Could my O2 have a bad battery?
 

Ok,I ordered the last refurbished 32GB Cowon O2 last week from Amazon,I received it on the 21st and it works fine,it didn't come with an AC adapter however I complained to the seller and there is one coming in the mail for me.Now my concern is this,right now I'm using a 500mah USB wall charger to charge it,I know the AC adapter that was made for it is 3000mah but with this wall charger,I have been charging it for about 7 hours now from a dead battery and it only shows 2 bars on the battery icon,should I worry if it has a bad battery? I know this usb wall charger charges it very slowly but should it be this slow? Or is it not taking a charge properly? The light stays red the entire time so I think its charging but I don't know if the battery is really taking the energy:confused:.