Hey guys just curious if anyone has some insights to offer regarding external cell-phone battery chargers. I am interested in something roughly the size of a pack cigarettes (or ideally, even smaller). I would love something that can take my Galaxy S3 from dead to 100% (or ideally, do so multiple times), but perhaps most importantly, something that I can charge once, and leave in my backpack for a couple of months without having the device drain power (as I know so many rechargeable batteries are prone to do).
I know the price range for these things is all over the map, and while I'd love something not too terribly expensive, I don't want something that can't hold a charge for more than a couple of weeks.
Thanks in advance for your help!