We have a fairly large (94"W x 82.5"H) picture window overlooking the backyard. Needless to say, it takes a lot of effort to get this bad boy up and down, but we've been using it for a little over a month and this solar panel keeps it charged and ready to go! I'm very happy that I don't have to constantly manually charge it (which requires a ladder). It rises and falls several times a day, is adjusted according to an individual schedule and also depends on whether we watch TV and so on. It definitely does the job! Very satisfied and to be recommended! A random voltage check during the day showed 9.12 V DC. Sitting on my couch, not even in the sun, I still went over 7V DC. Update: I bought a second one for dimming my theater room. It comes with a 3.5mm DC jack and for this shade I needed a 5.5mm DC jack. I bought a cable, cut off the end, removed it and soldered it to the solar panel. Very easy, just unscrew the 4 screws on the back and it slides right out. You can also do this to shorten the original cable so you don't have anything to hide, but that wasn't a problem for me in my first case.