What is the minimum operating voltage for the FT-817 using the internal batteries?
The FT-817 is set to terminate operation (to turn itself off) went the indicated voltage is 7.2 V. This is the full discharge voltage of both NiCd and NiMH batteries (8 cells times 0.9 V per cell = 7.2 V). If you wait a few minutes, the battery pack will recover slightly (showing 8 V or so) and will run the radio for another minutes or so.