These lights are not for the impatient. I ordered two sets. The first set did not work, after a full day in the cloudless sky and having triple checked to make sure I had switch on the "on" switch. Also, a bulb was missing in the second set. I called Wayfair customer customer service, and Hunter, the representative I spoke with,  was great. He sent out 2 more sets  of lights. One string works wonderfully and dependably. The second string will only work with the back-up battery. I have the 4th string charging now so will see if that will work. On the plus side, if you want a wonderfully magical look, you will get it with these lights. They are not too bright, nor too dim...they create a fairy-tale like atmosphere...which is why I will definitely keep them and enjoy their beauty.  Plus, I tend to be patient with their idiosyncrasies....