A method for wireless charging power control is disclosed. In a wireless charging system, a wireless radio frequency (RF) charging signal transmitted by a wireless charging station is harvested and converted to a direct-current (DC) charging signal to charge a battery. To prevent overcharging damage to the battery, an effective charging power in the DC charging signal is measured and compared to a target charging power required by the battery. A battery charging signal indication (BCSI) is provided to the wireless charging station to decrease the effective charging power if the effective charging power is greater than the target charging power, or to increase the effective charging power if the effective charging power is less than the target charging power. By dynamically adjusting the effective charging power, it is possible to provide fast charging to the battery while protecting the battery from overcharging damage.