The Powerfilm rollable are very durable. Leave it out in the weather all year without worry. The size you need probably depends on how fast you need a recharge but I'm no expert on this. I just know from personal use of this panel, they are tough. They come with grommet holes so you can easily attach to your dock, boatlift, or top of boat cover. Then when you're fishing you could move into the boat and use it as a rug.
powerfilm