It is not recommended to use a 40w fast charge to charge a wireless Bluetooth headset, because the battery in the wireless Bluetooth headset is particularly small, and the 40w charger fast charge her current is very large, the battery loss of this Bluetooth headset is very huge, and the Bluetooth battery headset will be scrapped after two charges.
Regarding whether the charger can charge the Bluetooth headset, first of all, it depends on the battery capacity inside the Bluetooth headset, such as: battery voltage, current, power rate and other parameters can be suitable, the output voltage, current, power and other parameters of the mobile phone charger, if it can be suitable, it can still be charged.