Your best power bank option is the zero lemon 30,000 mah. I paid like $80 for mine when I went and took q 7 day trip to Washington where I'd have no power. It charged my phone from 0%-100% over 12 times before the bank needed a recharge. Its heavy and a decent size, but not too large to be portable. Its about the size of my 3ds in its zip up case. It has 6 ports to charge stuff at one time and has a USB c as well. Its the best money i ever spent and I never leave home without it. It is also airline friendly to bring on airplanes. I use mine everyday all the time for trips/work/ or too lazy to plug my phone into a wall at home and i only charge it up like once every 2 weeks. It takes like 24 hours to charge the battery all the way up is the only downside. Its my best friend. Highly recommended !