Unlike panels that are normally used of roof of buildings the panels that I use are lighter and can flex a bit. The individual cells , encapsulated in very stiff plastic (ETFE) are made of Silicium, which is a material like glass thsat can break.
When this flex panel has no rigid underground it will break easily by for instance by hail stones. The result is very much reduced output. Johan experienced this. To inspect a panel for micro-cracks put a bright light behind it in a dark room and view the panel from the front. When you see micro cracks it is not good news for the panel. You may stil be able to use it but the output will be reduced.
The weight of each panel is about 2.3 kg. I have added an aluminium frame increasing the weight to 3.3 kg per panel. The panels are specified at a peak output of 100Wp. This is however in ideal conditions. I have not seen the panels go above 75W each on a clear blue day. I also noticed a big difference between individual panels output of about 20%.
If you want to buy such panels just look on AliExpress for webshop JingJangSolar, flex solar panel and you will find it. Note these materials are shipped from China to Europe by air which is not very green. Unfortunately I could not find sellers that have such abundance of solar materials for end users that are made in Europe. If you know such a place please send me the web address.