Fixed vs. Tilting array

Shannonsman229

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I'm building a mount for my 54 panel array.

My questions and concerns are:

Tilt vs fixed

Will I really need to tilt them with the seasons to keep up with my loads?

I have no trees that would block and keep me from benefiting with tilt.

Load details:
Powering 1200sq ft. Space ac with soft start, heat pump water heater, electric appliances dryer oven etc., misc. Loads fridge fans and such.

System details:
54 235w canadian solar, 3 5000es connected to grid stacked ran through 15kva isolation transformer with and 6 eg4 48v 100ah battery bank for night/cloudy days.

Material on hand:
8 30ft sticks of 2 3/8 drill pipe
8 22ft 1 3/4 in galvanized (chain link) fence post
100 1 3/4 in exhaust clamps
8 7ft 8in plus cedar post
Scrap 4ft sticks of 12 in i beams

Tilt array plan:
Three rows of 18 ground-mounted panels. Each row would consist of 6 vertical Cedar Post. I would weld 2 and 7/8 6in long pieces of drill pipe on to pieces of I beams. My 2 and 3/8 in drill pipe would be horizontal through these 2 in 7/8 inch drill pipe mounted on top of the Cedar Posts That way I can swivel it back and forth to do the Tilt motion.
Plus Sides I have enough Pv wire for this set up
Easily cleaned and maintained. I can tilt to accommodate season changes
Downsides clutters up my already grouped together property.

Fixed array plan:
Utilize drill pipe for vertical uprights. Span galvanized pipes across as horizontal mounting panels to galvanized pipe with exhaust clamps

Plus sides I can put it out in the pasture high enough for the horses to have shelter on second Paddock. Spreads out preventing clutter of property
Downsides the height of it would make it difficult for maintenance and cleaning. I would need to purchase more wire and accommodate for voltage drop. May not provide adequate power during certain seasons.



Screenshot_20220313-232526~2.png
 

rhino

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Are you net metering, off-grid, or other? Asking since if you are trying to match loads to PV output a single array pointing one direction may not be optimal. I for example have one of my smaller arrays pointing due east right now so that I can have PV power when I get up.. Otherwise it would be hours later before I had "useable" power from the other arrays.
 

Shannonsman229

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Are you net metering, off-grid, or other? Asking since if you are trying to match loads to PV output a single array pointing one direction may not be optimal. I for example have one of my smaller arrays pointing due east right now so that I can have PV power when I get up.. Otherwise it would be hours later before I had "useable" power from the other arrays.
Off grid with the grid as backup. This way if I run through my batteries during the night the grid will kick in and charge them while powering inverters until the sun comes up. Also multiple cloudy days grid will power my batteries during the day. I'm hoping six batteries will make it through the night but I have not tested it yet. That is the least active time in my household so I think it should.
 

boondox

Chief Engineer, RedNeckTech Industries
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I don't think that tilting or tracking arrays are worth the trouble. I built or helped build a couple back when panels where a LOT more expensive than they are now and it wasn't cost or performance effective. The juice just wasn't worth the squeeze.

BTW, if you have a connection to the grid, you aren't off grid. Off grid is, well, off the grid.
 

Shannonsman229

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BTW, if you have a connection to the grid, you aren't off grid. Off grid is, well, off the grid.

Yes I thought about that after I said that. So other. I'm using off-grid inverters not feeding back to the grid but using it as backup another words. My goal is for my system to be enough to handle everything so that it would have to be dark and rainy for a long time before I need the grid
 

Shannonsman229

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I don't think that tilting or tracking arrays are worth the trouble. I built or helped build a couple back when panels where a LOT more expensive than they are now and it wasn't cost or performance effective. The juice just wasn't worth the squeeze.
This is what I'm understanding as well. The squeeze for me would only be taking up space. But that is important to me.
 

boondox

Chief Engineer, RedNeckTech Industries
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Well, in order to know if your proposed system can do what you need you really have to do a thorough energy audit. Then if you find that you are really, really close but not quite you can dive into how much more you would get from a tiltable array. But I am willing to bet right now that it won't be close enough and if it is finding a spot for a few more panels will be way easier and cheaper.
 

45North

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Sounds like you should set them at 28deg with possible seasonal tilt of +/- 15 deg.
So now decide on the incremental material and labour cost to make them tiltable and your additional effort to tilt them seasonally.
 

timselectric

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Tilting, just really isn't worth the trouble.
Moving parts require maintenance.
It is a good idea to spread your array in beneficial direction. 1/3 SE, 1/3 S, and 1/3 SW. This way you get solar output all day.
 

Shannonsman229

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It is a good idea to spread your array in beneficial direction. 1/3 SE, 1/3 S, and 1/3 SW. This way you get solar output all day
This carport over my pool is facing two of these directions I would be set then space and material. Then I could just do one Row behind it tilting due south. I have the material to easily do a row tilting would not be an inconvenience. They pitch east and west at 11 degrees I could Shim them to Face South. If I'm facing south east and Southwest what would be my optimal fixed tilt on top of the carport. 28 degrees south x degrees east one side and west the other x=?
 

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Shannonsman229

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They pitch east and west at 11 degrees I could Shim them to Face South. If I'm facing south east and Southwest what would be my optimal fixed tilt on top of the carport. 28 degrees south x degrees east one side and west the other x=? Or face them 28 degrees South East 28 degrees Southwest???
 

timselectric

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You would optimally want a steeper angle, for the E and W array. Because you are trying to catch the morning and evening sun. I didn't bother with that, I just went with my existing roof angle. It looks better, and solar panels are cheap.
 

Shannonsman229

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You would optimally want a steeper angle, for the E and W array. Because you are trying to catch the morning and evening sun. I didn't bother with that, I just went with my existing roof angle. It looks better, and solar panels are cheap.
Nice that would be perfect. So utilize the pitch of the carport which is 12 degrees then tilt them slightly South?
 

timselectric

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Just remember that anything that sticks up, can catch the wind. And therefore, is increasing the chances of damage from high winds.
 

45North

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Also consider the weight. Carports tend to be light, flimsy structures. Not really intended to support a lot of stuff on top without reinforcement.
I assume at your latitude (28 deg) you don't need to consider snow load.
 

Shannonsman229

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Also consider the weight. Carports tend to be light, flimsy structures. Not really intended to support a lot of stuff on top without reinforcement.
I assume at your latitude (28 deg) you don't need to consider snow load.
Thank goodness no snow. It looks like my carport holds at least 20 pounds per square foot. My panels are 47 lb. Should work great.
 

Shannonsman229

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Thanks for all the help. It looks like I'm going a route I never even dreamed of going. I'm going to do three arrays facing 3 directions. 18 panels Facing East 18 panels facing west 18 panels facing south on a tilt mount. We will see if that changes before I go to mount everything
 
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