My suitcase panels came with a bag -- the zippers soon broke. So I made my own bag out of thick vinyl sheeting that I bought at a fabric store -- I glued the edges. It looks like a huge black letter envelope.
Then I took some sheets of dense foam and sewed them onto the insides of the envelope. This is the kind of foam that is used for floor mats in a garage. I sewed them on with waxed linen thread and a big sailmaking needle. The folded solar panel slips between the foam sheets.
I store the whole thing on the dinette cushion of the trailer while in transit.
A bag for a boogie board would not be big enough to do the job -- my panel, even when folded, would not fit. I am an avid bodyboarder, and my bodyboard is a custom "huge" size to fit my weight and height. So my board bag is the biggest one made. It did not work for my solar panel -- I tried it. No way.
If your solar panel is smaller, it might work, though. I would still add extra padding inside the bag. The foam panels not only protect the panels -- they also make the bag slightly stiffer, so that it is easier to slip the panel into the bag.
