I was playing around with auxiliary batteries this weekend. The one that takes 4 AA batteries only charged my phone from 48% to 65% overnight; the Li ion took it from 58% to 83%, overnight in each case.


My conclusion? I've got a darn big battery in my cell phone, and it's going to take a heck of a lot of juice to recharge it.


I'll continue to use an auxiliary battery for the GPS, but I think I'll plug my phone charger into a wall socket.