AirPower will not work with the Apple Watch prior to Series 3
AirPower, the pad for wireless charging that Apple will release in 2018, can only be used with the Apple Watch Series 3, and not with the previous models.
AirPower is the basis of charging by Apple that will be available in the early months of 2018 and which will serve to recharge via wireless, iPhone 8, iPhone 8 Plus and iPhone X. For the Apple Watch, the compatibility is limited only to the 3 Series, although the previous models have the wireless charging.
To report it was the same Apple, with no reason given. Theoretically, in fact, all the Apple Watch should be compatible with the protocol of Qi, but apparently the AirPower needs of a particular hardware is not present on the smartwatch earlier than the Series 3.
Link to the original article: AirPower will not work with the Apple Watch prior to Series 3