Yes. I use Gaia GPS on my Android (I think they have an ios version too). The key to preserving battery life is running in airplane mode. As long as I'm not constantly checking the GPS every couple of minutes mine will last all day. I have a 9000 mAh battery that I use to recharge. If I leave the truck with my phone and external battery both at 100% I can get by for 3-4 days, maybe more if I turn the phone off at night.
