I'm sure two batteries won't cut it for a week of backpacking in the high peaks. So what do you do for power?
So a charged up external power pack wouldn't work?
I do not leave the phone on. It's for emergency! Using the phone and getting a distant back country signal eats up A LOT of juice.
I carry spare batteries for my headlamp and gps. An extra battery for an emergency phone has been mandatory.