Hi
So, I finally got round to reading this properly... are you running the fridge from the inverter too, or is it a 12V?
Mine is a Dometic cool box style and uses only 0.5ah/h, so about 12Ah per day, I can see that kicking up in warm weather to maybe twice that.
So finally getting up a ladder to the van roof with a tape measure in hand is quite sobering, the ridges on the roof don't help...
I reckon to get two panels side by side lengthways they'll have to be between 400 to 490mm wide to sit onto the outer 3 ridges.
Narrowest I've found so far are 505mm wide & might work with the edge carefully filleted with adhesive... lots of masking needed here tape!
Photonics Universe (PU) do a 130W in this width with the circular rear junction box, which will keep the roof lines clean & drop nicely through the middle of the three ridges.
A pair of these gives 260W and comes out at £1.86/w
Going to a single panel is the next option.
PU do a 180W which is 665mm wide; this will site nicely on the middle 4 ridges, though the rear cable junction box will sit in the central trough, so will need some care to ensure a seal; I'm imagining a PU closed cell foam gasket around it, which I'd back fill with sealant from the inside; I'd appreciate comments.
Cutting this out of cardboard and laying it on the roof is pretty sobering too.
180W at £1.83/w
I'm currently leaning toward the twin panels; gets 44% more power and better shading resilience.