From looking at all the information I can find on the web, it is my understanding that the E6 battery can be charged via USB. My E6 charges fine when connected to a computer (Mac and PC) and the E6 is in phone is in PC Suite mode.
However, charging via USB doesn't work when using a AC-USB charging port or using a 12V-USB (car) charger (using the same USB cable that works when connected to a computer). I've tried a number of different chargers and none of them work with the E6 but they do work with other devices like the iPod, and they work with the USB->single-pin charger cable for the E6. This seems to directly contridatice the information about USB charging on the Nokia website.
Any idea what's going on here? Is there a setting somewhere that will allow charging when non in PC-Suite mode?