Portable AA battery Mobile Charger?

There are too many unknown variables for anyone to give you a definite answer to your question.

That depends on how much of a charge your phone has on it when you use your charger. The charge times will also depend on the model of phone that you have. The brand and age of the battery you are using to charge your phone will change the charge times as well..

I would keep some extra batteries with your charger at all times. I would also try the charger out when you are at home, so you can see how much power it takes to charge your phone and recharge the battery right away. Always try out emergency items you buy when you buy them. So you know that they work and don't fail when you need them the most.

I have a portable rechargeable battery pack that allows me to recharge my phone from the battery pack. But it also includes a car charger and wall charger in case the battery pack does not charge my phone all of the way. Or I need to recharge the battery pack once I have used it.