I have tested both the Anker and Samsung wireless chargers with my Otterbox Defender case. Both work, but the alignment of the wireless antenna on the phone has to be lined up with the charging pad antenna or the charging doesn't happen. 9/10 times, that's what goes wrong when people try to use a charging pad and it doesn't help that many of the pads are now using compact designs while the phones are significantly larger. It's my understanding that the older pad designs were larger than the phones or about the same size, so they were easier to work with. I myself bought a bunch of Anker pads in addition to a single Samsung one and I gave up on using them because it's simply easier, faster, and more efficient to just use USB charging because it JUST WORKS. Put your phone on a charging pad and the connection might be good, but if someone bumps your phone even half an inch or a few centimeters, it goes off the charging path and you're no longer charging your phone.