You can do that, and I tested it a long time ago in a similar way.
The result: of course, it can be charged, no matter how you change it, but the charging efficiency is difficult to say.
Each charging device is designed with charging protection, no matter how small the Bluetooth wireless headset also has, such as you use the 5V5A mobile phone to quickly charge the original charger for the 5V1A Bluetooth headset device, affected by the Bluetooth headset charging IC, even if the 5V5A is really completely input, the Bluetooth headset that end will reduce the power, How much lower is really anybody's guess. If it is true as the above case, under normal circumstances, the Bluetooth ear will reduce the power to 4W~5W, that is, 5V0.8A to 5V1A.
Therefore, rest assured that the charge is good, but the mobile phone and Bluetooth headset charger change to charge, the mobile phone charging can be slow...