A wireless battery charging system for wirelessly charging a battery of an electronic device, the system comprising: an adaptor configured to convert an AC voltage, received from an AC power supply, into a DC voltage; a wireless power receiver RX and a wireless power transmitter TX, configured to accept an input voltage (Vin) and in dependence thereon transmit power wirelessly to the wireless power receiver RX, wherein the input voltage (Vin) accepted by the wireless power TX is based on the DC voltage produced by the adaptor; the wireless power RX configured to receive power wirelessly from the wireless power TX and in dependence thereon produce a DC output voltage (Vout); first and second chargers (247, 249) each including a voltage input terminal and a voltage output terminal, the voltage input terminal of each of the first and second chargers (247, 249) accepting the output voltage (Vout) from the wireless power RX, and the voltage output terminal of each of the first and second chargers (247, 249) configured to be coupled to a terminal of the battery that is to be charged; the first charger comprising a closed-loop DC-DC converter; the second charger comprising an open-loop DC-DC converter; and a controller configured to selectively enable one of the first or second chargers (247, 249) at a time so that during a first set of charging phases the first charger is used to charge the battery, and during a second set of the charging phases the second charger is used to charge the battery, wherein: the closed-loop DC-DC converter of the first charger comprises a buck charger; and the open-loop DC-DC converter of the second charger comprises a switched capacitor charger, a load switch charger, or a flash charging charger. an adaptor configured to convert an AC voltage, received from an AC power supply, into a DC voltage; a wireless power receiver RX and a wireless power transmitter TX, configured to accept an input voltage (Vin) and in dependence thereon transmit power wirelessly to the wireless power receiver RX, wherein the input voltage (Vin) accepted by the wireless power TX is based on the DC voltage produced by the adaptor; the wireless power RX configured to receive power wirelessly from the wireless power TX and in dependence thereon produce a DC output voltage (Vout); first and second chargers (247, 249) each including a voltage input terminal and a voltage output terminal, the voltage input terminal of each of the first and second chargers (247, 249) accepting the output voltage (Vout) from the wireless power RX, and the voltage output terminal of each of the first and second chargers (247, 249) configured to be coupled to a terminal of the battery that is to be charged; the first charger comprising a closed-loop DC-DC converter; the second charger comprising an open-loop DC-DC converter; and a controller configured to selectively enable one of the first or second chargers (247, 249) at a time so that during a first set of charging phases the first charger is used to charge the battery, and during a second set of the charging phases the second charger is used to charge the battery, wherein: the closed-loop DC-DC converter of the first charger comprises a buck charger; and the open-loop DC-DC converter of the second charger comprises a switched capacitor charger, a load switch charger, or a flash charging charger. the closed-loop DC-DC converter of the first charger comprises a buck charger; and the open-loop DC-DC converter of the second charger comprises a switched capacitor charger, a load switch charger, or a flash charging charger.