Fixed solar upgrade. Flexi or rigid?

[Captain Quick]

Mines fixed to 4mm twin wall using the eyelets in the panel and then the twin wall stuck on with VHB tape - it’s holding strong. Can’t understand why more people don’t use twin wall, it only raises it 4mm but gives the panel airflow under it.

Me too. It’s what I’m planning to do but on a sheet of 10mm twinwall. This will still only increase the van height by 13mm. It’ll be mounted so the tubes run fore and aft, with the leading edge sealed up to stop water ingress. Any moisture that finds its way inside will get drained out when the pop-top is lifted up.

 

[Green Giant]

I think I will also seal up the front leading edge under the panel, I guess the hot air will find its way out of the back, and like you say, with the poptop up, it will drain anything out,