https://www.pveurope.eu/solar-modules/solar-foils-flexible-solar-modules-camping-vehicles
Flexible solar modules for camping vehicles
Because even during the cold, grey season, many campers cannot do without solar energy. Conventional roof panels on motor homes or caravans hardly achieve any yield in the winter months. The situation is completely different with solar pockets placed vertically on the side wall of the vehicle.
See also: Complete solar systems for the balcony
Once attached with the appropriate suction cup or magnetic holders, they achieve maximum energy yield precisely because of the low sun and provide a trickle charge for the starter battery or charge the consumer battery in the vehicle. For this purpose, a solar controller is installed between the solar pocket and the battery. If the vehicle is parked unattended, the solar bag is simply placed in the interior behind the windscreen and provides battery charging there without fear of the bag being stolen. (mfo)