Can I use a 2 cell lipo in my tactic 650 and 850 transmitter? Will the radio accept the higher voltage without damage? Thanks in advance for the help Neil

From the tech notes:

TTX650--"Input Power: 3.40-7.00V DC, four 1.5V alkaline or 1.2V NiCd/NiMH "AA" single cells, jack included for connecting optional 4.8V NiCd
or NiMH pack (not included).

TTX850--"Input Power: Four AA alkaline, NICd or NiMH cells"