Advice wanted on Mounting 2 Solar Panels on Caravan Roof
Submitted: Monday, Dec 15, 2008 at 14:00
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PeterInSa
Am looking at DIY installing of 2x 80watt BP Poly Crystal Solar Panels on the roof of our 21’6” van. Any comments on the items below appreciated. Will only be used for TV at night and to run our Fluro’s. Getting 2 old to lug the Honda E20i in and out of our Cruiser.
Since I do not know the location of the roof supports am going to mount the panels just forward of the roof top air conditioner (on the flat section NOT on the slope) with an aluminium right angle strip 75mm x 50mm for the full length of each side of the solar panel , Riveted onto the panel (75mm) and the van roof (50mm).ie Panel approx 25cm above roof. Rivets approx 150mm apart.
Of course, AL strip and rivets on the roof will be silicon’ed in, as will be the rivets and strip to the Solar panel.
Have seen some vans using screws, but I prefer rivets as they can take more vibration, before coming loose, the downside is that they can wear thru. Have seen some 80 watt panels held on by 4 angle brackets each having two screws to the roof and two to the Solar panel.
Will use the standard White Conduit and plastic saddles to connect the roof top units together and go thru the roof to the floor then the boot via a Floor to ceiling cupboard.
Will mount the Controller in the front boot, will cut down cabling and its not something that I want to look at often.
Am also think of installing the right angle strip in the front forward direction of the solar panel as have heard that some panels are working loose, because of the wind pressure of passing semi’s. However do not know if this pertains to solar units that have only 4 brackets or units that have the full AL strip on both sides
Any comments on the BP Ploy Crystal as am looking at Ordering/Buying them this week prior to the New Year price rise.
Peter
Reply By: hazo - Monday, Dec 15, 2008 at 14:32
Monday, Dec 15, 2008 at 14:32
Peter
I have done several solar installs on my previous vans.
Firstly 50mmx50mmx3mm aluminium angle, is perfectly adequate for the panel supports and easily available and cheaper than the 75mm.
I would steer away from silicones and go with Silastic 292 or Goldflex (half the price of Sikaflex).
I used 3/16" alloy rivets to fix to roof and 12mm stainless screws to fit panels to side brackets (no sealant), as you may need to remove a panel down the track.
Beware of steel electrical conduit saddles as they rust like buggery!
I found that it was much neater to Sikaflex the conduit to the roof (hold in place with "gaffa" tape till dry) and ran my conduit to a plastic conduit box then out the back of the box directly through the roof into an overhead cuboard.
A conduit box can be also sealed to the roof much easier and also looks much neater.
I then ran the cabling from the regulator in the top cupboard down through the cupboards to the floor and through underneath, then in 20mm flexible conduit to the battery compartment,in the boot.
Fit a decent quality regulator like a Morningstar Prostar or similar, and allow enough sizing (amperage) of regulator in case you decide to add another panel later.
Also use good quality correct sized cables to avoid any voltage drop.
Most installers use too small a cabling for the panels they fit.
Brian
AnswerID:
339843
Reply By: PeterInSa - Monday, Dec 15, 2008 at 16:30
Monday, Dec 15, 2008 at 16:30
hazo,Darian,All,
Since my post above have further looked into the mounting methods.
My understanding now is that the roof of the van is not necessarily stuck down to the roof supporting frame. One installer in
Adelaide uses the Al Angle and puts it as close as possible to the edge of the roof and the vertical side but not over the AL Strip that has the plastic fitting. The other side is rivetted to the roof panel.
Another installer uses square tubes (2) going from one side of the van to the other and screws/seals it into the AL Strip with the Plastic Fitting to avoid rivets/screw in the roof. The square tube can be siliconed to the roof in the middle. Various users of Silicon are not as impressed as myself based upon their experience ie. over time it can leak.
As Big Mal use to say "Life was not meant to be easy" especially if your a DIY'er.
Was told by a mate "pay for an installer to do it then if it leaks/blows off the roof you can claim against him". The thing is if it happens when you are out in the sticks and it
ruins your trip, getting your money back for a faulty install is the last thing on your mind when you have a hole in the roof and rain coming in.
Peter
AnswerID:
339859
Reply By: Peter_n_Margaret - Monday, Dec 15, 2008 at 18:14
Monday, Dec 15, 2008 at 18:14
1. Sikaflex only, no holes, no silicone.
2. Consider hinging one side to allow cleaning out the dirt, leaves and crap. Very difficult otherwise.
3. Select a location that allows you to add a couple more panels later.
4. 25mm is a bit too close to the roof. Performance degrades when they get hot. The instructions will recommend a bigger air gap.
5 Use muli-strand cable of generous proportions to reduce voltage drop. Again, see Colyn Rivers book.
Cheers,
Peter
OKA196 Motorhome
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