Last night I went from being very happy to very disappointed. Based on a post I read on TB a while back, I bought some Maha Energy PowerEx rechargeables. I opted for the 9.6v model assuming that they would provide a little longer life in my wireless which had been consuming my Energizer rechargeables about 1 per set. I put a fresh one in and the transmitter powers up and shows a full 3 bars of juice. Very happy. But when I play, nothing happens. Very disappointed. I duplicated my test this morning at home and sure enough, a standard new alkaline works just fine, but the 9.6v PowerEx's won't work in the unit. It powers up, it shows full juice, but something is preventing the audio from flowing. So, I'm going to order one of the standard Maha 9v models and see how they do. Anyone else have similar experiences with Maha batteries or Shure ULX wireless systems? I was thinking of upgrading to an X2, but the Shure is working fine, sounds okay, and a 4 new rechargeable 9 volts is still a couple hundred less than a new X2.