Weak Signal Questions/ Minimed CGM

In a side conversation with my Quick Start contact at Medtronics (for new pump users), I mentioned that I have had this happening, and she told me that a charge on the transmitter should last 14 days. However, I also think that the battery I had in my transmitter charger was probably dying. I replaced it, and have not had any issues since. I haven't tested the length of time completely - I charged mine after 7 days just to be safe.