I fitted four flexible solar panels on the roof of my NB with Sikaflex, zig zagging the adhesive over the area of the panel, also carefully sealing around the edges to ensure that no water could get underneath to rust the roof. I only recently found out that the flexible panels do not last as long as the rigid panels due to the flex and stresses on the panel (I was not told of this when purchasing them!!).
My four stainless steel backed flexible panels, when first installed put out around 15amps on a clear sunny summers day, but that reduced to 1amp under the same conditions after around five years - extremely disappointing for an outlay of over £2,000!!
I have now replaced two flexible's with two rigid panels and was shocked to see the extend of rust under the flexible "sealed" panels, possibly from condensation, I'm not sure, but I will never fit flexible panels again.
Andy M.