Just got a great deal on a little system

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  • mcgivormcgivor Posts: 2,201Solar Expert ✭✭✭✭✭
    Personally I've never understood the single pole approach  in a fixed ground mounted array, looks nice yes, but four legs along with some triangulation adds ridgity, lighter gauge steel can be used to provide a space frame which is way stronger.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    I do worry about the diameter/thickness of the "mono-pole" here too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 22 #34
    I'm not worried about the pipe bending as it is filled with high strength concrete. I have the same concrete filled poles holding up my pool shade and have had no worries from them in 10 years even with 6" of snow cover it's 12' x 24' size.
    There is no weldment where the clamps attach. The 110 lbs of panels and frame are being held up by the angle resting on the top of the pole. The clamps are pretty much keeping it from twisting.
    The panels are bolted together at 2 locations wherever they join another panel. The lader is bolted to the panels and the rungs bolted to the ladder. Also the u-bolts the mount the pipe to the ladder rungs extend through the lip of the panels and now have a nut added to help maintain rigidity.
    I plan on adding a couple of braces that extend to the pipe. Just had to get it up to decide how to do it while being able to change the angle through the seasons.I think I have it figured out. I'll post a pic of what i come up with later.
    One benefit is that the array is near the corner of an 8' privacy fence so hopefully the fence will offer a bit of a wind break.
    My plan is to motorize the array on 2 planes; hence the single pole configuration. I built a 2DOF flight simulator platform (prior to going VR) and plan on using the knowledge gained from that on this. I already have 2 wheelchair motors, an Arduino Mega, and a sketch written that will follow the sun acurrately and reset to the morning position at sunset each day.
  • mike95490mike95490 Posts: 7,901Solar Expert ✭✭✭✭
    Filling a pipe with concrete only adds mass, not much strength, unless it has rebar embedded in it.
    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 ,

  • PhotowhitPhotowhit Posts: 4,701Solar Expert ✭✭✭✭
    So I've had a couple EZ ups, this isn't very heavy metal. And bolting the panels together makes for a nice fulcrum. Looks like the EZ up frame material is also strapped together... Looks too fragile to me!

    Ever try to pass a sheet of plywood onto a roof on a windy day? Doesn't take much wind to make it an effective sail!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 23 #37
    mike95490 said:
    Filling a pipe with concrete only adds mass, not much strength, unless it has rebar embedded in it.

    I researched this pretty thoroughly when I put the sunshade over the pool. It makes quite a difference.


  • mike95490mike95490 Posts: 7,901Solar Expert ✭✭✭✭
    OK, I'm not a mech engineer.  As I understand it, plain steel pipe is not good. If it's chewed up/roughed up on the inside so the concrete can attach/bind to the pipe, then it gets stronger.  But just plain water pipe, not a big improvement.
    https://www.eng-tips.com/viewthread.cfm?qid=264916  gives this quote from some body on the internet
    It is my understanding that flexural strength of the composite section is not increased much by the addition of concrete, at least not as much as axial capacity.  However, your stiffness is increased so deflections can be smaller.




    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 ,

  • Thick8Thick8 Posts: 47Registered Users ✭✭
    Did you read the document that is referenced a couple posts below that opinion? It's quite interesting. The gist is that in order for a metal cylinder to bend it must deform or tear. When filled with concrete it can't deform without the concrete being removed. it can tear but I'm not putting those kind of stresses on the pole.
  • EstragonEstragon Posts: 2,838Registered Users ✭✭✭✭✭
    Do you do the math from the linked-to paper?

    There's a point load at the base of the pole where it's imbedded in the concrete base, and a long lever arm relative to pole diameter. The concrete will stiffen the pole along its entire above-ground length, putting almost all the bending stress at the base. Over time, the repeated stress makes a concrete crack most likely there, further limiting the point load to the base, and weakening it at that point It's a bit like a stiff tree growing in rock. Less give in the trunk puts more stress on the base in a wind.

    The paper shows ways of dealing with these kinds of loads (eg reinforcing sleeves at beam-column connections) and the math to define when it's needed.

    It looks like the trees and fence should be a pretty good windbreak for you though, so it may not matter.
    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
  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 24 #41
    Trial by storm today. 45 mph winds with heavy gusts followed by 2.53” of rain in less than an hour with run and hide tornado advisories. Still solidly pointing south with a 68 degree tilt. My wife said it looked like a waterfall when she could still see out to the yard from the kitchen window.
    So would it be best to hook up the panels in a 80v/5.5a or 40v/11a to feed the mppt controller? 8 or 10 gauge wire is the same cost. I was looking at another post here where it is recommended to have the array supply only 30% more voltage than the battery to keep heat down.
  • mcgivormcgivor Posts: 2,201Solar Expert ✭✭✭✭✭
    The rule of thumb is to have at least 30-50% over the nominal battery voltage for the MPPT to take advantage of the higher voltage, the efficiency of the controller will largely dictate how much loss, in the form of heat, there will be. Sometimes choosing a higher voltage to compensate for volt drop over distance is advantageous, in my case with 24V nominal I wired for 60V first then 90V, there was negligible difference in output, or difference in temperature of the controller, obviously this is comparing apples to oranges as the controllers are of a different make. For a 12V nominal system running 80V may be excessive, use a volt drop calculator to get an idea how each configuration would impact results, remembering the amount of voltage drop multiplied by the current will give the amount of power loss over the conductors. The controller losses will be reflected by the difference between watts in versus watts out, it's difficult to accurately monitor because of the dynamic nature of MPPT controllers, an IR thermometer is handy to monitor temperatures, my best suggestion is use the rule of thumb to start with.
    https://www.calculator.net/voltage-drop-calculator.html 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • PhotowhitPhotowhit Posts: 4,701Solar Expert ✭✭✭✭
    Thick8 said:
    I was looking at another post here where it is recommended to have the array supply only 30% more voltage than the battery to keep heat down.
    It's a trade off, with a long distance you will either lose more in voltage drop, or have to run heavier wire for long distances. You will want to measure your distance of wire run and plug it into a voltage drop calculator.

    For the record 30% above the charging voltage is the minimum, and about double is near ideal with many.

    Your VMP is 36, so it is doubtful you will ever see more than that. If 8 and 10 gauge are the same cost somebody likely made a mistake go with heavier wire!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • littleharbor2littleharbor2 Posts: 1,026Solar Expert ✭✭✭✭
    Photowhit said:
    Thick8 said:
    I was looking at another post here where it is recommended to have the array supply only 30% more voltage than the battery to keep heat down.
     You will want to measure your distance of wire run and plug it into a voltage drop calculator.




    Remember, when measuring distance for DC voltage drop you need to figure round trip distance. 45 feet away is actually 90 feet round trip.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • westbranchwestbranch Posts: 5,087Solar Expert ✭✭✭✭
    +2 on the 8 awg wire IF it is the same price for the right type. I always opt for the largest wire when the price is the same. For ease of mind check out the 6 AWG and 12 AWG.

     
    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
  • mcgivormcgivor Posts: 2,201Solar Expert ✭✭✭✭✭
    Photowhit said:
    Thick8 said:
    I was looking at another post here where it is recommended to have the array supply only 30% more voltage than the battery to keep heat down.
     You will want to measure your distance of wire run and plug it into a voltage drop calculator.




    Remember, when measuring distance for DC voltage drop you need to figure round trip distance. 45 feet away is actually 90 feet round trip.
    Different calculator perhaps but the one I posted a link to, post 42, says use one way, not round trip.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • PhotowhitPhotowhit Posts: 4,701Solar Expert ✭✭✭✭
    Yeah, most only want one way distance;


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 28 #48
    My plan is to get everthing hooked up this weekend. I was able to trade out the 5000w and a 2500w modified sine wave inverter for 2 2000w Magum dimensions pure sine wave inverters. with the 1000w one that I already have that should give me enough power to run my garage and have emergency backup for th house.
    below is the recommended battery configuration (thanks Photowhit) and below that is how I currently have my batteries hooked up. Is my way going to create too great of an imbalance? I'd have to go make new cables and don't have access to the cable reels at work over the weekend.

  • Thick8Thick8 Posts: 47Registered Users ✭✭
    I also didn’t know if the fact that using pretty heavy cabling negated some of the imbalance.

  • mcgivormcgivor Posts: 2,201Solar Expert ✭✭✭✭✭
    edited July 28 #50
    The crimped terminals need attention, that's a fault waiting to happen, a fuse wouldn't be a bad idea between batteries and on the output, there are thousands of amps there looking for a short circuit, be safe.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 28 #51
    Yea they do look pretty crappy. They are not just crimped but soldered as well. The lugs are made for a smaller gauge of wire so the cable was trimmed around the outer circumference.  The green is from flux.
    I hooked everything up to get an idea of the output. a re-wire with circuit protection and disconnects will happen over the next couple of weeks before I put it into use. I broke down and spent some money on a more moblie platform than what I had. This way I can wheel it up to the house when power is out (about 4 times a year from a few days to a week).

     
  • mike95490mike95490 Posts: 7,901Solar Expert ✭✭✭✭
    Thick8 said:
    Yea they do look pretty crappy. They are not just crimped but soldered as well. The lugs are made for a smaller gauge of wire so the cable was trimmed around the outer circumference.  The green is from flux. ....... 
    You have pretty much ruined your cables.
    1) poor crimps
    2) soldered
    3) green flux is usually plumbing based acid flux, it will dissolve fine wires in months.

    So be prepared to do it right pretty soon.
    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 ,

  • Thick8Thick8 Posts: 47Registered Users ✭✭
    edited July 29 #53
    No it was a rosin core flux. Those hammer type crimpers don't do a great job is the reason for the solder. It was old 24 volt starter cables from a 99 Kenworth so the quality of the wire is suspect. I'm wondering if the green is because he battery pack was stored near my pool supplies; there is always a smell of clorine in that corner. It's been moved. I work for a company the outfits/modifies trucks for the power company so I'll have one of the guys make up a set of 2/0 cables.
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