Not sure if this is just isolated to the unit I have, but I am having trouble getting my n900 to charge from an external source. I have 3 items that I tend to use for emergency power and have not had an issue with anything else I own charging from them. I have tried the following:

APC external power pack = won't charge n900
ZaggSparq = won't charge n900
cig lighter adapter w/usb ports = won't charge n900
computer usb port = charges n900
Included charger = charges n900

Like I said I have charged other devices including my n800 and n810, hell the zaggsparq will charge them both at the same time, but alas no n900 love. Anyone else having an issue?