Few things will draw your phone battery down faster than hunting for a signal. If you're out in the boonies, and you have very weak signal, I wouldn't expect your phone to make it much past lunch. The more features you can turn off, the better. As for charging, I would do it in the TV; its battery is easily recharged with a short sight-seeing trip.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!