Flexible light weight solar panels

Mitsi Fendt

I am looking for some advice from those with more technical knowledge than myself. I am considering installing one or two flexible solar panels ( The type that are very thin and adhere to the caravan roof following the contours. Done a fair bit of research into the different types and I am aware of how the installation should be done regarding regulaters etc. My main question is are they efficient and what problems might I encounter? Thanks in adavance for all answers.