Solar Panel Installation

[Silver-Fox]

This might be a daft question but is there any specific height people install there panels at on the roof.

So do you put them close to the roof or have say 30 or 40 mm gap under them.

TiA

 

[TinaLes]

The purpose made UPVC brackets dictated the height the panels sit above the roof for me. I understand they need a 20/25mm gap to allow for cooling as they apparently get hot. I cannot vouch for that theory though as we haven't had enough sun recently.
Les

 

[Sandancers]

I thought some panels were fixed with adhesive directly to the MH roof ?

 

[Gaston aires]

Flexible panels stick to the roof using sikkaflex adhesive. Easy Peasy. l have a 100 watt solar connected to an AGM battery. Never ran short of leccy yet.
Phil

 

[ianthebuilder]

I had a look at mine the other day,, when I cleaned the roof,, it seems that the brackets to both ends of the panels, lift them about 30 mm off the roof! Just enough for the roof under them to go green and not be reachable!! Lol

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[tonka]

Leaving a gap for air flow and cooling is advised but never seen a specific height.
Mine was done with home made ali brackets, i just left maybe a 20mm gap same as i did on my past van. Never had any issues.

 

[TinaLes]

The Flexi panels are designed to be stuck down directly to the roof, the rigid ones need a space between roof and underside of panel to allow for ventilation.
Dont ask me why there is a difference between the two, other than I imagine the flexi panels have some for of insulation on the back of them, but that doesn't answer the question as to why the rigids need a cooling air gap, or does it?Why one type needs cooling and the other doesn't, if after all they are both the same as in Mono types.
Mystery eh?
Les

 

[MR. FUSION]

I stuck my flexible one directly onto the MH roof. When we were in Holland in 2016 it was unusually hot around + 35°c and the panel got very hot. I disconnected it as I put an inline fuse on the +ve output, which helped a bit. At some stage I am going to remove the panel and put it on the smaller type raised corner brackets for flexible panels. I haven't been anywhere that hot again so haven't bothered so far

 

[MR. FUSION]

The Flexi panels are designed to be stuck down directly to the roof, the rigid ones need a space between roof and underside of panel to allow for ventilation.
Dont ask me why there is a difference between the two, other than I imagine the flexi panels have some for of insulation on the back of them, but that doesn't answer the question as to why the rigids need a cooling air gap, or does it?Why one type needs cooling and the other doesn't, if after all they are both the same as in Mono types.
Mystery eh?
Les

My flexible one got very hot in a hot summer, I know that because I can stand on the seat and am 6'3" and can reach it through the roof vent to check.

 

[DBK]

I stuck my flexible one directly onto the MH roof. When we were in Holland in 2016 it was unusually hot around + 35°c and it got very hot. I disconnected it as I put an inline fuse on the +ve output, which helped. At some stage I am going to remove the panel and put it on the smaller type raised corner brackets for flexible panels.

I think you are worrying too much. Flexible panels are widely used and are able to cope. Stuck to a roof they can dissipate heat into the roof itself if necessary.

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[MR. FUSION]

I think you are worrying too much. Flexible panels are widely used and are able to cope. Stuck to a roof they can dissipate heat into the roof itself if necessary.

Mrs Fusion says I overthink things as well

 

[Jaws]

As said, the flexy ones use what they are attached to as a heat sink.. The rigid ones use an air gap because ( from the original spec sheet ) the hotter they get the less efficient they become

 

[funflair]

I used I think 40mmx40mm alloy angle and that gave about a 20mm air gap which looks about right to me,

Martin

 

[bigtwin]

Flexible panels stick to the roof using sikkaflex adhesive. Easy Peasy. l have a 100 watt solar connected to an AGM battery. Never ran short of leccy yet.
Phil

You’re clearly not trying hard enough!

Ian

 

[andy63]

prepared to be told I'm wrong , but last time I was looking into it flexible solar panels as a general rule they are slightly less efficient than rigid panels and they will suffer more from heat and lack of cooling if mounted directly on a surface than rigid panels mounted with an air flow gap
their advantages are that you can mount on a curved surface and they are a good deal lighter..

all panels will have a temp coefficient that can be used to calculate the drop in efficiency for every degree centigrade
rise in temp above 25 deg c which is the temp they are usually specked at.. its the voltage that drops off quickly when their temp rises..
Andy

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[treetops1]

I think the plastic corner brackets you can buy are excellent .I fastened the corner brackets to the corner of the panels plenty of adhesive on the corners then just pressed the panel down in position.Then just wipe off excess adhesive job done lol.

 

[PeteH]

I have experience of both types. But not having been in any "hot" climates lately. It is not clear as to how much difference it might make. The Flexi; ones where bonded direct to the roof, and I experienced no apparent issues. The rigid ones on the R-V (older types, 4 off) where fastened with ally, brackets made from old rail I had in the garage. gap about 15mm. again not had issues. I suspect that any deterioration due to high temperature would be marginal in the temperate climate we get in the UK.? The ones on the current `van where fitted prior to my ownership and have a gap of only about 10mm or maybe 12mm.

 

[Guigsy]

prepared to be told I'm wrong , but last time I was looking into it flexible solar panels as a general rule they are slightly less efficient than rigid panels and they will suffer more from heat and lack of cooling if mounted directly on a surface than rigid panels mounted with an air flow gap
their advantages are that you can mount on a curved surface and they are a good deal lighter..

all panels will have a temp coefficient that can be used to calculate the drop in efficiency for every degree centigrade
rise in temp above 25 deg c which is the temp they are usually specked at.. its the voltage that drops off quickly when their temp rises..
Andy

Correct. However, I don't think you should stick flexible panels to curves surfaces if you can avoid it. Basically, the bit of the panel that's receiving the least bit of sun (because it's facing the sun slightly less) will drag the whole panel down to that voltage. So you'll never get maximum output from your panel if it's glued to a curved bit.

 

[Silver-Fox]

Thanks for the replies.
I’m using some Ali angle so looks like I’ll gap it as suggested at around 20mm then