Upgraded last week from the 16G 3G to the 32G 3GS. I have the battery pack listed above. For those of you not familiar, it charges any USB type device. It is about the size of a deck of cards but half the thickness (model# K38021). The package claims to charge an iPhone 5 full times on a single battery pack charge. With my 3G, I would get 3-4 full charges in before it ran out of juice. But with the 3GS, I don't even get 1 full charge. The phone gets really hot and the battery pack does too. Anyone know if the 3GS handles battery charging differently for some reason? Do external battery packs not work well with the new phone for some reason? Doesn't make sense to me why that would be the case but there is definitely a difference. Anyone experiencing something similar with this battery or any other ones?