If the battery voltage is too low, the wireless system is much more susceptible to interference. The interference will show itself in pops, fizzes, distortions, or other strange noises. For long life, use brand name alkaline-type batteries. Yes, you can use lithium batteries. However, they are very expensive and although they often last longer, they may not be cost effective in the long-run.
Rechargeable batteries are very convenient and environmentally friendly.
However, you must be certain that your rechargeable battery produces the proper voltage required by your wireless system. Rechargeable batteries generally discharge to a certain level and then immediately die without warning. This can be potentially very embarrassing during a performance. Inc. All rights reserved.