Now that I have that new battery cap, started with another new sensor and it ran fine for a few hours, calibrating sucessfully. In the past half hour though, I got "weak signal" , for 30 mins; then "lost sensor". so I had it "find lost sensor" and then the thing gave me a "hi Alert". for the next 10 mins, now it shows "weak signal" again. Recently, Medtronic gave me a new transmitter because they thought that was the cause of this continually erratic perfromance but, after just a week, we're back at the same old game.
Prior to that, I had periods where the monitor would show only one bar remaining, on the battery status icon; then later in the day it would miraculously show that the battery must have re-charged itself, with 4 or 5 bars. Medtronic replaced the whole 723 pump/ monitor at that time.

Anyone else having similar problems??