Semi DIY PV Installation. Comments Please

[smegal]

With a proper support replacing the wood, using the unistrut calculator, it passes as single channel, so will be ample with back to back. But the ~3m span without additional support just won't work.

I have seen that size and layout of array on offshore installations. It would normally be mounted on a 8" dia galvanized post so you have done well with what you have. If you have offcuts of spare unitstrut fair enough, other than that i'd go with timber from the shed woodpile purely for the Womble ethos. Last thing you need is metal fatigue over time in the wind then down she goes. Is it connected yet or is that next week? (excited for you)!

My wife isn't happy, so I'll have to order some cantilever arms. I found that wedging the wood in to put a slight preload on the uprights has made it all solid.

It's not connected yet. Just got to terminate the AC isolator to inverter cable (it's a plastic armoured cable, so is taking some stripping) and run the DC and earth cables from the external isolator to the inverter and its ready to flick the switch.

Then I'm going to try to add some more concrete to the bases and make the lawn as good as I can.

[MoSTiE]

you might want to consider just putting them on that roof, the Mrs will forget all about them ...

[smegal]

Smegal,

I would suggest a tie bar from the horizontal under the panel back to the vertical channel intersecting a minimum of two thirds from the base ( at the base even better ) that will dampen any flex in the vertical by transmitting the load to nearer the base.

Bracing off the garage will work but it could over time break out the mortar around the bricks as you will be cyclically compressing and releasing the pressure. Note if the mortar does break out it will be on the inner tension bearing face not the point where the brace interfaces with the brickwork on the outer face of the wall.

Moxi

You may have just solved my problem! Thank you for the suggestion. I'm a little stuck in the weeds on this project.

For aesthetic reasons, the tie bar would have to be at the garage side, but it should reduce deflection nicely. For some reason, it does get quite windy on my estate and I don't want this to behave like a trampoline in the wind.

Thankfully, I used back to back for the rails that the pabel rails are mounted to, so adding the tie bar will be a case of buying 6 hinges and some more unistrut.

[Moxi]

Smégal

If you have some rope or wire try tying off both sides of the upright and if that works then a permanent fix of a pair of wire tensioners a set of four cable clamp nuts and some stainless wire may well be a lot cheaper and aesthetically pleasing than more unistrut.

Needs to be both sides though as it’s flexible so unable to take compressive loads, tension only.

Moxi

[Moxi]

Mostie,

Smegal is playing the long game here, a few panels to see how it goes then when SHWMBO is at a weak moment boom! Garage roof full of new shiny goodness!

dangerous but worth a shot

Moxi

[cojmh]

Mostie,

Smegal is playing the long game here, a few panels to see how it goes then when SHWMBO is at a weak moment boom! Garage roof full of new shiny goodness!

dangerous but worth a shot

Moxi

Even better .... as that garage roof does not belong to Smegal .... would be nice to be able to install panels on someone else's roof

[Moxi]

If only! I would have a field day around here lol

Moxi

[smegal]

I've had some power off my install today. I plugged it in around 6pm, and it started at 130W, then went down to 20. Then wouldn't boot which is understandable. The screen is currently flashing which worried me, so I've isolated the DC, will switch it on tomorrow and see what happens. I've got a few questions about earthing, but I'll start a new thread.

Regarding my ground mount. I can move the array like half an inch by pushing on it ('m not strong). I am not sure what to do, it's more movement than I am happy with.

My options are

Sure the ground mount up
Move to my garage roof.

As you can see, my garage roof is FAR from ideal.



I'm reluctant to throw good money after bad at a hobby installation.

[Moxi]

Smegal,

I think you are worrying about nothing - stand and watch a streel lamp when the wind is gusting 15 to 20 mph and you will see that they are moving around 20 to 30 mm from their fixed vertical position - its correct for a tall structure to move. As long as you are not seeing the ground flex around the uprights, which could suggest the concrete mass is pulling out of the ground, then they are fine.

As before if you are very unhappy after a few months of getting to know your install then consider solid tie bars to add stiffness or the cheaper cable stays that I mentioned earlier.

Moxi

[nowty]

I didn't really look close enough at what you were doing on your initial plans. I assumed you were going to build a tall lean to shed against the garage (which I also assumed to be yours) with uprights at all 4 corners with a steep sloping roof.

Quite a structure you've built with its single columns so I'm glad you did not do it with fenceposts. Something that tall is bound to flex, my only worry would be, are the ground concrete foundations strong enough.

Anyway, you should get some nice blasts of power from it tomorrow.