Tracking Array

[RossW]

Will post pics when I've got something to show

Well, it's only finger-tight, haven't squared it all up or anything yet, just more or less a "test fitting" to make sure all the bits are ok, holes where they need to be, no glaring errors etc....



Conditions permitting, tomorrow I'll square it up, fit the actuator, tighten things up and then I'll be right to start whacking panels on it! If that all works as expected - I'll order the parts for the other 3.

[ralph day]

Ross, are you sure you have enough ballast holding down your array(s)?  I'd check around and find out how much ballast per square foot of panel (sail) before putting panels up.  Maybe some bracing welded to the posts in both directions 90deg to panel.  It would make grass cutting a pain, but might save a panel faceplant (or tip over backwards).

I made a somewhat familiar setup to hold some snow fencing...rims filled with concrete, t posts and plastic snow fence.  Wind over 60km/hr blows it down all the time.  But that's just a simple stand up fix, the fencing is flexible.

Ralph

[ralph day]

Ross, are you sure you have enough ballast holding down your array(s)?  I'd check around and find out how much ballast per square foot of panel (sail) before putting panels up.  Maybe some bracing welded to the posts in both directions 90deg to panel.  It would make grass cutting a pain, but might save a panel faceplant (or tip over backwards).

I made a somewhat familiar setup to hold some snow fencing...rims filled with concrete, t posts and plastic snow fence.  Wind over 60km/hr blows it down all the time.  But that's just a simple stand up fix, the fencing is flexible.

Ralph

[mike90045]

Wind/Array tire ballast   yikes !!
If those poles are not several feet down in the dirt with concrete, wind is going to tip that over.  unless those are giant truck tires and weigh more than they look.

[RossW]

Ross, are you sure you have enough ballast holding down your array(s)?

Cripes, no, the tyres are only there to make slashing around the posts easier and keep the weeds and water away from them. The posts go well down, thanks!

Maybe some bracing welded to the posts in both directions 90deg to panel.

Already planned/intended. Diagonals front and back just for stability.

[TomW]

Ross;

I knew you were not relying on that bit of ballast to secure things. But, then, I know you ain't the average dimwit doing stuff the don't comprehend.

Or not.

I figured you would explain so I let it be.

Looks pretty sweet!

Are those bits on top of the posts top rail connectors from a chain link fence system?


Since we are drifting off topic here in this off topic area I will toss out that we had our first 40+ KWH day yesterday and have produced 1,424.3 kWh from our GT array since it was commissioned Nov 19, 2016 Much better than I actually expected.

Regularly see over  8KW from the 7,740  watt array (24  310 watt panels). Must have got a pallet of "hot" panels. I expected it to be nearer to 6KW due to the derating of 80% of nameplate that is often stated for actual production

Anyway, back to your regularly scheduled programming.

Tom

[RossW]

Are those bits on top of the posts top rail connectors from a chain link fence system?

They're Downee 'T' fittings. Very sturdy, 2-part T fittings, cast then hot dipped. Since all the weight is pretty much straight down, they seemed like the perfect way to go. The "bushes" that the axle turns in, is just a piece of pipe of a slightly larger size, popped in the lathe and bored to (close to) round. Basically just to remove the worst of the welded seam.

It's very rare for us to get wind over 60kmh here, and the once-in-25-year storm events that see 100kmh winds are pretty rare. The plan is that where there is such wind, the arrays will quickly set themselves to "flat". Sure, greatest chance of hail damage but the modules are designed to withstand most of what mother nature sends down.

[russ_drinkwater]

Nice job and what voltage do the actuators run at?
How many are you going to run for the 10 panel strings?

[RossW]

Nice job and what voltage do the actuators run at?
How many are you going to run for the 10 panel strings?

The actuators are nominally 36V, but operate perfectly happily on 12 (although somewhat slow). I usually run them on 24V (it was convenient, one side to the mid-point of my 48V bank, then two SPST relays let me drive forward or reverse... but I've since changed and use DPDT, interlocked relays and a 24V SMPS)

The array is so nicely balanced that it's easy to tilt it by hand. The actuator has no trouble with it. Yes, "it", singular. The Z purlins are 100mm (4") and quite stiff. There isn't much flex in the array, and I think the single actuator (per group of 10) is going to do fine.

*IF* I have problems, I'll use two actuators, 1/4 and 3/4 the way along the array, wire them in series, and hope they track at the same rate. But so far, I don't think that's going to be necessary.

[russ_drinkwater]

What trigger sensor are you using to fire the actuators?

[RossW]

What trigger sensor are you using to fire the actuators?

Thanks Tom (presumably!) for splitting this out.

Russ, this particular array is the first part of a 40-panel expansion of my existing system.
I didn't want to go to the effort of full tracking arrays since PV has become so cheap, and the whole reason for all these new panels is simply to get enough in the air on overcast days to avoid running the genset if possible.

So I have 1 array facing north-east to get morning sun, and one array facing north-west for afternoon sun. When its overcast, it doesn't much matter which way they face, they still collect some power.

I was initially just going to make a frame to hold them, but I couldn't convince myself what angle to make it, so I decided to make them adjustable. Then I can set it where works out best, and change it a few times a year. Perhaps even make it change every month.

But... now that I've made it, it's actually possible to tilt it right up to horizontal - and back the other way again.
This gives me the option of facing the "afternoon" array over-centre and looking east to get extra morning sun, and the "morning" array over-centre in the afternoon to get afternoon sun!

The option is there, how much I do with it will depend on how much time and enthusiasm I get.

(The other trackers use home-made PLC controllers to position them based on time-of-day and day-of-year)

[TomW]

Thanks Tom (presumably!) for splitting this out.

De nada

One reason I get the big bux!

Sweet upgrade.

I like the tires as a trimming aid!

Last forever., easy to trim close all around

Tom

[RossW]

I forgot to post.

I've added the first four panels.



The mounting "clips" I used were standard aluminium extrusion cut into about 3" lengths. Cheap as chips, and gives me the inter-panel-spacing, as well as a clamping mechanism:

[russ_drinkwater]

Nice job, I had toyed with the idea of adjustable arrays but with so panels available it is not worth the drama.
Cheaper to just buy another 150 and another 150 and so on.