FYI … Don’t forget that the solar panel also comes with an included 13 ft. cable! That is a total length of 46 ft. for your application. Which is significantly longer than my cable length. As previously posted, I only extended my cable a total of 33 ft. (13 ft. included solar panel cable + 20 ft. (2 ea. - 10 ft cables)).
Please let me know how you make out. I am interested in seeing if it works for you.
Good Luck!!!