Bluetooth headphones have very little power. Because the battery capacity inside the Bluetooth headset is very small. It does not need to charge fast at all, and the ordinary 5 volt 1 amp charger is more than enough to charge it. Even if it is fully charged, it is only likely to have about 100-200 MA, which is no problem for Bluetooth headphones to use for a few days. If you use a large capacity charger, the battery may be damaged.