8125 won't charge with USB after it runs out of juice
A lot of people have been using a V3 charger with the 8125 in their car. Some of them have waited until the 8125 is totally out of juice before trying to charge it with no luck. This is because you need to have some juice left in the phone for the USB charger to work, otherwise you will need to use the home charger to get it working then use your USB based one for regular re-charging.