My RAZR uses an AC charger with a mini USB plug. I have several other devices (Bluetooth headset & GPS) that are also charged using a mini USB. I'm wondering if these chargers are interchangeable - can I just use the same charger for all 3 devices. Each charger has a listed output of 5.0 Volts, however the GPS output is listed as 2.0 A, the cell phone charger at 550 mA and the Bluetooth at 350 mA. Thanks for your help.