Hate to bash your sales ad but those things are crap. They use really small LEDs that have lower efficiency than the 1w or 3w LED emitters. You'd probably be better off just using an ordinary white LED bulb.
I can't speak for the particular version you got, but I got one of the panels slightly better than yours that has 1w LED emitters (a little bit bigger) and after being left on for over six months most of the emitters stopped working. For some reason the blue ones burn out before the red ones. That's what you get with cheap Chinese quality.
That may not be problem with the one you have since your panel uses much smaller emitters that are likely underdriven.
I would only recommend these panels for someone who's already using white LED and thinks adding a bit of red wavelength light to the spectrum would help. (White LED light actually does not have as much red light in its spectrum as other white light sources)