i will be doing a distance bicycle ride from philadelphia to atlantic city for charrity soon... i was going to stream pandora during my ride (going through the speaker on my hip) ... how long do you think the battery would last streaming on my hip? how much more charge do you think a double a battery would give my droid with this device? i'm thinking of getting this device so i can just plug in and charge my phone and keep on peddling my way along. this will be an all day event.