Fitting Solar Panel to Aluminium roof

PA · Newbie

Fitting Solar Panel to Aluminium roof

Cruising Cruze · Guru

Hi Peter

First of all welcome to this forum mate
I'm no expert at all by any means
I had the same problem with our pop top and never installed any thing on it
Maybe just an idea can't you install it on top of your truck
with the solar regulator beside your caravan batteries and use 6B/S cable with some Anderson plugs between the truck and caravan

Cheers John

mr glassies · Guru

I got em riveted and glued to my pop top

Dibs

Aus-Kiwi · Guru

4 X 200 mm 50 X 50mm alloy L plate . Sikoflexed and screwed ., Been like that for 10 years .

macka17 · Guru

Hi.

I've done several over the yrs.
Rivetted and SIKA PRO (the best sticky stuff)

The one thing I've noticed on ALL of them.
That when drilling rivet holes. I ALWAYS... Hit roof framework in (usually)
several places.

I just replace rivets with stainless wood screws in those holes.
Unless ally frame (this one) of course.
I also ALWAYS use blind. (CUP Head) rivets.
so there's no chance of water getting through??.
Yea. Justin'.

IF panel that big\heavy you nervous about it.

Get some Heavy angle, or oblong, box sect ally tube.

Mount that to outer frame of van roof. Then rivet panel to that.

You'll get a good airflow under panel then.

That's a big panel for a pop top.
I swapped a 200w for 2 x 130w for that reason, basically. Smaller items.
LESS Stress on mounting points. Panels cost less per W. del.

Peter_n_Margaret · Guru

Macka, Sikaflex Pro is a sealer, not an adhesive.
The adhesive recommended for this type of application is Sikaflex 11FC.

Cheers,
Peter

Jaahn · Guru

PA wrote:
I have a 220 watt panel to fit to my pop top roof. The roof is Aluminum sheet that is fixed and siliconed all around the perimeter. I am concerned that if I Sikaflex glue the Aluminum angle to the roof the solar panel may cause fatigue in the roof sheet as the panel is subjected to wind and other loads.
Does anyone have a similar installation and how is it?
Thanks.

HI PA smile

I do not have that setup so accept this as a general comment.

A 220watt panel is very large and I would not recommend you use one that big for mobile use on a van. The glass sheet that is the panel surface is only supported around the edges so is more prone to cracking on large panels. If you do use it then provide some extra central soft support under it IMHO. Several smaller panels are always better for reliability and also more output when partly shaded as they often are.

Good luck jaahn

-- Edited by Jaahn on Sunday 22nd of October 2017 07:39:53 PM

PA · Newbie

Thanks for the replies.

I have the panel already and have bought the aluminium angle so I am a little committed to this panel.

Had expected to screw the angle to the panel, glue the angle to the roof and place a small weight above each bracket for 24 hours and then wire it up. But my only concern is when I looked at the roof it is the aluminium sheet that has 15 mm of flex before it lands on any supports.

I will take one of the light fittings out and see if I can see inside the roof gap. I suspect it is a frame not a panel. It's a 1998 Royal Flair so I might give them a call this week before I stuff anything up.

Another option would be to put a pair of aluminium ribs from one side to the other and fix the panel to that.

macka17 · Guru

Pete.

PRO. Yes. It is a sealer. But have you ever tried to release it after it sealed with atmo.

Yea... Yust as good as the marine adhesive when flush not used as filler..
I use both for around 40 yrs or more. (marine mainly)
The Pro is a better all rounder. and recommended by a lot of "pro's" in business.

PA.
Rivet angles to panel first with (say?) 3-4 rivets to panel 3-4 rivets to Roof
Using adh to roof also. and longer screws over rivets if you hit any framework.
LONG Sealed, rivet heads if ALLY frame.
Remember to seal OVER the rivet heads after applying.
And fill the small Junction box with it too where the cable goes in. Then down through roof.
DON'T just drill hole in roof and run cable through. Flex WILL cause leaking.
Small white Junc box does a good job. $7.

With larger panels flex.

Get some lengths of Aluminium sq tube.

Dia to fit under back of panel sheet and flush INSIDE framework surround

Length to fit right up inside side framework..

Tube of SIKA Pro or otherwise.

Adhesive it in place with a 1\8th to 1\4 in thick layer to form a buffer

while damping centre flex. (Some use timber. Ally more rigid. 2.5mm wall)

Apply. then let stand for a while to half formb4 installing it.

Gives some compression flex.

Last one I then screwed a S\S screw into ends to stop it sliding front\back out of place?.

Not that it's likely to. But Murphy always around.

-- Edited by macka17 on Monday 23rd of October 2017 11:11:24 AM

Tony Bev · Guru

Welcome to the forum PA

I had the same problem with a fibreglass type roof, it had much too much flex to have any type of solar panel glued/rivet/screw to roof

As I can not get high enough to take a picture, the sketch below will hopefully explain how I fitted the solar panel

My problem was that I wanted 400 watts of panel, but at any one time, some small panels would be partly obscured by shade

The cavity between my roof, and ceiling is about 45 mm of nothing

Cautiously drilling a couple of 1 mm test holes I realised that the only type of stiffness was along the edge of the roof

I made a frame from 40x40x6 aluminium angle

What keeps the frame to the roof is two pieces of 40x40x6 angle 2200 mm long

It is fixed on with 6 tubes of Sikaflex 11FC, (the only adhesive in Bunnings which is suitable for outdoors)

I also put 10 screws through to the roof, with luckily 4 of those screws contacting sheet steel

The solar panel with its 30x2 mm aluminium angle frame, fits inside my 40x40x6 aluminium angle frame, which in turn is bolted to the 2200 mm long legs

The bottom of the solar panel is 46 mm from the roof, the top of the solar panel would be 76 mm from the roof, as the panel is 30 mm thick

Just to be sure about vibrations along the long edge of the panel doing any damage
I placed some pool noodle in the centre, between the roof and frame

I have now travelled about 35,000 kilometres, without any problems

Hope that this gives you some ideas when fixing your panel

Top of motorhome.png

Cupie · Guru

Welcome from me too.

I am a novice in this area, but have done lots of research.

I intend to use what Sika themselves recommend ... Sikaflex 252.

Rather than use the popular angle ally, I am going to use UV treated 'plastic' corners & centre supports, using the method described by the Sika technical people in their DIY work sheet, 'How to install a solar panel on your Caravan'.

I might just use a few blind pop rivets & self tappers too, just for peace of mind, but I know of many who, like the pro's, just use the sikaflex.

Oh yes .. the mounting bracket kit comes with a waterproof box, that goes over the roof penetration.

Edit .. I have ordered a cable that connects to the MC4 solar connectors and uses an Anderson plug to attach to my 10m of AWG 6 cable to the MPPT controller in my DC-DC Charger. I've now Got a spare PWM controller.

-- Edited by Cupie on Tuesday 24th of October 2017 08:37:39 AM

-- Edited by Cupie on Tuesday 24th of October 2017 07:27:17 PM

Aus-Kiwi · Guru

I run the wires down the fridge roof vent .,

Tony Bev · Guru

Some Jayco's had the solar wiring, and a roof junction box, pre fitted, (mine did)

They just never seemed to worry, that there were not many places to fit panels, without being partly in the shade

swamp · Senior Member

hi
If u select to use alloy angle . A good way of preventing the rivets shearing or coming loose . Use adhesive between the panel edge frame and the alloy angle . Use 3/16 rivets with very large heads eg around 14mm .

There is a 3M tape called VHB = very high bond use 3mm thick and pretreat surface . Have to remove with hot hair dryer .

Jaahn · Guru

Hi smile

A general comment if you are going to use rivets and want a good strong job. Use monel rivets. They are at least twice as strong as good aluminium types and three times as strong as the cheap crap ones. Monel will not corrode with the ally like steel does. Monel are commonly available in bigger hardware stores or marine supplies. A little harder to set but OK to use. hmm

Cheers

Bardos · Newbie

Gedday, perhaps a stud finder, the type used to find timber in house walls might help as well to locate the roof supports, they are very cheap and batt operated. cheers nev.

PS good info guys, lookin at doing it myself soon.