walk.

     :) 
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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