Sticking flexible solar panels to a painted steel roof

[rogerc]

my solar panel failed after 3 years and i think the problem was water between it and the steel and all the paint came off in a sticky mess below the panel.

what would people recommend to stick on the new panel?

[Tony Brooks]

2 minutes ago, rogerc said:

my solar panel failed after 3 years and i think the problem was water between it and the steel and all the paint came off in a sticky mess below the panel.

what would people recommend to stick on the new panel?

 

Brackets to hold a rigid panel clear of the roof. Flexible are well known to have a short life. More likely  excess heat from the roof during periods of high sun. If you already have the panel, think about stocking it to a sheet of aluminium and bracket that up from the roof to give air flow underneath.

[Alan de Enfield]

21 minutes ago, rogerc said:

what would people recommend to stick on the new panel?

 

 

I think that most people would recommend not sticking them down at all.

Your panels will shortly start to fail (electrically) so it could be a good time to not only repaint your boat roof, but buy some panels that will not damage your boat, and will last 25+ years.

[BWM]

I plan to fit these and am going to attach using thick beads of adhesive/sealant parallel with the cabin top to leave a small air gap between the two. 

[Tony Brooks]

8 minutes ago, BWM said:

I plan to fit these and am going to attach using thick beads of adhesive/sealant parallel with the cabin top to leave a small air gap between the two. 

 

To trap water? If you seal all round, any slight pinhole in the sealer will allow water to build up in the gap and the air will be trapped so can't convect away as its heated. Remember, most boat paints are porous if water is kept in contact with them so it might not do the roof much good if water does get trapped.

[Higgs]

If they have some rigidity to them, they could be mounted with six support brackets; four corners and centres. But mounted directly onto the roof, they can suffer from heat build up and blister. 

 

 

Edited June 25, 2021 by Higgs

[Phoenix_V]

We woud like to add some extra panels but there is little room left on our main roof we have a canvas roof on our wheelhouse It would be impractical to attempt to stick normal panels  would it e possible to use flexibles with some sort of removable attachement, what sort of weight are they?

[Tony Brooks]

2 minutes ago, Phoenix_V said:

We woud like to add some extra panels but there is little room left on our main roof we have a canvas roof on our wheelhouse It would be impractical to attempt to stick normal panels  would it e possible to use flexibles with some sort of removable attachement, what sort of weight are they?

 

 

As the ones I have seen  seem to be all plastic lighter than the rigid ones with glass. I am sure you could stick them onto alloy or plywood sheet and glue that to battens that run lengthways across your roof beams. If the roof is held in place by Liftadots or turn-buckles I am sure you can get double length ones to allow you to hold the lot on the roof with fabric strapping yet be easy to  remove when required. That  will not address the flexible panels propensity to  delaminate over a few years.

[Alan de Enfield]

5 minutes ago, Phoenix_V said:

We woud like to add some extra panels but there is little room left on our main roof we have a canvas roof on our wheelhouse It would be impractical to attempt to stick normal panels  would it e possible to use flexibles with some sort of removable attachement, what sort of weight are they?

 

We have a similar canvas Bimini on the 'Cat'.

 

You could always make a mounting to go over the stern (we have got 3x 100w on this 'tray')

 

 

 

 

[MoominPapa]

Having had the same problems with water pooling under flexible panels and wrecking the paint, I stuck mine down with Sikaflex, onto newly-done paint. A year on, and so far, so good.

 

MP.

[Woodwych]

Our flexible panel is attached using exterior Velcro. A strip all round the edge- it does leave a little air gap under the panel which maybe useful to reduce the heat problems

[Phoenix_V]

1 hour ago, Tony Brooks said:

 

As the ones I have seen  seem to be all plastic lighter than the rigid ones with glass. I am sure you could stick them onto alloy or plywood sheet and glue that to battens that run lengthways across your roof beams. If the roof is held in place by Liftadots or turn-buckles I am sure you can get double length ones to allow you to hold the lot on the roof with fabric strapping yet be easy to  remove when required. That  will not address the flexible panels propensity to  delaminate over a few years.

I don't think the first would work but the second sounds promising I might buy one to try, one benefit being I could remove the panel when not in use and prolong it's life

1 hour ago, Alan de Enfield said:

 

We have a similar canvas Bimini on the 'Cat'.

 

You could always make a mounting to go over the stern (we have got 3x 100w on this 'tray')

 

 

 

 

bit complex I'll keep that in reserve

[Mad Harold]

1 hour ago, MoominPapa said:

Having had the same problems with water pooling under flexible panels and wrecking the paint, I stuck mine down with Sikaflex, onto newly-done paint. A year on, and so far, so good.

 

MP.

Sikaflex is excellent stuff but is pretty permaneant.

When sticking things on fibreglass (little security lights) on trying to replace them,it actually started pulling the gel coat off!

[BWM]

7 hours ago, Tony Brooks said:

 

To trap water? If you seal all round, any slight pinhole in the sealer will allow water to build up in the gap and the air will be trapped so can't convect away as its heated. Remember, most boat paints are porous if water is kept in contact with them so it might not do the roof much good if water does get trapped.

No, not to trap water. Would be lines running parallel with the boat, open at both ends.

[Kendorr]

I stuck mine down with Gorilla double sided tape, it worked well holding the panel on. The panel delaminated after just under 3 years and I was able to remove the panel and the tape with very little damage to the roof, for which I was very happy.

[ditchcrawler]

Ortomarine stick theirs down on brand new boats

[Alan de Enfield]

3 minutes ago, ditchcrawler said:

Ortomarine stick theirs down on brand new boats

 

Some manufacturers don't black the bow-thruster tubes from new.

 

Just because a manufacturer does, or doesn't, do something doesn't make it right. They are building to a budget, not to a quality standard.

[rogerc]

thanks for all your input. i take the point about rigid Vs flexible but having flexible suits me better at the moment. i like the idea of sticking it with strips along the curve to allow drainage with Stikaflex. and i will ask the supplier what they recommend so as not to invalidate the 5 yr warranty.
more suggestions welcome too.

[MoominPapa]

11 hours ago, rogerc said:

thanks for all your input. i take the point about rigid Vs flexible but having flexible suits me better at the moment. i like the idea of sticking it with strips along the curve to allow drainage with Stikaflex. and i will ask the supplier what they recommend so as not to invalidate the 5 yr warranty.
more suggestions welcome too.

I don't think you'll get a large enough gap to allow drainage even when first done, and by the time dust and muck have accumulated in there, you'll find it's permanently wet against the paint. The best option is probably to go for a good seal around the edge and enough sealant inside that to firmly stick it down.

 

MP.