I dont know if in your life you have used an actual paper map, but do consider picking up some local regional maps as you go along, just so you have a non battery using backup, and have some paper and a pen also to jot down simple road names and town names that are easy to forget.
this way you dont always have to use your phone battery, and you have a backup.

you dont mention, but I am assuming that you are staying in indoor accommodation at night, so recharging will not be a problem.

have a good trip, and good luck wiht the weather.