Solar panel installation

[merl]

Good idea about support for the middle just wondering if it might create a hot spot where the ventilation can't get to it?

Good point, I really don't know? I know that partial shading limits the output of the whole panel to the current in the shaded zone, I suppose it makes sense that the same thing happens with a hot zone, ie the total panel current is limited to the current in the hot spot?
I guess it's something you could experiment with after they're fitted, wait for a day with constant sun and then push a piece of polystyrene under the centre of one panel and see if it's output drops compared to the other.

 

[Robmac]

@Robmac
You are sensible to be concerned, domestic panels are large heavy and imho must be secured using mechanical fixtures.
The simplest method is to use unistrut bolted and bonded to the roof, three lengths minimum to give sufficient support.

The lighter 41x21x1.5mm slotted stuff is more than adequate and provides flexibility for upgrades, tilt mechanisms and other additions e.g satellite dishes at a later date

The panels are attached using conventional solar mounting clamps into M8 unistrut nuts

I have done many installations using Unistrut, e.g. I used 5x3m lengths on the van below because the owners were also adding a deck.



View attachment 133902

I'm liking this idea more and more since David showed it as well yesterday. What swings it is that if I use 3 channels it caters for the support in the middle which Merl alluded to yesterday, as I am mounting them Lengthways I reckon 3 would be fine.

I have looked at the sizes you suggest and notice that you can buy exactly that size much more cheaply from other manufacturers.

 

[Robmac]

Good point, I really don't know? I know that partial shading limits the output of the whole panel to the current in the shaded zone, I suppose it makes sense that the same thing happens with a hot zone, ie the total panel current is limited to the current in the hot spot?
I guess it's something you could experiment with after they're fitted, wait for a day with constant sun and then push a piece of polystyrene under the centre of one panel and see if it's output drops compared to the other.

See my post above Merl.

I reckon that would suffice?

 

[Pudsey Bear]

It sounds like a lot of work in front of you there Rob, try not to fall through the roof while doing it mate

 

[trevskoda]

It sounds like a lot of work in front of you there Rob, try not to fall through the roof while doing it mate

More likely to slip of to the pub.

 

[Robmac]

It sounds like a lot of work in front of you there Rob, try not to fall through the roof while doing it mate

Added bonus Kev - the repair will be covered over by the panels.

 

[merl]

See my post above Merl.

I reckon that would suffice?

I was concerned about the actual glass flexing and resonating but stopping the flex in the frame would help that for sure. In my mind I can envisage the resonant frequency of the glass/panel being excited by road vibrations and the internal gubbins within the panel suffering from this constant flexing over time but I really Dunno, I've a tendency to maybe over think stuff like this

 

[Pudsey Bear]

If doing a frame, you could glass in some struts to stop flexing resonance easily, it's probably not a problem yet, but some air will be forced under the panels now.

 

[Robmac]

If doing a frame, you could glass in some struts to stop flexing resonance easily, it's probably not a problem yet, but some air will be forced under the panels now.

I can still put a spoiler on the front Kev.

 

[Pudsey Bear]

Too late Rob we already know what you're planning

 

[Robmac]

Well that was an epic failure, van battery as flat as the proverbial.

It went flat at the weekend so after a 60 mile run back from the meet I thought it would be Ok so I reckon it's goosed. I've stuck it on charge and then I'll go and pick up the panels and take Julie with me so I can leave the engine running outside the store.

 

[caledonia]

Dont need to be forced just an air flow Rob, cool panels work better, hence the stick on flat jobs die after a few years, also look at home roof panel, air gap under them.

Modern panels on roofs have no air gap. Stick on flat jobs are pretty robust if you buy quality.

 

[merl]

Modern panels on roofs have no air gap. Stick on flat jobs are pretty robust if you buy quality.
View attachment 133908

Pahh, Robs going for a bigger setup than that, 1.21 GiggWatts is a lot of power Marty, hopefully the flux capacitor will handle it

 

[Tezza33]

I remember when I bought the Trojans and you showed me the maintenance manual - frightened me to death. T

The Trojans that I bought have died through lack of maintenance Rob, I wasn't there to check electrolyte levels so they dried out, I never even managed to use the van with them so I will always wonder if they were any good

 

[Robmac]

The Trojans that I bought have died through lack of maintenance Rob, I wasn't there to check electrolyte levels so they dried out, I never even managed to use the van with them so I will always wonder if they were any good

That's all I ever did Terry topping up the electrolyte. They've lasted 7 years though and have been brilliant.

 

[Tezza33]

That's all I ever did Terry topping up the electrolyte. They've lasted 7 years though and have been brilliant.

I am just pleased that they are heavy, the scrap yard will pay more for them

 

[Pudsey Bear]

Have you tried to recover them Terry?

 

[Robmac]

I am just pleased that they are heavy, the scrap yard will pay more for them

Good point Terry - I should get something back for mine. (not that they owe me anything)

 

[Robmac]

Got the panels home now, they look great.

Well, they're big and oblong and black.

 

[Tezza33]

Well, they're big and oblong and black.

Sometimes it is better if I don't post a reply