I use my Motorolla Razor's USB sized car charger for my 60CSX in the car. So far it works great. Works the same as the PC USB. I use it to also charge up my Blacberry too.
I have a 60CSX and I use the Motorolla Razor car charger to power my GPRs. It works great. If you have a similar charging device you could test with your GPRs to make sure it not a connector issue on the unit.
Good luck