180mA versus 850mA? Yes, quite a bit of difference. Charging the Droid from a PC's USB port is already slow and powered USB ports provide 500mA.Well, just checked the chargers and the headset is 5.1v/180mA, and the moto one is 5.1/850. Guess that current makes a difference. The phone charger works with the headset, but not the other way around.