Android devices use a combination of GPS and cell towers. But if you don't plan ahead and have the maps it doesn't matter what location method is available. Also, my phone lasts around 4 hours when navigating via GPS (screen on) while the GPS tends to last longer. Yes, both can be plugged into the car while driving. My dog collar receiver works for around a day of hunting but that's primarily dependent on how the collar communications is set up. Without the collar turned on, it would last for several days I imagine.