We've had it for a month and it works perfectly. Great price,Installation was tricky only because I had to make my own template.As with any solar panel, I made sure it was facing south.The South side of any building is the side that gets the most sun.Set up was easy.I went with a time to open and close vs the light, because the area was covered. Getting the percentage of light was going to take time in trial and error.I don't have that kind of time.It's open every day at 6am and closes every day at 6pm.In the summer I'll change those times but for now, it's doing it's job perfectly.