Does anybody know what the minimum voltage the uwatec transmitters will go to before failing?

I have just changed one over as it was flashing up Batt, when I check the voltage it is at 2.94v on a 3v battery, the new one was on 3.24v

The new one is working fine with no battery warning, it just seems there isn't much difference and would have thought it should go a lot lower before giving a warning.

Many thanks