That would depend on how long you owned your device. If the BB is only 45 days old, an new battery should be covered since it is defective by the manufacturer.
Posted from my CrackBerry at wapforums.crackberry.com
I know with my pearl when the battery gets really low I can't use a USB port on my computer to charge it, I have to use a wall charger. That may be just a pearl problem, but I would give it a try, just in case.
Posted from my CrackBerry at wapforums.crackberry.com
Where did you buy the phone from? Carrier? Well it may indeed be the battery and if bought it through the carrier even refurbs have 90 day warranties. Have you tried charging via a wall or auto charger? It is also a (slim) possibility that the issue may be in the amount of current being delivered by that specific USB port............