The Renogy Suitcase Solar Panels are equipped with adjustable kickstand legs that fold down to hold the panels up at the best angle to absorb sunlight. During winter months the sun is at too low of an angle for the legs to be effective; they simply don't have the range to hold the panels upright enough. To remedy this I simply drilled new bolt holes through the bottom half of the aluminum frame and flipped the legs. Now the panels are able to stand much more upright to capture that weak winter sun. I hope this tip helps others in the future.
Factory leg position
Flipped leg
Factory leg position
Flipped leg
These renogy suitcase panels are pretty heavy though, I'm sure they'll be fine. Love mine being heavy as I am always camping in the wind.