It really is amazing how necessity is the mother of invention and further that nothing ever really goes as planned. It was my plan to fit the panels running alongside each other and running down the length of the vehicle. This was all good until I realised even though the roof looked quite flat, ot was far from it. Fitting the panels lengthways on the roof was just not going to happen, the curve was too much.
Of great importance was getting the terminals on the panels within as short a distance as possible from the point where I'd run the wires to from the battery box. The other main consideration was that the panels were fitted so that air coulod flow under them. Solar panels get hot and the hotter they get the less efficient they are, so by allowing air to flow under them - better efficiency. I think sometimes perople forget that they use light not heat to create electricity. Apparently they work best in freezing climates when there is bright sunshine.
In the end there was only one option and that was to fit the panels across the roof. To compensate for the curve I had to be a little inventive. Rather than buy commercially made mounts (too expensive) I used aluminium 40mm x 20mm angle which I cut to length before drilling and screwing it to both ends of each panel. I used stainless steel, heavy guage screws and Sikaflex sealant/adhesive under all of the joints. I then had to mount the fabricated brackets onto the roof and the only way to compensate for the curve was to cut 25mm box section and fix these to the roof like rails, then fix the panel brackets to them.
All of the joints have been sealed and glued, I will give it all a thorough strength test once the adhesive has had a proper time to cure. The pics below give an idea of how it all came together.
I had just finished and it started to rain, so there is water all beaded on the glass oin the above pics. While the sun was shining, I measured 20 plus volts on each panel. Yesterday it was really dark and overcast in the afternoon, and I measured 18.9 volts plus or minus. They appear to be working to specification. Those of you who have been reading this blog for sometime will remember that these panels came direct from China at less than the price of one purchased locally. I note that the prices in Australia have come down alot in the last few months.
The pic below shows the electrical junction box I used to join the heavy guage wire that runs to the battery box to the 4mm wire that goes onto the panel terminals.
