I have 2 DT900 transmitters and haven't had a problem with charging my S5 using a wafer thin, on battery receiver, with either of two different Spigen cases. I also have a RavPower wcn7 transmitter that I use, also with no problems.I haven't used the DT910, but I did try the DT900. It didn't work very well. It kept dropping the charge and reconnecting.