I'm going to take this opportunity to complain about Google Navigation app, on every device I've owned.

Their directions really should say "ETA: 3 Hours from now. ETToBatteryDrained: 1.5 hours from now. Shoulda remembered your car charger, dumbass". 'Cause I do forget to pack it every goddamned time.

I don't know if this is really possible, but they really should have a "low-accuracy" mode, where if you're on a freeway with no turns for an hour, they should turn off the GPS, and just use inertial or cell-phone navigation mostly. Then only periodically check the GPS. If you are going to turn soon, or appear to have deviated, they can go back into active GPS mode, but the goal is to avoid wasting battery when you're probably just following the road.