I'm going out of town in a couple of weeks and won't always have a computer available for charging Ego batteries. My dad (74 yo, you're never too old to try something new!) will be with me and he has an Ego, too. So, I'm looking for something that will charge Egos pretty quickly and doesn't require a USB port. I tried using my USB cable with an adaptor, but it took forever. Maybe I had the wrong kind of adaptor? Any help would be appreciated.